Transcranial Doppler ultrasonography in tuberculous meningitis: A systematic review.

BACKGROUND AND PURPOSE: Tuberculous (TB) meningitis is a common type of central nervous system infection, and may cause multifocal cerebral infarctions due to the involvement of cerebral vasculature. This systematic review aims to review and synthesize the utility of transcranial Doppler (TCD) in TB meningitis.

METHODS: This is a systematic review of observational studies on the use of TCD in patients diagnosed to have TB meningitis. Study outcomes included changes in TCD parameters during stages of TB meningitis, frequency of neurologic complications (such as hydrocephalus, vasculopathy, and cerebral infarction), correlation of TCD findings with neuroimaging, and functional outcomes.

RESULTS: Five studies were included with a total of 141 participants, with ages from 4 months to 75 years. The most common neurologic complication was hydrocephalus (87.1%), cerebral infarction (29.2%), and arterial stenosis (26.3%). There was increased mean flow velocity (MFV) most commonly in the middle cerebral artery in the early stage of TB meningitis, and decreased MFV in the advanced disease stage. TCD findings of stenosis were well correlated with CT or MR angiogram. Among patients with hydrocephalus, pulsatility indices were significantly decreased after ventriculoperitoneal shunting.

CONCLUSIONS: A considerable proportion of patients with TB meningitis develop cerebral hemodynamic disturbances which lead to cerebral ischemia and affect clinical outcomes. TCD is a reliable tool for the diagnosis of vasculopathy and increased intracranial pressure and can thus help monitor disease progression and treatment response. Future studies with larger populations and longer follow-ups are recommended to determine the association of TCD findings with functional outcomes.