Chronic benign lymphocytic meningitis

Chronic meningitis

Chronic meningitis is a syndrome commonly defined by the presence of continuously persistent meningeal inflammation for at least 4 weeks. Presenting neurologic features are often nonspecific, and the list of differential diagnoses is broad. Despite the development of modern molecular diagnostic methods, establishing a specific cause may challenge the acumen of the treating neurologist with clues to the diagnosis residing outside the nervous system and requiring focused investigation. This review discusses selected etiologies illustrating issues in diagnosis and etiologic categories to be considered in the evaluation of this challenging syndrome.

Chronic meningitis presenting with acute obstructive hydrocephalus

A previously healthy 24-year-old woman presented to the Emergency Department unresponsive with a Glasgow Coma Scale score of 4 and evidence of brainstem herniation. She was intubated and hyperventilated. Computed axial tomography scan of the brain demonstrated four-chamber hydrocephalus. Continued hyperventilation and mannitol diuresis were sufficient to arrest the impending herniation while emergent ventriculostomy was arranged. The patient recovered without sequelae and ultimately received a diagnosis of chronic idiopathic meningitis. This case highlights a rarely diagnosed disorder that presented with an acutely life threatening condition.

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.

Idiopathic steroid responsive chronic lymphocytic meningitis--clinical features and long-term outcome in 17 patients

BACKGROUND

Some patients with chronic lymphocytic meningitis appear to respond to corticosteroid treatment, but investigations fail to identify the cause. The use of corticosteroids in patients with chronic meningitis is controversial and the long-term outcome is unclear.

AIM

To review the long-term outcome in 17 patients with the syndrome of idiopathic steroid responsive chronic lymphocytic meningitis.

METHODS

Review of patients' records and examination of surviving patients 1.5 to 17.5 years (median 8.8 years) after presentation.

RESULTS

The cause of the steroid responsive chronic meningitis was found during follow up in two of the 17 patients: Wegener's granulomatosis and multiple sclerosis in one patient each. A cause was not found in the other 15 patients. Seven of these patients eventually recovered and corticosteroids were withdrawn after six weeks to six years without a recurrence of symptoms. Four patients improved transiently, but died six months to 26 years after starting treatment; in two, steroids were withdrawn a few weeks before death. Four patients had active chronic meningitis and reduction in the dose of corticosteroids was associated with a recurrence of symptoms. Leptomeningeal and brain biopsy in eight patients showed non-specific abnormalities which were not helpful in the diagnosis.

CONCLUSIONS

A subgroup of patients with idiopathic chronic lymphocytic meningitis responds to corticosteroids. Leptomeningeal biopsy and long-term follow up seldom identify the underlying cause in these patients. Steroid treatment must be undertaken with caution, even after infective causes of chronic meningitis have been excluded.

Leptomeningeal and brain biopsy in chronic meningitis

BACKGROUND

The cause is not found in one third of patients presenting with chronic meningitis. Biopsy of the leptomeninges and brain is often recommended in these patients, but the value of a biopsy is uncertain.

AIMS

To review the results of leptomeningeal and brain biopsies and their effect on diagnosis and management in patients with chronic meningitis, if the diagnosis was uncertain after clinical assessment, lumbar puncture and radiological investigations.

METHODS

The clinical features, investigations and the results of leptomeningeal and brain biopsies were reviewed retrospectively in 25 patients presenting with chronic meningitis between 1967 and 1990.

RESULTS

The biopsy identified the cause of the chronic meningitis in five patients (neoplastic meningitis in three, tuberculous meningitis in one, granulomatous angiitis in one). In 17 patients the biopsy was abnormal but it did not identify the cause (non-granulomatous lymphocytic meningitis in eight, granulomatous meningitis in two, non-specific abnormalities in seven). In two patients the biopsy was normal and in one patient the tissue was used only for culture. The results of the biopsy led to a beneficial change in treatment in two patients but did not influence management in the other patients.

CONCLUSIONS

A leptomeningeal and brain biopsy was of limited practical value in diagnosis and management in most patients with chronic meningitis.

Outcome of chronic idiopathic meningitis

OBJECTIVE

To record long-term follow-up data on patients with chronic idiopathic meningitis.

DESIGN

We retrospectively reviewed the outcome of 49 patients who were examined at the Mayo Clinic between 1978 and 1990.

MATERIAL AND METHODS

For all patients, symptoms, signs, laboratory values, results of imaging studies, findings on biopsies, results of any empiric treatment, and results of autopsy, if applicable, were assessed. Some of these findings were stratified on the basis of good versus poor outcome of the patients and were analyzed statistically.

RESULTS

Of the 49 patients who fulfilled the criteria for chronic idiopathic meningitis, 10 had a cause identified after repeated studies, brain biopsy, or autopsy (8 of these had a neoplasm). Of 21 brain biopsies, 5(24%) yielded a diagnosis. Follow-up of the 39 undiagnosed cases showed that 33 (85%) had a good outcome despite an often prolonged illness. Two patients (5%) died of the meningeal process. Of the eight patients treated empirically with antituberculous medications, none responded. Corticosteroid therapy was effective in 52% of the patients thus treated, but it did not influence the outcome.

CONCLUSION

In this study, 85% of undiagnosed cases of chronic meningitis were benign. No clinical or laboratory findings predicted those patients who had a fatal outcome. In our study population, the most useful empiric therapy was corticosteroids rather than antituberculous medications.

Infections of the central nervous system

Infections of the central nervous system are common, serious medical conditions. One hundred consecutive adult cases with purulent meningitis of known etiology encountered by the Medical Service at Parkland Memorial Hospital were reviewed. Streptococcus pneumoniae was the most common pathogen (56 cases), followed by Neisseria meningitidis (16 cases) and Listeria monocytogenes (seven cases). Hemophilus influenzae, Staphylococcus aureus, and streptococci each accounted for five cases. An additional 15 patients had purulent meningitis with a pathogen being isolated. Twenty five purulent meningitis cases of known etiology after trauma or neurosurgery were reviewed. Staphylococcus aureus (five cases), Staphylococcus epidermidis (four cases), and gram negative bacilli (14 cases) were the most common pathogens. Review of intracranial suppurative infections demonstrated advances in microbiology, antibiotic therapy, and imaging, leading to improvements in therapy. Subdural empyema continues to be a difficult diagnosis to make and apparently is related to the anatomic pathology of the infectious process. To illustrate salient features about granulomatous meningitis and encephalitis, cases of tuberculous meningitis, herpes simplex encephalitis, St. Louis encephalitis, and encephalitis of undetermined etiology are presented and discussed.

Chronic meningitis caused by a penicillin-sensitive microorganism?

21 patients studied had persistent or progressive chronic meningitis not associated with a demonstrable infectious or other disease, except Streptococcus milleri antigen in the cerebrospinal fluid of 1 patient. The cerebrospinal-fluid (CSF) abnormalities consisted of a moderate, predominantly mononuclear, pleocytosis, a sharp rise in CSF protein (mean 2.3 g/l), intrathecal synthesis of considerable quantities of oligoclonal immunoglobulin G, and, in half the patients, a fall in the CSF-glucose/blood-glucose ratio. In all patients symptoms began during summer or autumn. In 4 patients the onset was preceded by localised cutaneous lesion, described as erythema chronicum migrans. 4 more patients had been bitten by ticks in the weeks before onset of symptoms. The patients had profound fatigue, malaise, and weight-loss. Half had fever, usually moderate. The neurological abnormalities included aseptic meningitis, cranial neuropathy (mostly facial-nerve paralysis), motor and sensory peripheral radiculoneuropathy, and myelitis. The patients improved or recovered, sometimes dramatically, during a 2-week course of intravenous penicillin G.

Chronic meningitis in patients with dental infections

4 patients with a history of initial fever 2--4 weeks passing on to fever peaks every 3rd to 6th day with afebrile intervals repeating for months are presented. Three of them had dental infectious foci mainly in maxillar teeth and 1 patient was treated by a dentist 1 month before onset. None showed meningism or clinical signs of encephalitis. Extensive investigations resulted only in findings from the central nervous system. The EEG was slightly pathological in all cases and papilloedema was found in 2 cases. In the cerebrospinal fluid (CSF) a pleocytosis extending over months, transient presence of plasma cells and increased proteins in the gamma region on agar electrophoresis was found. In 1 case antigen from Streptococcus milleri, a commensal of the mouth flora at times isolated from infectious dental foci, was detected in CSF by counterimmunoelectrophoresis 6 weeks after onset of the disease. Treatment with penicillin had no effect on the fever. Three patients received antiphlogistic drugs with benefit and their dental foci were treated by a dentist.

Studies on the humoral and cell-mediated immune response in a patient with Mollaret's meningitis

A patient with Mollaret's meningitis with protracted course and a strong immune response within the central nervous system is described. The findings of IgG bands in agarose gel electrophoresis of CSF together with elevated CSF IgG index values are in accordance with intrathecal synthesis of IgG, possibly against an antigen persistent in the CNS. Subgrouping of CSF lymphocytes morphologically (B/T, active T cells) and functionally (stimulation with mitogens) showed that these cells differed from peripheral blood lymphocytes. A defect in the regulatory function of T cells may be responsible for the continuing pathologic process in Mollaret's meningitis.