Paradoxical reaction with exacerbation of clinical or radiographic manifestations occur in patients with different infections. Mycobacterium avium-complex (MAC) lung disease is a rare infection in patients presenting with a solitary pulmonary nodule (SPN) or with an endobronchial lesion (EBL) as part of a paradoxical reaction in advanced HIV disease. We describe an HIV patient (CD4 count >100 cells/mm3) with an asymptomatic SPN and evidence of endobronchial invasion due to an infection with MAC.
A 37 year-old male with a history significant for hepatitis C virus, heavy tobacco use, and HIV (diagnosed in 10/2000 with a CD4 count of 41 cells/mm3), was admitted in 1/2001 with a 3-month history of watery diarrhea since beginning antiretroviral therapy (combivir, nelfinavir, and delavirdine) with a CD4 count of 125 cells/mm3. Normal chest radiograph (CXR) was normal at initiation of medications. Other complaints included intermittent nausea and vomiting, dysphagia, and substernal chest pain for 1 week prior to admission, which all resolved following treatment for gastroenteritis. He had subjective fever and chills, a nonproductive cough, and a 40 lb weight loss over the prior 6 months. The physical examination and laboratory data were unremarkable. His skin test for tuberculosis (which was nonreactive in 10/00) was now positive (10 mm) this admission. His CXR demonstrated a new SPN in the anterior segment of the left upper lobe (LUL), which was not present on previous films in 10/00. The chest CT revealed a 1.5 cm LUL soft tissue nodule without significant hilar or mediastinal adenopathy. A large EBL was seen at bronchoscopy, and was completely obstructing the apical-posterior segment of the LUL. Although the transbronchial biopsies in the area of the SPN were nondiagnostic, the biopsies of the EBL revealed caseating granulomatous inflammation with stains positive for rare acid-fast bacilli. The endobronchial biopsy specimens and his initial sputum samples eventually all grew MAC organisms. Initial empiric tuberculosis treatment was changed to clarithromycin and ethambutol upon identification of MAC. The patient continues on MAC and antiretroviral therapy with improvement in his clinical condition and radiographic appearance.DISCUSSION: Infections with MAC typically occur in a subpopulation of HIV patients with low CD4 counts (<100 cells/mm3). EBL caused by mycobacterial infections has been reported with MAC and other mycobacteria. Only 3 cases of endobronchial MAC have previously been reported in the literature, but none of this cases was a result of a paradoxical reaction in HIV patients. This paradoxical reaction presumably develops as a consequence of reconstitution of immune response. Histopathologically, these EBLs demonstrate an intense granulomatous inflammatory reaction, unlike the poor inflammatory response seen in pulmonary MAC without endobronchial involvement. The EBL in our case was an incidental finding and was not suspected prior to the bronchoscopy. A high clinical suspicion and further evaluation of pulmonary disease with fiberoptic bronchoscopy may help further define these issues. Treatment for MAC pulmonary disease consists of a prolonged course of combination therapy with a newer-generation macrolide, ethambutol, and either rifampin or rifabutin.CONCLUSIONS: Endobronchial involvement and SPNs are uncommon manifestations of infections with MAC in the HIV population and have been rarely reported as a consequence of immune reconstitution. Our patient’s presentation of MAC is unique because he presented with a new SPN (with an incidental finding of EBL) after initiation of antiretroviral therapy with evidence of increasing numbers of CD4 cell count. Therefore, MAC should be considered in the differential diagnosis of HIV patients with immune reconstitution syndrome presenting as pulmonary nodules and endobronchial lesions.
M.I. Restrepo, None.