C57-10 Navigating Pulmonary Nocardiosis in Chronic Methadone Associated QTc Prolongation

Abstract Introduction Nocardiosis is an uncommon but clinically significant infection caused by Nocardia species. Pulmonary nocardiosis often presents with nonspecific respiratory and constitutional symptoms, leading to diagnostic delays. Management can be further complicated by comorbidities and medication-related adverse effects. QT prolongation, particularly in patients on methadone, adds therapeutic challenges, as trimethoprim-sulfamethoxazole (Bactrim)—a first-line agent for nocardiosis—can further prolong the QT interval. We describe a case of pulmonary nocardiosis in an immunocompetent adult with chronic methadone-associated QT prolongation, emphasizing diagnostic and cardiac safety considerations. Case A 39-year-old male with prior opioid use disorder on methadone presented with progressively worsening dyspnea on exertion, nausea, vomiting, diarrhea, and poor oral intake, associated with a 30-pound unintentional weight loss. He reported living in a homeless shelter for two years but denied incarceration or intravenous drug use. On arrival, he appeared cachectic and fatigued. Vital signs showed tachycardia and moderate hypoxia. Lung examination revealed scattered rhonchi and decreased air entry at the bases. Laboratory studies demonstrated electrolyte abnormalities with marked eosinophilia. The electrocardiogram (ECG) showed severe QT prolongation to 598 ms. Methadone was initially held with limited symptomatic spot dosing. Computed tomography (CT) chest imaging revealed patchy infiltrates and ground-glass nodular opacities. Sputum culture and bronchoalveolar lavage confirmed Nocardia species. HIV testing was negative, and there was no evidence of immunosuppression. With supportive therapy, gastrointestinal symptoms and electrolytes improved, accompanied by gradual QTc improvement. Broad-spectrum antibiotics were narrowed to trimethoprim-sulfamethoxazole, and methadone was cautiously reintroduced back to the original home dose. Serial ECGs remained at QTc 500 ms. Discussion Nocardia species are opportunistic pathogens that can cause disseminated infection, particularly in immunocompromised individuals. QT prolongation in this case was likely secondary to a combination of factors, including electrolyte imbalances from acute vomiting and diarrhea alongside the chronic use of QT-prolonging medications such as methadone. This case highlights the diagnostic challenges and cardiac manifestations associated with Nocardia infection and Bactrim therapy in an immunocompetent host with social risk factors. Careful medication changes and dose adjustments alongside serial ECG’s are imperative to ensure a safe discharge for continued therapy. This abstract is funded by: None