[Central nervous tuberculosis in patients non-VIH: seven case reports]

PURPOSE

Tuberculosis involving the central nervous system (CNS) is rarely observed in non immuno-compromised hosts. We report herin the various clinical, biological and radiological manifestations observed in 7 patients with CNS tuberculosis.

METHODS

Clinical and biological records of 7 patients with CNS tuberculosis were retrospectively studied. All patients had encephalic CT-scan and MRI in the course of the disease.

RESULTS

5 women and 2 men with a mean age of 38.4 years initially initially presented with headache (n = 6), fever (n = 5), meningeal irritation (n = 3), localizing neurological signs (n = 1). Lumbar punction revealed lymphocytic meningitis (n = 6/7). Mycobacterium tuberculosis or bovis was isolated in 3 patients only. Cerebral tomodensitography or magnetic resonance imaging were initially normal in most of cases (n = 4/7), but discovered in the course of disease basilar meningitis (n = 6), hydrocephalus (n = 6), abcess or tuberculoma (n = 4). In all the patients, initiation of the treatment was complicated by clinical and/or biological deterioration, called paradoxal reaction, leading in all cases to glucocorticoid adjunction, with various final results. Indeed, 4 patients developed neurological sequelae. No patient died.

CONCLUSION

CNS tuberculosis is a rare disease in non immunocompromised patients whose diagnostic may be difficult due to the absence of specific clinical symptoms, negative initial radiological examination, as well as delayed and often negative bacterial isolation. Paradoxal reaction appeared to be frequent despite specific antibiotherapy and underlines the beneficial effects of addictive corticosteroids.

[Tuberculous meningoencephalitis--own observations]

Nine cases of the tuberculous meningoencephalitis in adult men and women treated in years 1993-2000 have been presented. The diagnosis was established on the basis of clinical picture and examination of the cerebrospinal fluid (CSF). Routine analysis of CSF was done, as well as the microscopic examination, biological assay, and culture on the Lowenstein-Jensena medium and using Bactec 460 TB system. Only in one case Mycobacterium tuberculosis was found in the smear of CSF stained by Ziehl-Nielsen method. In one case the biologic assay was positive and Mycobacterium tuberculosis was cultured on Lowenstein-Jensen medium. In another 4 cases the pathogen was detected by Bactec 460 TB technique. In 4 cases Mycobacterium tuberculosis was also cultured from the secretion of the respiratory tract, and in one patient urine. On chest X-ray characteristic changes for pulmonary tuberculosis were observed in 5 cases (56%). Seven patients (78%) had hydrocephalus detected on CT scan of the head. One patient died, one (11%) developed persistent complication in form of spastic paralysis of lower extremities and sphincters dysfunction. Seven patients (78%) recovered completely after the 12 months therapy with standard chemotherapeutic regimen for tuberculosis.

Polymerase chain reaction for the rapid diagnosis of tuberculous meningitis

(i)

AIM OF THE STUDY

The study was carried out with the aim to evaluate a polymerase chain reaction (PCR) based on the amplication of a 169 bp DNA fragment specific for the Mycobacterium tuberculosis complex for the rapid diagnosis of tuberculous meningitis (TBM). (ii)

METHODOLOGY

A total of 105 CSF specimens from clinically suspected cases of TBM were studied. Clinical details of the cases and cytochemical parameters of the CSF specimens were recorded. In addition to the 105 specimens, 10 CSF specimens from cases other than TBM, 4 non-mycobacterial culture isolates (1 strain of E. coli, 1 strain of Proteus species and 2 strains of Salmonella species) and 1 sample of sterile distilled water were processed as negative controls. For positive control standard culture of Mycobacterium tuberculosis H37Rv was processed with every batch of specimens. Besides PCR, smear for AFB by the Ziehl Neelsen Carbol Fuchsin (ZNCF) and the fluoro chrome method and culture on LJ medium was also carried out. (iii)

RESULTS

By PCR, 31.42% specimens were found positive, whereas by conventional culture on LJ medium only 3.8% specimens were positive. Only 1.9% specimens were found to be smear positive by the fluorochrome staining method, while none was positive by the ZNCF method. The PCR results showed complete correlation with the clinical findings of the patients. (iv)

CONCLUSION

The PCR was found to be superior to the currently available techniques for the diagnosis of tuberculous meningitis in terms of sensitivity, specificity and rapidity and could play a critical role in the diagnosis of suspected cases.

Rapid diagnosis of tuberculous meningitis by ligase chain reaction amplification

A total of 87 cerebrospinal fluid (CSF) samples obtained from 85 patients with suspected meningitis were examined for the presence of Mycobacterium tuberculosis by means of ligase chain reaction amplification (LCx; Abbott Laboratories). The results were compared with direct smear and culture results. Of 61 patients with pathological CSF, 9 (14.8%) were scheduled to receive treatment for tuberculous meningitis. The sensitivity of the smear and culture tests was 11.1 and 33.3%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value of the LCx assay were 55.5, 100, 100 and 92.9%, respectively. The results reveal that amplification by ligase chain reaction is valuable for the diagnosis of tuberculous meningitis.

Long-term follow up of childhood tuberculous meningitis

The purpose of the present study was to determine the long-term outcome of 76 children (40 females and 36 males) diagnosed and treated with modern antituberculosis drugs. The median age of the children on admission was 29.5 months and on follow-up 9 years. Antituberculosis therapy consisted of daily isoniazid (20 mg/kg), rifampicin (20 mg/kg), ethionamide (20 mg/kg), and pyrazinamide (40 mg/kg) for 6 months. Twenty-three children received daily prednisone (2-4 mg/kg) for the first month of treatment. Raised intracranial pressure was actively monitored and treated. Patients with non-communicating hydrocephalus received ventriculo-peritoneal shunts shortly after admission while communicating hydrocephalus was treated with oral acetazolamide (100 mg/kg/day) and furosemide (1 mg/kg/day) in 3-4 divided doses. Communicating hydrocephalus that did not respond to this regimen within the first month of treatment also underwent ventriculo-peritoneal shunting. Only 20% of children were functionally completely normal at follow-up. Main areas of functional deficit were cognitive impairment (80%), poor scholastic progress (43%), and emotional disturbance (40%). Twenty-five per cent of children had evidence of motor impairment, but all could walk and only 5 of 76 children (6% of total) were unable to run. One child was blind but no child had sensori-neural deafness. It was concluded that these disabilities in children from mainly deprived socioeconomic backgrounds have serious implications for their future social, academic, and career prospects. A high index of suspicion of TBM in high tuberculosis incidence communities will help prevent the morbidity documented in this study.

Use of IMiD3, a thalidomide analog, as an adjunct to therapy for experimental tuberculous meningitis

Tuberculous meningitis (TBM), the most severe form of Mycobacterium tuberculosis infection in humans, is associated with significant morbidity and mortality despite successful treatment with antituberculous drugs. This is due to the irreversible brain damage subsequent to the local inflammatory response of the host to M. tuberculosis. Corticosteroids have been used in conjunction with antituberculous therapy in an attempt to modulate the inflammatory response, but this strategy has been of limited success. Therefore, we examined whether combining antituberculous drugs with the immunomodulatory drug thalidomide or with a new thalidomide analog, immunomodulatory drug 3 (IMiD3), would be effective in reducing morbidity and mortality in an experimental rabbit model of TBM. Intracisternal inoculation of 5 x 10(4) CFU of Mycobacterium bovis Ravenel in rabbits induced progressive subacute meningitis characterized by high cerebrospinal fluid (CSF) leukocytosis, protein influx, release of tumor necrosis factor (TNF), substantial meningeal inflammation, and mortality by day 28. Treatment with antituberculous drugs or with antituberculous drugs plus thalidomide improved the clinical course of disease somewhat and increased survival to about 50%. In contrast, treatment with antituberculous drugs in combination with IMiD3 limited pathological neurologic changes and resulted in marked improvement (73%) in survival. IMiD3 treatment was also associated with reduced leukocytosis in the CSF and significantly lower levels of TNF in CSF and plasma. Histologically, the meningeal inflammation in animals treated with antituberculous drugs plus IMiD3 was considerably attenuated compared to that of the other treatment groups. These results suggest a potential role for IMiD3 in the management of TBM in patients.

[Actual clinical and immunological problems of neurosyphilis and neurotuberculosis]

In the past neurosyphilis and tuberculosis of the nervous system were the basic clinical problems in neurology. The decrease of the incidence rate has changed the situation. However, in the last few years, especially in connection with HIV infection, the incidence has even started to increase. In Poland the epidemiological situation is not alarming, but there exists some concern connected with the epidemic of syphilis and tuberculosis in countries near the Polish eastern border. In the laboratory diagnosis of syphilis the highest specificity and sensitivity has the TPHA test. In the therapy till now the best results are obtained with megadoses of penicillin. Early diagnosis of tuberculous meningitis, what is the decisive factor for positive results of the treatment can be obtained by PCR technique for detection of DNA genome of mycobacterium. In the treatment the method of choice is the concomitant use of four antimycobacterial drugs. However, there exists the serious problem of often observed drug resistance of mycobacterium.

Evaluation of integral membrane antigens of Mycobacterium habana for serodiagnosis of extrapulmonary tuberculosis: association between levels of antibodies and Mycobacterium tuberculosis antigens

The performance of integral membrane antigens (IMAs) of Mycobacterium habana TMC 5135 in detecting antimycobacterial antibodies in serum and body fluids of patients mainly of extrapulmonary tuberculosis was evaluated. The IMAs were recovered from the detergent phase during Triton X-114 treatment of the plasma membrane of M. habana. Antimycobacterial antibodies were detected by ELISA using IMAs in serum and body fluids of 42 patients and 62 control subjects. As authentic adjunct Mycobacterium tuberculosis antigens were also detected (by ELISA) in body fluids and circulating immune complexes using anti-M. tuberculosis H37Ra antibodies. Anti-M. habana IMA antibody detection increased the positivity rate from 26.% (11/42) and 10% (4/42) obtained by culture and smear microscopy, respectively, to 86% (36/42). M. tuberculosis antigens were also found in 29 out of 36 anti-M. habana IMA antibody-positive cases. Interestingly, all 11 culture-positive cases were also positive for anti-M. habana IMA antibodies. The mean antigen titres in 23 cases, positive for antigens in body fluids, were 2.34 times higher in those who were also positive for anti-IMA antibodies in serum than in those negative for these antibodies. M. habana IMAs may be promising non-tubercular candidate antigens in ELISA-based serodiagnosis of extrapulmonary tuberculosis with substantial sensitivity, specificity and safety.

Assessment of antibody responses to antigens of Mycobacterium tuberculosis and Cysticercus cellulosae in cerebrospinal fluid of chronic meningitis patients for definitive diagnosis as TBM/NCC by passive hemagglutination and immunoblot assays

Tanned sheep erythrocytes stabilized with pyruvic aldehyde and glutaraldehyde, called double-aldehyde-stabilized cells, were used to standardize passive hemagglutination assay (PHA) for detection of antibody responses to sonicate extract of Mycobacterium tuberculosis and Cysticercus cellulosae soluble antigens. PHA was performed in the following groups of cerebrospinal fluid (CSF) samples: group I - chronic infections of the central nervous system with the possible diagnosis of tuberculous meningitis (TBM), tuberculoma and neurocysticercosis (NCC) (n=88), and group II - controls which included (a) non-infectious non-neurological conditions (n=30), (b) infectious neurological conditions (n=21) and (c) non-infectious neurological conditions (n=133). PHA could detect anti-mycobacterial antibodies at the sensitivity level of 80.76% with a specificity of 92.4% and anti-cysticercal antibodies with a sensitivity of 100% and specificity of 92.94%. However, in 6.33% (i.e. 14/221) of group I and group II (c) CSFs both anti-mycobacterial and anti-cysticercal antibodies were detected. Immunoblot analysis of CSFs derived from TBM patients reacted predominantly to 120-kDa, 96-kDa, 65-kDa, 38-kDa, 26-kDa, 23-kDa, 19-kDa and 12-14-kDa and 4-6-kDa antigens of M. tuberculosis sonicate extract (MTSE), whilst CSFs of proven NCC reacted to >110-kDa, 96-kDa, 80-kDa, 66-68-kDa, 52-kDa and 26-28-kDa antigens of porcine whole cyst sonicate extract (PCSE). On immunoblot analysis, some of the CSFs of TBM patients were PHA positive for both MTSE and PCSE showed antibody reactivity to 70-kDa and 10-kDa antigens of C. cellulosae. Similarly CSF antibody of some Guillain Barre syndrome and myeloradiculopathy patients reacted with cysticercal antigens. But per se no cross-reactivity between MTSE and anti-cysticercal antibodies and vice-versa were observed. However, findings of this study should alert laboratory personnel especially in endemic areas to be extra careful in interpretation of antibody detection results.

[A case of disseminated tuberculosis requiring extended period for the identification of Mycobacterium tuberculosis on culture]

A 80-year-old male visited an outpatient department of a nearby hospital complaining of fever, cough, and poor appetite on June 2000. The patient was diagnosed as bacterial pneumonia and was treated with antibiotics although specific cause could not be identified. After one month, he was hospitalized due to lack of improvement. After admission, acid-fast bacilli (AFB) was found from the bronchial washing. The patient was then transferred to our hospital. Upon admission, sputum smear examination was positive for AFB and MTB was confirmed by PCR. Therapy was initiated with INH 300 mg, RFP 450 mg, EB 1000 mg, and PZA 1000 mg, orally daily. However, on the day following the admission, he became unconscious. Brain MRI showed several small granulomas on the cortex of the bilateral anterior and temporal brain. Although AFB was not detected from the cerebrospinal fluid, tuberculous meningitis was suspected and steroid was given. Nine days after admission, the patient died due to tuberculous meningitis. The isolation of MTB had been attempted on Ogawa culture medium using patient's sputum and liquor, and it took 14 weeks to find colony growth both from sputum and liquor. In the autopsy, numerous granulomas were detected in his lung, liver, kidney, and pancreas. These findings indicate that disseminated growth of MTB occurred in vivo in spite of very slow growth of MTB in vitro.

A comparative evaluation of dot immunobinding assay (Dot-Iba) and polymerase chain reaction (PCR) for the laboratory diagnosis of tuberculous meningitis

The results of a Dot immunobinding assay (Dot Iba) for the detection of mycobacterial antigen in the cerebrospinal fluid (CSF) of 45 patients with tuberculous meningitis (TBM) were compared with the results of a polymerase chain reaction (PCR) for the detection of Mycobacterium tuberculosis. In eight patients with culture proven TBM, Dot-Iba gave positive results, while PCR yielded positive results only in six patients. The overall sensitivities of Dot-Iba and PCR in 37 patients with culture negative (probable) TBM were 75.67% and 40.5% respectively. Dot-Iba, in contrast to PCR is a rapid and relatively easier method. More importantly, Dot-Iba is suitable for the routine application for the laboratory diagnosis of TBM and therefore best suited to laboratories in the developing world.

Bacterial pathogens and outcome determinants of childhood pyogenic meningitis in Ilorin, Nigeria

Empirical antimicrobial therapy remainsjustifiable in childhood pyogenic meningitis (CPM), but the continuing efficacy in a particular setting requires periodic microbiological surveillance. It was this need that informed the present five-year retrospective study of consecutive admissions for CPM at the Emergency Paediatric Unit (EPU) of the University of Ilorin Teaching Hospital, Ilorin, Nigeria. Of the 71 cerebro-spinal fluid [CSF] analyses, 41 (57.6%) were Gram-smear positive (GSP). Gram-positive cocci (GPC) were identified in 23 (56.1%) smears, while 14 (34.2.%) had Gram-negative bacilli (GNB). Only three (7.3%) had Gram-negative diplococci (GND). Despite corroborative biochemical findings, the remaining 30 (42.3%), including two with tuberculous meningitis proved smear-negative. GPC cases had a mean age of 4.49 +/- 5.3yrs, GNB, 3.06 +/- 4.8yrs and GND, 4.47 +/- 4.9yrs. CSF isolates were made in 28 (39.4%) cases. Streptococcus pneumoniae accounted for a predominant 22 (78.6%) (P = 0.00), Haemophilus influenzae for 2 (7.1%), and Neisseria meningitidis for only 1 (3.5%) case. Whereas Strept. pneumoniae and H. influenzae isolates were uniformly sensitive to each of sultamicillin, cefuroxime, ceftriaxone and ceftazidime, 7.7% of Strept. pneumoniae were resistant to crystalline penicillin, 6.7% to ampicillin, and 69.2% to chloramphenicol; one of the two H. influenzae isolates was chloramphenicol-resistant. Amongst the 30 (42.3%) fatal cases, the length of stay was significantly shorter in GNB-positive cases (P = 0.045). Mortality was significantly higher amongst cases with purulent/turbid CSF at admission (P = 0.03), and in those with CSF protein of >150mg/dl (P = 0.02) and glucose <1mg/dl (P = 0.047). The present aetiological preponderance of GPC and Strept. pneumoniae in our study population, the high case-fatality, and the emerging resistance profile suggest the need for exploring additional control options including vaccination. We emphasize the need for periodic auditing of local antimicrobial policies in CPM.

Tuberculous meningoencephalitis in HIV-seronegative patients: variety of clinical presentation and impact on diagnostics and treatment

Tuberculous meningoencephalitis (TBM), an infrequent disease in Western European countries, shows a wide heterogeneity of clinical symptoms.

MATERIAL AND METHODS

We present 4 patients (age range 42-72 years) with the definite diagnosis of isolated TBM. All patients were HIV-seronegative, only 1 patient was known to be immunoincompetent on admission due to acute myelocytic leukemia; other reasons for immune suppression were detected in 2 other patients (leukemia and idiopathic CD4+ T-lymphocytopenia, respectively).

RESULTS

The diagnosis of TBM was confirmed in 3 cases by culture from CSF, in 1 case Mycobacterium tuberculosis was proven only in tracheal aspirate. In 1 patient M. bovis was found, which is an extremely rare cause of TBM in Germany. We report the contributions of different diagnostic tools (CSF analysis, neuroimaging) in reaching the presumptive diagnosis and in monitoring the further course. All patients developed neurological complications despite prompt tuberculostatic treatment. Three of the patients presented a chronic severe loss of consciousness of unclear origin.

CONCLUSION

The possible causative relationships of these complications and their impact on the prognosis are discussed.

[Pathology of tuberculosis meningitis in adults (autopsy findings)]

An analysis was performed of 112 protocols of autopsies of those adult subjects having died of generalized tuberculosis presenting with tuberculous meningitis over the last 50 years. A significant pathomorphism of tuberculosis of meninges and central nervous system was found out to have taken place over that period of time. Over the last decade, reversion of generalized tuberculosis has been noted together with an increase in the incidence of tuberculous meningitis and younger age of those patients who die of grave forms of the specific process.

[Influence of specimen processing method on Mycobacterium tuberculosis detection by PCR-reversed dot hybridization]

OBJECTIVE

To evaluate specimen processing with sodium dodecyl (lauryl) sulfate (SDS) on the detection of Mycobacterium tuberculosis by PCR-reversed dot hybridization.

METHODS

Totally 266 specimens were collected from sputum, pleural fluid, ascites, urine or blood of patients with active tuberculosis and were treated with SDS or routine method. All specimens handled were tested for detecting M. tuberculosis by PCR-reversed dot hybridization.

RESULTS

The detection rate of M. tuberculosis from specimens prepared by SDS method was 65.0% (173/266) as compared with 51.5% (136/168) by routine method. Results from two methods were considered statistically significant (chi(2) = 35.03, P < 0.001).

CONCLUSION

The SDS processing method may be used to detect M. tuberculosis from clinical specimens by PCR and enhances the detection rate of M. tuberculosis.

Evaluation of PCR using TRC(4) and IS6110 primers in detection of tuberculous meningitis

We have evaluated a new set of primers (TRC(4)) in comparison with the IS6110 primers commonly used in PCR to detect tuberculous meningitis among children. The levels of concordance between the results of IS6110 PCR and TRC(4) PCR with cerebrospinal fluid specimens from patients with clinically confirmed tuberculous meningitis were 80 and 86%, respectively. Results with the two primer sets were concordant for 55 positive and 22 negative specimens (n = 98). We conclude that the sensitivity of PCR can be increased by using both IS6110 and TRC(4) primers.

Identification of a matrix-degrading phenotype in human tuberculosis in vitro and in vivo

Tuberculous meningitis is characterized by cerebral tissue destruction. Monocytes, pivotal in immune responses to Mycobacterium tuberculosis, secrete matrix metalloproteinase-9 (MMP-9), which facilitates leukocyte migration across the blood-brain barrier, but may cause cerebral injury. In vitro, human monocytic (THP-1) cells infected by live, virulent M. tuberculosis secreted MMP-9 in a dose-dependent manner. At 24 h, MMP-9 concentrations increased 10-fold to 239 +/- 75 ng/ml (p = 0.001 vs controls). MMP-9 mRNA became detectable at 24--48 h. In contrast, tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) gene expression and secretion were similar to constitutive levels from controls at 24 h and increased just 5-fold by 48 h. In vivo investigation revealed MMP-9 concentration per leukocyte in cerebrospinal fluid (CSF) from tuberculous meningitis patients (n = 23; median (range), 3.19 (0.19--31.00) ng/ml/cell) to be higher than that in bacterial (n = 12; 0.23 (0.01--18.37) ng/ml/cell) or viral meningitis (n = 20; 0.20 (0.04--31.00) ng/ml/cell; p < 0.01). TIMP-1, which was constitutively secreted into CSF, was not elevated in tuberculous compared with bacterial meningitis or controls. Thus, a phenotype in which MMP-9 activity is relatively unrestricted by TIMP-1 developed both in vitro and in vivo. This is functionally significant, since MMP-9 concentrations per CSF leukocyte (but not TIMP-1 concentrations) were elevated in fatal tuberculous meningitis and in patients with signs of cerebral tissue damage (unconsciousness, confusion, or neurological deficit; p < 0.05). However, MMP-9 activity was unrelated to the severity of systemic illness. In summary, M. tuberculosis-infected monocytic cells develop a matrix-degrading phenotype, which was observed in vivo and relates to clinical signs reflecting cerebral injury in tuberculous meningitis.

Mycobacterium tuberculosis meningitis and other etiologies of the aseptic meningitis syndrome

Mycobacterium tuberculosis is one of the most common infectious agents in the world. It causes an insidious form of meningitis characterized by headache, low-grade fever, stiff neck and cranial nerve palsies, and an acute meningoencephalitis characterized by coma, raised intracranial pressure, seizures, and focal neurological deficits. This review focuses on the diagnosis and therapy of the insidious form of tuberculous meningitis and discusses the differential diagnosis of infectious and noninfectious etiologies of the aseptic meningitis syndrome.

[How I investigate...difficult cases of tuberculous meningitis]

To formally document the presence of the bacillus of Koch in meninges still remains difficult and depends on many variables. We report two cases where the diagnosis proved difficult. The presentation of tuberculous meningitis can take several aspects. Mantoux reaction is frequently negative. The BK cultures, which demonstrate the diagnosis, depend on the volume of CSF and on the importance of BK dissemination. It, unfortunately, remains difficult to make the diagnosis of tuberculous meningitis even though this pathology can have extremely deleterious consequences.

Novel treatment of meningitis caused by multidrug-resistant Mycobacterium tuberculosis with intrathecal levofloxacin and amikacin: case report

We report the case of a 25-year-old HIV-negative man with disseminated multidrug-resistant tuberculosis (MDRTB), who-on a retreatment regimen-experienced total resolution of TB miliary disease, but progressive TB meningitis. Therefore, intrathecal treatment with amikacin and levofloxacin was instituted, with successful clinical and microbiological results.

Role of IS6110-targeted PCR, culture, biochemical, clinical, and immunological criteria for diagnosis of tuberculous meningitis

An open prospective clinical, microbiological, and molecular analysis of a national molecular diagnostic service for tuberculous meningitis (TBM) using an in-house IS6110-targeted PCR for molecular "Fastrack" diagnosis was carried out. Between April 1997 and June 1998. Consecutive cerebrospinal fluid (CSF) samples from 131 patients were assessed. Against a culture on the same sample, PCR had a sensitivity of 75% and a specificity of 94%. Of samples from patients classified as definite or probable TBM cases based on clinical criteria, 81% had raised CSF protein levels and 73% had a lymphocytosis, although 57% of all submitted samples showed a raised lymphocyte count. While only 46% had a CSF glucose level below the normal range, the CSF glucose level was significantly lower (P = 0. 0281) than in cases of meningitis of other etiologies. Levels of tumor necrosis factor alpha were also found to be significantly raised in definite or probable TBM cases (P = 0.028), while adenosine deaminase levels were not. The study showed IS6110-targeted PCR to be a rapid, sensitive, and specific test in routine use for the diagnosis of TBM.

Tuberculous meningitis in children: clinical features and outcome in 40 cases

In order to assess the epidemiology, clinical features and outcome of tuberculous meningitis, a retrospective review of patients was conducted between January 1989 and December 1995. Forty cases (representing 10%, of all paediatric patients with tuberculosis) were included. Mean age was 46 months (range 1-165 months). Eighteen (45%) children were classified as stage I (non-specific febrile illness without neurological signs), 16 (40%) as stage II (neurological signs without marked changes in sensorium) and 6 (15%) as stage III (major neurological signs with sensorial changes and/or coma). Twenty-seven (67%) patients had received BCG vaccination and 14 (35%) displayed an induration zone higher than 10 mm after a 2-TU PPD test. Mycobacterium tuberculosis was recovered from 24 (61%) patients. Hydrocephalus was demonstrated by cranial computed tomography in 31 (78%) children. Overall, 18 (45%) children had a full recovery. Mild, moderate and severe neurological sequelae were shown by 7 (18%), 3 (8%) and 9 (22%) of the patients, respectively. Three fatal cases (7%) were observed. The presence of seizures (RR 15.6, 2.02-119.1) and absence of extrameningeal foci (RR 4.95, 1.10-22.1) were identified as risk factors by multivariate analysis. These findings emphasize the need quickly to diagnose tuberculosis in children in order to give appropriate and early treatment.

Limits of detection of Mycobacterium tuberculosis in spiked cerebrospinal fluid using the polymerase chain reaction in tuberculous meningitis

The limit of detection of Mycobacterium tuberculosis in spiked cerebrospinal fluid (CSF) using polymerase chain reaction (PCR) was compared to that of a radiometric liquid culture. Serial dilutions of clinical isolates of Mycobacterium tuberculosis were prepared in CSF (n=3) or broth (n=11) with estimated concentrations of 0-550 cfu/ml. Each dilution was examined concurrently by PCR and radiometric culture. PCR and radiometric culture detected Mycobacterium tuberculosis DNA in all dilutions with an estimated 2 cfu/ml in the CSF. At lower concentrations (estimated <2 cfu/ml), PCR and radiometric culture were positive in three of five (60%) and five of five (100%) CSF samples, respectively. In comparison to PCR in broth dilutions, no evidence of inhibition or interference was noted. These results imply that PCR can provide a rapid and reliable diagnosis of tuberculous meningitis, although there is a potential for false-negative results to occur in samples containing very few organisms ( < 2 cfu/ml).

Rapid diagnosis of tuberculous meningitis by a dot immunobinding assay To detect mycobacterial antigen in cerebrospinal fluid specimens

In the present prospective study, a dot immunobinding assay (Dot-Iba) was standardized to measure the circulating mycobacterial antigen in cerebrospinal fluid (CSF) specimens for the laboratory diagnosis of tuberculous meningitis (TBM). Immunoglobulin G antibody specific for Mycobacterium tuberculosis in a CSF specimen from a patient with culture-proven TBM was isolated and was coupled with activated cyanogen bromide-Sepharose 4B. By immunosorbent affinity chromatography, a 14-kDa antigen was isolated from the culture filtrate of M. tuberculosis. Antibody to the 14-kDa mycobacterial antigen was raised in rabbits. The Dot-Iba in this study gave no false-positive results with CSF specimens from patients with nontuberculous neurological diseases. The assay gave positive results for all five patients with culture-proven TBM. The Dot-Iba described in the present report is simple, rapid, sensitive, specific, and, more importantly, suitable for routine application in laboratories in developing countries.