Background: Miliary coccidioidomycosis indicates hematogenous or lymphatic spread of Coccidioides immitis and is characterized by the development of multiple small granulomas throughout the lungs and other organs. Previous reports have suggested that this disorder occurs almost exclusively in immunocompromised patients, with most patients succumbing to progressive respiratory failure. In this article, we describe the largest series of immunocompetent patients with miliary coccidioidomycosis, define clinical characteristics, and outline important aspects of diagnosis and treatment.
Materials and methods: We identified eight patients (five men and three women; age range, 23 to 65 years) with miliary coccidioidomycosis diagnosed at Kern Medical Center (located in an endemic area) from 1990 to 1997. Four of the patients were white, two were African American, and two were Hispanic. A miliary pattern was defined as the presence of discrete 2- to 10-mm lesions diffusely distributed throughout both lung fields, as shown on chest radiograph. Microscopic examination and culture of C immitis from sputum, tissue, or body fluid confirmed diagnosis. Patients with HIV were excluded.
Results: These patients constituted approximately 1% of those admitted to our institution for coccidioidomycosis from 1990 to 1997. Four patients had symptoms for < or = 1 week before admission (acute), and four had symptoms for between 5 and 12 weeks (chronic). Four patients demonstrated a miliary pattern on initial chest radiograph, and two of these patients received an initial diagnosis of miliary coccidioidomycosis. Five patients required mechanical ventilation. Arterial blood gas measurements revealed a mean PO(2) of 54.2 +/- 8. 6 mm Hg and a mean PCO(2) of 32.5 +/- 3.2 mm Hg. Five patients developed ARDS. Five patients had extrapulmonary involvement, with the meninges (n = 4) and skin (n = 4) being the most common sites. All patients were treated with fluconazole and/or amphotericin B. Three patients died; all had chronic involvement and received mechanical ventilation.
Conclusion: We present eight immunocompetent patients with a lower mortality rate and better outcome than previously reported. In our series, miliary coccidioidomycosis manifested as either an acute respiratory illness or an advanced stage of a chronic illness occurring in the context of widespread dissemination. All who died had chronic involvement. Prompt recognition of miliary coccidioidomycosis is crucial, but may be hindered by the large differential diagnosis. Important diagnostic factors include a history of travel through endemic areas, ethnicity, immunologic status, involvement of multiple organ sites, and pronounced hypoxemia not accounted for by the degree of pulmonary involvement seen on chest radiograph.