Source / episode info
- **Episode:**585
- **Title:**DIP Ep 585: 2025 USMLE Step 1 Free 120 Discussion Part 5a (Q41-45, super helpful for Step 2 and 3!)
- **Published:**2025-03-26
- Source:Episode page
One-liner
This episode covers developmental staging using Tanner criteria, differentiating causes of pediatric rectal bleeding (constipation vs. Hirschsprung's), recognizing the classic presentation and diagnostic testing for Ebola virus disease, understanding molecular biology techniques (Northern/Southern/Western blots), identifying diabetic peripheral neuropathy findings, and diagnosing pertussis with appropriate antibiotic therapy.
High-yield summary
- Tanner Staging: Used to assess sexual maturity; Stage 1 = Nothing; Stage 2 = Basics (initial development); Stage 3 = Increasing (more developed).
- Pediatric Rectal Bleeding: The most common cause is simple constipation leading to mucosal abrasion. Rule out CF, Hirschsprung's disease, and Crohn's based on a thorough history/physical exam.
- Ebola Virus Disease: Characterized by an initial flu-like illness (fever >101°F, myalgia, fatigue) before hemorrhagic manifestations appear. Diagnosis relies on detecting the viral genome via PCR.
- Molecular Blotting: Northern blot detects RNA (used to measure gene expression); Southern blot detects DNA; Western blot detects Protein.
- Diabetic Neuropathy: The classic finding is loss of pain and temperature sensation in a stocking-glove distribution, often preceding motor deficits.
- Pertussis (Whooping Cough): Classic triad includes paroxysmal coughing spells, post-tussive vomiting/gagging, and subconjunctival hemorrhage. Treatment requires Macrolides or DTaP components.
Learning objectives
- Differentiate between various causes of pediatric rectal bleeding, prioritizing simple constipation over inflammatory or structural diseases.
- Recognize the classic clinical triad and appropriate diagnostic testing for Ebola virus disease following travel to endemic areas.
- Correctly interpret molecular blotting techniques (Northern/Southern/Western) based on the target molecule (RNA, DNA, Protein).
- Identify the hallmark sensory deficits of diabetic peripheral neuropathy and understand its pathophysiology.
- Master the diagnosis and treatment protocol for pertussis, recognizing the importance of vaccine status and antibiotic choice.