Source / episode info
- **Episode:**537
- **Title:**Divine Intervention Episode 537: 2024 USMLE Step 2CK Free 120 Discussion Part 13 (Q101-110, worksheet included)
- **Published:**2024-05-18
- Source:Episode page
One-liner
This episode covers critical board topics including RhD prophylaxis in pregnancy, delayed hypersensitivity reactions (Poison Ivy), the spectrum of hematologic malignancies (CML, ALL, AML, CLL), interpreting COPD PFTs and gas exchange abnormalities, managing anxiety disorders, recognizing neurodegenerative associations (Parkinson's triad), identifying elder abuse, differentiating substance-induced cardiomyopathies (meth vs. cocaine), and diagnosing pheochromocytoma.
High-yield summary
- RhD Prophylaxis: Rh-negative women require {Rho(D)} immune globulin administration at 28 weeks gestation, following any bleeding episode, or within the first 72 hours postpartum to prevent alloimmunization.
- Delayed Hypersensitivity: Contact dermatitis (e.g., Poison Ivy) is a Type IV hypersensitivity reaction, requiring avoidance of the causative agent.
- CML Diagnosis: Chronic Myeloid Leukemia (CML) is characterized by the {t}(9;22) translocation, creating the Philadelphia chromosome and the BCR-ABL fusion gene, managed with Tyrosine Kinase Inhibitors ({TKIs}) like Imatinib.
- COPD Gas Exchange: Chronic {CO}_2 retention leads to respiratory acidosis, which is compensated by metabolic alkalosis (increased {HCO}_3^-). The hallmark gas exchange abnormality is a high A-a gradient and decreased DLCO due to V/Q mismatch.
- Pheochromocytoma Workup: Clinical suspicion (episodic headache, hypertension, sweating) requires measuring plasma or urine fractionated metanephrines for diagnosis; the mass itself is often in the adrenal medulla.
- Parkinson's Triad: The classic triad suggesting underlying neurodegenerative disease is constipation, anosmia, and REM sleep behavior disorder (acting out dreams).
Learning objectives
- Differentiate the timing and indications for \text{Rho(D)} immune globulin administration during pregnancy.
- Interpret gas exchange abnormalities (A-a gradient, DLCO) in chronic lung diseases like COPD.
- Recognize the key features and diagnostic workup of common hematologic malignancies (\text{CML}, \text{ALL}, \text{AML}).
- Identify the classic clinical presentations associated with pheochromocytoma and its biochemical confirmation.
- Master the differential diagnosis and management principles for various psychiatric disorders (e.g., GAD, anticholinergic toxicity).