Subdural Hemorrhage (Clinical)

Overview

Definition

Subdural hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception ( SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage) is bleeding, usually caused by head trauma Head trauma Head trauma occurs when external forces are directed to the skull and brain structures, resulting in damage to the skull, brain, and intracranial structures. Head injuries can be classified as open (penetrating) or closed (blunt), and primary (from the initial trauma) or secondary (indirect brain injury), and range from mild to severe and life-threatening. Head Trauma, into the space between the dural and arachnoid meningeal layers surrounding the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification, creating a space called the subdural space Subdural space Potential cavity which separates the arachnoid mater from the dura mater. Subdural Hemorrhage.^[1]

Epidemiology^[1,11]

• Prevalence Prevalence The total number of cases of a given disease in a specified population at a designated time. It is differentiated from incidence, which refers to the number of new cases in the population at a given time. Measures of Disease Frequency:
  • 10% of cases of head trauma Head trauma Head trauma occurs when external forces are directed to the skull and brain structures, resulting in damage to the skull, brain, and intracranial structures. Head injuries can be classified as open (penetrating) or closed (blunt), and primary (from the initial trauma) or secondary (indirect brain injury), and range from mild to severe and life-threatening. Head Trauma necessitating hospitalization Hospitalization The confinement of a patient in a hospital. Delirium
  • 20% of cases of severe traumatic brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification injuries (TBIs)
  • 8% of term deliveries (associated with use of forceps Forceps Surgical Instruments and Sutures or vacuum extraction)
• More common in older individuals
• More common in persons on antiplatelet/anticoagulant therapies

Etiology^[1,11]

SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage is caused by rupture of vasculature (typically bridging veins Bridging Veins Subdural Hemorrhage) between the arachnoid and dural meningeal layers. The primary etiology is trauma. 

Acute SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage:

• Blunt head trauma Head trauma Head trauma occurs when external forces are directed to the skull and brain structures, resulting in damage to the skull, brain, and intracranial structures. Head injuries can be classified as open (penetrating) or closed (blunt), and primary (from the initial trauma) or secondary (indirect brain injury), and range from mild to severe and life-threatening. Head Trauma (e.g., impact during road traffic accident) 
• Nonaccidental trauma (e.g., shaken baby syndrome Shaken baby syndrome Brain injuries resulted from vigorous shaking of an infant or young child held by the chest, shoulders, or extremities causing extreme cranial acceleration. It is characterized by the intracranial and intraocular hemorrhages with no evident external trauma. Serious cases may result in death. Child Abuse) 
• Acceleration– deceleration Deceleration A decrease in the rate of speed. Blunt Chest Trauma injury 

Chronic SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage:

• Traumatic:
  • In adults, falls:
    • Especially in older adults and those with alcohol use disorder Alcohol use disorder Alcohol is one of the most commonly used addictive substances in the world. Alcohol use disorder (AUD) is defined as pathologic consumption of alcohol leading to impaired daily functioning. Acute alcohol intoxication presents with impairment in speech and motor functions and can be managed in most cases with supportive care. Alcohol Use Disorder
    • Often from standing height
  • In infants:
    • Shaken baby syndrome Shaken baby syndrome Brain injuries resulted from vigorous shaking of an infant or young child held by the chest, shoulders, or extremities causing extreme cranial acceleration. It is characterized by the intracranial and intraocular hemorrhages with no evident external trauma. Serious cases may result in death. Child Abuse 
    • Birth trauma 
• Nontraumatic:
  • Intracranial hypotension Intracranial hypotension Reduction of cerebrospinal fluid pressure characterized clinically by orthostatic headache and occasionally by an abducens nerve palsy; hearing loss; nausea; neck stiffness, and other symptoms. This condition may be spontaneous or secondary to cerebrospinal fluid leak; spinal puncture; neurosurgical procedures; dehydration; uremia; trauma; and other processes. Chronic hypotension may be associated with subdural hematomas or hygromas. Subdural Hemorrhage (low CSF volume, usually due to a leak)
    • Spontaneous: connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology disorders 
    • Iatrogenic Iatrogenic Any adverse condition in a patient occurring as the result of treatment by a physician, surgeon, or other health professional, especially infections acquired by a patient during the course of treatment. Anterior Cord Syndrome: epidural, lumbar puncture Lumbar Puncture Febrile Infant 

Risk factors 

The 2 main risk factors are cerebral atrophy Cerebral Atrophy Subdural Hemorrhage and antithrombotic therapy.^[1,5] 

• Cerebral atrophy Cerebral Atrophy Subdural Hemorrhage:
  • The larger space between the dural membrane and the cortical surface of the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification stretches the bridging veins Bridging Veins Subdural Hemorrhage, increasing the risk of tearing.
  • Due to:
    • Advanced age 
    • Chronic alcoholism Alcoholism A primary, chronic disease with genetic, psychosocial, and environmental factors influencing its development and manifestations. The disease is often progressive and fatal. It is characterized by impaired control over drinking, preoccupation with the drug alcohol, use of alcohol despite adverse consequences, and distortions in thinking, most notably denial. Each of these symptoms may be continuous or periodic. Wernicke Encephalopathy and Korsakoff Syndrome 
    • Neurodegenerative diseases 
    • Chronic diabetes Diabetes Diabetes mellitus (DM) is a metabolic disease characterized by hyperglycemia and dysfunction of the regulation of glucose metabolism by insulin. Type 1 DM is diagnosed mostly in children and young adults as the result of autoimmune destruction of β cells in the pancreas and the resulting lack of insulin. Type 2 DM has a significant association with obesity and is characterized by insulin resistance. Diabetes Mellitus mellitus 
    • Previous traumatic brain injury Traumatic brain injury A form of acquired brain injury which occurs when a sudden trauma causes damage to the brain. Le Fort Fractures 
• Increased risk of hemorrhage due to:
  • Antithrombotic therapy  (e.g., aspirin Aspirin The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Nonsteroidal Antiinflammatory Drugs (NSAIDs), clopidogrel Clopidogrel A ticlopidine analog and platelet purinergic p2y receptor antagonist that inhibits adenosine diphosphate-mediated platelet aggregation. It is used to prevent thromboembolism in patients with arterial occlusive diseases; myocardial infarction; stroke; or atrial fibrillation. Antiplatelet Drugs, direct oral anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants)
  • Coagulopathy (e.g., thrombocytopenia Thrombocytopenia Thrombocytopenia occurs when the platelet count is < 150,000 per microliter. The normal range for platelets is usually 150,000-450,000/µL of whole blood. Thrombocytopenia can be a result of decreased production, increased destruction, or splenic sequestration of platelets. Patients are often asymptomatic until platelet counts are < 50,000/µL. Thrombocytopenia, liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease, hemophilia Hemophilia The hemophilias are a group of inherited, or sometimes acquired, disorders of secondary hemostasis due to deficiency of specific clotting factors. Hemophilia A is a deficiency of factor VIII, hemophilia B a deficiency of factor IX, and hemophilia C a deficiency of factor XI. Patients present with bleeding events that may be spontaneous or associated with minor or major trauma. Hemophilia)
  • Vascular malformation 
  • Intracranial aneurysm Intracranial aneurysm Abnormal outpouching in the wall of intracranial blood vessels. Most common are the saccular (berry) aneurysms located at branch points in circle of willis at the base of the brain. Vessel rupture results in subarachnoid hemorrhage or intracranial hemorrhages. Giant aneurysms (>2. 5 cm in diameter) may compress adjacent structures, including the oculomotor nerve. Brain Aneurysms 
  • Hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension 
  • Atherosclerosis Atherosclerosis Atherosclerosis is a common form of arterial disease in which lipid deposition forms a plaque in the blood vessel walls. Atherosclerosis is an incurable disease, for which there are clearly defined risk factors that often can be reduced through a change in lifestyle and behavior of the patient. Atherosclerosis 
  • Brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification tumor Tumor Inflammation/neoplasm (primary or metastatic)

Pathophysiology

SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage occurs because of bleeding within the subdural space Subdural space Potential cavity which separates the arachnoid mater from the dura mater. Subdural Hemorrhage. This may resolve by resorption or may become chronic by membranous encapsulation.^[1,6]

Acute subdural hematoma Acute Subdural Hematoma Accumulation of blood in the subdural space with acute onset of neurological symptoms. Symptoms may include loss of consciousness, severe headache, and deteriorating mental status. Subdural Hemorrhage:^[1]

• Vascular rupture:
  • Results mostly from rupture of bridging veins Bridging Veins Subdural Hemorrhage between the arachnoid and dural meningeal layers 
  • Rupture of small arteries Small arteries Arteries: Histology (< 1 mm diameter), which are often in the temporoparietal area, can also contribute to SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage formation (seen in 30%).
  • Blood then collects between layers. Hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception is crescent-shaped (following the contours of the dura).
  • Bleeding is blocked by rising ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) or direct compression Compression Blunt Chest Trauma by the forming thrombus.
• Intracranial hypotension Intracranial hypotension Reduction of cerebrospinal fluid pressure characterized clinically by orthostatic headache and occasionally by an abducens nerve palsy; hearing loss; nausea; neck stiffness, and other symptoms. This condition may be spontaneous or secondary to cerebrospinal fluid leak; spinal puncture; neurosurgical procedures; dehydration; uremia; trauma; and other processes. Chronic hypotension may be associated with subdural hematomas or hygromas. Subdural Hemorrhage:
  • Low CSF pressure decreases brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification buoyancy  → traction on meningeal support  → vascular rupture
  • Even minor trauma or whiplash injury can result in SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage.

Chronic subdural hematoma Chronic Subdural Hematoma Accumulation of blood in the subdural space with delayed onset of neurological symptoms. Symptoms may include loss of consciousness, severe headache, and deteriorating mental status. Subdural Hemorrhage:^[1]

• Forms from an acute SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage that has thrombosed:
  • Fibroblasts Fibroblasts Connective tissue cells which secrete an extracellular matrix rich in collagen and other macromolecules. Sarcoidosis elaborate collagen Collagen A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of skin; connective tissue; and the organic substance of bones (bone and bones) and teeth (tooth). Connective Tissue: Histology over the dural layer, stabilizing the outer surface of the thrombus.
  • Thinner membrane develops over the inner surface of the clot → complete encapsulation 
  • Process takes approximately 2 weeks.
• Formation of subdural hygroma:
  • Occurs with accumulation of cerebrospinal fluid Cerebrospinal Fluid A watery fluid that is continuously produced in the choroid plexus and circulates around the surface of the brain; spinal cord; and in the cerebral ventricles. Ventricular System: Anatomy (CSF) within the subdural space Subdural space Potential cavity which separates the arachnoid mater from the dura mater. Subdural Hemorrhage
  • A tear in the arachnoid and the dural border cell layer allows passage of CSF → formation of hygroma
  • Hygroma is protein-rich, thus, is a potential osmotic draw of fluid into the cavity, leading to the expansion of the hygroma.

Acute-on-chronic SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage:^[1,8]

• Recurrent trauma may cause bleeding into an otherwise stable (i.e., thrombosed) SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage or hygroma causing enlargement.
• Older patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship and alcoholic Alcoholic Persons who have a history of physical or psychological dependence on ethanol. Mallory-Weiss Syndrome (Mallory-Weiss Tear) patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship are at an increased risk (↑ risk of falls, causing recurrent traumatic injuries).

Clinical Presentation

Neurologic presentation depends on the size, location, and rate of growth of the hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception, as well as the length of time since the initiating event.^[1,6]

Onset of symptoms:^[3,6]

• Acute SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage: presents immediately (up to 72 hours after the event)
• Subacute SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage presents 3–21 days after the event.
• Chronic SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage presents > 21 days after the event.
• In the absence of trauma, SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage may be difficult to categorize.

Neurologic symptoms and signs:^[5]

• Nature of neurologic symptoms/signs depend largely on the following characteristics of the hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception:
  • Location 
  • Size 
  • Rate of growth 
  • Acuity
• Acute SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage:
  • Altered level of consciousness Altered Level of Consciousness Intracerebral Hemorrhage:
    • ½ present as coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma 
    • Remainder may have a “ lucid interval Lucid Interval Epidural Hemorrhage” between injury and onset of progressive neurologic decline.
    • Subacute or chronic SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage may present with gradual deterioration in level of consciousness/somnolence/depression.
  • Features of raised ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP):
    • Headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess
    • Nausea Nausea An unpleasant sensation in the stomach usually accompanied by the urge to vomit. Common causes are early pregnancy, sea and motion sickness, emotional stress, intense pain, food poisoning, and various enteroviruses. Antiemetics/ vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia
    • Cushing triad 
    • Cerebral herniation Herniation Omphalocele syndromes 
    • Dizziness Dizziness An imprecise term which may refer to a sense of spatial disorientation, motion of the environment, or lightheadedness. Lateral Medullary Syndrome (Wallenberg Syndrome)
  • Focal neurologic deficits Neurologic Deficits High-Risk Headaches (dependent on brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification region affected):
    • Contralateral motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology or sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology loss 
    • Cranial nerve palsies Cranial Nerve Palsies Cranial nerve palsy is a congenital or acquired dysfunction of 1 or more cranial nerves that will, in turn, lead to focal neurologic abnormalities in movement or autonomic dysfunction of its territory. Head/neck trauma, mass effect, infectious processes, and ischemia/infarction are among the many etiologies for these dysfunctions. Diagnosis is initially clinical and supported by diagnostic aids. Management includes both symptomatic measures and interventions aimed at correcting the underlying cause. Cranial Nerve Palsies 
    • Balance/ gait Gait Manner or style of walking. Neurological Examination disturbance 
    • Impaired speech 
  • Features of meningism:
    • Nuchal rigidity Nuchal Rigidity Meningitis 
  • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures
  • Abnormal posturing:
    • Decorticate (flexor)
    • Decerebrate (extensor)
• Chronic SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage:
  • Altered mental state:
    • Delirium Delirium Delirium is a medical condition characterized by acute disturbances in attention and awareness. Symptoms may fluctuate during the course of a day and involve memory deficits and disorientation. Delirium 
    • Somnolence 
    • Progression to coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma 
  • Cognitive decline:
    • Impaired memory Memory Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory. Psychiatric Assessment/ dementia Dementia Major neurocognitive disorders (NCD), also known as dementia, are a group of diseases characterized by decline in a person’s memory and executive function. These disorders are progressive and persistent diseases that are the leading cause of disability among elderly people worldwide. Major Neurocognitive Disorders 
    • Confusion 
  • Personality changes 
  • Seizures Seizures A seizure is abnormal electrical activity of the neurons in the cerebral cortex that can manifest in numerous ways depending on the region of the brain affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons, creating a net excitation. The 2 major classes of seizures are focal and generalized. Seizures

Diagnosis

Suspect SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage in any elderly person presenting with head trauma Head trauma Head trauma occurs when external forces are directed to the skull and brain structures, resulting in damage to the skull, brain, and intracranial structures. Head injuries can be classified as open (penetrating) or closed (blunt), and primary (from the initial trauma) or secondary (indirect brain injury), and range from mild to severe and life-threatening. Head Trauma, altered mental status Altered Mental Status Sepsis in Children, decreased level of consciousness, or neurologic symptoms/signs. Head CT should be performed emergently.^[3,6]

History and examination^[6] 

• Features:
  • Recent history of trauma
  • Neurologic signs and symptoms (e.g., loss of consciousness or period of decreased alertness, potential seizure activity)
• Inquire about:
  • Use of aspirin Aspirin The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. Nonsteroidal Antiinflammatory Drugs (NSAIDs), antithrombotics, or anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants
  • History of liver Liver The liver is the largest gland in the human body. The liver is found in the superior right quadrant of the abdomen and weighs approximately 1.5 kilograms. Its main functions are detoxification, metabolism, nutrient storage (e.g., iron and vitamins), synthesis of coagulation factors, formation of bile, filtration, and storage of blood. Liver: Anatomy disease, renal disease, or bleeding disorders Bleeding disorders Hypocoagulable conditions, also known as bleeding disorders or bleeding diathesis, are a diverse group of diseases that result in abnormal hemostasis. Physiologic hemostasis is dependent on the integrity of endothelial cells, subendothelial matrix, platelets, and coagulation factors. The hypocoagulable states result from abnormalities in one or more of these contributors, resulting in ineffective thrombosis and bleeding. Hypocoagulable Conditions 
• Look for:
  • Physical signs of trauma such as:
    • Scalp and face abrasions Abrasions Corneal Abrasions, Erosion, and Ulcers, lacerations
    • Periorbital Periorbital Orbital and Preseptal Cellulitis or retroauricular ecchymosis Ecchymosis Extravasation of blood into the skin, resulting in a nonelevated, rounded or irregular, blue or purplish patch, larger than a petechia. Orbital Fractures, otorrhea Otorrhea Otitis Externa, or rhinorrhea Rhinorrhea Excess nasal drainage. Respiratory Syncytial Virus (may indicate occult basilar skull Skull The skull (cranium) is the skeletal structure of the head supporting the face and forming a protective cavity for the brain. The skull consists of 22 bones divided into the viscerocranium (facial skeleton) and the neurocranium. Skull: Anatomy fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures). 
  • Check cervical spine Spine The human spine, or vertebral column, is the most important anatomical and functional axis of the human body. It consists of 7 cervical vertebrae, 12 thoracic vertebrae, and 5 lumbar vertebrae and is limited cranially by the skull and caudally by the sacrum. Vertebral Column: Anatomy in all patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with suspected head injury (immobilize until injury is ruled out) 
  • Glasgow Coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma Scale Scale Dermatologic Examination ( GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma)

Neuroimaging Neuroimaging Non-invasive methods of visualizing the central nervous system, especially the brain, by various imaging modalities. Febrile Infant^[3,6,10,11]

Noncontrast head CT:

• Imaging method of choice (1st line):
  • For acute head trauma Head trauma Head trauma occurs when external forces are directed to the skull and brain structures, resulting in damage to the skull, brain, and intracranial structures. Head injuries can be classified as open (penetrating) or closed (blunt), and primary (from the initial trauma) or secondary (indirect brain injury), and range from mild to severe and life-threatening. Head Trauma
  • For acute loss of consciousness
  • For suspected SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage (and other intracranial bleeds)
• Characteristic findings:
  • Morphology:
    • Crescent-shaped, concave collection of blood along the convexity of the affected hemisphere 
    • Can cross cranial suture lines
    • Does not cross the midline ( subdural space Subdural space Potential cavity which separates the arachnoid mater from the dura mater. Subdural Hemorrhage is bound by the falx cerebri)
    • Can cause midline shift if unilateral
  • Density depends on duration:
    • Acute: hyperdense 
    • Subacute: heterogeneously hyperdense/isodense
    • Chronic: hypodense 
    • Acute on chronic: hyperdense regions superimposed on hypodense or isodense regions
  • Unilateral SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage creates an obvious distortion Distortion Defense Mechanisms of cerebral contours. 
  • Bilateral SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage may create symmetric distortion Distortion Defense Mechanisms of cerebral contours and be less obvious.

Head MRI:

• Indicated if neurologic features are not accounted for by CT head:
  • Sensitivity is superior to that of noncontrast CT in the detection of intracranial hemorrhage Intracranial hemorrhage Subarachnoid hemorrhage (SAH) is a type of cerebrovascular accident (stroke) resulting from intracranial hemorrhage into the subarachnoid space between the arachnoid and the pia mater layers of the meninges surrounding the brain. Most sahs originate from a saccular aneurysm in the circle of willis but may also occur as a result of trauma, uncontrolled hypertension, vasculitis, anticoagulant use, or stimulant use. Subarachnoid Hemorrhage.
  • Acute, subacute, and chronic subdural blood appears hyperintense Hyperintense Magnetic Resonance Imaging (MRI) in CSF (fluid attenuated inversion recovery ( FLAIR FLAIR Magnetic Resonance Imaging (MRI)) sequences).
    • May detect small SDHs that may be missed on noncontrast CT
    • May detect dural lesions (e.g., dural tears, neoplasm) missed on noncontrast CT
• Can be used to elucidate the degree of brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification injury, including parenchymal microhemorrhages, diffuse axonal injury Diffuse axonal injury A relatively common sequela of blunt head injury, characterized by a global disruption of axons throughout the brain. Associated clinical features may include neurobehavioral manifestations; persistent vegetative state; dementia; and other disorders. Head Trauma, and areas of ischemia Ischemia A hypoperfusion of the blood through an organ or tissue caused by a pathologic constriction or obstruction of its blood vessels, or an absence of blood circulation. Ischemic Cell Damage
• Not as readily available as CT

Angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery:

• Used to determine the etiology of a nontraumatic/ idiopathic Idiopathic Dermatomyositis SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage 
• Options include digital subtraction, MR MR Calculated as the ratio of the total number of people who die due to all causes over a specific time period to the total number of people in the selected population. Measures of Health Status, and CT angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery.
  • Noninvasive MRA MRA Imaging of the Heart and Great Vessels or CTA CTA A non-invasive method that uses a ct scanner for capturing images of blood vessels and tissues. A contrast material is injected, which helps produce detailed images that aid in diagnosing vascular diseases. Pulmonary Function Tests:
    • Indicated for evaluation of nontraumatic or idiopathic Idiopathic Dermatomyositis SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage
    • May reveal small intracranial aneurysms or other vascular lesions
  • Conventional angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery may be considered if a vascular lesion is suspected but not detected by noninvasive angiography Angiography Radiography of blood vessels after injection of a contrast medium. Cardiac Surgery.

Contraindicated procedures

Lumbar puncture Lumbar Puncture Febrile Infant:^[1]

• Contraindicated when SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage is suspected
• Increased ICP Increased ICP Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage due to expanding hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception increases risk of herniation Herniation Omphalocele and death.

Management

Acute SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage, especially that presenting with neurologic compromise or coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma, is an emergent neurologic situation often requiring surgical intervention. Failure to promptly stabilize, diagnose, evaluate, and intervene could result in hemorrhagic expansion, parenchymal brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification injury, elevated ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP), brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification herniation Herniation Omphalocele, and death.^[1,3,6,7]

Stabilization^[6,7.9–11]

• Individual should be evaluated and stabilized using advanced trauma life support/advanced cardiac life support (ATLS/ACLS) protocols.
• Address life-threatening injuries.
• Immediately discontinue (and possibly reverse) antiplatelets Antiplatelets Drugs or agents which antagonize or impair any mechanism leading to blood platelet aggregation, whether during the phases of activation and shape change or following the dense-granule release reaction and stimulation of the prostaglandin-thromboxane system. Heart Failure and Angina Medication/ anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants.
  • Monitor serial labs:
    • Prothrombin time Prothrombin time Clotting time of plasma recalcified in the presence of excess tissue thromboplastin. Factors measured are fibrinogen; prothrombin; factor V; factor VII; and factor X. Hemostasis, partial thromboplastin time Partial thromboplastin time The time required for the appearance of fibrin strands following the mixing of plasma with phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides). It is a test of the intrinsic pathway (factors VIII, IX, XI, and XII) and the common pathway (fibrinogen, prothrombin, factors V and X) of blood coagulation. Hemostasis, and international normalized ratio International normalized ratio System established by the world health organization and the international committee on thrombosis and hemostasis for monitoring and reporting blood coagulation tests. Under this system, results are standardized using the international sensitivity index for the particular test reagent/instrument combination used. Hemostasis
    • Platelet count
    • Fibrinogen Fibrinogen Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides a and b, the proteolytic action of other enzymes yields different fibrinogen degradation products. Hemostasis levels 
  • Options for warfarin Warfarin An anticoagulant that acts by inhibiting the synthesis of vitamin K-dependent coagulation factors. Warfarin is indicated for the prophylaxis and/or treatment of venous thrombosis and its extension, pulmonary embolism, and atrial fibrillation with embolization. It is also used as an adjunct in the prophylaxis of systemic embolism after myocardial infarction. Warfarin is also used as a rodenticide. Anticoagulants reversal:
    • Prothrombin Prothrombin A plasma protein that is the inactive precursor of thrombin. It is converted to thrombin by a prothrombin activator complex consisting of factor Xa, factor V, phospholipid, and calcium ions. Hemostasis complex concentrate
    • Fresh frozen plasma Fresh Frozen Plasma Transfusion Products
    • Vitamin K Vitamin K A lipid cofactor that is required for normal blood clotting. Several forms of vitamin K have been identified: vitamin K 1 (phytomenadione) derived from plants, vitamin K 2 (menaquinone) from bacteria, and synthetic naphthoquinone provitamins, vitamin K 3 (menadione). Vitamin k 3 provitamins, after being alkylated in vivo, exhibit the antifibrinolytic activity of vitamin k. Green leafy vegetables, liver, cheese, butter, and egg yolk are good sources of vitamin k. Fat-soluble Vitamins and their Deficiencies
  • Consult hematology on reversal options in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship taking direct oral anticoagulants Anticoagulants Anticoagulants are drugs that retard or interrupt the coagulation cascade. The primary classes of available anticoagulants include heparins, vitamin K-dependent antagonists (e.g., warfarin), direct thrombin inhibitors, and factor Xa inhibitors. Anticoagulants.
• Achieve/maintain hemodynamic stability and apply neuroprotective measures (to prevent secondary injury).
  • ICU ICU Hospital units providing continuous surveillance and care to acutely ill patients. West Nile Virus admission
  • Serial neurologic examination
  • Head elevation 30–45°
  • Maintain SpO₂ ≥ 94% (mechanical ventilation Ventilation The total volume of gas inspired or expired per unit of time, usually measured in liters per minute. Ventilation: Mechanics of Breathing when indicated)
  • Avoid hypotension Hypotension Hypotension is defined as low blood pressure, specifically < 90/60 mm Hg, and is most commonly a physiologic response. Hypotension may be mild, serious, or life threatening, depending on the cause. Hypotension (maintain SBP SBP Ascites at ≥ 100 mm Hg for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship 50–69 years old or at ≥ 110 mm Hg for patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship 15–49 or > 70 years old).
  • Manage temperature to prevent fever Fever Fever is defined as a measured body temperature of at least 38°C (100.4°F). Fever is caused by circulating endogenous and/or exogenous pyrogens that increase levels of prostaglandin E2 in the hypothalamus. Fever is commonly associated with chills, rigors, sweating, and flushing of the skin. Fever.
  • Analgesia Analgesia Methods of pain relief that may be used with or in place of analgesics. Anesthesiology: History and Basic Concepts and sedation as indicated (to reduce agitation Agitation A feeling of restlessness associated with increased motor activity. This may occur as a manifestation of nervous system drug toxicity or other conditions. St. Louis Encephalitis Virus)
• Additional interventions:
  • Central line insertion
  • End-tidal CO₂ monitoring
  • Consider antiseizure medication (e.g., levetiracetam Levetiracetam A pyrrolidinone and acetamide derivative that is used primarily for the treatment of seizures and some movement disorders, and as a nootropic agent. Second-Generation Anticonvulsant Drugs or phenytoin Phenytoin An anticonvulsant that is used to treat a wide variety of seizures. The mechanism of therapeutic action is not clear, although several cellular actions have been described including effects on ion channels, active transport, and general membrane stabilization. Phenytoin has been proposed for several other therapeutic uses, but its use has been limited by its many adverse effects and interactions with other drugs. First-Generation Anticonvulsant Drugs):
    • Prophylaxis Prophylaxis Cephalosporins is generally given up to 7 days after presentation.
    • If seizure occurs beyond the 1st 7 days, consult neurology.
  • Consider arterial line for continuous blood pressure monitoring.
  • Avoid hyponatremia Hyponatremia Hyponatremia is defined as a decreased serum sodium (sNa+) concentration less than 135 mmol/L. Serum sodium is the greatest contributor to plasma osmolality, which is very tightly controlled via antidiuretic hormone (ADH) release from the hypothalamus and by the thirst mechanism. Hyponatremia.
  • Maintain hemoglobin > 7 g/dL.
• Manage raised intracranial pressure Intracranial Pressure Idiopathic Intracranial Hypertension ( ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP)):
  • ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) monitoring with ventriculostomy Ventriculostomy Surgical creation of an opening in a cerebral ventricle. Neurosurgery, subarachnoid bolt, or intraparenchymal monitor in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score < 9.
  • Targets:
    • Cerebral perfusion Cerebral Perfusion Syncope pressure of 60 to 70 mm Hg
    • ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) < 20 mm Hg (in adults)
• Emergent neurosurgical consultation:
  • Surgical clinical decision-making 
  • Placement of ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) monitoring device

Stratification^[1,6]

Clinical decision tools used to determine operative or nonoperative management include:

• GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score
• Head CT findings:
  • Clot thickness
  • Degree of midline shift
  • Presence of associated brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification lesion
• Neurologic examination
• Presence of pupillary palsy Palsy paralysis of an area of the body, thus incapable of voluntary movement Cranial Nerve Palsies
• Acuity of SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage
• Presence of comorbidities Comorbidities The presence of co-existing or additional diseases with reference to an initial diagnosis or with reference to the index condition that is the subject of study. Comorbidity may affect the ability of affected individuals to function and also their survival; it may be used as a prognostic indicator for length of hospital stay, cost factors, and outcome or survival. St. Louis Encephalitis Virus 
• Severity of associated trauma
• Age

Nonoperative management^[6,10,11]

• May be appropriate for:
  • Clinically stable individuals ( GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score > 9)
  • Small hematomas (< 10 mm thickness on CT)
  • Absence of brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification herniation Herniation Omphalocele signs by clinical and/or radiographic evaluation:
    • Absent or minimal midline shift on CT (< 5 mm)
    • Absence of direct visualization of herniation Herniation Omphalocele on CT
    • Absence of physical examination findings of elevated ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) (e.g., patient has reactive, symmetric pupils)
    • Absence of elevated ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) on neuromonitoring (should be < 20 mm Hg)
• Should be monitored in a neurologic ICU ICU Hospital units providing continuous surveillance and care to acutely ill patients. West Nile Virus with continuous ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) monitoring:
  • Perform serial neurologic examination at least every 1–2 hours in the 1st 24 hours.
  • Monitor mental status ( GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma), pupillary function, and sensorimotor function.
• Serial head CT every 6–8 hours for 36 hours
• Hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception may resolve through resorption over weeks.

Operative management^[6,10,12]

• May be appropriate for:
  • SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage of < 10 mm and midline shift < 5 mm but clinically unstable individuals:
    • GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score < 9, reduced by ≥ 2 from the time of injury to the time of evaluation
    • GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score < 9,with pupillary palsy Palsy paralysis of an area of the body, thus incapable of voluntary movement Cranial Nerve Palsies (fixed, or asymmetric pupils)
    • GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score < 9 with ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP) > 20 mm Hg (suspect in patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship with Cushing triad: hypertension Hypertension Hypertension, or high blood pressure, is a common disease that manifests as elevated systemic arterial pressures. Hypertension is most often asymptomatic and is found incidentally as part of a routine physical examination or during triage for an unrelated medical encounter. Hypertension, respiratory depression, bradycardia Bradycardia Bradyarrhythmia is a rhythm in which the heart rate is less than 60/min. Bradyarrhythmia can be physiologic, without symptoms or hemodynamic change. Pathologic bradyarrhythmia results in reduced cardiac output and hemodynamic instability causing syncope, dizziness, or dyspnea. Bradyarrhythmias)
  • Large hematomas (> 10 mm thickness on CT), regardless of GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score
  • Midline shift on CT > 5 mm, regardless of GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score
  • Brainstem compression Compression Blunt Chest Trauma or hydrocephalus Hydrocephalus Excessive accumulation of cerebrospinal fluid within the cranium which may be associated with dilation of cerebral ventricles, intracranial. Subarachnoid Hemorrhage
  • Structural lesion such as arteriovenous malformation Arteriovenous malformation Abnormal formation of blood vessels that shunt arterial blood directly into veins without passing through the capillaries. They usually are crooked, dilated, and with thick vessel walls. A common type is the congenital arteriovenous fistula. The lack of blood flow and oxygen in the capillaries can lead to tissue damage in the affected areas. Erysipelas or fracture Fracture A fracture is a disruption of the cortex of any bone and periosteum and is commonly due to mechanical stress after an injury or accident. Open fractures due to trauma can be a medical emergency. Fractures are frequently associated with automobile accidents, workplace injuries, and trauma. Overview of Bone Fractures in the setting of SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage
• Surgical indications for chronic SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage are similar to above, with post-operative recurrence also included.
• Should be undertaken as soon as clinically feasible for individuals meeting these criteria (within 2–4 hours after onset of neurologic deterioration)
• Surgical techniques:
  • Craniotomy Craniotomy Surgical incision into the cranium. Neurosurgery with hematoma Hematoma A collection of blood outside the blood vessels. Hematoma can be localized in an organ, space, or tissue. Intussusception evacuation: most commonly performed
  • Burr hole Burr Hole Subdural Hemorrhage trephination
  • Decompressive craniectomy Decompressive Craniectomy Excision of part of the skull. This procedure is used to treat elevated intracranial pressure that is unresponsive to conventional treatment. Neurosurgery 
  • Subdural evacuation port system
• Culprit vessel identification Identification Defense Mechanisms and tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis may be undertaken simultaneously:
  • Traditional tamponade Tamponade Pericardial effusion, usually of rapid onset, exceeding ventricular filling pressures and causing collapse of the heart with a markedly reduced cardiac output. Pericarditis with ligatures
  • Endovascular embolization Embolization A method of hemostasis utilizing various agents such as gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and intracranial arteriovenous malformations, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage. Gastrointestinal Bleeding of the middle meningeal artery Middle Meningeal Artery Epidural Hemorrhage

Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas^[1,6,10,11]

• Mortality Mortality All deaths reported in a given population. Measures of Health Status rate:
  • Approximately 50% in SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage requiring surgery
  • Approximately 40% if surgical intervention is prompt (2–4 hours after injury)
  • Approximately 85% if surgical intervention is delayed
  • Approximately 60%–70% in SDH SDH Subdural hemorrhage (SDH) is bleeding into the space between the dural and arachnoid meningeal layers surrounding the brain. The most common mechanism triggering the bleeding event is trauma (e.g., closed head injury) causing a tearing injury to the extracerebral “bridging” veins. Subdural Hemorrhage presenting with coma Coma Coma is defined as a deep state of unarousable unresponsiveness, characterized by a score of 3 points on the GCS. A comatose state can be caused by a multitude of conditions, making the precise epidemiology and prognosis of coma difficult to determine. Coma prior to evaluation
• Age and GCS GCS A scale that assesses the response to stimuli in patients with craniocerebral injuries. The parameters are eye opening, motor response, and verbal response. Coma score are the most important prognostic indicators.

Management after discharge^[6,10]

• Follow-up CT:
  • 2–3 weeks after discharge
  • ASAP if with new neurologic symptoms ( headache Headache The symptom of pain in the cranial region. It may be an isolated benign occurrence or manifestation of a wide variety of headache disorders. Brain Abscess, dizziness Dizziness An imprecise term which may refer to a sense of spatial disorientation, motion of the environment, or lightheadedness. Lateral Medullary Syndrome (Wallenberg Syndrome), vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia)
• Neurosurgery Neurosurgery Neurosurgery is a specialized field focused on the surgical management of pathologies of the brain, spine, spinal cord, and peripheral nerves. General neurosurgery includes cases of trauma and emergencies. There are a number of specialized neurosurgical practices, including oncologic neurosurgery, spinal neurosurgery, and pediatric neurosurgery. Neurosurgery follow-up
• In patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship requiring anticoagulation Anticoagulation Pulmonary Hypertension Drugs (e.g., atrial fibrillation Atrial fibrillation Atrial fibrillation (AF or Afib) is a supraventricular tachyarrhythmia and the most common kind of arrhythmia. It is caused by rapid, uncontrolled atrial contractions and uncoordinated ventricular responses. Atrial Fibrillation, venous thromboembolism Thromboembolism Obstruction of a blood vessel (embolism) by a blood clot (thrombus) in the blood stream. Systemic Lupus Erythematosus), discussion with cardiologist and/or hematologist is recommended to decide on restarting medication.

Differential Diagnosis

• Ischemic stroke Ischemic Stroke An ischemic stroke (also known as cerebrovascular accident) is an acute neurologic injury that occurs as a result of brain ischemia; this condition may be due to cerebral blood vessel occlusion by thrombosis or embolism, or rarely due to systemic hypoperfusion. Ischemic Stroke: ischemic infarct Infarct Area of necrotic cells in an organ, arising mainly from hypoxia and ischemia Ischemic Cell Damage of the cerebral parenchyma caused by occlusion of a cerebral artery by atherosclerotic lesions or cardioembolic emboli. Ischemic stroke Ischemic Stroke An ischemic stroke (also known as cerebrovascular accident) is an acute neurologic injury that occurs as a result of brain ischemia; this condition may be due to cerebral blood vessel occlusion by thrombosis or embolism, or rarely due to systemic hypoperfusion. Ischemic Stroke presents with neurologic deficits Neurologic Deficits High-Risk Headaches and/or altered mental status Altered Mental Status Sepsis in Children/ altered level of consciousness Altered Level of Consciousness Intracerebral Hemorrhage that depends on the size and location of infarct Infarct Area of necrotic cells in an organ, arising mainly from hypoxia and ischemia Ischemic Cell Damage. Diagnosis is clinical and confirmed by neuroimaging Neuroimaging Non-invasive methods of visualizing the central nervous system, especially the brain, by various imaging modalities. Febrile Infant. Management includes initial stabilization, possible cerebrovascular intervention, addressing identifiable underlying etiologies ( severe hypertension Severe hypertension A confirmed blood pressure ≥ 180 mm Hg systolic and/or ≥ 120 mm Hg diastolic. Uncontrolled Hypertension, embolus), and management of cardiovascular risk factors. 
• Other hemorrhagic cerebral conditions: Carotid/cerebral artery dissection, epidural hemorrhage Epidural Hemorrhage Epidural hemorrhage (EDH) is an event characterized by bleeding into the epidural space between the dural layers of the meninges and the skull. The primary mechanism triggering bleeding is trauma (i.e., closed head injury), which causes arterial injury, most commonly middle meningeal artery injury. Epidural Hemorrhage, and intraparenchymal hemorrhage are other hemorrhagic manifestations of the cerebral vasculature that can present with neurologic deficits Neurologic Deficits High-Risk Headaches and/or altered mental status Altered Mental Status Sepsis in Children/ altered level of consciousness Altered Level of Consciousness Intracerebral Hemorrhage. Diagnosis is clinical and confirmed by neuroimaging Neuroimaging Non-invasive methods of visualizing the central nervous system, especially the brain, by various imaging modalities. Febrile Infant. Management depends on the hemorrhagic etiology and includes initial stabilization, neurosurgical/endovascular consultation, management of ICP ICP Normal intracranial pressure (ICP) is defined as < 15 mm Hg, whereas pathologically increased ICP is any pressure ≥ 20 mm Hg. Increased ICP may result from several etiologies, including trauma, intracranial hemorrhage, mass lesions, cerebral edema, increased CSF production, and decreased CSF absorption. Increased Intracranial Pressure (ICP), and monitoring in a neurologic ICU ICU Hospital units providing continuous surveillance and care to acutely ill patients. West Nile Virus. 
• Hypertensive encephalopathy Encephalopathy Hyper-IgM Syndrome: neurologic deficits Neurologic Deficits High-Risk Headaches and/or altered mental status Altered Mental Status Sepsis in Children/ altered level of consciousness Altered Level of Consciousness Intracerebral Hemorrhage that present in the setting of severe hypertension Severe hypertension A confirmed blood pressure ≥ 180 mm Hg systolic and/or ≥ 120 mm Hg diastolic. Uncontrolled Hypertension. Diagnosis is based on the presence of elevated blood pressure and neurologic signs/symptoms. Neuroimaging Neuroimaging Non-invasive methods of visualizing the central nervous system, especially the brain, by various imaging modalities. Febrile Infant is useful to rule out ischemic or hemorrhagic cerebrovascular accident Cerebrovascular accident An ischemic stroke (also known as cerebrovascular accident) is an acute neurologic injury that occurs as a result of brain ischemia; this condition may be due to cerebral blood vessel occlusion by thrombosis or embolism, or rarely due to systemic hypoperfusion. Ischemic Stroke.