Diagnosis of chronic brucellar meningitis and meningoencephalitis: the results of the Istanbul-2 study

Chronic meningitis in adults: a comparison between neurotuberculosis and neurobrucellosis

BACKGROUND

In regions endemic for tuberculosis and brucellosis, distinguishing between tuberculous meningitis (TBM) and brucella meningitis (BM) poses a substantial challenge. This study investigates the clinical and paraclinical characteristics of patients with TBM and BM.

METHODS

Adult patients diagnosed with either TBM or BM who were admitted to two referral hospitals between March 2015 and October 2022, were included, and the characteristics of the patients were analyzed.

RESULTS

Seventy patients formed the study group, 28 with TBM and 42 with BM, were included. TBM patients had a 2.06-fold (95% CI: 1.26 to 3.37, P-value: 0.003) higher risk of altered consciousness and a 4.80-fold (95% CI: 1.98 to 11.61, P-value: < 0.001) higher risk of extra-neural involvement as compared to BM patients. Cerebrospinal fluid (CSF) analysis revealed a significantly higher percentage of polymorphonuclear leukocytes (PMN) in TBM compared to BM (Standardized mean difference: 0.69, 95% CI: 0.18 to 1.20, P-value: 0.008). Neuroimaging findings indicated higher risks of hydrocephalus (P-value: 0.002), infarction (P-value: 0.029), and meningeal enhancement (P-value: 0.012) in TBM compared to BM. Moreover, TBM patients had a 67% (95% CI: 21% to 131%, P-value:0.002) longer median length of hospital stay and a significantly higher risk of unfavorable outcomes (Risk ratio: 6.96, 95% CI: 2.65 to 18.26, p < 0.001).

CONCLUSIONS

Our study emphasizes that TBM patients displayed increased frequencies of altered consciousness, PMN dominance in CSF, extra-neural involvement, hydrocephalus, meningeal enhancement, and brain infarction. The findings emphasize the diagnostic difficulties and underscore the importance of cautious differentiation between these two conditions to guide appropriate treatment strategies.

Comparative Study on the Efficacy of Two Perioperative Chemotherapy Regimens for Lumbar Brucellosis

Objective

The clinical efficacy of perioperative chemotherapy regimen (rifampicin, doxycycline, levofloxacin, ceftriaxone) was evaluated for lumbar brucellosis spondylitis patients with neurological injury.

Methods

In Beijing Ditan Hospital affiliated with Capital Medical University, 32 patients with lumbar brucellosis spondylitis underwent surgery and triple perioperative chemotherapy (rifampicin, doxycycline, levofloxacin) between 2011 and 2021 due to neurological injury, and 34 patients matched up with the triple group underwent rifampicin, doxycycline, levofloxacin, and ceftriaxone. Both groups were compared in terms of changes in inflammation index, low back/leg pain, lumbar function, neurological function, and adverse drug reactions.

Results

There was no significant difference in erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), low back pain visual analogue scale (VAS), leg pain VAS, lumbar Oswestry disability index (ODI) and nerve function injury rate between the two groups before chemotherapy (P>0.05). The ESR, CRP at 1 week and 2 weeks after chemotherapy and 1 week, 2 weeks, 1 month postoperatively in the quadruple group were significantly lower than those in the triple group, which is the same to ESR 3 months postoperatively (P<0.05). The low back pain VAS, leg pain VAS and lumbar ODI in the quadruple group were significantly lower than those in the triple group at 1 month and 3 months postoperatively (P<0.05). The recovery rate of neurological function in the quadruple group was significantly higher than that in the triple group at 3 and 6 months postoperatively (P<0.05). Both groups did not experience significantly different perioperative and postoperative adverse reactions (P>0.05).

Conclusion

For lumbar brucellosis spondylitis with neurological injury, quadruple perioperative chemotherapy of rifampicin, doxycycline, levofloxacin and ceftriaxone can significantly reduce perioperative inflammation, and improve low back/leg pain, as well as promoting neurological function recovery in the short term.

Neurobrucellosis

PURPOSE OF REVIEW

Brucellosis is one of the most common zoonosis worldwide, affecting 500 000 people, annually. Neurobrucellosis incidence is approximately 4%, and it is almost always heterogeneous. As there are no typical clinical features, its diagnosis is frequently misdiagnosing by other infections.

RECENT FINDINGS

Neurobrucellosis picture includes meningitis, meningoencephalitis, encephalitis, cranial neuropathies, intracranial hypertension, sinus thrombosis, hemorrhages radiculitis, peripheral neuropathy, myelitis, and psychiatric manifestations. The diagnosis should be based on symptoms and signs suggestive of neurobrucellosis, not explained by other neurological disease, cerebrospinal fluid analysis, a positive Brucella serology or culture, and a response to specific antibiotics, with a significant improvement of cerebrospinal fluid parameters.

SUMMARY

Neurobrucellosis can be insidious, and despite its global distribution, it is still unrecognized and frequently goes unreported. The understanding of the current epidemiology is necessary for eradication of the disease in humans, as well as the disease control in animals and prevention based on occupational hygiene and food hygiene.

Neurobrucellosis Complicated by Sensorineural Hearing Loss: A Case Report

Brucellosis is a zoonotic disease. It is also one of the neglected infectious diseases and is less well-known compared to other diseases. It is acquired from infected animals (cattle, sheep, goats, camels, pigs, or other animals) through the consumption of unpasteurized dairy products or contact with tissues or fluids. Sensory neural hearing loss (SNHL) in neurobrucellosis had been described in the literature, mostly as an incidental finding that otolaryngologists should consider in any patient with fever and a history of travel to the Middle East, Central or South America, or other brucellosis-endemic countries. We present a neurobrucellosis case with profound bilateral SNHL that was treated with combination antibiotic therapy for long periods of time and highlight the clinical course of the patient.

Encephalomyelitis with hearing loss: case report on neurobrucellosis

Neurobrucellosis is a zoonotic infection transmitted by infected animals or by contact with animal products and is an important health problem in resource-limited settings. In this case report, we present the case of a middle-aged man presenting with encephalomyelitis with hearing loss and diagnosed with neurobrucellosis based on imaging and serological tests. Because brucellosis infection is indolent, a high index of suspicion should be maintained in individuals presenting with fever, neurological signs and symptoms so that early management can prevent long-term neurological sequelae such as focal neurological deficits, hydrocephalus and psychiatric sequelae.

Laboratory and clinical predictors of focal involvement and bacteremia in brucellosis

Early diagnosis of organ involvement and bacteremia in brucellosis increases treatment success and may prevent poor clinical outcomes. This study aimed to investigate the predictors of focal involvement and bacteremia in patients with brucellosis. A total of 139 brucellosis patients aged 16 years and older were included in the study. Patients with and without organ involvement and bacteremic and non-bacteremic patients were compared separately. Low back pain, lymphadenomegaly, absence of fever on admission, ESR, AST, and neutrophil-lymphocyte ratio (NLR) were predictors of focal involvement (OR: 2.604; 3.167; 7.224; 1.039; 1.032; 1.738, respectively). The AUC value of ESR was 0.669 (0.573-0.765, p = 0.002) with the cutoff point > 30 mm/h (sensitivity 89.74% and specificity 37.00%) in predicting focal involvement in patients with brucellosis. Myalgia and headache (OR: 2.970; 2692) were defined as clinical predictors of Brucella bacteremia. Focal involvement should be considered in patients with brucellosis in the absence of myalgia and fever, presence of low back pain, and sedimentation > 30 mm/h. Brucella bacteremia should be considered regardless of fever, especially in patients with myalgia and headache in endemic areas.

Neurobrucellosis: the great mimicker

Neurobrucellosis is caused by bacteria of the genus Brucella and is responsible for several clinical manifestations, making diagnosis challenging. The most common route of infection is through the consumption of unpasteurized or raw dairy products such as fresh milk, butter, and cheese. As neurological complications can develop chronically, they are frequently misdiagnosed as other infections, such as tuberculosis. This report reviews the clinical manifestations, diagnostic approach, treatment, and prognosis of neurobrucellosis, illustrating a case of chronic intracranial hypertension and meningoencephalitis secondary to brucellosis. The clinical presentation of brucellosis can mimic several systemic diseases, resulting in diagnostic delays and clinical complications. A high degree of suspicion is required, and neurobrucellosis should always be considered in the differential diagnosis of chronic meningitis.

Isolated neurobrucellosis-characteristic clinical and laboratory features

To report various neurological syndromes, CSF findings, imaging and diagnostic methods used in neurobrucellosis patients admitted in our Neurology department over a period of 6 years. Case records of patients admitted to our department from August 2014 to May 2020 were searched for neurobrucellosis and data were obtained. A total of 19 patients were diagnosed as neurobrucellosis over a period of 6 years. Ten patients had chronic meningitis, five had VIII nerve involvement, one had optic neuritis, two had acute meningitis, one had subacute meningitis, four had myelopathy, five had polyradiculitis and two had spondylodiscitis. CSF was abnormal in 17 patients. Neutrophilic pleocytosis was seen in 12 patients who included nine patients with chronic symptomatology. Brain imaging was abnormal in three chronic meningitis patients. One had diffuse meningeal enhancement, another had hydrocephalus while the third patient had meningeal enhancement with basal exudates and contrast enhancement of bilateral VIII nerve. One of the patients of acute meningitis had hydrocephalus while the other one had bilateral T2/FLAIR hyperintensities with enhancement of meninges and leptomeningeal vessels. Elevated antibody titers only in serum was seen in six patients while elevated antibody titers only in CSF was seen in seven patients. Four patients had elevated antibody titers in both serum and CSF. CSF culture was positive in three patients. Neurobrucellosis is a rare clinical complication of brucellosis but may pose a problem in diagnosis as it can mimic tuberculosis. Involvement of VIII nerve and neurophilic pleocytosis in CSF despite chronic symptomatology can be diagnostic clues favoring neurobrucellosis.

Neurobrucellosis: a Case Report with an Unusual Presentation

BACKGROUND

Brucellosis is a highly infectious multi-systemic zoonosis, and it is caused by Gram-negative bacteria, Brucella. Despite the low incidence of neurobrucellosis, it is the most dangerous consequence of brucellosis.

CASE REPORT

A 30-year-old Sudanese male patient presented to our hospital with a complaint of fever associated with confusion for three days. He had signs of meningeal irritation in the form of neck stiffness, positive Kernig's, and Lesage's sign. The computerized tomography of the brain was normal. The CSF analysis showed a clear colorless sample with normal tension, decreased glucose, and slightly increased CSF protein level. We reviewed his occupational history; the patient was a farmer with regular contact with cattle and camels. The patient had positive Brucella antibodies for both B.Abortus and B. melitensis with a high titer (1/640). As described in various patents, we administrated triple therapy for brucellosis for two weeks. A marked improvement of the conscious level was observed, and the patient was back to normal within a few days post-treatment.

CONCLUSIONS

We encourage physicians to consider the diagnosis of neurobrucellosis with any neurologic sign without a known cause. Our case highlights the importance of occupational history in clinical medicine.

Utility of the Rose Bengal Test as a Point-of-Care Test for Human Brucellosis in Endemic African Settings: A Systematic Review

In endemic African areas, such as Tanzania, Brucella spp. cause human febrile illnesses, which often go unrecognized and misdiagnosed, resulting in delayed diagnosis, underdiagnosis, and underreporting. Although rapid and affordable point-of-care tests, such as the Rose Bengal test (RBT), are available, acceptance and adoption of these tests at the national level are hindered by a lack of local diagnostic performance data. To address this need, evidence on the diagnostic performance of RBT as a human brucellosis point-of-care test was reviewed. The review was initially focused on studies conducted in Tanzania but was later extended to worldwide because few relevant studies from Tanzania were identified. Databases including Web of Science, Embase, MEDLINE, and World Health Organization Global Index Medicus were searched for studies assessing the diagnostic performance of RBT (sensitivity and specificity) for detection of human brucellosis, in comparison to the reference standard culture. Sixteen eligible studies were identified and reviewed following screening. The diagnostic sensitivity (DSe) and specificity (DSp) of RBT compared to culture as the gold standard were 87.5% and 100%, respectively, in studies that used suitable "true positive" and "true negative" patient comparison groups and were considered to be of high scientific quality. Diagnostic DSe and DSp of RBT compared to culture in studies that also used suitable "true positive" and "true negative" patient comparison groups but were considered to be of moderate scientific quality varied from 92.5% to 100% and 94.3 to 99.9%, respectively. The good diagnostic performance of RBT combined with its simplicity, quickness, and affordability makes RBT an ideal (or close to) stand-alone point-of-care test for early clinical diagnosis and management of human brucellosis and nonmalarial fevers in small and understaffed health facilities and laboratories in endemic areas in Africa and elsewhere.

Diagnostic Testing in Central Nervous System Infection

Patients with central nervous system (CNS) infection experience very high levels of morbidity and mortality, in part because of the many challenges inherent to the diagnosis of CNS infection and identification of a causative pathogen. The clinical presentation of CNS infection is nonspecific, so clinicians must often order and interpret many diagnostic tests in parallel. This can be a daunting task given the large number of potential pathogens and the availability of different testing modalities. Here, we review traditional diagnostic techniques including Gram stain and culture, serology, and polymerase chain reaction (PCR). We highlight which of these are recommended for the pathogens most commonly tested among U.S. patients with suspected CNS infection. Finally, we describe the newer broad-range diagnostic approaches, multiplex PCR and metagenomic sequencing, which are increasingly used in clinical practice.

Neurobrucellosis

PURPOSE

Neurobrucellosis (NB) is a rare complication of brucellosis. NB presents with avariety of clinical manifestations, and the symptoms are always atypical. Our aim was to analyze the demographic characteristics, clinical manifestations, laboratory findings, imaging findings, treatments and outcomes of patients with NB.

MATERIAL AND METHOD

We retrospectively reviewed the data from 17 patients with NB hospitalized at the Chinese People's Liberation Army General Hospital between 1 January 2005 and 31 October 2016.

RESULTS

The following symptoms were recorded: 10/17 (59%) patients had fever, and 9/17 (53%) patients had a disorder affecting urination and defecation. Involvement of the cranial nerves was documented in 12/17 (71%) patients. The positivity rates of the tests were as follows: serum standard tube agglutination (STA), 15/17 (88.2%); cerebrospinal fluid STA, 10/17 (59%). The radiologic findings were categorized into four types: normal, white matter changes, vascular insult and inflammatory changes. Patients were treated with different combinations of rifampicin, doxycycline, ceftriaxone sodium and sulphamethoxazole for a total of six months. Two (12%) patients deteriorated, and two (12%) patients were lost to follow-up. The remaining patients (76%) were cured, but sequelae occurred in six patients.

CONCLUSIONS

NB should be kept in mind in patients with autonomic dysfunction, especially disorders of urination and defecation. Hearing loss due to vestibulocochlear nerve injury seems to be typical for NB. The high incidence of sequelae may be related to a long disease course and the involvement of the central nervous system. Early detection, diagnosis and treatment could decrease mortality and sequelae.

Cerebrospinal fluid cytology in nonmalignant aseptic meningeal disorders

Cerebrospinal fluid cytology examination is a common and reliable primary and/or complementary procedure for the diagnosis of central nervous system (CNS) disorders. This review provides an update of aseptic meningeal disorders that may be encountered in cytopathology practice. The article covers the cytological findings and helpful ancillary studies needed of nonmalignant aseptic CNS disorders such as viral, bacterial, fungal and parasitic infections, and other noninfectious diseases, such as Mollaret's meningitis (recurrent benign lymphocytic meningitis), Guillain-Barré syndrome, multiple Sclerosis, subarachnoid haemorrhage, and drug-induced disorders.

The burden and epidemiology of community-acquired central nervous system infections: a multinational study

Risk assessment of central nervous system (CNS) infection patients is of key importance in predicting likely pathogens. However, data are lacking on the epidemiology globally. We performed a multicenter study to understand the burden of community-acquired CNS (CA-CNS) infections between 2012 and 2014. A total of 2583 patients with CA-CNS infections were included from 37 referral centers in 20 countries. Of these, 477 (18.5%) patients survived with sequelae and 227 (8.8%) died, and 1879 (72.7%) patients were discharged with complete cure. The most frequent infecting pathogens in this study were Streptococcus pneumoniae (n = 206, 8%) and Mycobacterium tuberculosis (n = 152, 5.9%). Varicella zoster virus and Listeria were other common pathogens in the elderly. Although staphylococci and Listeria resulted in frequent infections in immunocompromised patients, cryptococci were leading pathogens in human immunodeficiency virus (HIV)-positive individuals. Among the patients with any proven etiology, 96 (8.9%) patients presented with clinical features of a chronic CNS disease. Neurosyphilis, neurobrucellosis, neuroborreliosis, and CNS tuberculosis had a predilection to present chronic courses. Listeria monocytogenes, Staphylococcus aureus, M. tuberculosis, and S. pneumoniae were the most fatal forms, while sequelae were significantly higher for herpes simplex virus type 1 (p < 0.05 for all). Tackling the high burden of CNS infections globally can only be achieved with effective pneumococcal immunization and strategies to eliminate tuberculosis, and more must be done to improve diagnostic capacity.

Neurobrucellosis: A Case Report from Himachal Pradesh, India, and Review of the Literature

Human brucellosis is a multisystem disease that commonly presents as a febrile illness along with variable spectrum of clinical manifestations. Neurological complications include encephalitis, meningoencephalitis, radiculitis, myelitis, peripheral and cranial neuropathies, subarachnoid hemorrhage, and psychiatric manifestations. We report a case diagnosed as neurobrucellosis who presented with fever and bilateral upper motor neuron symptoms and signs along with bilateral sensorineural deafness. Diagnosis was confirmed by Rose Bengal Test (RBT) and standard tube agglutination test (SAT).

Cranial imaging findings in neurobrucellosis: results of Istanbul-3 study

OBJECTIVE

Neuroimaging abnormalities in central nervous system (CNS) brucellosis are not well documented. The purpose of this study was to evaluate the prevalence of imaging abnormalities in neurobrucellosis and to identify factors associated with leptomeningeal and basal enhancement, which frequently results in unfavorable outcomes.

METHODS

Istanbul-3 study evaluated 263 adult patients with CNS brucellosis from 26 referral centers and reviewed their 242 magnetic resonance imaging (MRI) and 226 computerized tomography (CT) scans of the brain.

RESULTS

A normal CT or MRI scan was seen in 143 of 263 patients (54.3 %). Abnormal imaging findings were grouped into the following four categories: (a) inflammatory findings: leptomeningeal involvements (44), basal meningeal enhancements (30), cranial nerve involvements (14), spinal nerve roots enhancement (8), brain abscesses (7), granulomas (6), and arachnoiditis (4). (b) White-matter involvement: white-matter involvement (32) with or without demyelinating lesions (7). (c) Vascular involvement: vascular involvement (42) mostly with chronic cerebral ischemic changes (37). (d) Hydrocephalus/cerebral edema: hydrocephalus (20) and brain edema (40). On multivariate logistic regression analysis duration of symptoms since the onset (OR 1.007; 95 % CI 1-28, p = 0.01), polyneuropathy and radiculopathy (OR 5.4; 95 % CI 1.002-1.013, p = 0.044), cerebrospinal fluid (CSF)/serum glucose rate (OR 0.001; 95 % CI 000-0.067, p = 0.001), and CSF protein (OR 2.5; 95 % CI 2.3-2.7, p = 0.0001) were associated with diffuse inflammation.

CONCLUSIONS

In this study, 45 % of neurobrucellosis patients had abnormal neuroimaging findings. The duration of symptoms, polyneuropathy and radiculopathy, high CSF protein level, and low CSF/serum glucose rate were associated with inflammatory findings on imaging analyses.

Comparison of brucellar and tuberculous spondylodiscitis patients: results of the multicenter "Backbone-1 Study"

BACKGROUND CONTEXT

No direct comparison between brucellar spondylodiscitis (BSD) and tuberculous spondylodiscitis (TSD) exists in the literature.

PURPOSE

This study aimed to compare directly the clinical features, laboratory and radiological aspects, treatment, and outcome data of patients diagnosed as BSD and TSD.

STUDY DESIGN

A retrospective, multinational, and multicenter study was used.

PATIENT SAMPLE

A total of 641 (TSD, 314 and BSD, 327) spondylodiscitis patients from 35 different centers in four countries (Turkey, Egypt, Albania, and Greece) were included.

OUTCOME MEASURES

The pre- and peri- or post-treatment spinal deformity and neurologic deficit parameters, and mortality were carried out.

METHODS

Brucellar spondylodiscitis and TSD groups were compared for demographics, clinical, laboratory, radiological, surgical interventions, treatment, and outcome data. The Student t test and Mann-Whitney U test were used for group comparisons. Significance was analyzed as two sided and inferred at 0.05 levels.

RESULTS

The median baseline laboratory parameters including white blood cell count, C-reactive protein, and erythrocyte sedimentation rate were higher in TSD than BSD (p<.0001). Prevertebral, paravertebral, epidural, and psoas abscess formations along with loss of vertebral corpus height and calcification were significantly more frequent in TSD compared with BSD (p<.01). Surgical interventions and percutaneous sampling or abscess drainage were applied more frequently in TSD (p<.0001). Spinal complications including gibbus deformity, kyphosis, and scoliosis, and the number of spinal neurologic deficits, including loss of sensation, motor weakness, and paralysis were significantly higher in the TSD group (p<.05). Mortality rate was 2.22% (7 patients) in TSD, and it was 0.61% (2 patients) in the BSD group (p=.1).

CONCLUSIONS

The results of this study show that TSD is a more suppurative disease with abscess formation requiring surgical intervention and characterized with spinal complications. We propose that using a constellation of constitutional symptoms (fever, back pain, and weight loss), pulmonary involvement, high inflammatory markers, and radiological findings will help to differentiate between TSD and BSD at an early stage before microbiological results are available.

Tuberculous and brucellosis meningitis differential diagnosis

BACKGROUND

The Thwaites and Lancet scoring systems have been used in the rapid diagnosis of tuberculous meningitis (TBM). However, brucellar meningoencephalitis (BME) has similar characteristics with TBM. The ultimate aim of this study is to infer data to see if BME should be included in the differential diagnosis of TBM when these two systems suggest the presence of TBM.

METHOD

BME and TBM patients from 35 tertiary hospitals were included in this study. Overall 294 adult patients with BME and 190 patients with TBM were enrolled. All patients involved in the study had microbiological confirmation for either TBM or BME. Finally, the Thwaites and Lancet scoring systems were assessed in both groups.

RESULTS

The Thwaites scoring system more frequently predicted BME cases (n = 292, 99.3%) compared to the TBM group (n = 182, 95.8%) (P = 0.017). According to the Lancet scoring system, the mean scores for BME and TBM were 9.43 ± 1.71 and 11.45 ± 3.01, respectively (P < 0.001). In addition, TBM cases were classified into "probable" category more significantly compared to BME cases, and BME cases were categorized into the "possible" category more frequently.

CONCLUSIONS

When the Thwaites or Lancet scoring systems indicate TBM, brucellar etiology should also be taken into consideration particularly in endemic countries.

Liver involvement in patients with brucellosis: results of the Marmara study

Brucellosis is a zoonotic disease that primarily affects the reticuloendothelial system. But, the extent of liver damage in due course of the disease is unclear. This study included 325 brucellosis patients with significant hepatobiliary involvement identified with microbiological analyses from 30 centers between 2000 and 2013. The patients with ≥5 times of the upper limit of normal for aminotransferases, total bilirubin level ≥2 mg/dl or local liver lesions were enrolled. Clinical hepatitis was detected in 284 patients (87.3 %) and cholestasis was detected in 215 (66.1 %) patients. Fatigue (91 %), fever (86 %), sweating (83 %), arthralgia (79 %), and lack of appetite (79 %) were the major symptoms. Laboratory tests showed anemia in 169 (52 %), thrombocytopenia in 117 (36 %), leukopenia in 81 (25 %), pancytopenia in 42 (13 %), and leukocytosis in 20 (6 %) patients. The most commonly used antibiotic combinations were doxycycline plus an aminoglycoside (n = 73), doxycycline plus rifampicin (n = 71), doxycycline plus rifampicin and an aminoglycoside (n = 27). The duration of ALT normalization differed significantly in three treatment groups (p < 0.001). The use of doxycycline and an aminoglycoside in clinical hepatitis showed better results compared to doxycycline and rifampicin or rifampicin, aminoglycoside, doxycycline regimens (p < 0.05). However, the length of hospital stay did not differ significantly between these three combinations (p > 0.05). During the follow-up, treatment failure occurred in four patients (1 %) and relapse was seen in three patients (0.9 %). Mortality was not observed. Hepatobiliary involvement in brucellosis has a benign course with suitable antibiotics and the use of doxycycline and an aminoglycoside regimen seems a better strategy in select patients.

The clinical and laboratory diagnosis of acute meningitis and acute encephalitis

INTRODUCTION

Acute bacterial meningitis (ABM) is a life-threatening infectious disease requiring prompt antimicrobial therapy. ABM must be differentiated from systemic disorders with CNS manifestations that may mimic ABM. ABM should also be differentiated from acute meningoencephalitis (AME) and acute viral encephalitis (AVE). Nonviral causes of AME are treatable. Among the causes of AVE, Herpes simplex encephalitis (HSE) is treatable. This article reviews the clinical diagnostic approach to ABM, AME and AVE.

AREAS COVERED

The differential diagnostic (DDx) approach to ABM, AME and AVE is based on clinical and laboratory findings. A specific pathogen diagnosis is based on serum/cerebrospinal fluid (CSF) tests. This overview presents the diagnostic approach to ABM, AME and AVE in normal hosts (excluding brain abscesses and chronic CNS infections).

EXPERT OPINION

It is time critical to diagnose ABM and begin empiric antimicrobial therapy based on the known/most likely pathogen. The diagnosis of ABM depends on clinical features and the CSF profile. The CSF Gram stain and CSF lactic acid (LA) levels provide the most rapid, reliable and cost-effective tests to diagnose ABM. CSF LA levels are also the best way to diagnose partially treated acute bacterial meningitis (PTABM). In those cases of AME/AVE due to viruses with a CSF profile mimicking ABM, for example, HSE, unelevated CSF LA levels rapidly/reliably rule out ABM as a diagnostic possibility.