Pulmonary infections in HIV/AIDS patients,
constitute a major cause of morbidity and mortality.
Pneumocystis jirovecii pneumonia (PJP) is the most common opportunistic,
life- threatening,
pulmonary infection in HIV/AIDS population.
Patients with <200 cells/mm are more susceptible to this infection. Pneumocystis jirovecii is a unicellular organism classified as a atypical fungus but behaves as a protozoan and is composed of small cysts which produce intracystic sporozoites.
Clinical findings are often subtle and non- specific,
the most common of which are dyspnea and non-productive cough.
Diagnosis is based on analysis of specimens acquired from sputum or bronchoalveolar lavage.
Monoclonal antibodies are also available in detecting PJ.
High resolution CT,
on the other hand,
may aid in the evaluation of these patients with suspected pneumonia and normal chest radiographic findings.
It is therefore important that the radiologists familiarizes themselves with the typical and atypical imaging manifestations of PJP in order to make a prompt and accurate diagnosis,
even if the patient is unaware of their HIV serostatus.
Differential diagnosis in general includes:
- Mycobacterium tuberculosis
- Viral pneumonitis (CMV): Cysts absent
- Angioinvasive aspergillosis
- Immune reconstitution inflammatory syndrome (IRIS): when under HAART medication
Differential diagnosis for cystic pattern:
- Langerhans cell histiocytosis
- Lymphangioleiomyomatosis (LAM)
- Cystic bronchiectasis
- Honeycombing
Differential diagnosis for reticulonodular pattern:
- Sarcoidosis
- Granulomatosis with polyangitis (Wegener granulomatosis)
- Sarcoma Kaposi
- Hypersensitivity pneumonitis
- Pneumoconiosis
Differential diagnosis for nodular pattern:
- TB
- Fungal infection
- Neoplastic conditions: sarcoma Kaposi,
Lymphoma
Differential diagnosis in case of a solitary mass:
- Lymphoma
- Bronchogenic carcinoma
Differential diagnosis when associated with bronchiolitis:
- Bacterial infection
- Fungal infection
Differential diagnosis when accompanied by lymphadenopathy:
- TB
- Fungal infection
- Lymphoma
- Sarcoma Kaposi
Differential diagnosis when pleural effusion is present:
- Tb
- Bacterial infection
- Neoplastic entities: Lymphoma,
Kaposi sarcoma