Pathology:
Infection of the meninges, with viral disease typically being self-limiting, but bacterial cases being potentially fatal.
Aetiology:
- Neonates: Streptococcus.B, E.coli
- Adults: Strep. pneumoniae, N. meningitidis
- Elderly: Listeria
- Other: Viral infections and TB
Symptoms:
Fever, chills, headache, photophobia, neck stiffness, vomiting, changes in mental state, and a non-blanching rash.
Signs:
- Kernig’s Sign Positive: Thigh flexed at hip and knee to 90 degree, and subsequent knee extension is painful.
- Brudzinski Sign Positive: Hip and knee flexion on neck flexion.
Investigations:
- Imaging: CT or MRI brain
- Other: Lumbar puncture, gram stain, PCR, and blood cultures.
Treatment:
- Medical: IV ceftriaxone immediately in suspected cases.
- IV vancomycin and ampicillin in elderly and immunocompromised.
- Four days dexamethasone in pneumococcal meningitis alongside antibiotics.
- If viral cause potential IV acyclovir should be given.
Prevention:
- Meningococcal and Pneumococcal vaccine.
- Chemoprophylaxis (ciprofloxacin, rifampicin) in close contacts.
Complications:
- Acute: Seizures, cerebral abscess, stroke, DIC, gangrene, coma, death.
- Long term: Deafness, cognitive impairment and focal deficits.
Prognosis:
Prognosis is dependent on early diagnosis and commencement of antibiotic therapy.
Increased Risk of Mortality and Morbidity
There is an increased risk of mortality around 10% and morbidity of around 30%. These risks are associated with the following:
CSF White Cell Count
- Raised Lymphocytes
- Raised Polymorphs
- Raised Lymphocytes
CSF Glucose
- Normal or Decreased
- Low
- Very Low
CSF Protein
- Normal or Increased
- Increased
- Very High
Figure 6.2 Classical Meningococcal Rash
