Source / episode info
- **Episode:**225
- **Title:**Divine Intervention Episode 225 – USMLE Step 2CK Rapid Review Series 35.
- **Published:**2020-03-28
- Source:Episode page
One-liner
This episode provides high-yield reviews of myocarditis causes (Coxac-B, Doxo/Trastu), peripheral nerve injury patterns (Radial, Axillary, Median), the four hard signs of myelopathy, and differential diagnoses for visual hallucinations (Alcoholic hallucinosis, NAL, Lewy body dementia).
High-yield summary
- Myocarditis: The most common cause is infection with Coxiella burnetii. Clinically presents as heart failure symptoms (pulmonary edema) and often causes a new S3 gallop and mitral regurgitation murmur due to ventricular dilation/diluted cardiomyopathy.
- Drug Cardiomyopathy Contrast: Doxorubicin (anthrocycline) causes irreversible dilated cardiomyopathy via free radical damage; Trastuzumab (anti-HER2 mAb) causes reversible cardiomyopathy.
- Radial Nerve Injury: The key principle is that proximal injuries yield more deficits than distal ones. Wrist drop occurs with injury at the elbow or more proximally, and sensation loss affects the dorsal aspect of the first three digits.
- Myelopathy Hard Signs: A spinal cord lesion (myelopathy) is strongly suggested by finding any combination of: 1) Urinary incontinence (overflowing continent), 2) Sensory level, 3) Upper Motor Neuron signs in lower extremities + Lower Motor Neuron signs in upper extremities, or 4) Injury to three distinct tracts (corticospinal, spinothalamic, and dorsal column).
- Visual Hallucinations: High-yield causes include: Alcoholic hallucinosis (withdrawal), NAL (anti-colonageics), and Lewy body dementia.
Learning objectives
- Differentiate between reversible and irreversible drug-induced cardiomyopathy.
- Identify the specific peripheral nerves affected by fractures at different levels of the humerus (Axillary, Radial, Median).
- Apply the "four hard signs" mnemonic to diagnose myelopathy.
- List the key differential diagnoses for visual hallucinations in a medical exam setting.
- Correlate clinical findings with anatomical structures (e.g., radial nerve distribution on the dorsal hand).
Board exam buzzwords