Source / episode info

• **Episode:**145
• **Title:**Divine Intervention Episode 145 – USMLE Step 2CK Rapid Review Series 14 (Surgery).
• **Published:**2019-09-07
• Source:Episode page

One-liner

This episode provides a high-yield review covering Meckel's diverticulum workup (Tc-99m pertechnetate scan), managing small bowel obstruction in Crohn's disease, recognizing toxic megacolon, differentiating thyroid nodules via RAIU scans, and reviewing classic CSF findings for subarachnoid hemorrhage and meningoencephalitis.

High-yield summary

• Meckel's Diverticulum: The most common cause of painless lower GI bleeding in children; diagnosis is suspected by finding a source of bleeding (e.g., positive stool guaiac) and confirmed by a Tc-99m pertechnetate scan showing ectopic gastric mucosa.
• Crohn's Disease SBO: Small bowel obstruction in Crohn's disease is often caused by strictures or fistulas, not just inflammation, requiring careful differentiation from adhesive obstruction.
• Toxic Megacolon: A life-threatening complication of colitis (e.g., C. difficile) presenting with severe abdominal distension and colon diameter >6 cm on imaging; requires immediate exploratory laparotomy.
• Thyroid Nodules/Cancer: The RAIU scan helps differentiate nodules: a single hot spot suggests a toxic adenoma, while multiple hot spots interspersed with cold areas suggest a toxic multinodular goiter. Medullary thyroid cancer (MTC) is associated with elevated calcitonin and can cause prolonged QT interval due to calcitonin's calcium-lowering effect.
• CSF Findings: The classic triad for Subarachnoid Hemorrhage (SAH) is the "worst headache of life," requiring a non-contrast CT head first, followed by lumbar puncture if negative. CSF findings include xanthochromia and elevated protein 14-3-3 in CJD.

Learning objectives

• Differentiate the pathophysiology and diagnostic imaging for Meckel's diverticulum.
• Recognize the signs of toxic megacolon and its required emergency management.
• Master the differential diagnosis of hyperthyroidism using RAIU scan patterns (Graves vs. Toxic Adenoma vs. TMG).
• Identify key tumor markers and associated syndromes for thyroid cancers (MTC, Papillary, Follicular).
• Correlate classic CSF findings with specific central nervous system pathologies (SAH, CJD, Herpes Encephalitis).

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