Chest radiography for predicting the cause of febrile illness among inpatients in Moshi, Tanzania

Abstract

Aim: To describe chest radiographic abnormalities and assess their usefulness for predicting causes of fever in a resource-limited setting.

Materials and methods: Febrile patients were enrolled in Moshi, Tanzania, and chest radiographs were evaluated by radiologists in Tanzania and the United States. Radiologists were blinded to the results of extensive laboratory evaluations to determine the cause of fever.

Results: Of 870 febrile patients, 515 (59.2%) had a chest radiograph available; including 268 (66.5%) of the adolescents and adults, the remainder were infants and children. One hundred and nineteen (44.4%) adults and 51 (20.6%) children were human immunodeficiency virus (HIV)-infected. Among adults, radiographic abnormalities were present in 139 (51.9%), including 77 (28.7%) with homogeneous and heterogeneous lung opacities, 26 (9.7%) with lung nodules, 25 (9.3%) with pleural effusion, 23 (8.6%) with cardiomegaly, and 13 (4.9%) with lymphadenopathy. Among children, radiographic abnormalities were present in 87 (35.2%), including 76 (30.8%) with homogeneous and heterogeneous lung opacities and six (2.4%) with lymphadenopathy. Among adolescents and adults, the presence of opacities was predictive of Streptococcus pneumoniae and Coxiella burnetii, whereas the presence of pulmonary nodules was predictive of Histoplasma capsulatum and Cryptococcus neoformans.

Conclusions: Chest radiograph abnormalities among febrile inpatients are common in northern Tanzania. Chest radiography is a useful adjunct for establishing an aetiologic diagnosis of febrile illness and may provide useful information for patient management, in particular for pneumococcal disease, Q fever, and fungal infections.

Figure 1

Radiographic appearance of pulmonary nodules with (a) H. capsulatum. Coned-down view of the right lower lung demonstrates uniform sized (1–2 mm in diameter) nodules, a miliary pattern, that was seen bilaterally in this patient with histoplasmosis. Again this is a pattern that is not unexpected with disseminated fungal infection (or occasionally tuberculosis). (b) C. neoformans. Anteroposterior chest film reveals several distinct bilateral lung nodules. The margins are discreet and in some cases well defined. The sizes range from approximately 1–1.5 cm in diameter. These larger nodules (as compared to the disseminated examples of histoplasmosis) have been described in patients with wide-spread pulmonary cryptococcosis.

Figure 2

Radiographic appearance of lung opacities with (a) C. burnetii. Mildly cropped anteroposterior film demonstrates coarse right perihilar and lower lobe linear and reticular heterogeneous opacities. Less well visualized are fine-medium left mid-lung reticular and small nodular opacities. (b) S. pneumoniae. Minimally croppedanteroposterior chest film demonstrates both homogeneous and heterogeneous opacities in the right lower lobe. Centrally the opacity is more uniform or homogeneous, whereas peripherally the pneumonia is more a combination of linear and reticular opacities or heterogeneous. This example was also typical of the type of abnormality seen on chest radiographs in patients with bacterial pneumonia, (e.g., S. pneumoniae).