OBJECTIVETo improve the differential diagnosis of tuberculous meningitis (TBM) and reduced potential misdiagnosis of TBM.

METHODSThe clinical data of 47 misdiagnosed cases of TBM between January, 1994 and June, 2009 were investigated retrospectively. The clinical presentations and causes for the misdiagnoses were analyzed.

RESULTSThe 47 patients with misdiagnosed TBM included 28 male and 19 female patients with a mean age of 36.84∓16.41 years. Eight patients had an acute onset, 10 had a subacute onset, and 29 had chronic disease. The initial symptoms, in the descending order of their frequencies, included fever and headache (87.2%), anergia and dyskinesia (27.7%), cerebral nerve damage (23.4%), decreased level of consciousness (14.9%), and urinary and fecal incontinence (2%). Meningeal irritation was present in 25 cases and positive Babinksi sign was found in 19 cases. Elevated intracranial pressure occurred in 51.1% of the cases, and 16 cases showed papilloedema. Non-purulent CSF with elevated protein was found in 86.7%, decreased glucose in 50%, and decreased chlorinate in 53.3% of the cases. Eight out of 23 cases showed a positive result of PPD test. MRI identified abnormitis with meningeal enhancement in 15 cases, hydrocephalus in 7 cases and infarction in 14 cases. Tuberculoma was found in 2 cases, and spinal cord lesions were found 4 cases. All the patients received anti-tuberculosis therapy, which resulted in symptomatic improvement in 39 cases, fluctuated condition in 2 cases; 5 patients discontinued the treatment and 1 died.

CONCLUSIONEarly TBM often presents with atypical features and its differential diagnosis can be difficult. CSF monitoring and careful inspection of the radiographic data can be helpful in the diagnosis of suspected cases, for which early anti-TB treatment is an important means to reduce misdiagnosis.