Myasthenia Gravis

Ptosis in myasthenia gravis

Overview Definition Myasthenia gravis (MG) is a chronic autoimmune disorder in which antibodies attack the acetylcholine receptor (AChR) complex at the neuromuscular junction. Epidemiology Etiology Classification and Pathophysiology Classification There are 2 main clinical forms of MG: In addition, rarer forms of MG exist that primarily affect the pediatric population: Myasthenia gravis may also be […]

Lambert-Eaton Myasthenic Syndrome

Lambert-eaton myasthenic syndrome pathophysiology

Overview Definition Lambert-Eaton myasthenic syndrome (LEMS) is an autoimmune disorder affecting the neuromuscular junction and has a strong association with small cell lung carcinoma. Epidemiology Etiology Pathophysiology and Clinical Presentation Pathophysiology Clinical presentation Muscle weakness: Bulbar involvement: Autonomic dysfunction: Respiratory failure: Diagnosis History and physical exam Electrodiagnostic studies Antibody tests Cancer screening Management Management General: […]

Disseminated Intravascular Coagulation

Schistocytes as diagnostic of dic

Overview Definition Disseminated intravascular coagulation (DIC) is a condition characterized by systemic bodywide activation of the coagulation cascade that results in both: Epidemiology Classification Acute DIC: Chronic DIC: Etiology Disseminated intravascular coagulation is always a complication of other conditions: Table: Etiologies of disseminated intravascular coagulation Infection Bacterial: Sepsis (both gram-positive and gram-negative species) Escherichia coli […]

Short Bowel Syndrome

Types of bowel resection

Overview Definition Epidemiology Etiology Pathophysiology Physiology Consequences of bowel resection Several factors determine the degree of intestinal function loss after bowel resection: Phases of SBS Acute phase: Adaptation phase: Maintenance phase: Clinical Presentation and Diagnosis General clinical presentation Nutritional deficiencies Laboratory findings The following table summarizes possible laboratory findings in SBS that correlate with signs […]

Renal Sodium and Water Regulation

Collecting duct water reabsorption

Background Concepts Fluid compartments To understand renal sodium and water regulation, it is important to understand how water is normally distributed in the body. Total body water (TBW): Intracellular fluid (ICF): Extracellular fluid (ECF):  Osmolality Plasma osmolality refers to the combined concentration of all solutes in the blood. Tonicity Plasma tonicity refers to the concentration […]

Wilms Tumor

Wilms tumor

Overview Epidemiology Etiology Pathophysiology Clinical Presentation Manifestations Physical examination Diagnosis Screening Serial abdominal ultrasonography for those at risk for Wilms tumor: Diagnostic imaging and laboratory studies Staging From National Wilms Tumor Study (NWTS)/Children’s Oncology Group (COG): Management Treatment Recommendations based on the NWTS/COG trials: Prognosis Differential Diagnosis References

Osteochondritis Dissecans

Osteochondritis dissecans knee mri

Overview Definition Osteochondritis dissecans (OCD) is a disorder characterized by aseptic necrosis of subchondral bone that results in focal detachment and displacement of bone and cartilage into the joint space. The term osteochondritis is a misnomer, as histologic analysis reveals a lack of inflammatory cells. Epidemiology Etiology and Pathophysiology Etiology The exact etiology is unknown. […]

Respiratory Failure

Hypoxemia

Definition and Classification Definition Respiratory failure is a syndrome that develops when the respiratory system is unable to maintain oxygenation and/or ventilation. Classification Respiratory failure may be classified based on:  The time course: The underlying issue: Etiology Etiology of hypoxemic respiratory failure Etiology of hypercapnic respiratory failure Pathophysiology Right-to-left shunt Ventilation-to-perfusion inequality A mismatch between […]

Hyperkalemia

Hyperkalemia ekg

Overview General considerations K+ is the main intracellular cation in all cells and is distributed unevenly between the intracellular fluid (98%) and extracellular fluid (2%).  Sites of action in the kidney Normal response to ingested K+ A normal Western diet contains approximately 70–150 mmol of K+ per day. This diet is unlikely to lead to […]

Coagulation Studies

Assessing the coagulation cascade

Overview Definition Coagulation studies are a group of hematologic studies that reflect the function of blood vessels, platelets, and coagulation factors, which all work in harmony to achieve hemostasis. Uses of coagulation studies Review: phases of the hemostatic process The following is a summary of the hemostatic process: Coagulation Studies The following studies can assist […]

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