Comparison of HRCT Features of Pneumocystis Jiroveci Pneumonia in Patients With and Without HIV

Abstract

Background: Pneumocystis jiroveci (carinii) pneumonia (PJP) is one of the most common opportunistic infections in immunocompromised patients, especially in patients with human immunodeficiency virus (HIV). High resolution computed tomography (HRCT) is more sensitive for diagnosis of PJP in patients with normal or equivocal chest X-ray. Bilateral ground glass opacities (GGOs) are the most common findings in HRCT. Administration of prophylactic antibiotic against PJP and possibility of co-infections in HIV patients may lead to atypical radiologic presentations of PJP in these patients. Some studies have shown that radiologic manifestations of PJP may be altered in HIV/AIDS patients, and possibility of encountering atypical presentations is higher. Different immune reactions to the parasite P. jirovecii in immunocompromised patients with and without HIV may result in a different time lag between symptoms and correspondingly different radiographic patterns. Objectives: The aim of this study was to compare the HRCT features of PJP in patients with and without HIV. Patients and Methods: Forty-eight consecutive patients (mean age 38.11 years; 83.7% male) with proven PJP (by lung biopsy or bronchoalveolar lavage) were enrolled to our study. Patients with co-infections (including two cytomegalovirus and three tuberculosis cases) were excluded. Twenty-seven patients (62.8%) were HIV positive and 16 (37.2%) were HIV negative. All but one of HIV negative patients had an immunocompromised condition such as immunoglobulin deficiency (n=2), malignancy (n=3), organ transplant (n = 9), or on glucocorticoids (n = 2). All chest HRCT images (Siemens Somatom Emotion, Germany) were reviewed by two expert pulmonary radiologists. The radiologists were not aware of the patients HIV status. Consequently, HRCT findings were compared between HIV+ and HIV- patients using the Chi square and Fischer exact tests. P values less than 0.05 were considered significant. Results: There was substantial interobserver agreement between two radiologists (Kappa = 0.8). Bilateral GGO was the most common HRCT manifestation of PJP in both HIV+ and HIV- patients; there was no statistically significant difference between the two groups (90% vs. 75%; P > 0.05). Most of GGOs in both groups had symmetric diffuse pattern. Centrilobular nodular opacities were the second most common HRCT manifestation of both HIV+ and HIV- patients without significant difference between the two groups(55.6% vs. 37.5%; P > 0.05). Reticulation and septal thickening in HIV+ group was significantly higher than HIV- group (44.4% vs. 12.5%; P = 0.03). There was no cavitary lesion in the HIV+ group, while 18.8% of the HIV- patients had cavitary lesion (P = 0.02). Conclusions: Bilateral diffuse GGO is the most common HRCT manifestation of PJP in both HIV+ and HIV- patients. Septal thickening and reticular opacities are more commonly seen in PJP in HIV+ patients than in HIV- patients. Cavitary lesions as a manifestation of PJP are more common in HIV- patients.