Pulmonary Nocardiosis: Risk Factors, Clinical Features, Diagnosis and Prognosis

Raquel Martínez; Soledad Reyes; Rosario Menéndez

Disclosures

Curr Opin Pulm Med. 2008;14(3):219-227. 

In This Article

Clinical Features

Important clinical features of Nocardia infection include diverse clinical and radiographic presentations; ability of the organism to disseminate to virtually any organ especially the central nervous system (CNS) (about 33% of patients); and tendency to relapse or remain nonresponsive despite appropriate therapy. Pulmonary nocardiosis manifests as an acute, subacute or chronic infection with a marked tendency towards remissions and exacerbations. There is often necrotizing pneumonia, commonly associated with cavitation, or as a slowly enlarging pulmonary nodule or infiltrate, often with an associated empyema. In our study,[31*] the most commonly found symptoms included fever (74%), cough (77%), expectoration (65%), dyspnea (65%), chest pain (39%), constitutional symptoms (42%) and, to a lesser degree, hemoptysis and abdominal pain. In patients with pulmonary nocardiosis, the frequency of dyspnea and leukocytosis was higher. When the dissemination involved the CNS (in our study, there were three patients, 10%), the following neurological symptoms were found: headache, vomiting, disorientation, cognitive impairment and decreased level of consciousness (in two cases, the symptoms of dissemination to the CNS were the first to appear).

The median time to diagnosis was 42 days, increasing to 45 days in cases with dissemination to other organs, and 55 days in those with dissemination to the CNS. In another review[28*] of a large number of patients (22 cases) with nocardial infections, of which 17 had pulmonary nocardiosis, the mean time to diagnosis was 32 days.

The reported radiographic appearance of pulmonary nocardiosis has historically been varied and nonspecific. In a retrospective study of 10 patients who developed pulmonary nocardiosis after lung transplantation, on chest radiography, Husain et al.[39] observed lobar consolidation in 40% and pulmonary nodules with a reticulonodular pattern of interstitial disease in 20%. Interestingly, none of the patients demonstrated cavitary lesions. In another recent retrospective study[29*] on pulmonary nocardiosis in lung transplanted patients, computed tomography(CT) findings in seven patients were reviewed. The findings consisted primarily of nodules and cavitary lesions without any significant zonal or anatomic distribution. In our study,[31*] the most common radiographic pattern was the alveolar pattern [22 cases (70%)], followed by lung nodules or masses in eight cases (27%), an interstitial pattern in one case, and an interstitial-alveolar pattern in another. Ten patients showed cavitations (32%), five of whom had disseminated nocardiosis, (Figs 1 and 2a,b). There were 11 cases of pleural effusion (36%), although in four of them, the effusion was visible by computed axial tomography only.

Figure 1.

Chest radiograph

Figure 2.

Brain abscess

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