Tuberculous brain abscess: clinical presentation, pathophysiology and treatment (in children).

BACKGROUND: Tubercular brain abscess (TBA) is a rare manifestation of CNS tuberculosis. It is characterised by an encapsulated collection of pus, containing viable tubercular bacilli without evidence of tubercular granuloma. PRESENTATION AND HISTORY: Patients may present with features of raised intracranial pressure and focal neurological deficit commensurate with the site of the abscess. A history of pulmonary tuberculosis may be present, as documented in one of our six cases; three of our six children developed TBA despite 3-weeks to 12-month courses of antitubercular chemotherapy prescribed for post-TBM hydrocephalus.

DIAGNOSIS: Contrast CT head, MRI, MR spectroscopy is helpful in making the diagnosis and planning the treatment. TBA may be unilocular or multilocular on contrast CT scan. A relatively long clinical history and an enhancing capsule with thick wall are suggestive of TBA. Pyogenic abscess, however, has a thin rim on contrast CT. The capsule of TBA is formed of vascular granulation tissue containing acute and chronic inflammatory cells, particularly polymorphs. Proof of tubercular origin must be demonstrated either by presence of acid fast bacilli in culture or staining of pus or wall.

TREATMENT: Treatment options include simple puncture, continuous drainage, fractional drainage, repeated aspiration through a burr hole, stereotactic aspiration and total excision of the abscess. Total excision usually becomes necessary in multilocular noncommunicating and thick-walled abscesses. Antitubercular therapy is the mainstay of management. The development of fulminant tubercular meningitis is sometimes problematic following surgical excision of TBA, as seen in one of our four operated cases. Mortality is reported to be high despite progress in treatment, while five of the six children treated by us responded well to the treatment.