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Seizures

A seizure is abnormal electrical activity of the neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology in the cerebral cortex Cerebral cortex The cerebral cortex is the largest and most developed part of the human brain and CNS. Occupying the upper part of the cranial cavity, the cerebral cortex has 4 lobes and is divided into 2 hemispheres that are joined centrally by the corpus callosum. Cerebral Cortex: Anatomy that can manifest in numerous ways depending on the region 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 affected. Seizures consist of a sudden imbalance that occurs between the excitatory and inhibitory signals in cortical neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology, creating a net excitation. The 2 major classes of seizures are focal and generalized. Diagnosis is clinical, relying on history and physical exam, but also may use EEG and other tools. Management includes both abortive and preventive medications but may not be required in self-limited cases with no etiology found during workup.

Last updated: Dec 5, 2022

Editorial responsibility: Stanley Oiseth, Lindsay Jones, Evelin Maza

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Overview

Definition

Seizures are episodes of neurologic dysfunction caused by abnormal excitatory activities of neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology characterized by a sudden change in senses, perception Perception The process by which the nature and meaning of sensory stimuli are recognized and interpreted. Psychiatric Assessment, motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology activity, or behavior.

  • Seizure occurrences with motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology activity are referred to as convulsions. 
  • Unprovoked seizures are those with an unknown etiology or those that result from a preexisting nervous system Nervous system The nervous system is a small and complex system that consists of an intricate network of neural cells (or neurons) and even more glial cells (for support and insulation). It is divided according to its anatomical components as well as its functional characteristics. The brain and spinal cord are referred to as the central nervous system, and the branches of nerves from these structures are referred to as the peripheral nervous system. Nervous System: Anatomy, Structure, and Classification disorder.
  • Epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy is a disorder consisting of recurrent, unprovoked seizures.
  • Status epilepticus is recurrent seizure activity lasting > 5 minutes or without return to baseline mental status between seizures.

Epidemiology

  • Occur very commonly
  • Lifetime 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: 8%–10%
  • Roughly 1%–2% of ED visits are due to seizures. 
  • 25% of these ED visits are 1st-time episodes. 
  • Risk of recurrent seizure after 1st episode is roughly 40%.

Seizure phases

  • Aura Aura Reversible neurological phenomena that often precede or coincide with headache onset. Migraine Headache:
    • Initial warning/ trigger Trigger The type of signal that initiates the inspiratory phase by the ventilator Invasive Mechanical Ventilation prior to seizure episode 
    • Individual may realize a seizure is about to happen. 
  • Ictal:
    • Initial onset of the seizure episode as well as the episode itself
    • Actual seizure symptomatology Symptomatology Scarlet Fever is manifested in this phase.
  • Postictal:
    • Period after the seizure episode during which the individual is disoriented
    • May last up to 2 hours
Timeline of seizure phases

Timeline of seizure phases

Image by Lecturio.

Pathophysiology

Step 1: short in the circuit

  • Also known as paroxysmal depolarization Depolarization Membrane Potential shift 
  • All seizures arise from cell bodies and the gray matter Gray matter Region of central nervous system that appears darker in color than the other type, white matter. It is composed of neuronal cell bodies; neuropil; glial cells and capillaries but few myelinated nerve fibers. Cerebral Cortex: Anatomy of neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology
  • Astrocytes Astrocytes A class of large neuroglial (macroglial) cells in the central nervous system – the largest and most numerous neuroglial cells in the brain and spinal cord. Astrocytes (from ‘star’ cells) are irregularly shaped with many long processes, including those with ‘end feet’ which form the glial (limiting) membrane and directly and indirectly contribute to the blood-brain barrier. They regulate the extracellular ionic and chemical environment, and ‘reactive astrocytes’ (along with microglia) respond to injury. Nervous System: Histology may inappropriately secrete glutamate Glutamate Derivatives of glutamic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure. Synthesis of Nonessential Amino Acids, the excitatory neurotransmitter, causing neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology to become hyperexcitable.
Step 1 seizures

Step 1: short in the circuit describing the 1st step of the pathophysiology of seizures
AMPA: α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid
NMDA: N-methyl-D-aspartate

Image by Lecturio.

Step 2: driving of normal neighbors

  • Repeated paroxysmal depolarizations of a large enough group of neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology will ↑ the extracellular K+ concentration → depolarization Depolarization Membrane Potential of surrounding neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology
  • As more K+ builds up in the extracellular space, less K+ diffuses out during the hyperpolarized state Hyperpolarized state The cell is in a more negative state (i.e., larger concentration gradients are present) Cardiac Physiology and the cell remains “partially depolarized” → ↑ hyperexcited neuronal activity leads to ↑ extracellular K+ concentration, which depolarizes surrounding neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology.
  • ↑ Extracellular K+ may also flow Flow Blood flows through the heart, arteries, capillaries, and veins in a closed, continuous circuit. Flow is the movement of volume per unit of time. Flow is affected by the pressure gradient and the resistance fluid encounters between 2 points. Vascular resistance is the opposition to flow, which is caused primarily by blood friction against vessel walls. Vascular Resistance, Flow, and Mean Arterial Pressure down its concentration gradient and aid in depolarization Depolarization Membrane Potential.
  • Normal, surrounding neurons Neurons The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the nervous system. Nervous System: Histology are co-opted into the seizure activity. 
Step 2 of the pathophysiology of seizures, driving of normal neighbors

Step 2 of the pathophysiology of seizures, driving of normal neighbors:
The diagram shows a membrane potential and steps that allow excess K+ to polarize surrounding cells.

Image by Lecturio.

Step 3: failure of inhibition

  • Failure arises as a result of repeated paroxysmal depolarization Depolarization Membrane Potential shifts, which causes:
    • ↓ Afterhyperpolarization
    • ↓ Surround inhibition
    • Glutamate Glutamate Derivatives of glutamic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure. Synthesis of Nonessential Amino Acids stimulation
    • ↑ Intracellular Ca CA Condylomata acuminata are a clinical manifestation of genital HPV infection. Condylomata acuminata are described as raised, pearly, flesh-colored, papular, cauliflower-like lesions seen in the anogenital region that may cause itching, pain, or bleeding. Condylomata Acuminata (Genital Warts)2+
    • Recurrent excitatory feedback circuit 
  • Goal of management is to restore inhibition of seizure activity.
Step 3 seizures

Step 3: failure of inhibition in pathophysiology of seizures

Image by Lecturio.

Related videos

Clinical Presentation

Focal seizures Focal Seizures Seizures in Children

  • With retained awareness:
    • Depends on the location of the seizure activity 
    • May present with various sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology, autonomic, motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology, or psychic symptoms 
  • With altered awareness:
    • Most common type in adults with epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy 
    • May engage in automatisms (repetitive, unconscious Unconscious Those forces and content of the mind which are not ordinarily available to conscious awareness or to immediate recall. Psychotherapy behaviors):
      • Facial grimacing
      • Lip smacking
      • Chewing
  • Focal to bilateral tonic-clonic seizure (previously called secondary generalized): start as focal seizures Focal Seizures Seizures in Children then progress to generalized type
Table: Types of focal or partial seizures
Simple Complex Secondary generalized
  • Retained consciousness
  • Abnormal smell Smell The sense of smell, or olfaction, begins in a small area on the roof of the nasal cavity, which is covered in specialized mucosa. From there, the olfactory nerve transmits the sensory perception of smell via the olfactory pathway. This pathway is composed of the olfactory cells and bulb, the tractus and striae olfactoriae, and the primary olfactory cortex and amygdala. Olfaction: Anatomy or taste
  • Staring spells without consciousness
  • Retained muscle tone Muscle tone The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch. In skeletal muscle, tonus is dependent upon efferent innervation. Skeletal Muscle Contraction
  • Loss of consciousness preceded by aura Aura Reversible neurological phenomena that often precede or coincide with headache onset. Migraine Headache
  • Postictal confusion
  • Complex ictal automatisms
  • Initial aura Aura Reversible neurological phenomena that often precede or coincide with headache onset. Migraine Headache
  • Convulsive +/– Jacksonian march
  • Postictal confusion +/– Todd’s paralysis

Generalized seizures

  • Absence:
    • Previously called petit mal
    • Typically occur in childhood
    • Lasts for short periods (5–10 seconds) 
    • Present with loss of awareness or behavioral arrest
  • Myoclonic: short, sudden, focal muscle contractions 
  • Tonic: focal stiffening of the muscles
  • Clonic: shaking/jerking of the muscles usually in arms, neck Neck The part of a human or animal body connecting the head to the rest of the body. Peritonsillar Abscess, and face
  • Tonic-clonic:
    • Combination of tonic and clonic 
    • Most often convulsive
  • Atonic:
Table: Types of generalized seizures
Absence First-degree generalized brief staring spells, often confused with daydreaming, with 3-Hz spike-and-wave EEG
Myoclonic Typically focal myoclonic jerks Myoclonic Jerks Neonatal Abstinence Syndrome with brief loss of consciousness but no convulsions and little postictal confusion
Tonic Focal, isolated rigidity Rigidity Continuous involuntary sustained muscle contraction which is often a manifestation of basal ganglia diseases. When an affected muscle is passively stretched, the degree of resistance remains constant regardless of the rate at which the muscle is stretched. This feature helps to distinguish rigidity from muscle spasticity. Megacolon
Generalized tonic-clonic Most often convulsive (but may be nonconvulsive) with first-degree generalization without aura Aura Reversible neurological phenomena that often precede or coincide with headache onset. Migraine Headache
Atonic Drop attacks Drop Attacks Seizures in Children are most common in children.
Types of seizures

Types of seizures and classifications

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Diagnosis

Initial evaluation and stabilization centers around screening Screening Preoperative Care for hypoglycemia Hypoglycemia Hypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia, hypoxia Hypoxia Sub-optimal oxygen levels in the ambient air of living organisms. Ischemic Cell Damage, and hemodynamic instability.

History

  • Interview witnesses whenever possible (without a witness, the diagnosis is often more difficult)
  • Identify onset and progression of symptoms.
  • Find potential triggers for seizures (e.g., noncompliance Noncompliance Clinician–Patient Relationship with antiepileptic medications). 
  • Questions that can determine type of seizure:
    • Was there a warning or aura Aura Reversible neurological phenomena that often precede or coincide with headache onset. Migraine Headache before the spell?
    • What happened during the spell?
    • Does the individual remember the spell?
    • Was the individual postictal? 
    • How long did it take to get back to baseline condition?
    • How long did the spell last?
    • How frequently have the spells occurred?
    • Are there any associated precipitants?

Physical exam

  • Type of seizure activity
  • Changes in level of arousal
  • Focal deficits
  • Pupillary changes
  • Physical findings are often normal after resolution of postictal period.
  • Examine seizure-related trauma secondary to a fall.
  • Tongue Tongue The tongue, on the other hand, is a complex muscular structure that permits tasting and facilitates the process of mastication and communication. The blood supply of the tongue originates from the external carotid artery, and the innervation is through cranial nerves. Lips and Tongue: Anatomy biting has high specificity in ruling out psychogenic nonepileptic seizures and syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope.
  • Urinary or bowel incontinence can occur.
  • Todd’s paralysis: The seizure is followed by a brief period of temporary paralysis.

Laboratory evaluation

  • CBC
  • Basic metabolic panel Basic Metabolic Panel Primary vs Secondary Headaches 
  • Calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes and magnesium Magnesium A metallic element that has the atomic symbol mg, atomic number 12, and atomic weight 24. 31. It is important for the activity of many enzymes, especially those involved in oxidative phosphorylation. Electrolytes levels 
  • Pregnancy Pregnancy The status during which female mammals carry their developing young (embryos or fetuses) in utero before birth, beginning from fertilization to birth. Pregnancy: Diagnosis, Physiology, and Care test for women of childbearing age 
  • Urine toxicology 
  • Prolactin Prolactin A lactogenic hormone secreted by the adenohypophysis. It is a polypeptide of approximately 23 kd. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Breasts: Anatomy levels obtained shortly after a seizure can differentiate epileptic from nonepileptic seizures.
  • Serum levels of anticonvulsant Anticonvulsant Anticonvulsant drugs are pharmacological agents used to achieve seizure control and/or prevent seizure episodes. Anticonvulsants encompass various drugs with different mechanisms of action including ion-channel (Na+ and Ca+2) blocking and GABA reuptake inhibition. First-Generation Anticonvulsant Drugs agents for determining:

Neuroimaging Neuroimaging Non-invasive methods of visualizing the central nervous system, especially the brain, by various imaging modalities. Febrile Infant

  • Routine neuroimaging Neuroimaging Non-invasive methods of visualizing the central nervous system, especially the brain, by various imaging modalities. Febrile Infant is not indicated in someone with previous seizure history.
  • Imaging with 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 CT or MRI recommended for:
    • New focal neurologic findings
    • Seizure activity without known etiology 
  • Noncontrast CT in the emergency setting to screen for immediate threats (structural causes, strokes, bleeding, etc ETC The electron transport chain (ETC) sends electrons through a series of proteins, which generate an electrochemical proton gradient that produces energy in the form of adenosine triphosphate (ATP). Electron Transport Chain (ETC).)
  • 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 MRI is most useful for new-onset seizure.

Electroencephalography (EEG)

  • Test that uses electrodes Electrodes Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum. Electrocardiogram (ECG) to monitor the electrical sensitivity 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 and thereby detect any disorders
  • Indicated for those who do not return to baseline consciousness in the emergent setting
  • Included as part of workup for new-onset seizures
  • More specific in adults than in children
  • Video-EEG monitoring is the standard test for classifying:
    • Type of seizure or syndrome
    • Diagnosis of pseudoseizures (psychiatric-related)
  • Exam:
    • Electrodes Electrodes Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum. Electrocardiogram (ECG) are placed on the scalp and connected to a computer.
    • The computer outputs lines 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 electrical activity.
  • In EEGs, can use:
    • Surface electrodes Electrodes Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum. Electrocardiogram (ECG): placed on the surface of the skin Skin The skin, also referred to as the integumentary system, is the largest organ of the body. The skin is primarily composed of the epidermis (outer layer) and dermis (deep layer). The epidermis is primarily composed of keratinocytes that undergo rapid turnover, while the dermis contains dense layers of connective tissue. Skin: Structure and Functions/scalp (most common)
    • Cortical electrodes Electrodes Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum. Electrocardiogram (ECG): placed on the 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 at the time of surgery
    • Depth electrodes Electrodes Electric conductors through which electric currents enter or leave a medium, whether it be an electrolytic solution, solid, molten mass, gas, or vacuum. Electrocardiogram (ECG): inserted deep into 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 to detect deeper foci of seizures
  • Abnormalities on an EEG may include:
    • Epileptiform discharges
    • Focal slowing
    • Diffuse background slowing
    • Intermittent diffuse slowing

Other testing

  • CSF examination by lumbar puncture Lumbar Puncture Febrile Infant:
    • Obtunded individuals
    • When meningitis Meningitis Meningitis is inflammation of the meninges, the protective membranes of the brain, and spinal cord. The causes of meningitis are varied, with the most common being bacterial or viral infection. The classic presentation of meningitis is a triad of fever, altered mental status, and nuchal rigidity. Meningitis or encephalitis Encephalitis Encephalitis is inflammation of the brain parenchyma caused by an infection, usually viral. Encephalitis may present with mild symptoms such as headache, fever, fatigue, and muscle and joint pain or with severe symptoms such as seizures, altered consciousness, and paralysis. Encephalitis is suspected
    • If concern exists for subarachnoid hemorrhage Subarachnoid 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
  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) is indicated for individuals with hypoxic seizure presenting as cardiogenic syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope.
  • Consider metabolic, cardiogenic, and psychiatric causes of seizure-like episodes.
Table: Different types of seizure-like episodes and appropriate work up to be initiated
Spell Seizure Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope PNES
Laboratories
  • CBC
  • CMP
  • Urinalysis Urinalysis Examination of urine by chemical, physical, or microscopic means. Routine urinalysis usually includes performing chemical screening tests, determining specific gravity, observing any unusual color or odor, screening for bacteriuria, and examining the sediment microscopically. Urinary Tract Infections (UTIs) in Children
  • UDS
  • Blood sugar
  • Lactic acid
  • CBC
  • Prolactin Prolactin A lactogenic hormone secreted by the adenohypophysis. It is a polypeptide of approximately 23 kd. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Breasts: Anatomy
  • Serum anticonvulsant Anticonvulsant Anticonvulsant drugs are pharmacological agents used to achieve seizure control and/or prevent seizure episodes. Anticonvulsants encompass various drugs with different mechanisms of action including ion-channel (Na+ and Ca+2) blocking and GABA reuptake inhibition. First-Generation Anticonvulsant Drugs levels
  • Orthostatic blood pressure
  • Cardiac monitoring
  • Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables
  • UDS
Imaging
  • +/- CT 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
  • 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 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 for stroke or SAH SAH 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 concern
  • CT 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 without contrast
  • +/- MRI 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
  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)
  • Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests
None needed
Other testing
  • Vital signs
  • ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG)
  • +/- LP
  • EEG
  • +/- video EEG
  • Psychiatric eval
  • Video EEG
PNES = psychogenic nonepileptic seizures
EEG = electroencephalography
UDS = urine drug screen, ECG = electrocardiogram
MRI = magnetic resonance imaging
TEE = transthoracic echocardiogram
CT = computerized tomography
LP = lumbar puncture
CTA = CT angiography
SAH = subarachnoid hemorrhage
Echo = echocardiogram

Comparison of seizure-like episodes

Table: Distinguishing features among common disorders included in the differential diagnosis of seizure
Seizure Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope Transient ischemic attack Transient ischemic attack Transient ischemic attack (TIA) is a temporary episode of neurologic dysfunction caused by ischemia without infarction that resolves completely when blood supply is restored. Transient ischemic attack is a neurologic emergency that warrants urgent medical attention. Transient Ischemic Attack (TIA)
Aura Aura Reversible neurological phenomena that often precede or coincide with headache onset. Migraine Headache Yes or none None, 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 and vomiting Vomiting The forcible expulsion of the contents of the stomach through the mouth. Hypokalemia, 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) None
Posture None Erect None
Onset Acute Acute/ variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables Acute
Duration 1–2 minutes Seconds to minutes Minutes to hours
Movements Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables/tonic-clonic Lost-tone myoclonus Myoclonus Involuntary shock-like contractions, irregular in rhythm and amplitude, followed by relaxation, of a muscle or a group of muscles. This condition may be a feature of some central nervous system diseases; (e.g., epilepsy-myoclonic). Nocturnal myoclonus is the principal feature of the nocturnal myoclonus syndrome. Neurological Examination Deficits
Incontinence Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables Very rare None
EEG Epileptiform General slow Focal slowing or generalized slowing with posterior circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment event
Trauma Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables Variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables Usually none
Offset Slow/confused Rapid/alert Alert

Management

Isolated or 1st-time seizures

  • Stabilize individual and then initiate evaluation in the ED and monitor for life-threatening causes of seizure.
  • Many seizures resolve on their own without intervention. 
  • Abortive therapy with benzodiazepines Benzodiazepines Benzodiazepines work on the gamma-aminobutyric acid type A (GABAA) receptor to produce inhibitory effects on the CNS. Benzodiazepines do not mimic GABA, the main inhibitory neurotransmitter in humans, but instead potentiate GABA activity. Benzodiazepines or anticonvulsant Anticonvulsant Anticonvulsant drugs are pharmacological agents used to achieve seizure control and/or prevent seizure episodes. Anticonvulsants encompass various drugs with different mechanisms of action including ion-channel (Na+ and Ca+2) blocking and GABA reuptake inhibition. First-Generation Anticonvulsant Drugs medications are not indicated in the initial stabilization of individuals with isolated seizures.
  • Admission is not needed, and close outpatient follow-up can be arranged.

Antiepileptic medications

  • Starting treatment after a single unprovoked seizure remains controversial.
  • Goal of treatment:
    • Seizure-free status 
    • No adverse effects
  • Causes of unprovoked seizure with higher chance of recurrences include:
    • Preexisting 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
    • Presentation with status epilepticus
    • Presence of epileptic discharges on EEG 
    • Family history Family History Adult Health Maintenance of epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy 
  • Antiepileptic drugs are sorted by mechanisms of action.
Mechanisms of action of anticonvulsants

Mechanisms of action of anticonvulsants
VGCC: voltage-gated calcium channels

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Status epilepticus

  • Rapid stabilization and history and physical screening Screening Preoperative Care 
  • Abortive therapy:
    • Hallmark is IV benzodiazepines Benzodiazepines Benzodiazepines work on the gamma-aminobutyric acid type A (GABAA) receptor to produce inhibitory effects on the CNS. Benzodiazepines do not mimic GABA, the main inhibitory neurotransmitter in humans, but instead potentiate GABA activity. Benzodiazepines 
    • Agents:
      • Lorazepam Lorazepam A benzodiazepine used as an anti-anxiety agent with few side effects. It also has hypnotic, anticonvulsant, and considerable sedative properties and has been proposed as a preanesthetic agent. Benzodiazepines
      • Diazepam Diazepam A benzodiazepine with anticonvulsant, anxiolytic, sedative, muscle relaxant, and amnesic properties and a long duration of action. Its actions are mediated by enhancement of gamma-aminobutyric acid activity. Benzodiazepines
      • Midazolam Midazolam A short-acting hypnotic-sedative drug with anxiolytic and amnestic properties. It is used in dentistry, cardiac surgery, endoscopic procedures, as preanesthetic medication, and as an adjunct to local anesthesia. The short duration and cardiorespiratory stability makes it useful in poor-risk, elderly, and cardiac patients. It is water-soluble at ph less than 4 and lipid-soluble at physiological pH. Benzodiazepines
  • Definitive treatments:
    • Indicated to prevent recurrence of seizures 
    • Equal efficacy among:
  • Refractory cases:
  • Surgical treatments:
    • Indicated in refractory status epilepticus or refractory epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy 
    • Examples of procedures include:
      • Resection of specific seizure nidus
      • Vagus nerve Vagus nerve The 10th cranial nerve. The vagus is a mixed nerve which contains somatic afferents (from skin in back of the ear and the external auditory meatus), visceral afferents (from the pharynx, larynx, thorax, and abdomen), parasympathetic efferents (to the thorax and abdomen), and efferents to striated muscle (of the larynx and pharynx). Pharynx: Anatomy stimulation
      • 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 stimulation and deep 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 stimulation

Seizure preventive measures

  • Psychoeducation Psychoeducation Psychotherapy of individuals to avoid common triggers:
    • Sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep deprivation
    • Alcohol
    • Certain drug types:
      • Opioid Opioid Compounds with activity like opiate alkaloids, acting at opioid receptors. Properties include induction of analgesia or narcosis. Constipation
      • Stimulants Stimulants Stimulants are used by the general public to increase alertness and energy, decrease fatigue, and promote mental focus. Stimulants have medical uses for individuals with ADHD and sleep disorders, and are also used in combination with analgesics in pain management. Stimulants
      • Some anticancer drugs
      • Some antibiotics
      • Some immunosuppressants Immunosuppressants Immunosuppressants are a class of drugs widely used in the management of autoimmune conditions and organ transplant rejection. The general effect is dampening of the immune response. Immunosuppressants
  • In certain countries or states, abstinence from operating motor Motor Neurons which send impulses peripherally to activate muscles or secretory cells. Nervous System: Histology vehicles may be required.

Differential Diagnosis

  • Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope: brief loss of consciousness and muscle tone Muscle tone The state of activity or tension of a muscle beyond that related to its physical properties, that is, its active resistance to stretch. In skeletal muscle, tonus is dependent upon efferent innervation. Skeletal Muscle Contraction with spontaneous recovery. Syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope has numerous causes but is usually a result of decreased blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure to 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. Those with syncopal events do not have the postictal confusion or prolonged duration of unconsciousness that are prevalent in those with seizure events. Management of syncope Syncope Syncope is a short-term loss of consciousness and loss of postural stability followed by spontaneous return of consciousness to the previous neurologic baseline without the need for resuscitation. The condition is caused by transient interruption of cerebral blood flow that may be benign or related to a underlying life-threatening condition. Syncope includes identifying and treating the secondary cause. 
  • Migraine Migraine Migraine headache is a primary headache disorder and is among the most prevalent disorders in the world. Migraine is characterized by episodic, moderate to severe headaches that may be associated with increased sensitivity to light and sound, as well as nausea and/or vomiting. Migraine Headache: 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 disorder characterized by headaches that may be associated with increased sensitivity to light and sound as well as 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. The clinical features of seizures depend on the location of the seizure focus and may not necessarily present with the severe headaches that are the hallmark of migraines. Management strategies of migraines include controlling acute episodes as well as prophylactic treatments.
  • Psychogenic nonepileptic seizure (PNES): resembles epileptic seizures but there is no defined cortical EEG activity, which would be diagnostic in epileptic seizures. Subtle physical exam findings differentiate PNES from true seizures, including closed eyes in a convulsing individual with PNES. Management includes potential admission to the epilepsy Epilepsy Epilepsy is a chronic brain disorder marked by recurrent and unprovoked seizures. These seizures can be classified as focal or generalized and idiopathic or secondary to another condition. Clinical presentation correlates to the classification of the epileptic disorder. Epilepsy observation unit with video-EEG monitoring.  
  • Hypoglycemia Hypoglycemia Hypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia: emergency condition defined as a serum glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance level ≤ 70 mg/dL. Hypoglycemia Hypoglycemia Hypoglycemia is an emergency condition defined as a serum glucose level ≤ 70 mg/dL (≤ 3.9 mmol/L) in diabetic patients. In nondiabetic patients, there is no specific or defined limit for normal serum glucose levels, and hypoglycemia is defined mainly by its clinical features. Hypoglycemia may present with a variety of nonspecific symptoms, including adrenergic symptoms and neuroglycopenic symptoms Neuroglycopenic Symptoms Hypoglycemia such as seizures. Diagnosis is based on serum glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance measurement and clinical presentation. Management is with oral glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance, IV dextrose Dextrose Intravenous Fluids, or IM glucagon Glucagon A 29-amino acid pancreatic peptide derived from proglucagon which is also the precursor of intestinal glucagon-like peptides. Glucagon is secreted by pancreatic alpha cells and plays an important role in regulation of blood glucose concentration, ketone metabolism, and several other biochemical and physiological processes. Gastrointestinal Secretions and frequent serum glucose Glucose A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement. Lactose Intolerance checks.
  • Narcolepsy Narcolepsy Narcolepsy is a neurological sleep disorder marked by daytime sleepiness and associated with cataplexy, hypnagogic hallucinations, and sleep paralysis. There are 2 types of narcolepsy: type 1 is associated with cataplexy and type 2 has no association with cataplexy. Narcolepsy: neurologic sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep disorder marked by daytime sleepiness Daytime sleepiness Narcolepsy and associated with cataplexy Cataplexy A condition characterized by transient weakness or paralysis of somatic musculature triggered by an emotional stimulus or physical exertion. Cataplexy is frequently associated with narcolepsy. During a cataplectic attack, there is a marked reduction in muscle tone similar to the normal physiologic hypotonia that accompanies rapid eye movement sleep (sleep, rem). Narcolepsy, hypnagogic hallucinations Hypnagogic hallucinations Narcolepsy, and sleep paralysis Sleep paralysis A common condition characterized by transient partial or total paralysis of skeletal muscles and areflexia that occurs upon awakening from sleep or less often while falling asleep. Stimuli such as touch or sound may terminate the episode, which usually has a duration of seconds to minutes. This condition may occur in normal subjects or be associated with narcolepsy; cataplexy; and hypnagogic hallucinations. The pathophysiology of this condition is closely related to the normal hypotonia that occur during rem sleep. Narcolepsy. Diagnostic criteria are identified using sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep studies that show a decrease in REM latency. Management includes good sleep Sleep A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility. Physiology of Sleep hygiene. Medications that act as CNS stimulants Stimulants Stimulants are used by the general public to increase alertness and energy, decrease fatigue, and promote mental focus. Stimulants have medical uses for individuals with ADHD and sleep disorders, and are also used in combination with analgesics in pain management. Stimulants and antidepressants are used to target the cataplexy Cataplexy A condition characterized by transient weakness or paralysis of somatic musculature triggered by an emotional stimulus or physical exertion. Cataplexy is frequently associated with narcolepsy. During a cataplectic attack, there is a marked reduction in muscle tone similar to the normal physiologic hypotonia that accompanies rapid eye movement sleep (sleep, rem). Narcolepsy

References

  1. Schachter, S. (2021) Evaluation and management of the first seizure in adults. UpToDate. Retrieved July 18, 2021, from https://www.uptodate.com/contents/evaluation-and-management-of-the-first-seizure-in-adults 
  2. Drislane, F. (2021) Convulsive status epilepticus in adults: treatment and prognosis. UpToDate. Retrieved July 18, 2021, from https://www.uptodate.com/contents/convulsive-status-epilepticus-in-adults-treatment-and-prognosis 
  3. Berg A. T. (2008). Risk of recurrence after a first unprovoked seizure. Epilepsia 49(Suppl 1):13–18. 
  4. Oliva, M., Pattison, C., Carino, J., Roten, A., Matkovic, Z., O’Brien, T. J. (2008). The diagnostic value of oral lacerations and incontinence during convulsive “seizures.” Epilepsia 49:962–967.
  5. Kapur, J., Elm, J., Chamberlain, J. M., et al. (2019). Randomized trial of three anticonvulsant medications for status epilepticus. New England Journal of Medicine 381:2103–2113.

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