Source / episode info
- **Episode:**644
- **Title:**DIP Ep 644: USMLE Free 86 Series 6 (Q47-56, for Step 2/3)
- **Published:**2026-03-30
- Source:Episode page
One-liner
This episode covers a broad range of topics including managing advanced melanoma pain/psychosocial care, identifying specific signs of Major Depressive Disorder (ahedonia), understanding the normal anatomy and implications of uterine malposition, recognizing Myocardial Infarction on ECG, initiating TB workup based on PPD results, diagnosing septic arthritis via joint aspiration, and recognizing the critical interaction between loop diuretics and Digoxin toxicity.
High-yield summary
- Digoxin Toxicity: The combination of a loop diuretic (e.g., Furosemide) causing hypokalemia significantly increases the risk of Digoxin toxicity by increasing the binding sites on the Na+/K+-ATPase pump, leading to increased cardiotoxicity and GI symptoms.
- Septic Arthritis Workup: Any patient presenting with acute monoarthritis must undergo immediate joint aspiration (arthrocentesis). A positive Gram stain is highly suggestive of septic arthritis, necessitating cultures and sensitivities for targeted antibiotic therapy.
- TB Screening: In a congregate setting (e.g., homeless shelter), a PPD reading 10 mm suggests exposure to TB. The next diagnostic step is always a Chest X-ray; if negative, latent TB infection (LTBI) is suspected and treated with INH + B6 for 9 months.
- HIV Prevention: For HIV-positive pregnant women, the primary prevention strategy against vertical transmission is initiating Antiretroviral Therapy (ART) to achieve an undetectable viral load, as breastfeeding increases risk.
- Uterine Malposition: Uterine retroflexion or anteflexion are common anatomical variations and do not increase the risk of spontaneous abortion; therefore, no specific prophylactic therapy is indicated.
Learning objectives
- Differentiate between common symptoms of depression that are confounded by chronic illness versus specific core symptoms like anhedonia.
- Outline the diagnostic workup and management steps for suspected septic arthritis in a joint with acute inflammation.
- Interpret PPD results (cutoff values) and determine the appropriate next step (CXR) in TB screening, especially in high-risk populations.
- Recognize the mechanism by which hypokalemia potentiates Digoxin toxicity via increased binding sites on the Na+/K+-ATPase pump.
- Understand the principles of HIV vertical transmission prevention, emphasizing ART initiation over prophylactic procedures like amniocentesis.
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