Evaluation of cerebrospinal fluid adenosine deaminase activity for the differential diagnosis of tuberculous and nontuberculous meningitis

Meningitis-retention syndrome: a review and update of an unrecognized clinical condition

OBJECTIVES

We summarized the clinical and radiological characteristics of meningitis-retention syndrome (MRS), its therapeutic options, and urological outcome, to better understand the pathogenesis of this syndrome and to evaluate the effectiveness of corticosteroids in reducing the period of urinary retention.

METHODS

We reported a new case of MRS in a male adolescent. We also reviewed the previously 28 reported cases of MRS, collected from inception up to September 2022.

RESULTS

MRS is characterized by aseptic meningitis and urinary retention. The mean length of the interval between the onset of the neurological signs and the urinary retention was 6.4 days. In most cases, no pathogens were isolated in cerebrospinal fluid, except for 6 cases in which Herpesviruses were detected. The urodynamic study resulted in a detrusor underactivity, with a mean period for urination recovery of 4.5 weeks, regardless of therapies.

DISCUSSION

Neurophysiological studies and electromyographic examination are not pathological, distinguishing MRS from polyneuropathies. Although there are no encephalitic symptoms or signs, and the magnetic resonance is often normal, MRS may represent a mild form of acute disseminated encephalomyelitis, without radiological detectable medullary involvement, due to the prompt use of steroids. It is believed that MRS is a self-limited disease, and no evidence suggests the effectiveness of steroids, antibiotics, and antiviral treatment in its clinical course.

Adenosine deaminase from the cerebrospinal fluid for the diagnosis of tuberculous meningitis: A meta-analysis

OBJECTIVE

To comprehensively evaluate the diagnostic efficacy of adenosine deaminase in cerebrospinal fluid (CSF) for tuberculous meningitis (TBM), and the potential influence of patients' age groups and cutoffs of measured adenosine deaminase.

METHODS

Systematic review and meta-analysis of relevant studies retrieved from PubMed, Embase, and Web of Science databases. Pooled sensitivity and specificity were calculated with a random-effect model.

RESULTS

Overall, 43 studies with 1653 patients with TBM and 3417 controls without were included. Pooled results showed that adenosine deaminase in CSF is associated with satisfactory diagnostic efficacy for TBM, with a pooled sensitivity of 0.86 (95% confidence interval [CI]: 0.82-0.90), specificity of 0.89 (95% CI: 0.86-0.91), positive likelihood ratio of 7.70 (95% CI: 6.16-9.63), and negative likelihood ratio of 0.15 (95% CI: 0.12-0.20). The pooled receiver operating characteristic (AUC) was 0.94 (95% CI: 0.91-0.96), suggesting good performance. Subgroup analyses showed good diagnostic efficacies of adenosine deaminase in CSF for both adults (AUC 0.95) and children (AUC 0.96) with TBM. AUCs indicating the diagnostic accuracies of adenosine deaminase in CSF for TBM were 0.93 for studies with cutoffs <10 U/L and and 0.94 for a cutoff =10 U/L, but only 0.90 for studies with cutoffs >10 U/L.

CONCLUSIONS

Measuring adenosine deaminase of CSF shows satisfactory diagnostic efficacy for TBM in children and adults, particularly if using a cutoff ≤10 U/L.

Autoimmune glial fibrillar acidic protein astrocytopathy mimicking tuberculous meningitis

Autoimmune glial fibrillar acidic protein (GFAP) astrocytopathy typically presents as acute or subacute meningoencephalitis with or without myelitis. We describe a case of autoimmune GFAP astrocytopathy that mimicked tuberculous meningitis. A man in his 70s was referred to our hospital with lethargy persistent for 2 months, appetite loss for 1 month and fever with headache for 10 days. The cerebrospinal fluid test revealed lymphocytic pleocytosis with elevated adenosine deaminase (ADA). Laboratory investigations ruled out microbial and neoplastic causes. Empirical therapy for tuberculous meningitis combined with corticosteroid improved the patient's condition. Culture for Mycobacterium tuberculosis failed to show microbial growth despite 1 month of incubation. The cerebrospinal fluid was examined for GFAP antibody and returned positive result. Antituberculous agents were discontinued, and corticosteroid was administered until patient's symptoms resolved completely. Thus, clinicians should consider autoimmune GFAP astrocytopathy as one of the differential diagnoses of lymphocytic meningitis with elevated ADA.

Isolated Myelitis and Intramedullary Spinal Cord Abscess in Melioidosis-A Case Report

Neuromelioidosis is a severe tropical infection with high morbidity and mortality. Isolated myelitis is an extremely rare manifestation of melioidosis which may evade diagnosis. We report a 69-year-old diabetic male patient who presented with acute flaccid paraplegia and longitudinally extensive myelitis and no systemic symptoms. MRI of spinal cord showed lower dorsal cord and conus T2 hyperintensity and microabscesses with dural enhancement. The diagnosis was clinched with blood culture growing Burkholderia pseudomallei. He rapidly developed colitis, septicemia and multiorgan dysfunction and succumbed to the illness in spite of antibiotics and aggressive supportive care. The case highlights that melioidosis should be considered as a differential diagnosis of infectious myelitis, especially in the tropics. Presence of a neutrophilic blood and cerebrospinal fluid picture and microabscesses in spinal cord are important diagnostic clues. The outcome is dismal unless the diagnosis is considered early in the disease course and managed expeditiously with sensitive antibiotics.

Neurobrucellosis: Brief Review

BACKGROUND

Brucella are small, nonmotile, intracellular, and aerobic gram-negative bacteria. Of the 10 species that currently form the genus Brucella, 5 were shown to be pathogenic in humans.

REVIEW SUMMARY

The epidemiology, clinical manifestations, diagnosis and imaging, and treatment of neurobrucellosis will be reviewed.Brucellosis's transmission to humans occurs by direct contact with contaminated animals. Older patients are at increased risk of nervous system involvement in brucellosis. Brucella spp. can lead to central nervous system involvement through direct damage via invasion of neural tissue or indirect damage caused by endotoxins or immune inflammatory reactions elicited by the presence of the bacteria in the body. Patients can have general nonspecific symptoms in addition to neurological and psychiatric symptoms. There are 4 diagnostic criteria for the diagnosis of neurobrucellosis, which include signs and symptoms suggestive of neurobrucellosis, a positive finding of Brucella spp. in the cerebrospinal fluid (CSF), and/or a positive titer of antibodies targeting brucella in the CSF, lymphocytosis with high protein levels and low glucose levels in CSF, and imaging findings (either cranial magnetic resonance imaging or computed tomography) peculiar to neurobrucellosis. For the treatment, a combined therapy is favored over monotherapy for the eradication of Brucella. Moreover, a multirouted therapy has been associated with increased treatment efficacy. The prognosis of neurobrucellosis is dependent on patients' clinical presentation: brucellar meningitis is associated with a good prognosis, whereas diffuse central nervous system involvement is associated with the development of long-term sequelae.

CONCLUSIONS

Neurobrucellosis affects patients globally and in endemic areas. Neurologists should familiarize themselves with its clinical presentation, diagnosis, and treatment to provide optimal care for their patients.

Central nervous system and spinal cord tuberculosis: Revisiting an important disease

Tuberculosis is a worldwide pandemic. Estimated that about 25% humans are colonized by Mycobacterium tuberculosis and about 1% are believed to develop the infection in the central nervous system (CNS-TB). Given the importance of this disease and its high levels of morbidity and mortality, it is imperative that every radiologist must be reminded of the most common findings of CNS-TB as there are several related differential diagnoses for this disease. The most common form CNS-TB is tuberculous meningitis (TBM), characterized mostly by basal meningitis, but infarction, hydrocephalus and tuberculomas could be present. Intracerebral tuberculosis is characterized by tuberculomas that can have different imaging features according to their stage. Vascular and spinal complications of tuberculosis are also reported. This review compiles the classic and unusual findings regarding CNS-TB together with new diagnostic scores in which neuroimaging have an important role.

Tuberculosis: a focused review for the emergency medicine clinician

INTRODUCTION

Tuberculosis (TB) is a common disease worldwide, affecting nearly one-third of the world's population. While TB has decreased in frequency in the United States, it remains an important infection to diagnose and treat.

OBJECTIVE

This narrative review discusses the evaluation and management of tuberculosis, with an emphasis on those factors most relevant for the emergency clinician.

DISCUSSION

TB is caused by Mycobacterium tuberculosis and is highly communicable through aerosolized particles. A minority of patients will develop symptomatic, primary disease. Most patients will overcome the initial infection or develop a latent infection, which can reactivate. Immunocompromised states increase the risk of primary and reactivation TB. Symptoms include fever, prolonged cough, weight loss, and hemoptysis. Initial diagnosis often includes a chest X-ray, followed by serial sputum cultures. If the patient has a normal immune system and a normal X-ray, active TB can be excluded. Newer tests, including nucleic acid amplification testing, can rapidly diagnose active TB with high sensitivity. Treatment for primary and reactivation TB differs from latent TB. Extrapulmonary forms can occur in a significant proportion of patients and involve a range of different organ systems. Patients with human immunodeficiency virus are high-risk and require specific considerations.

CONCLUSIONS

TB is a disease associated with significant morbidity and mortality. The emergency clinician must consider TB in the appropriate setting, based on history and examination. Accurate diagnosis and rapid therapy can improve patient outcomes and reduce the spread of this communicable disease.

Validation of Mycobacterium tuberculosis real-time polymerase chain reaction for diagnosis of tuberculous meningitis using cerebrospinal fluid samples: a pilot study

Background

Timely diagnosis of tuberculous meningitis (TBM) remains challenging. Molecular diagnostic tools are necessary, particularly in low- and middle-income countries. There is no approved commercial polymerase chain reaction (PCR) assay that can be used to detect Mycobacterium tuberculosis in non-respiratory samples, such as the cerebrospinal fluid (CSF). We aimed to validate the threshold cycle (Ct) cut-off points; calculate the operational characteristics of real-time PCR for detection of M. tuberculosis (MTb qPCR) in the CSF; and the inhibitory affect of CSF red blood cells (RBC) and total proteins on MTb qPCR.

Methods

A total of 334 consecutive participants were enrolled. Based on clinical, laboratory and imaging data, cases of suspected TBM were categorized as definite, probable, possible or not TBM cases. Receiver operating characteristic curve analysis was used to select the best discriminating Ct value.

Results

For TBM cases categorized as definite or probable (n=21), the Ct validated for CSF (≤39.5) improved the diagnostic performance of MTb qPCR on CSF samples. The sensitivity was 29%, specificity was 95%, positive predictive value was 26%, negative predictive value was 95%, efficiency was 90% and positive likelihood was 5.3. The CSF RBC and total protein did not affect the positivity of the MTb qPCR.

Conclusions

These data support the validation of a highly specific but low sensitive MTb qPCR assay for the TBM diagnosis using CSF samples. MTb qPCR contributes significantly to the diagnosis, mainly when associated with conventional microbiology tests and clinical algorithms.

Rational application of adenosine deaminase activity in cerebrospinal fluid for the diagnosis of tuberculous meningitis

PURPOSE

Tuberculous meningitis (TBM) is one of the most serious and difficult to diagnose manifestations of TB. An ADA value >9.5 IU/L has great sensitivity and specificity. However, all available studies have been conducted in areas of high endemicity, so we sought to determine the accuracy of ADA in a low endemicity area.

METHODS

This retrospective study included 190 patients (105 men) who had ADA tested in CSF for some reason. Patients were classified as probable/certain TBM or non-TBM based on clinical and Thwaite's criteria. Optimal ADA cutoff was established by ROC curves and a predictive algorithm based on ADA and other CSF biochemical parameters was generated.

RESULTS

Eleven patients were classified as probable/certain TBM. In a low endemicity area, the best ADA cutoff was 11.5 IU/L with 91 % sensitivity and 77.7 % specificity. We also developed a predictive algorithm based on the combination of ADA (>11.5 IU/L), glucose (<65 mg/dL) and leukocytes (≥13.5 cell/mm(3)) with increased accuracy (Se: 91 % Sp: 88 %).

CONCLUSIONS

Optimal ADA cutoff value in areas of low TB endemicity is higher than previously reported. Our algorithm is more accurate than ADA activity alone with better sensitivity and specificity than previously reported algorithms.

Prospective Analysis of 55 Cases of Tuberculosis Meningitis (TBM) in North India

INTRODUCTION

To assess the clinical profile, laboratory and neuroimaging data of adult tuberculous meningitis (TBM) patients and to determine the predictors of mortality.

MATERIALS AND METHODS

A total of 55 TBM patients and 60 controls were enrolled in this prospective study. Detailed clinical, radiological, biochemical and microbiological evaluation was performed.

STATISTICAL ANALYSIS

Done using SPSS 15.0 for Windows. P value of <0.05 was considered to be significant.

RESULTS

61.8% were males and majority of the study subjects belonged to age group of 21-40 years. Duration of symptoms in all cases was >14 days and commonly included fever, headache, neck rigidity, altered sensorium and vomiting. Biochemical features of cerebrospinal fluid (CSF) showed significant results where 94.5%, 85.45%,83.63% and 81.81% of patients showed CSF sugar levels <2/3 corresponding blood sugar, proteins>100mg%, CSF total leucocyte count of >20 cells/mm(3) and ADA >9.5IU/L respectively while neuroimaging revealed hydrocephalus, basal exudates and meningeal enhancement as significant findings. More than half of TBM patients presented in stage II of disease and overall mortality was 43.63%. A model for prediction of mortality in TBM cases was framed which included variables of age>40 years, past history of tuberculosis (TB), presence of basal exudates and hydrocephalus.

CONCLUSION

TBM is a serious extrapulmonary form of TB and should arise suspicion in mind of clinician based on clinical, laboratory and radiologic results. Further, a model for prediction of mortality in such patients may be helpful for early intervention and better prognosis.

Predictive performance of serum procalcitonin for the diagnosis of bacterial meningitis after neurosurgery

BACKGROUND

Postoperative bacterial meningitis (PBM) is a serious potential complication after neurosurgery. Early diagnosis and introduction of antimicrobial therapy are necessary to reduce the rate of fatal outcomes from PBM. However, PBM is not easily differentiated from postoperative aseptic meningitis (PAM), which usually has favorable clinical outcomes. Serum procalcitonin (S-PCT) has been found to be a useful marker for distinguishing community-acquired bacterial from viral meningitis. We investigated the predictive performance of S-PCT for PBM in patients who underwent neurosurgery.

MATERIALS AND METHODS

Between September 2009 and August 2010, we prospectively collected data from patients who underwent neurosurgery and had cerebrospinal fluid (CSF) pleocytosis within 14 days of surgery. Based on the CSF culture results, patients were categorized as either PBM or PAM cases. We compared the laboratory test results including S-PCT levels between PBM and PAM cases, and investigated the predictive performance of S-PCT for PBM.

RESULTS

During the study period, PBM and PAM occurred in 14 and 64 patients, respectively. There was no significant difference in CSF profiles between PBM and PAM cases. S-PCT level ≥ 0.15 ng/mL (50.0% vs. 20.0%, P = 0.07) and C-reactive protein (CRP) level ≥ 2.5 mg/dL (75.0% vs. 46.5%, P = 0.16) tended to be more frequent in PBM than in PAM cases. A blood white blood cell (B-WBC) count ≥ 9,500/mm(3) was more frequently found in PBM cases (85.7% vs. 50.8%, P = 0.02) than in PAM cases. For the diagnosis of PBM, an S-PCT level ≥ 0.15 ng/mL had a specificity of 80.0%. The combined criteria of a CRP level ≥ 2.5 mg/dL, B-WBC count ≥ 9,500/mm(3), and an S-PCT level ≥ 0.15 ng/mL had the highest specificity (92.6%) of all the criteria. An S-PCT level ≥0.15 ng/mL had low sensitivity (50.0%), and the combined criteria of CRP level ≥ 2.5 mg/dL, B-WBC count ≥ 9,500/mm(3), and S-PCT level ≥ 0.15 ng/mL had an improved sensitivity of 85.7%. However, the sensitivity did not significantly differ from that of a B-WBC count ≥ 9,500/mm(3) (85.7%).

CONCLUSIONS

S-PCT showed limited performance for the diagnosis of postoperative meningitis. However, it could be a useful adjunct for the improvement of diagnostic sensitivity when used in combination with other inflammatory markers.

The validity of cerebrospinal fluid parameters for the diagnosis of tuberculous meningitis

OBJECTIVES

To assess the diagnostic validity of laboratory cerebrospinal fluid (CSF) parameters for discriminating between tuberculous meningitis (TBM) and other causes of meningeal syndrome in high tuberculosis incidence settings.

METHODS

From November 2009 to November 2011, we included patients with a clinical suspicion of meningitis attending two hospitals in Lima, Peru. Using a composite reference standard, we classified them as definite TBM, probable TBM, and non-TBM cases. We assessed the validity of four CSF parameters, in isolation and in different combinations, for diagnosing TBM: adenosine deaminase activity (ADA), protein level, glucose level, and lymphocytic pleocytosis.

RESULTS

One hundred and fifty-seven patients were included; 59 had a final diagnosis of TBM (18 confirmed and 41 probable). ADA was the best performing parameter. It attained a specificity of 95%, a positive likelihood ratio of 10.7, and an area under the receiver operating characteristics curve of 82.1%, but had a low sensitivity (55%). None of the combinations of CSF parameters achieved a fair performance for 'ruling out' TBM.

CONCLUSIONS

Finding CSF ADA greater than 6 U/l in patients with a meningeal syndrome strongly supports a diagnosis of TBM and permits the commencement of anti-tuberculous treatment.

Scrub typhus meningitis in South India--a retrospective study

Background

Scrub typhus is prevalent in India although definite statistics are not available. There has been only one study on scrub typhus meningitis 20 years ago. Most reports of meningitis/meningoencephalitis in scrub typhus are case reports

Methods

A retrospective study done in Pondicherry to extract cases of scrub typhus admitted to hospital between February 2011 and January 2012. Diagnosis was by a combination of any one of the following in a patient with an acute febrile illness- a positive scrub IgM ELISA, Weil-Felix test, and an eschar. Lumbar puncture was performed in patients with headache, nuchal rigidity, altered sensorium or cranial nerve deficits.

Results

Sixty five cases of scrub typhus were found, and 17 (17/65) had meningitis. There were 33 males and 32 females. Thirteen had an eschar. Median cerebrospinal fluid (CSF) cell count, lymphocyte percentage, CSF protein, CSF glucose/blood glucose, CSF ADA were 54 cells/µL, 98%, 88 mg/dL, 0.622 and 3.5 U/mL respectively. Computed tomography was normal in patients with altered sensorium and cranial nerve deficits. Patients with meningitis had lesser respiratory symptoms and signs and higher urea levels. All patients had received doxycycline except one who additionally received chloramphenicol.

Conclusion

Meningitis in scrub typhus is mild with quick and complete recovery. Clinical features and CSF findings can mimic tuberculous meningitis, except for ADA levels. In the Indian context where both scrub typhus and tuberculosis are endemic, ADA and scrub IgM may be helpful in identifying patients with scrub meningitis and in avoiding prolonged empirical antituberculous therapy in cases of lymphocytic meningitis.