PCP treatment with antibiotics can cause which complication, potentially requiring steroids and arterial blood gas assessment?

• A. Respiratory decompensation
• B. Hypertensive crisis
• C. Hyperglycemia
• D. Nephrotoxicity

Answer: (A)

When treating Pneumocystis jirovecii pneumonia with antibiotics like high-dose trimethoprim-sulfamethoxazole, the dying organisms can trigger a pronounced inflammatory response in the lungs. This can worsen oxygenation and lead to respiratory decompensation. In patients with significant hypoxemia, adjunctive corticosteroids are added to reduce the inflammatory damage and improve outcomes. Arterial blood gas assessment helps quantify hypoxemia (for example, PaO2 measuring <70 mmHg on room air or an elevated A-a gradient) and guides both the decision to start steroids and the level of respiratory support needed. The other options describe potential drug toxicities, but they do not specifically necessitate steroids and ABG-guided management in PCP treatment.