Teaching Case

A 34-year-old male patient was referred to the emergency department for a cough with expectoration, dyspnoea, fever, anorexia and weight loss (8kg) for one month. At physical examination he had white lesions in the oral cavity. He referred a personal history of unprotected sex.

Chest X-ray showed bilateral ground-glass opacities and a right basal consolidation (Fig. 1a, 1b). A chest CT was also performed. It revealed multiple bilateral ground-glass opacities with central distribution and a consolidation in the right middle lobe (RML)(Fig. 2a-2b). There was also a smooth septal thickening in the right lower lobe (RLL) (not shown). No pleural effusion was observed.

A laboratory and serological test were performed. The patient was HIV-positive. The leukocyte count was 3, 300 (CD4: 16 cells / mm3). In the bronchoalveolar lavage fluid pneumocystis jirovecii (PCJ) was identified. In the oropharyngeal exudate, candida was isolated too. Finally, the patient was diagnosed with pneumocystis jirovecii pneumonia (PJP), HIV primo-infection, and oral candidiasis.

Subacute pneumonia is a key diagnostic clue between two main aetiologies: tuberculosis and PJP. PJP is the most frequent opportunistic infection in HIV-positive patients. It usually develops when CD4< 200 cells/mm3 [1]. The characteristic findings in the chest X-Ray are nonspecific: tenuous opacities with central predominance, a reticular or nodular pattern [2]. In addition, one-third of infected patients may have a normal chest X-Ray [1]. CT is more sensitive to detect the disease. Features include ground-glass opacities predominantly involving perihilar or middle zones of the lung, reticular opacities or septal thickening and pulmonary cysts of varying shape and size. Cysts are associated with an increase of pneumothorax risk. [1, 2]. Pleural effusion and lymphadenopathies are rare.
In our case, the diagnosis was suspected with the combination of chest X-Ray findings, the subacute presentation, the presence of sexual risk behaviour and the oral lesions. All of them, make us suspect the possibility of PJP as a first presentation of a HIV infection. Otherwise, the differential diagnosis of ground glass opacities of the lung is broad and highly nonspecific; thus, taht is why a clinical scenario is essential to narrow the diagnosis. In fact, hypersensitive pneumonitis is probably the most common cause in isolated ground glass opacities of the lung in normal hosts [3].
Ground glass opacification disorders can be split into 4 categories: diffuse pneumonias, chronic interstitial diseases, acute alveolar diseases; and other unusual disorders like drug toxicity or pulmonary alveolar proteinosis [3].
Our case is included in the group of immunocompromised patients (HIV +, transplanted patients or patients with high-dose corticosteroid treatment). In this scenario, opportunistic infections should be considered as the first diagnostic option. PJP remains the most common opportunistic infection in this population. Other possibilities could be cytomegalovirus or herpes simplex virus pneumonias. Imaging findings of cytomegalovirus include ground glass opacities predominantly and in some cases micronodules and consolidations. This is why PCJ and CMV pneumonias often have similar imaging findings and cannot be distinguished radiologically [3].
Herpes simplex virus pneumonia may appear as ground glass opacities or/and widespread consolidations. Rarely, only ground glass opacities will be present. Small pleural effusions are common [3].
Treatment of choice of PCP is trimethoprim-sulfamethoxazole [1]. The same agent may be used as prophylaxis.
Prognosis of PCP in HIV patients is good with a 10% mortality rate. However, PCP has an ominous prognosis in non-HIV patients, with a 30–60 % mortality rate [3].