Unremitting Asthma as a Presentation of Pulmonary Nocardiosis: A Case Report

Abstract

Severe, refractory asthma requires a combination of multiple maintenance inhalers and medications including high-dose inhaled corticosteroids and immunomodulators to achieve control of symptoms. The use of inhaled corticosteroids, however, increases the susceptibility of opportunistic bacterial infections, such as Nocardia, resulting in pulmonary nocardiosis. This case describes a 46-year-old patient with a history of severe, refractory asthma who presented with progressively worsening asthma exacerbation symptoms. She was treated with immunomodulators, high-dose inhaled corticosteroids and oral steroids, and several courses of antibiotics. CT imaging revealed bibasilar peri-bronchial thickening and tree-in-bud nodularity in the right lower lobe. Pulmonary cultures collected from bronchoscopy grew Nocardia nova complex. This was a rare case of persistent asthma exacerbation by N. nova complex bronchopulmonary infection. Broad differentials should be considered in patients with severe, refractory asthma who were previously controlled and were found to fail treatment therapies. Immunocompromised patients with chronic lung disease are at higher risk of severe infection with disseminated nocardiosis. These patients have a higher mortality and morbidity risk if early diagnosis of pulmonary nocardiosis does not occur.

Keywords: immunocompromised hosts; inhaled corticosteroids; pulmonary infections; pulmonary nocardiosis; severe refractory asthma.

Figure 1. Regression of pulmonary nocardiosis during the treatment course from May 2022 to December 2022.

(A, C) CT chest from May 2022 revealed mild linear opacities mostly in the right lower lobe; (B, D) Follow-up CT chest in December 2022 after seven months of treatment with TMP-SMX revealed bibasilar peribronchial thickening and tree-in-bud nodularity slightly increased in the right lower lobe and decreased in the left lower lobe. TMP/SMX: trimethoprim/sulfamethoxazole