Source / episode info
- **Episode:**335
- **Title:**Divine Intervention Episode 335 – USMLE Step 2CK Rapid Review Series 63 (+ Upcoming Step 2CK/3 Course Reminder).
- **Published:**2021-08-18
- Source:Episode page
One-liner
This episode provides rapid review for high-yield infectious diseases, focusing heavily on differentiating congenital infections (CMV vs Toxoplasmosis), recognizing the unique presentations of tick-borne illnesses (RMSF, Lyme), and managing severe systemic infections like Toxic Shock Syndrome and Melioidosis.
High-yield summary
- Lyme Disease: Caused by Borrelia burgdorferi, transmitted by the Dermacentr tick. Treatment involves Doxycycline or an aminoglycoside (e.g., Gentamicin). Be aware of derivative answer traps, such as seronegative glandular disease.
- Toxic Shock Syndrome (TSS): Associated with superantigens from Staphylococcus pyogenes (higher mortality risk) and S. aureus. Pathophysiology involves massive cytokine storm. Management requires source control, fluids, broad-spectrum antibiotics, and initial pressor support with Norepinephrine.
- Melioidosis: Caused by Burkholderia pseudomallei, classically seen in patients with diabetes exposed to soil/water. Presents as septic shock with neurological manifestations (e.g., fluid collections in the brain). Treated with IV Ceftazidime.
- Rocky Mountain Spotted Fever (RMSF): Caused by Rickettsia rickettsii, transmitted by the Dermacentr tick. Classic presentation includes fever and a rash that starts on the wrists/ankles and spreads centrally. Doxycycline is mandatory for all ages, including pregnant women.
- CMV vs Toxoplasmosis: CMV typically causes periventricular calcifications and associated microcephaly; Toxoplasmosis classically presents with a triad of chorioretinitis, hydrocephalus, and diffuse intracranial calcifications, often leading to macrocephaly.
Learning objectives
- Differentiate between congenital CMV and Toxoplasmosis based on imaging findings (calcification pattern, head size).
- Identify key risk factors and pathogens for severe systemic infections like Melioidosis and Q fever.
- Understand the pathophysiology and management of Toxic Shock Syndrome, including appropriate initial pressor agents.
- Recognize the classic clinical presentation and mandatory treatment regimen for tick-borne illnesses (RMSF, Lyme).
- Master the mechanism of action and resistance patterns for antiviral drugs used in CMV infection (Ganciclovir vs Foscarnet).
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