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Neurology India, Vol. 59, No. 5, September-October, 2011, pp. 779-782 Letter to Editor Nocardial brain abscess in an immunocompetent individual Akshay Patil1, Ajith Cherian2, Thomas Iype2, P Sandeep2 1 Department of Neurosurgery, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India PMID: 22019679 Cerebral nocardiosis is uncommon, accounting for only 2% of all cerebral abscesses. [1] Nocardia asteroides , is responsible for up to 86% of nocardial infections. [2] Cerebral nocardiosis is associated with significant morbidity and mortality (34%), highest with brain abscess. Nocardiosis is often an opportunistic infection in an immunocompromised individual. We report a case of brain abscess due to Nocardia brasiliensis in an immunocompetent individual, which required repeated surgeries. A 53-year-old male, with no preceding medical illness, presented with complaints of headache, visual disturbances, and generalized seizures of 3 months' duration. Examination showed bilateral papilledema and left homonymous hemianopia. Brain imaging with contrast computed tomography (CT) and contrast magnetic resonance imaging (MRI) revealed a 2.5 × 2.2 × 2.1-cm ring-enhancing lesion in the right occipital area, with significant perilesional edema [Figure - 1]a-f. CT of chest and abdomen revealed a fibrotic band lesion in the apical segment of the left lung [Figure - 1]h. The patient underwent right parieto-occipital craniotomy and abscess excision[Figure - 1]g. Pus showed gram-positive bacilli with faint AFB staining, while culture grew N brasiliensis , sensitive to linezolid, trimethoprim/sulfamethoxazole (TMP/SMZ), imipenem, rifampin, and fluoroquinolone. The patient was initially followed up on linezolid, but 4 months later he presented with headache. Evaluation with contrast MRI showed a recurrent thick-walled right occipital abscess with a small epidural collection [Figure - 2] a-f. He underwent re-exploration, and the lesion was excised in toto. Histopathology showed acute exacerbation of chronic inflammation. The patient has now completed 9 months of follow-up after the second surgery. He was on two anticonvulsants, TMP/SMZ, and rifampin when he developed TMP/SMZ-induced leukopenia that required drug withdrawal. Follow-up imaging showed no recurrence [Figure - 3] a-c. At present, the patient has residual hemianopia but is otherwise symptom free. Nocardia spp. infection is acquired by inhalation of airborne bacteria from environmental sources and the lung is the commonest site of initial infection. [3] From India reports are scanty, possibly as a result of underreporting and lack of awareness. [4],[5] The hallmark of nocardial lesions is abscess formation, and in the central nervous system (CNS) these lesions often mimic brain tumors. [6] Hematogenous dissemination from either the primary pulmonary or cutaneous infection can result in disease in virtually any part of the body, but the brain and soft tissues are most commonly affected. Unlike primary pulmonary and cutaneous infections, which may be self-limiting, lesions of disseminated nocardiosis progress unless treated. [7] On CT scan, a nocardial lesion is evident as a hypodense area that is predominantly supratentorial (in 57% of cases). [1] The abscess usually consists of a multiloculated structure resulting from coalescence of multiple daughter abscesses. Nocardiosis should be considered as a differential diagnosis if brain abscesses heal less rapidly or less completely than expected with standard empiric therapy. Excision of the abscess and antibiotic therapy results in rapid improvement and successful resolution of symptoms. Aspiration of the abscess, in combination with antibiotic therapy, may be tried as the first approach in immunosuppressed patients if poor wound healing is of concern. Patients may often require more than one surgical intervention for complete removal, as in our patient. The reported mortality in CNS nocardiosis varies, being 24% in patients treated with craniotomy and excision and 50% in patients treated with aspiration alone. Our patient is unique in that he was an immunocompetent individual and the species isolated was N brasiliensis , an extremely uncommon organism even in Central and South America, which are endemic for nocardiosis. In patients with multiloculated ring-enhancing lesions, nocardiosis should be suspected even in nonendemic regions. References
Copyright 2011 - Neurology India The following images related to this document are available:Photo images[ni11239f3.jpg] [ni11239f2.jpg] [ni11239f1.jpg] |
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