Specific clinical manifestations of Nocardia: A case report and literature review

Abstract

Nocardiosis is a rare bacterial infection of either the lungs (pulmonary) or body (systemic) that usually affects immunocompromised individuals. It is caused by Gram-positive, aerobic actinomycetes of the Nocardia genus. Multiple high-density sheet shadows in both lungs along with nodules or cavities are the most common presentations of nocardiosis, whereas a large pulmonary mass is considered to be rare. However, there is no specificity in the clinical manifestation of the disease. Therefore, isolation and identification of Nocardia strains is the only reliable diagnostic method. The present study describes the cases of two male patients of Asian descent with nocardiosis. Chest computed tomography scans showed a suspected tumor mass in both patients. Microscopic analysis and culturing of tissue samples obtained using a bronchoscope detected the presence of Nocardia wallacei. Neither patient showed signs of immunosuppression. The present study aimed to improve the understanding of lung nocardiosis and demonstrated that pulmonary nocardiosis should be suspected in the case of non-immunocompromised patients with a large mass in the lung. Furthermore, a review of the literature on infection with Nocardia was conducted.

Keywords: clinical manifestation; nocardia; opportunistic infection; pulmonary nocardiosis.

Figure 1.

Chest computed tomography scan (July 4th, 2011) of case 1 showed a shadow of effusion and consolidation in the upper right lung.

Figure 2.

Chest computed tomography scan (July 15th, 2011) of case 1 showed the sheet shadow in the upper right lung had enlarged and contained cavitation.

Figure 3.

Biopsy results for case 1 indicated epithelioid cell granuloma, small-foci infarction, and nuclear fragmentation in the tissue. (Hematoxylin staining; magnification, ×200).

Figure 4.

Chest computed tomography scan (August 4th, 2011) of case 1 showed progressive pneumonia and enlargement of the shadow of consolidation along with cavity formation.

Figure 5.

Chest computed tomography scan (August 15th, 2011) of case 1 showed the large mass in the upper right lung lobe had decreased with fewer cavities and pneumonia had improved.

Figure 6.

Chest computed tomography scan (September 9th, 2011) of case 2 showed the lesion in right lung had markedly decreased and the cavity disappeared.

Figure 7.

Chest computed tomography scan (June 25th, 2014) of case 2 showed central lesions in the upper right lung and middle lung mass with obstructive pneumonia. The lesions were considered to be malignant and had metastasized into the bilateral lungs. The scan showed cancerous lymphangitis, multiple lymph node metastasis, and a large amount of pleural effusion in the right lobe.

Figure 8.

Neck mass biopsy for case 2 showed inflammatory granuloma and abscesses showed inflammatory granuloma and abscesses. (Hematoxylin staining; magnification, ×200).

Figure 9.

Abdominal computed tomography enhanced scan (July 7th, 2014) of case 2 revealed multiple metastases in the right lobe of the liver.

Figure 10.

Chest computed tomography scan (July 9th, 2014) of case 2 showed the lesions in the upper and the middle right lung had markedly resorbed.