Usefulness of cranial and chest imaging in the diagnosis of tuberculous meningitis among infants and young children

We retrospectively evaluated the clinical and laboratory data of children with tuberculous meningitis (TBM) treated at our hospital from 1990 to 1999 to determine the optimal method of diagnosing TBM. The evaluated diagnostic criteria for TBM were as follows: (1) fever and malaise as symptoms of acute/subacute inflammation, (2) positive cerebrospinal fluid and/or gastric aspirate cultures for Mycobacterium tuberculosis, (3) pleocytosis of cerebrospinal fluid, and (4) a good response to anti-tuberculous therapy. The data for eleven patients (6 boys, 5 girls) with TBM (mean age, 10.7 months) were reviewed. Three patients (27%) were previously vaccinated with BCG. A known contact with tuberculosis was established at the time of admission in four patients (36%). Symptoms related to tuberculosis appeared on the average 14.8 days before the diagnosis. Three patients (27%) were diagnosed as clinical stage I, three (27%) as stage II, and five (46%) as stage III; all patients had fever (100%). With regard to the cerebrospinal fluid examinations, pleocytosis with mononuclear predominance was noted in all patients but one (91%), and mycobacterial staining was positive in three patients (27%). Tuberculin skin test was positive in four out of 10 patients (40%). Mycobacterial staining of gastric aspirate was positive in four patients (36%). Chest radiological examinations showed a swelling of the mediastinal lymphonodes and/or parenchymal infiltration in all patients (100%). A cranial CT examination demonstrated a basal meningeal enhancement in all patients (100%), hydrocephalus in nine patients (82%), and infarction in eight patients (73%). These results suggest that chest and cranial CT examinations are useful adjunct methods for diagnosis of TBM in infants and young children suffering from meningitis with pleocytosis of the cerebrospinal fluid and mononuclear predominance, in addition to conventional methods such as the tuberculin skin test, plain chest radiography, and staining for mycobacteria in body fluids.