For patients receiving bleomycin, which complication is most likely?

• A. Peripheral neuropathy
• B. High-frequency hearing loss
• C. Pulmonary fibrosis
• D. SIADH

Answer: (C)

Bleomycin carries a distinctive risk of lung injury that can progress to pulmonary fibrosis. This happens because the lungs have relatively low levels of the enzyme that inactivates bleomycin, so the drug can accumulate there and damage the alveolar and interstitial tissues. The result is a dose-dependent pneumonitis that can progress to fibrosis if not recognized.

Key context to understand: risk rises with higher cumulative doses, older age, preexisting lung disease, smoking, and exposure to supplemental oxygen (which can worsen toxicity). Clinically, patients may develop a dry cough, progressive shortness of breath, and hypoxia, with interstitial changes seen on imaging and a restrictive pattern on lung testing. If suspected, the drug is stopped and management is supportive; corticosteroids may be used in some cases, though evidence varies.

Other listed toxicities don’t fit bleomycin’s pattern. Peripheral neuropathy is more typical of certain other chemotherapy classes, high-frequency hearing loss is a hallmark of platinum-based drugs like cisplatin, and SIADH is not a characteristic complication of bleomycin.