Multibacillary Leprosy With Pulmonary Involvement: A Case Report

Leprosy is a chronic infectious disease caused by Mycobacterium leprae that, although curable, remains a public health challenge in Brazil. The bacillus affects skin and peripheral nerves but can also involve other tissues. Respiratory tract involvement has been reported, mainly in the upper airways, while lung parenchyma is often spared. Because it is infrequent in both the literature and clinical practice, this paper reports a case of multibacillary leprosy with concomitant involvement of upper and lower airways. A 30-year-old male with no comorbidities, from an urban area, was admitted to a tertiary hospital with two years of epistaxis and nasal congestion, later developing productive cough, fever, asthenia, and painful erythematous nodular lesions on the limbs for one month. Exam showed pain and thickening of the left ulnar nerve. Lymph smear microscopy was positive with bacillary index 5.25, and nasal mucosa biopsy was compatible with leprosy. Sinus CT showed mucosal thickening with bone rarefaction and irregularities in the nasal septum; chest CT showed centrilobular nodular opacities with a branching “tree-in-bud” pattern in the right lung apex. Sputum smear showed globi; rapid molecular test for Mycobacterium tuberculosis was negative, and solid culture showed no mycobacterial growth. The patient was diagnosed with multibacillary leprosy with nasal mucosa involvement, pulmonary parenchymal involvement, and type II leprosy reaction. Treatment was started with rifampicin, dapsone, and clofazimine, plus thalidomide and prednisone. Leprosy affects skin, nerves, and mucosa (especially upper airways) and may infiltrate internal organs; manifestations correlate with infiltration severity, highest in the lepromatous pole. Multibacillary patients often have nasolaryngeal lesions, but few bacilli are found in lung parenchyma. Although coinfection with M. tuberculosis is possible, clinicians should consider pulmonary involvement by M. leprae given the disease’s broad clinical spectrum.