The Immunocompromised Host

• When ANC <0.5 ×10⁹/L or expected to fall to ≤0.5 within 48 h and T ≥38.3 (or ≥38.0 ×1 h): cultures, then antipseudomonal β-lactam inside 1 h.
• Reserve vancomycin for shock, suspected line/SSTI/pneumonia or relevant resistant Gram-positive risk. Severe mucositis qualifies especially with fluoroquinolone prophylaxis and inadequate viridans cover. Stop at 48–72 h if no ongoing indication.
• High-risk prolonged neutropenia: persistent/recurrent fever at 72–96 h despite adequate antibiotics → CT/fungal workup and mold-active therapy if no systemic antifungal prophylaxis, or a monitored preemptive pathway (AGIHO 2025).
• Examine daily with focus on lines, mouth, perianal area, lungs; avoid rectal exams.
• MASCC ≥21 supports low risk only with clinical stability, no organ dysfunction, reliable oral intake/support and rapid follow-up; an ICU/septic patient is not an outpatient candidate because of the score alone.

First tests: Full blood count, Sodium, potassium, bicarbonate, urea and creatinine, Liver biochemistry, Blood cultures.

Only if indicated: Chest X-ray, Site-directed microbiology, CT and fungal investigations.

Repeat monitoring: Full blood count, Sodium, potassium, bicarbonate, urea and creatinine.

• Managing Neutropenic Fever