The Clinical Problem Solvers Episode 433 – RLR – A Red Leg
Dec 2, 2025
A clinical mystery about a rapidly red, painful leg in an older patient with diabetes and venous stasis unfolds. The discussion follows diagnostic branching between cellulitis, DVT, and necrotizing infection and the use of imaging and LRINEC. Surprise blood cultures reveal gram negative rods and an unexpected zoonotic source from cats, shifting treatment and teaching points.
AI Snips
Chapters
Books
Transcript
Episode notes
Cellulitis Is The Default For A Red Swollen Leg
- For lower‑extremity redness and edema, cellulitis is the highest‑base‑rate diagnosis and should be prioritized until contradicted.
- Diabetes and tinea pedis increase vulnerability, while DVT is less likely to produce overt erythema.
Classify Cellulitis Severity And Mechanism Before Choosing Antibiotics
- When diagnosing cellulitis, categorize it as suppurative vs non‑suppurative and mild/moderate/severe to guide antibiotic choice and disposition.
- Elevate the leg and consider ceftriaxone for typical strep/MSSA coverage rather than empiric broad MRSA agents.
Do Not Automatically Admit Mild Cellulitis If Stable
- You can safely trial oral antibiotics outpatient for mild/moderate cellulitis if vitals are stable and you provide clear return precautions.
- Use contingency planning: admit or escalate if persistent fever, hypotension, or worsening symptoms develop.
