Indian Pediatrics 1998; 35:887-890 

Tuberculous Meningitis in Early Infancy

Tuberculous meningitis (TBM) may develop 6 months to 1 year after primary infection, most cases occuring in 9 months to 3 years of age(1-3). Although, youngest reported case of TBM was 3^1/2 months old in these series, TBM is rare before 6 month of age(2). BCG vaccination in newborn confers valuable protection and prevents hematogenous dissemination and development of TBM to the extent of 60-80%(3-6). Since immunity following vaccination takes about 8-10 weeks to develop, exposure to tubercle bacilli during this interval can cause disseminated infection(7). The present descriptive study was done over two years from 1995 to 1996 to study the clinical profile of cases developing TBM in first 6 months of life. Thirteen cases in age group of 3 month to 6 month constituted the study material.

Subjects and Methods

Cases with TBM below six month of age were included in the study. Six cases were enrolled prospectively. Data was collected about clinical features, history of contact with tuberculosis case, BCG vaccination along with BCG scar mark. Cases were diagnosed on the basis of: (i) clinical features; (ii) X-ray picture suggestive of tuberculosis; (iii) Mantoux test; (iv) Cere-brospinal fluid (CSF) showing pleocytosis and protein level more than 0.4 g/L; (v) CT scan or, ultrasound skull showing ventricular enlargement and/or basal exudates; (vi) Isolation of acid fast bacilli by Ziehl-Neelsen staining and culture of gastric aspirate and CSF. TBM cases were classified into three stages according to the British Medical Council Classification(7). Malnutrition was classified according to the Indian Academy of Pediatrics Classification.

Confirmed TBM cases were put on four drug antitubercular treatment (INH, Rifampicin, Pyrazinamide; Streptomycin or Ethambutol) for two months followed by INH and Rifampicin for 10 months. Prednisolone 2 mg/kg/day was given for one month and then gradually tapered. In cases having seizures, phenobarbitone was used along with diazepam as and when needed. Nutrition and fluid requirement were taken care of by intravenous maintenance fluid and nasogastric feeding. In cases of raised intracranial tension mannitoI, acetazolamide ,or glycerol were used. After management of acute stage the cases were discharged and were followed up in the Neurotuberculosis Clinic of the hospital.

Results

A total 973 cases of tuberculosis were admitted during 2 years period from January 1995 to December 1996. Out of these, 509 cases (52.3%) were diagnosed to have TBM. Thirteen cases (12 male, 1 female) of TBM (2.55%) were below the age of six months. The distribution of cases in various age group was as follows: (i) 3 months - 1 case; (ii) 4 months - 4 cases; (iii) 5 months- 5 cases and (iv) 6 months - 3 cases. Two cases were in Stage 1, eight in Stage 2 and three in Stage 3. Moderate to severe malnutrition was present in 54% of these cases. The duration of symptoms varied between 1 day to 2 months (mean-14.9 days, median 10 days); however 8 cases (61.5%) had a short duration of less than 10 days. Four children had a history of contact. Five children had received BCG vaccination at birth. Out of these five cases, two and three cases were in Stages 2 and 3, respectively. The Clinical features are summarized in Table 1.

All cases below 4 months of age had hepatosplenomegaly along with features of TBM, showing disseminated form of tuberculosis. In eight cases beyond 4 months of age only two cases had disseminated tuberculosis. Seven cases (54%) had altered sensorium and eight cases (62%) had various types of neurological deficits.


 

Results of various investigations for confirmation of diagnosis and studying the extent of disease are summarized in Table II. Isolation of the mycobacterium from gastric aspirate or CSF was not possible in. any of the case. Diagnosis was based on CSF suggestive of TBM (10 cases) or CT scan (7 cases)/ultrasound skull (5 cases) showing hydrocephalus and basal exudates. Three cases with normal CSF had basal meningitis on CT scan. Chest radiograph showed a positivity of 77% with miliary tuberculosis (4 cases), tubercular bronchopneumonia (4 cases), pleural effusion (1 case) and consolidation (1 case).

All 13 cases showed initial improvement and were discharged from the hospital. The hospital mortality of older children with TBM was 19%. Since most of the cases were from distant places, only 6 cases reported for follow up. These 6 cases showed neurological improvement and weight gain when last seen during six month of follow up.

Discussion

In developing countries, tuberculosis still continues to be a major health problem, most of the mortality being due to TBM and disseminated forms of tuberculosis. Occurrence of TBM in infancy is regarded as an indicator of prevalence of pulmonary form of tuberculosis in community with high morbidity and mortality(8). Usually recognized as a disease of later part of infancy and toddler years, stray cases of TBM younger than 6 months have been reported in the literature(2,3). In our hospital, infants younger than 6 months accounted for 2.55% of total TBM cases, as compared to 3.8% reported from Bombay almost 3 decades ago in the same age group(9).



 

BCG vaccinatipn in newborn prevents hematogenous infection and serious forms of tuberculosis(4-6). In this series, five cases developed TBM despite BCG vaccination at birth which raises doubts about its efficacy in preventing hematogenous infection. However, due to the small sample size, definite conclusions can not be drawn about efficacy of BCG vaccine. In one prospective study, 35% patients developed TBM despite BCG vaccination which also raised similar doubts(10).

Positive chest radiographs are not usually encountered in most of the cases. In earlier series, 36% cases had positive chest radiographs(11). In our series, Chest radio- graph suggestive of tuberculosis in 77% cases and presence of hepatomegaly andl or splenomegaly in nearly half of the cases suggests that these cases had disseminated form of tuberculosis. This was more true of infants in 3 and 4 months age group.

The clinical presentation of 5 of these cases was in conformity with the usually described clinical features of TBM(7). In the remaining 8 cases, the duration of symptoms was 10 days or less. The younger infants reported by earlier workers also had 2 and 3 weeks duration of symptoms(2,3). A shorter duration of illness may make the diagnosis even more difficult. None of the cases had history of active tuberculosis in mother and they did not manifest features during the neonatal period. It seems likely that infection was acquired post- natally(12,13).

Follow up of most of the subjects could not be done, hence the total outcome of these cases is difficult to comment upon. However the fact that compared to 19% overall hospital mortality of TBM cases, none of these cases died is encouraging. Early diagnosis with the help of suggestive CSF, CT scan, ultrasound skull, chest radio- graph and prompt institution of four drug antitubercular chemotherapy might have contributed to a favorable outcome.

To conclude, TBM can occur as early as 3 month of age. A high degree of suspicion, CSF examination, CT scan and ultrasound help in diagnosis. Younger children have milliary or disseminated form of tuberculosis. Cases can develop TBM at an early age despite neonatal BCG vaccination. Complications depend upon stage of presentation. With early and prompt therapy, outcome is favorable even in the younger age group.

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