Background: Pulmonary tuberculosis (TB), bacterial pneumonia (BP) and Pneumocystis pneumonia (PCP), account for the major causes of pneumonia-like syndromes seen in HIV-AIDS patients and have overlapping clinical and chest x-ray findings pausing challenge to early diagnosis and treatment in Africa. The accuracy of chest x-ray (CXR) interpretations, inter-observer agreement, degree of chest x-ray overlapping, and distinguishing features among these common lung infections was assessed at Tĩkur Anbessa hospital, a tertiary care referral hospital in Addis Ababa, Ethiopia.
Patients and methods: chest x-rays were independently assessed by two radiologists blinded to the clinical between March 2004 and July 2005, the radiographic presentation of 131 smear-negative, HIV-positive patients with atypical laboratory data.
Results: One hundred and twenty-four definite diagnoses were made in 107 (82%) of the 131 patients and PCP, BP and pulmonary TB combined accounted for 92% of the diagnoses. The chest x-ray interpretation had high sensitivity (88%), negative predictive value (NPV) (90%), and inter-observer agreement (84%) for PCP Thirty-six percent of the infections mimicked one another, of which BP accounted for the major share. BP mimicked PCP and pulmonary TB in 39% and 20% respectively. Diffuse and bilateral alveolar infiltrates (DBAI) and acinar CXR features discriminated between PCP, pulmonary TB and BP (P < 0.05) while Diffuse bilateral fine interstitial infiltrates (DBFI) did not (p > 0.05). The level of agreement between the radiologists was 79%. There was no exclusively distinguishing radiographic feature amongst the three diseases.
Conclusions: Overlapping clinical and radiographic features often occurs as is co-existing infections in HIV-AIDS patients with respiratory symptoms. Therefore, definitive microbiological method should be the main tool to expedite early diagnosis and treatment in HIV-infected patients with respiratory symptoms.