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ALL / Infectious Diseases
Viral meningitis
Viral meningitis
Meningitis is an inflammation of the leptomeninges and the cerebrospinal fluid of the subarachnoid space. Viral meningitis is inflammation attributed to a viral agent. In comparison with bacterial meningitis, it may be considered to be a more benign condition and is much more common. Approximately 3,000 cases of confirmed viral meningitis are reported yearly, however, the actual number of cases is likely to be much higher, as patients often do not present to medical services.Causes
- non-polio enteroviruses e.g. coxsackie virus, echovirus
- mumps
- herpes simplex virus (HSV), cytomegalovirus (CMV), herpes zoster viruses
- HIV
- measles
Risk factors
- patients at the extremes of age (< 5 years and the elderly)
- immunocompromised, e.g. patients with renal failure, with diabetes
- intravenous drug users
Clinical presentation
- common features
- headache
- evidence of neck stiffness
- photophobia (often milder than the photophobia experienced by a patient with bacterial meningitis)
- confusion
- fevers
- less common features
- focal neurological deficits on examination
- seizures: suggests a meningoencephalitis
Investigation and management
Patients should have a lumbar puncture to confirm the diagnosis. Cerebrospinal fluid findings in viral meningitis:
| Opening Pressure | 10 - 20 cm³ H²O | (10 - 20 cm³ H²O) |
| Cell count | 10-300 cells/µL | (0 - 5 cells/µL) |
| Cell differential | Lymphocytes | (0 - 5 cells/µL lymphocyte-predominant) |
| Glucose | 2.8 - 4.2 mmol/L or 2/3 serum glucose mmol/L | ( 2.8 - 4.2 mmol/L or 2/3 paired serum glucose mmol/L) |
| Protein | 0.5 - 1 g/dL | (0.15 - 0.45 g/L) |
Viral polymerase chain reaction (PCR) may demonstrate an underlying organism.
Management
- whilst awaiting the results of the lumbar puncture, treatment should be supportive and if there is any question of bacterial meningitis or of encephalitis, the patient should be commenced on broad-spectrum antibiotics with CNS penetration e.g. ceftriaxone and aciclovir intravenously. This is particularly the case if the patient has risk factors e.g. elderly, immunocompromised
- generally speaking, viral meningitis is self-limiting, with symptoms improving over the course of 7 - 14 days and complications are rare in immunocompetent patients
- aciclovir may be used if the patient is suspected of having meningitis secondary to HSV
+PassMedicine Notes
Meningitis is an inflammation of the leptomeninges and the cerebrospinal fluid of the subarachnoid space. Viral meningitis is inflammation attributed to a viral agent. In comparison with bacterial meningitis, it may be considered to be a more benign condition and is much more common. Approximately 3,000 cases of confirmed viral meningitis are reported yearly, however, the actual number of cases is likely to be much higher, as patients often do not present to medical services.
Causes- non-polio enteroviruses e.g. coxsackie virus, echovirus
- mumps
- herpes simplex virus (HSV), cytomegalovirus (CMV), herpes zoster viruses
- HIV
- measles
- patients at the extremes of age (< 5 years and the elderly)
- immunocompromised, e.g. patients with renal failure, with diabetes
- intravenous drug users
- common features
- headache
- evidence of neck stiffness
- photophobia (often milder than the photophobia experienced by a patient with bacterial meningitis)
- confusion
- fevers
- less common features
- focal neurological deficits on examination
- seizures: suggests a meningoencephalitis
Investigation and management
Patients should have a lumbar puncture to confirm the diagnosis. Cerebrospinal fluid findings in viral meningitis:
Opening Pressure_ 10 - 20 cm³ H²O _ (10 - 20 cm³ H²O) | Cell count _ 10-300 cells/µL _ (0 - 5 cells/µL) | Cell differential _ Lymphocytes _ (0 - 5 cells/µL lymphocyte-predominant)| Glucose _ 2.8 - 4.2 mmol/L or 2/3 serum glucose mmol/L _ ( 2.8 - 4.2 mmol/L or 2/3 paired serum glucose mmol/L)| Protein _ 0.5 - 1 g/dL _ (0.15 - 0.45 g/L)|Viral polymerase chain reaction (PCR) may demonstrate an underlying organism.
Management- whilst awaiting the results of the lumbar puncture, treatment should be supportive and if there is any question of bacterial meningitis or of encephalitis, the patient should be commenced on broad-spectrum antibiotics with CNS penetration e.g. ceftriaxone and aciclovir intravenously. This is particularly the case if the patient has risk factors e.g. elderly, immunocompromised
- generally speaking, viral meningitis is self-limiting, with symptoms improving over the course of 7 - 14 days and complications are rare in immunocompetent patients
- aciclovir may be used if the patient is suspected of having meningitis secondary to HSV