Source / episode info
- **Episode:**199
- **Title:**Divine Intervention Episode 199 – USMLE Step 2CK Rapid Review Series 29.
- **Published:**2020-01-06
- Source:Episode page
One-liner
This rapid review covers critical board associations including optimal nutrition support in ventilated patients, zinc chelation therapy contraindications, prosthetic valve endocarditis timing, muscular dystrophy differentials (Duchenne vs Becker), chagas disease manifestations, and the pathophysiology of mineralocorticoid excess syndromes.
High-yield summary
- Nutrition Support: Internal nutrition via a feeding tube is preferred over Total Parenteral Nutrition (TPN) due to better gut integrity maintenance and lower infection risk; TPN carries a high risk of selenium deficiency.
- Endocrine/Mineralocorticoids: 11-hydroxylase deficiency leads to the accumulation of 11-deoxycorticosterone (DOC), which has mineralocorticoid activity, causing hypertension, hypokalemia, and metabolic alkalosis.
- Infectious Disease Timing: Prosthetic valve endocarditis must be classified by timing: < 60 days (S. bacteremias); > 60 days (S. furus); > 12 months (Strep viridans).
- GI Emergencies: Toxic megacolon is a surgical emergency, often caused by C. difficile, and requires consideration of distal colonic pseudo-obstruction (e.g., in-be-em-examptus) or other causes like scleroderma/bacterial overgrowth.
- Genetics & Screening: Down Syndrome (Trisomy 21) is most commonly due to maternal non-disjunction; the quad screen findings are high -hCG and hIN, with low AFP and TSF.
Learning objectives
- Differentiate between various types of nutrition support based on patient stability and GI tract function.
- Recognize the specific timing criteria for prosthetic valve endocarditis pathogens.
- Identify key clinical features and differential diagnoses for muscular dystrophies (DMD vs Becker).
- Understand the pathophysiology and management of mineralocorticoid excess syndromes (e.g., 11\beta-hydroxylase deficiency).
- Master the high-yield associations in genetic screening (Down Syndrome, Trisomy 18) and infectious disease (Chagas, Leptospirosis).
Board exam buzzwords