Source / episode info

• **Episode:**351
• **Title:**Divine Intervention Episode 351 – USMLE Step 2CK/3 Rapid Review Series 66.
• **Published:**2021-11-22
• Source:Episode page

One-liner

This episode provides a rapid review of high-yield board topics including the diagnosis and management of GBS, ITP, rheumatic fever, APML/DIC, IIH, drug-induced Type 2 RTA, and endocrine tumors like granulosa cell carcinoma.

High-yield summary

• Guillain-Barré Syndrome (GBS): Characterized by ascending paralysis following a mucosal infection; CSF shows albuminocytologic dissociation (high protein, normal/near-normal WBC count). Treatment involves IVIG or PLEX.
• Immune Thrombocytopenia (ITP): An autoimmune condition where autoantibodies target platelet glycoproteins (e.g., GP2b3a), leading to thrombocytopenia and bleeding; treatment progression is Steroids -> IVIG -> Splenectomy.
• Idiopathic Intracranial Hypertension (IIH): Diagnosed by lumbar puncture showing elevated CSF pressure (>200 mm H2O) in the absence of mass effect; Acetazolamide (a carbonic anhydrase inhibitor) can be used, but this drug class risks Type 2 RTA and hypokalemia.
• Type 2 Renal Tubular Acidosis (RTA): Caused by proximal bicarbonate wasting (e.g., due to CAIs); results in Normal Anion Gap Metabolic Acidosis (NAGMA) and is associated with volume contraction/RAAS activation, leading to concurrent hypokalemia.
• Acute Promyelocytic Leukemia (APML): A specific type of AML (M3) associated with the t(15;17) translocation; it carries a high risk of DIC due to promelocyte release into circulation and is treated with All-trans retinoic acid (ATRA).
• Granulosa Cell Tumor: The most common cause of peripheral precocious puberty in females <8 years old, resulting from estrogen overproduction by the tumor. Biopsy reveals Call-Exner bodies.

Learning objectives

• Differentiate between various causes of peripheral neuropathy and their characteristic CSF findings.
• Outline the diagnostic workup and stepwise management for autoimmune thrombocytopenia.
• Understand the pathophysiology of molecular mimicry in rheumatic diseases.
• Recognize the specific hematologic malignancy (APML) associated with DIC risk and its primary treatment.
• Master the clinical presentation, diagnosis, and metabolic consequences of elevated intracranial pressure.