Source / episode info
- **Episode:**628
- **Title:**DIP Ep 628: USMLE Step 2/3 Rapid Review Series 131
- **Published:**2026-01-17
- Source:Episode page
One-liner
This episode provides a high-yield review of diabetic gastroparesis management using prokinetic agents like metoclopramide (D2 antagonist) and erythromycin (motilin agonist), while also integrating concepts of GI malabsorption following gastric bypass leading to iron deficiency anemia, which is associated with restless legs syndrome, porphyria cutanea tarda, and polycythemia vera.
High-yield summary
- Diabetic Gastroparesis: Characterized by delayed gastric emptying due to autonomic neuropathy (often diabetic). Diagnosis requires a gastric emptying study; initial management involves prokinetic agents.
- Metoclopramide Use: Metoclopramide is a D2 receptor antagonist and effective for gastroparesis, but its use carries risks of tardive dyskinesia and neuroleptic malignant syndrome (NMS).
- NMS/Rhabdomyolysis Cascade: NMS can present with severe muscle rigidity and fever. The resulting rhabdomyolysis releases myoglobin into the bloodstream, causing acute kidney injury (AKI) and potentially life-threatening hyperkalemia.
- Gastric Bypass & Iron Deficiency: Bypassing the duodenum (the primary site of iron absorption) leads to malabsorption and subsequent iron deficiency anemia. This is a critical complication requiring close follow-up and supplementation.
- Iron Deficiency Syndromes: Low iron stores are key determinants in several conditions: 1) Restless Legs Syndrome (RLS), 2) Porphyria Cutanea Tarda (PCT, where bleeding helps symptoms), and 3) Polycythemia Vera (PV, where menstrual blood loss can improve symptoms).
Learning objectives
- Differentiate the clinical presentation and management of diabetic gastroparesis.
- Recognize the side effects associated with prokinetic agents (e.g., metoclopramide).
- Understand the metabolic cascade linking rhabdomyolysis, NMS, and hyperkalemia.
- Identify common causes of malabsorption following GI surgery (e.g., gastric bypass) and their specific deficiencies.
- Correlate iron deficiency with multiple systemic conditions (RLS, PCT, PV).
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