Central nervous system tuberculosis

Role of Adenosine Deaminase Estimation in Differentiation of Tuberculous and Non-tuberculous Exudative Pleural Effusions

BACKGROUND

Tuberculosis kills five lakh patients every year in India, commonest being pulmonary tuberculosis and is often associated with effusion. Delay in diagnosis and treatment results in poor prognosis. Several studies have suggested the role of adenosine deaminase (ADA) in the diagnosis of tuberculous pleural effusions, but false-positive results from lymphocytic effusions have also been reported. The purpose of this study is to find out the role of ADA levels in differentiation of tuberculous and non-tuberculous exudative pleural effusions of different etiologies.

METHODS

Ninety-six lymphocytic pleural fluid samples were consecutively selected and divided into two groups: tuberculous (n = 56) and non-tuberculous (n = 40), depending upon the etiology [Malignancy (n = 16), Infectious diseases (n = 18), Pulmonary embolism (n = 1), Collagen vascular diseases (n = 3) and Sarcoidosis (n = 2)]. ADA was estimated in pleural fluid in all the cases.

RESULTS

In all 56 samples, ADA level of tuberculous group was above diagnostic cut-off (40 U/L), while only one sample was above cut-off in non-tuberculous group (2.5%). The negative predictive value of ADA for the diagnosis of non-tuberculous etiology was 97.5% (39 of 40) lymphocytic pleural effusion patients.

CONCLUSIONS

In this study, ADA levels in nontuberculous exudative pleural effusions rarely exceeded the cut-off; set for tuberculous disease. The pleural fluid ADA levels were significantly higher in tuberculous exudative pleural effusions when compared with non-tuberculous exudative pleural effusions.

KEYWORDS

Adenosine deaminase; Tuberculous effusion; Pleural fluid; Exudative pleural effusions.

Utility of a novel lipoarabinomannan assay for the diagnosis of tuberculous meningitis in a resource-poor high-HIV prevalence setting

Background

In Africa, tuberculous meningitis (TBM) is an important opportunistic infection in HIV-positive patients. Current diagnostic tools for TBM perform sub-optimally. In particular, the rapid diagnosis of TBM is challenging because smear microscopy has a low yield and PCR is not widely available in resource-poor settings.

Methods

We evaluated the performance outcome of a novel standardized lipoarabinomannan (LAM) antigen-detection assay, using archived cerebrospinal fluid samples, in 50 African TBM suspects of whom 68% were HIV-positive.

Results

Of the 50 participants 14, 23 and 13 patients had definite, probable and non-TBM, respectively. In the non-TB group there were 5 HIV positive patients who were lost to follow-up and in whom concomitant infection with Mycobacterium tuberculosis could not be definitively excluded. The test sensitivities and specificities were as follows: LAM assay 64% and 69% (cut-point 0.22), smear microscopy 0% and 100% and PCR 93% and 77%, respectively.

Conclusion

In this preliminary proof-of-concept study, a rapid diagnosis of TBM could be achieved using LAM antigen detection. Although specificity was sub-optimal, the estimates provided here may be unreliable because of a classification bias inherent in the study design where it was not possible to exclude TBM in the presumed non-TBM cases owing to a lack of clinical follow-up. As PCR is largely unavailable, the LAM assay may well prove to be a useful adjunct for the rapid diagnosis of TBM in high HIV-incidence settings. These preliminary results justify further enquiry and prospective studies are now required to definitively establish the place of this technology for the diagnosis of TBM.

Immunologic paradox in the diagnosis of tuberculous meningitis

We report a patient with microbiologically documented tuberculous meningitis showing that the therapeutic paradox, a therapy-induced switch to a neutrophil-predominant situation in the differential cell counts of cerebrospinal fluid specimens, had a correlation with an immunologic paradox, an increased Mycobacterium tuberculosis-specific gamma interferon-producing T-cell response.

Choroidal Tubercles in Neurotuberculosis: Prevalence and Significance

PURPOSE

Neurotuberculosis is a relatively common form of tuberculosis and may be seen in 1-10% of patients of systemic tuberculosis and may present in several forms. Ocular lesions are frequently seen, most commonly optic nerve lesions. Limited data are available for choroidal tubercles. We conducted a prospective study 1) to determine the prevalence of choroidal tubercles in a cohort of patients of neurotuberculosis as well as its relative prevalence in the various morphological manifestations and 2) to study the role of co-existent systemic tuberculous infection.

METHODS

IRB-approved prospective cross-sectional observational study. A hospital-based cohort of patients underwent a detailed physical, laboratory and ocular evaluation.

RESULTS

A total of 52 (20 male, 32 female) patients were evaluated with tubercles being seen in 23 eyes (18 patients, 34.6%). Twenty four patients (46.12%, 16 female, 8 male) presented with intracranial granulomas and 28 (53.8%, 16 female, 12 male) presented with tuberculous meningitis. Tubercles were seen in 10 eyes of 8 (28.5%) patients with tuberculous meningitis and in 13 eyes of 10 patients (41.6%) with intracranial granulomas. This result is not statistically significant. Twenty seven patients (51.9%) had neurotuberculosis without systemic infection, whereas 25 (48.1%) patients had systemic foci. Tubercles were seen in 18 eyes (13 patients) with systemic foci and in 5 eyes (5 patients) of neurotuberculosis alone. The odds ratio for the presence of systemic tuberculosis when choroidal tubercles are present is 5.6 (95% confidence interval: 1.39-24.49, statistically significant [p = 0.005]).

CONCLUSIONS

Tubercles were equally likely to occur in either manifestation of neurotuberculosis, and their presence was related to the presence of systemic focus of tuberculous infection. The presence of choroidal tubercles may serve as a diagnostic marker for the presence of an underlying systemic infection.

Atypical cerebrospinal fluid profile in tuberculous meningitis

The aim of this study was to describe atypical cerebrospinal fluid (CSF) alterations in tuberculous meningitis (TBM) and to analyse the differences in outcome between patients with typical and atypical profiles. We did a retrospective study during the period of 2000 to 2005 including the cases of TBM assisted in a referral centre for infectious diseases in Rio de Janeiro State, Brazil. Neutrophilic plecytosis at the first spinal tap was found in 32.4% of TBM patients, who had a worse outcome when compared with those patients with typical CSF profiles. One factor that might have a major impact was the delay in starting empirical treatment (27.5 versus 11.6 days). We conclude that, in cases with clinical and epidemiological data compatible with TBM but with an atypical CSF profile, empirical treatment should be considered if CSF culture and direct examination for bacteria are negative.

Acute forms of tuberculosis in adults

Although typically considered a chronic disease, tuberculosis (TB) has protean acute manifestations, the major forms of which are reviewed in this article. The pathogenesis of acute TB, although still incompletely understood, may be related to both epidemiologic and genetic host factors. Miliary TB manifests as a nonspecific clinical syndrome with a high mortality rate. The most well-known form of acute TB is meningitis, characterized by fever, nuchal rigidity, and a lymphocytic pleocytosis of the cerebrospinal fluid. Acute abdominal TB may present with obstruction or less commonly as perforated viscus or peritonitis. Critically ill patients may have acute respiratory distress syndrome, shock, or disseminated intravascular coagulopathy. The spectrum of disease makes diagnosis of acute TB difficult unless clinical suspicion of disease is high, but the high mortality mandates its consideration. Early initiation of therapy is crucial to optimize clinical outcome.

Update in the diagnosis and management of central nervous system infections

Central nervous system (CNS) infections presenting to the emergency room include meningitis, encephalitis, brain and spinal epidural abscess, subdural empyema, and ventriculitis. These conditions often require admission to an intensive care unit (ICU) and are complications of ICU patients with neurologic injury, contributing significantly to morbidity and mortality. Reducing morbidity and mortality is critically dependent on rapid diagnosis and, perhaps more importantly, on the timely initiation of appropriate antimicrobial therapy. New insights into the role of inflammation and the immune response in CNS infections have contributed to development of new diagnostic strategies using markers of inflammation, and to the study of agents with focused immunomodulatory activity, which may lead to further adjunctive therapy in human disease.

Diagnosis of tuberculous meningitis: clinical and laboratory parameters

BACKGROUND

Confirming the clinical suspicion of tuberculous meningitis (TBM) has always been problematic. Whilst smear and culture positivity are diagnostic, these tests have low sensitivity. The polymerase chain reaction (PCR) assay has given variable results.

AIM

This study attempted to improve the diagnostic yield by: (a) increasing the cerebrospinal fluid (CSF) volumes; (b) testing the yield from three specimens of CSF assumed to represent lumbar, cervico-thoracic cord, and base of brain CSF samples; (c) undertaking PCR assays using multiple primer sets; and (d) using real-time PCR.

METHOD

Patients suspected of having cranial or spinal meningeal tuberculosis were entered into the study. Three aliquots of CSF were subjected to smear, culture, and conventional and real-time PCR. Three sets of primers - IS6110, MPB64, and PT8/9 - were used. Patients were retrospectively classified into four categories: 'definite TB' (culture positive), 'probable TB' (clinical and other tests suggestive of TB), 'not TB', and 'uncertain diagnosis'.

RESULTS

A total of 68 patients were studied. There were 20 patients classified as definite TB, 24 probable TB, 17 not TB, and seven uncertain diagnosis. Forty-eight of 57 (84.2%) patients tested were HIV seropositive. The IS6110 PCR was positive in 27 patients which included 18/20 culture positive cases, six in the probable TB group, and three in the not TB group. The MPB64 and PT8/9 primers did not increase the yield. Real-time PCR was positive in seven additional patients. Combining the definite and probable TB, the sensitivity of all PCR assays was 70.5% (31/44) and specificity 87.5% (21/24).

CONCLUSION

Targeting multiple sites of the TB genome using conventional PCR did not increase the number of positive cases. Real-time PCR was more sensitive. However, all the current techniques are still too insensitive to confidently exclude the diagnosis on laboratory grounds.

Biopsy-proven tuberculous meningitis mimicking CNS sarcoidosis

We report a 31-year-old man with tuberculous meningitis (TM) mimicking CNS sarcoidosis. Although Mycobacterium tuberculosis (MTB) was not detected in CSF, the level of adenosine deaminase (ADA) in CSF was significantly raised. Brain biopsy showed caseous granuloma and a diagnosis of TM was made. The diagnosis of TM is often difficult and brain biopsy should be considered if MTB is not detected in the CSF. Evaluation of CSF ADA level could also strongly contribute to distinguishing TM from other meningitis. In addition to antituberculosis drugs, corticosteroid therapy was effective in our patient but careful reduction of its dosage was required.

Rapid diagnosis of tuberculous meningitis: a comparative evaluation of in-house PCR assays involving three mycobacterial DNA sequences, IS6110, MPB-64 and 65 kDa antigen

A PCR was standardized for amplifying three different mycobacterial--IS6110, MPB-64, 65 kDa DNA sequences. A comparative evaluation of the three PCR assays was carried out for the rapid diagnosis of tuberculous meningitis (TBM) using cerebrospinal fluid (CSF) specimens. While the IS6110 PCR was a single-step amplification reaction, the MPB-64 and 65 kDa antigen PCR assays were nested reactions. A total of 176 cerebrospinal fluid (CSF) samples from 176 patients were subjected to amplification of the three different mycobacterial sequences. Amongst them, 45 samples were obtained from confirmed cases of TBM (culture positive) and 56 samples were obtained from clinically suspected cases of TBM which were culture-negative. The remaining 75 CSF samples were categorized under the non-infectious and infectious illness of the central nervous system (CNS). Against a gold standard of culture, a sensitivity of 98% (NPV=99%) and a specificity of 100% (PPV=100%) was observed with the IS6110 PCR. Among the nested PCRs, a sensitivity of 91% (NPV=94%) and a specificity of 91% (PPV=85%) was observed with the MPB-64 assay, while the 65 kDa protocol had an associated sensitivity of 51% (NPV=76%) and a specificity of 92% (PPV=79%). These findings suggest that among the nested PCR assays, the MPB-64 PCR assay was associated with an enhanced degree of sensitivity and was comparable in terms of specificity. Our study also demonstrates that the IS6110 assay, while being a single-step PCR had the advantage of being a rapid test for the diagnosis of TBM, with increased sensitivity and enhanced specificity as compared to the nested PCR protocols.

Neuroimaging of Tuberculous Myelitis: Analysis of Ten Cases and Review of Literature

We retrospectively reviewed the clinical and neuroimaging features of 10 patients with tuberculous myelitis. The most common presenting symptoms were fever (70%) and paraplegia (60%). Bladder and bowel symptoms were present in 90% patients. On MRI, the involvement of the cervical/thoracic segment of the spinal cord was most commonly seen (90%). The most consistent finding was hyperintense signals on T2-weighted MRI. T1-weighted images showed isointense (n= 5) and hypointense (n= 4) signals in the spinal cord lesions. Post-contrast enhancement was present in 6 patients, epidural enhancement in 4 patients, and cord swelling in 2 patients. We reviewed more than 250 published cases with the diagnosis of tuberculous myelitis and radiculomyelitis with special attention to MRI findings. It is predominantly a disease of the thoracic spinal cord. Most spinal cord lesions appear as hyperintense on T2 and iso- or hypointense on T1-weighted images. MRI findings in patients with spinal cord tuberculosis have both diagnostic and prognostic significance. Cord atrophy or cavitation and the presence of syrinx on MRI may be associated with poor outcome.

Subphrenic abscess and recurring focal lesions due to tuberculosis in a patient with IgA deficiency

Subdiaphragmatic abscess has not yet been reported as a manifestation of tuberculosis. We report an IgA deficient patient with recurrent episodes of unusual extrapulmonary manifestations of tuberculosis including subdiaphragmatic abscesses and metacarpophalangeal osteomyelitis that was improved each time with antituberculosis drugs. There was not any resistance to the drugs used against mycobacterium despite repeated courses of antituberculosis regimens. In such recurrent cases, one should rule out any immunodeficiency states.

Traitement des tuberculoses cérébro-méningées

INTRODUCTION

Tuberculous meningitis and brain tuberculomas are currently rare in the western world but remain serious. Improved outcome requires early recognition and treatment of these conditions.

STATE OF ART

Treatment is usually begun before diagnostic confirmation. Therapeutic principles are now better defined thanks to recent recommendations and studies. Antituberculous therapy begins with two months of a combination of four drugs: isoniazid, rifampicin, ethambutol and pyrazinamid. Then follows a longer phase of bitherapy with isoniazid and rifampicin, lasting at least four months but usually extended to seven or ten months as a precaution. Patients at risk of toxic neuropathy should receive pyridoxine supplementation. Corticosteroids must be systematically added during the first eight weeks of treatment, beginning with high dose before progressive tapering. Hyponatremia is common, often induced by emesis and cerebral salt wasting syndrome. Therefore saline supply rather than water restriction is required. Non-obstructive hydrocephaly can usually be managed with diuretic therapy including acetazolamid, sometimes complemented by serial lumbar punctures. Neurosurgical interventions are rarely needed. Monitoring of treatment tolerance and efficacy is mainly clinical. Central nervous system imaging and cerebro-spinal fluid analysis are only required to explain clinical deterioration.

CONCLUSION

With adequate and prompt anti-tuberculous, anti-inflammatory and supportive treatment, the prognosis of central nervous system tuberculosis can be greatly improved.

Clinical and radiological features of symptomatic central nervous system tuberculomas

Tuberculomas may present with meningitis, may lead to meningitis, or may develop during the treatment of TBM. In this study, we report a series of 22 adult cases of symptomatic central nervous system tuberculomas, in eight of them tuberculomas were coexisting with TBM on admission and in 14 of them symptomatic tuberculomas developed during anti-tuberculosis therapy. We also aimed to compare the clinical, laboratory and outcome data of the 14 TBM patients that developed symptomatic tuberculomas, with the data of 41 TBM that did not, under the same treatment regimen. Most of the patients developed symptomatic tuberculomas in the first 6 weeks of treatment. Five patients developed late tuberculomas. The characteristics of tuberculomas and the role of corticosteroids in TBM patients are discussed. In conclusion, although steroids may diminish neurologic symptoms and improve outcome, tuberculomas may appear during the course of anti-tuberculosis and steroid treatment. Because of the possibility of late development of tuberculomas after initial successful treatment, all TBM patients need to be followed-up carefully for a long period.

Treatment of neuro-ophthalmologic manifestations of tuberculosis

In the absence of obvious pulmonary or disseminated tuberculosis, ocular and central nervous system (CNS) tuberculosis may represent a significant diagnostic challenge. Refinements in polymerase chain reaction techniques and neuroimaging have strengthened the battery of tests used to diagnose CNS and ocular tuberculosis, yet in many cases, the diagnosis remains one of exclusion; it may ultimately be determined through exacerbation by anti-inflammatory therapy with subsequent improvement by antitubercular medication treatment. Because of emerging drug resistance, at least a two-drug regimen is required for therapeutic testing and treatment of isolated ocular tuberculosis. If pulmonary or miliary disease coexists, a 6-month, four-drug regimen with isoniazid, rifampin, pyrazinamide, and ethambutol is required for treatment. Tubercular meningitis is treated with the same four-drug regimen for at least 9 to 12 months. Burden of therapeutic compliance rests on the treating physician and public health sector. Best compliance is realized with directly observed therapy.

An infant with central nervous system complications of disseminated tuberculosis

A previously well, nine-month-old, Canadian-born, Caucasian infant presented with one month history of cough, irritability, and poor weight gain. Her past medical history was significant for open-heart surgery at age four months, with repair of a ventricular septal defect, closure of an atrial septal defect, and ligation of patent ductus arteriosus. There were no operative complications. Her development was normal for age. She had received her routine immunizations.There was no known infectious diseases contact or exposure to farm animals.

Encephalomyelitis following mumps

STUDY DESIGN

A case report with review of literature since 1961.

SETTING

Departments of Neurology and Radiology, Faculty of Medicine, Zonguldak Karaelmas University, Zonguldak, Turkey.

METHOD

A 22-year-old male patient diagnosed and treated as mumps encephalomyelitis is described. The clinical findings of the patient and the difficulties in differential diagnosis are discussed with the help of previously reported eight adult cases.

RESULTS

Increased T2 signals in the spinal cord from C4 to C6 and T5 to T10 were seen by magnetic resonance imaging. This was the largest spinal involvement in the reported mumps cases. He was treated with supportive therapy oral steroids and early rehabilitation. On the sixth month, his neurological examination revealed bilateral 2/5 paresis in lower extremities.

CONCLUSION

Encephalomyelitis following mumps is an uncommon but serious event in adults.

New Times for an Old Disease: Intracranial Mass Lesions Caused by Mycobacterium tuberculosis in 5 HIV-Negative African Immigrants

BACKGROUND

The tuberculosis epidemic is still a global emergency, and its spread in the past 20 years has been fueled by the acquired immune deficiency syndrome pandemic and increasing drug resistance. International travel and migration may increase the incidence of tuberculosis in industrialized countries.

METHODS

We reviewed the clinical charts of patients admitted to the infectious diseases unit of Ospedali Riuniti (Bergamo, Italy) to identify patients with intracranial mass lesions caused by Mycobacterium tuberculosis.

RESULTS

During the past 6.5 years, 5 of 30 patients with a mass of infectious origin in the brain had tuberculous brain lesions diagnosed. All 5 were human immunodeficiency virus (HIV)-negative adults and African immigrants. No patient had concomitant meningitis, 1 had a concomitant pulmonary disease, and 3 subjects reported a past history of tuberculosis. At presentation, no patient had fever and 3 had seizures. Examination of cerebrospinal fluid revealed normal findings for 4 of 4 subjects, and neuroimaging showed multiple intracranial mass lesions in 4 of 5 patients. The diagnosis was definite for 2 subjects (based on analysis of brain specimens) and presumptive for 3 subjects (1 had concomitant pulmonary tuberculosis, and 2 had clinical response to therapy). Results of susceptibility tests for M. tuberculosis were available for 2 patients: both isolates were resistant to isoniazid, and 1 was also resistant to streptomycin. Duration of medical treatment ranged from 11 to 23 months, and 2 subjects underwent surgical procedures at the time of diagnosis. All 5 patients recovered.

CONCLUSIONS

Clinicians in western countries should consider the possible role of tuberculosis in causing mass lesions in the brain, particularly in immigrants from regions where tuberculosis is endemic.

Adenosine deaminase levels in cerebrospinal fluid as a diagnostic test for tuberculous meningitis in children

Adenosine deaminase activity (ADA) was estimated in cerebrospinal fluid (CSF) of 30 patients of tuberculous meningitis (TBM) and 10 patients each of partially treated pyomeningitis (PTM), aseptic meningitis (AM) and pyogenic meningitis (PM). Mean ADA levels in CSF of TBM patients were higher (18.22 U/L) as compared to 6.28 U/L, 3.43 U/L and 7.98 U/L in PTM, AM and PM respectively. This difference of ADA values in CSF between TBM and other types of meningitis was statistically significant (p<0.01) different. Sensitivity and specificity of ADA levels in CSF of children to diagnose tuberculous meningitis was 66.6% and 90% respectively at 10 U/L cut off of ADA levels in CSF. ADA levels in CSF could also differentiate PTM, AM and PM from TBM with a specificity of 90%, 100% and 80% respectively.

Optic pathways tuberculoma mimicking glioma: case report

BACKGROUND

Optochiasmatic tuberculomas are very rare lesions. They can occur with concomitant tuberculous meningitis, and pulmonary tuberculosis or as the only manifestation of the disease. The authors present a case of optic pathways tuberculoma with radiologic appearance simulating an optic pathways glioma.

CASE DESCRIPTION

We report a case of a 20-year-old man with mental retardation due to anoxic encephalopathy who developed a sudden bilateral amaurosis. He also presented with diabetes insipidus, panhypopituitarism, right proptosis, and chemosis. Computed tomography (CT) and magnetic resonance imaging (MRI) showed an enhancing lesion in the optochiasmatic region extending to both optic nerves, with a mass in the right orbit, mimicking an optic pathways glioma. There was no other evidence of systemic involvement of the tuberculosis. The lesion was explored through a right pterional transylvian approach with opening of the optic canal and orbital roof, and a biopsy and an internal decompression were performed. Histopathological studies demonstrated a granulomatous lesion with central caseous necrosis with acid-fast bacilli. The patient improved after treatment with tuberculostatic drugs, but vision recovery could not be achieved.

CONCLUSIONS

Visual compromise in tuberculosis is associated with hydrocephalus, optical neuritis or tuberculomas involving the optic pathways. Reviewing the literature on tuberculomas of the optochiasmatic area, we could not find any other case with such extensive involvement of the optic pathways that was radiologically suggestive of an infiltrating glioma. Histopathological studies remain crucial in the diagnosis of intrinsic expansive processes of the optochiasmatic region.

A surgical revisitation of Pott distemper of the spine

BACKGROUND CONTEXT

Pott disease and tuberculosis have been with humans for countless millennia. Before the mid-twentieth century, the treatment of tuberculous spondylitis was primarily supportive and typically resulted in dismal neurological, functional and cosmetic outcomes. The contemporary development of effective antituberculous medications, imaging modalities, anesthesia, operative techniques and spinal instrumentation resulted in quantum improvements in the diagnosis, management and outcome of spinal tuberculosis. With the successful treatment of tuberculosis worldwide, interest in Pott disease has faded from the surgical forefront over the last 20 years. With the recent unchecked global pandemic of human immunodeficiency virus, the number of tuberculosis and secondary spondylitis cases is again increasing at an alarming rate. A surgical revisitation of Pott disease is thus essential to prepare spinal surgeons for this impending resurgence of tuberculosis.

PURPOSE

To revisit the numerous treatment modalities for Pott disease and their outcomes. From this information, a critical reappraisal of surgical nuances with regard to decision making, timing, operative approach, graft types and the use of instrumentation were conducted.

STUDY DESIGN

A concise review of the diagnosis, management and surgical treatment of Pott disease.

METHODS

A broad review of the literature was conducted with a particular focus on the different surgical treatment modalities for Pott disease and their outcomes regarding neurological deficit, kyphosis and spinal stability.

RESULTS

Whereas a variety of management schemes have been used for the debridement and reconstruction of tuberculous spondylitis, there has also been a spectrum of outcomes regarding neurological function and deformity. Medical treatment alone remains the cornerstone of therapy for the majority of Pott disease cases. Surgical intervention should be limited primarily to cases of severe or progressive deformity and/or neurological deficit. Based on the available evidence, radical ventral debridement and grafting appears to provide reproducibly good long-term neurological outcomes. Furthermore, recurrence of infection is lowest with such techniques. Posterior operative techniques are most effective in the reduction and prevention of spinal deformity.

CONCLUSIONS

Unlike historical times, effective medical and surgical management of tuberculous spondyitis is now possible. Proper selection of drug therapy and operative modalities, however, is needed to optimize functional outcomes for each individual case of Pott disease.

Characterization of Mycobacterium tuberculosis complex isolates from the cerebrospinal fluid of meningitis patients at six fever hospitals in Egypt

Mycobacterium tuberculosis complex isolates from cerebrospinal fluid of 67 meningitis patients were obtained from six fever hospitals in Egypt. One M. bovis and 66 M. tuberculosis isolates were identified by PCR-restriction fragment length polymorphism (RFLP) analysis of oxyR. Among the M. tuberculosis isolates, 53 unique strain types (with 3 to 16 copies of IS6110) were found by RFLP analyses. Nine clusters (eight with two isolates each and one with six isolates) were also found. Thirty-six spoligotypes, including at least 10 that have been previously reported from other countries, were also observed. Forty-one (62.1%) of the isolates were in spoligotype clusters, and 22 (33%) of the isolates were in RFLP clusters. Fifty-one of the isolates were susceptible in vitro to all of the antituberculosis drugs tested, 11 were monoresistant to capreomycin, rifampin, isoniazid (INH), pyrazinamide, or streptomycin (STR), 4 were resistant to STR and INH, and 1 was resistant to STR, INH, and ethambutol.

Tuberculosis Meningitis

Treatment of tuberculous meningitis should begin with an anti-tuberculous regimen of at least three drugs: isoniazid, pyrazinamide, and rifampin. Early in the course of therapy, ethambutol or streptomycin may be of some added benefit. If the local incidence of drug resistance to Mycobacterium tuberculosis is greater than 4%, or is unknown, then a fourth drug (ethambutol or streptomycin) should be added. If the patient is from an area with organisms resistant to multiple drugs, or is likely to be infected with a multiply resistant organism for any reason, then the patient should be on enough drugs to insure that at least two active anti-tubercular drugs are included in the therapy. An expert should be consulted Length of therapy is not standardized. For sensitive organisms, a regimen of three drugs daily for 2 months, followed by two-drug therapy (isoniazid and rifampin) has been recommended. The American Thoracic Society (ATS) and the Centers for Disease Control (CDC) have recommended a minimum of 12 months of therapy for tuberculous meningitis. If cultures remain positive for extended periods, or signs or symptoms respond slowly, therapy should be extended to 18 months. Patients with HIV also may need longer courses of therapy. The severity of tuberculous meningitis can be classified based on a system devised by the British Medical Research Council. Stage I patients are fully conscious, rational, and do not have neurologic signs. Stage II patients are confused or have neurologic signs such as cranial nerve palsy or hemiparesis. Stage III patients are comatose or stuporous with more severe neurologic signs. Corticosteroids are recommended if the patient is mentally confused, has neurologic signs, or is comatose (Stages II and III). In patients with moderate disease (Stage II), corticosteroids appear to improve neurologic sequelae and survival. Dexamethasone 6 to 12 mg per day and prednisone 60 to 80 mg per day tapered over 4 to 8 weeks has been used. Symptoms of central nervous system (CNS) inflammation may recur if the corticosteroid taper is implemented too soon or too fast. Steroids and diuretics such as furosemide and acetazolamide are sometimes used to treat hydrocephalus. Ventriculoperitoneal or ventriculoatrial shunting may be required to relieve signs and symptoms of hydrocephalus.

Leukocyte-facilitated entry of intracellular pathogens into the central nervous system

Microbes use numerous strategies to invade the central nervous system. Leukocyte-facilitated entry is one such mechanism whereby intracellular pathogens establish infection by taking advantage of leukocyte trafficking to the central nervous system. Key components of this process include peripheral infection and activation of leukocytes, activation of cerebral endothelial cells with or without concomitant infection, and trafficking of infected leukocytes to and through the blood-brain or blood-cerebrospinal fluid barrier.

Chronic Meningitis

Treatment of chronic meningitis depends on the underlying cause. Once a specific cause has been established, appropriate targeted therapy is initiated. When the cause is unknown, a decision must be made whether to employ empiric therapy while the diagnostic evaluation is ongoing. This decision is based on three factors: 1) the clinical status of the patient; 2) the most likely cause based on demographic, historical, examination, and initial laboratory data; and 3) the risk-to-benefit ratio of the proposed treatment regimen. Initial efforts focus on deciding whether the meningitis is infectious or noninfectious. When a decision is made to start empiric therapy, antituberculous treatment is generally given for several weeks to judge therapeutic response. Patients who do not respond to antituberculous therapy are next treated with broad-spectrum antibiotics for unusual bacterial pathogens such as Actinomyces (penicillin), the Lyme disease spirochete Borrelia burgdorferi (ceftriaxone), Brucella (doxycycline plus rifampin), or Francisella tularensis (streptomycin plus gentamicin). Antifungal therapy is generally reserved for patients who are at particular risk for mycotic infection (owing to underlying immunosuppression or an extraneural infection site). Finally, empiric glucocorticoids are generally reserved for patients with consistently negative culture results and a probable noninfectious cause.