Meningitis 

Description

Meningitis is the inflammation of the meninges, the protective coverings of the brain and spinal cord. It may be caused by bacteria, viruses, fungi, or parasites. Severity varies from mild symptoms to life-threatening complications such as sepsis, raised intracranial pressure, and death.

Types of Meningitis

1. Bacterial Meningitis

Common Causes:

• Streptococcus pneumoniae

• Group B Streptococcus

• E. coli

• Haemophilus influenzae type b

• Neisseria meningitidis

Signs and Symptoms:

• Headache, neck stiffness, and photophobia

• Fever and vomiting

• Seizures, confusion, drowsiness, or loss of consciousness

• Vascular collapse and hypotension (Waterhouse-Friderichsen syndrome)

• Petechial skin rash

• Positive Kernig and Brudzinski signs

• Cranial nerve palsies (facial, oculomotor) and occasional hearing loss

Investigations:

• CSF analysis: cloudy fluid, low glucose, positive Gram stain, culture and organism identification, rapid antigen tests, PCR if available

• Supportive tests: HIV testing, FBC, KFTs, electrolytes, malaria testing, blood cultures

• Imaging: CT scan if available (should not delay therapy)

Treatment:

• Empiric therapy:

  • Benzylpenicillin IV 2.4 MU 4 times daily plus

  • Chloramphenicol IV 1g 4 times daily

  • OR Ceftriaxone IV 2g 12 hourly

  • OR Cefotaxime IV 2g 8 hourly

• Specific treatment is guided by CSF culture results

Prevention and Post-Exposure Prophylaxis:

• Vaccination for hyposplenic individuals

• Prophylaxis for close contacts (household, dormitory, prolonged exposure):

  • Ceftriaxone 250 mg IM stat

  • Ciprofloxacin 20 mg/kg (max 500 mg) single dose

  • Azithromycin 500 mg single dose

Complications:
Seizures, loss of consciousness, hydrocephalus, cranial palsies, hemiplegia, hearing loss, blindness, mental retardation, epilepsy, and death

Referral Criteria:

• Complications like hydrocephalus

• No improvement in 48–72 hours

• Suspected atypical infection

• Resistant pathogens detected

• Suspected TB meningitis

2. Cryptococcal Meningitis

Cause:

• Cryptococcus neoformans

• High-risk groups: Advanced HIV disease, cancer treatment, severe immunosuppression

Signs and Symptoms:

• Headache, fever, nausea, projectile vomiting

• Seizures, visual impairment

• Altered mental status, somnolence

• Photophobia, cranial nerve palsies

• Hemiplegia or hemiparesis

Investigations:

• Lumbar puncture with CSF analysis

• Cryptococcal antigen (CrAg) assay, India ink, culture for Cryptococcus

• Serum CrAg

• Contrast-enhanced CT scan of the brain

Treatment:

• Induction Phase:

  • Liposomal Amphotericin B 3–4 mg/kg IV daily plus Flucytosine 25 mg/kg PO every 6 hours for 7 days

  • OR Amphotericin B deoxycholate 0.7–1 mg/kg IV daily plus Flucytosine

  • Amphotericin B plus Fluconazole 800–1200 mg daily for 14 days

• Consolidation Phase:

  • Fluconazole 400–800 mg/day for 8 weeks after induction

• Maintenance Phase:

  • Fluconazole 200 mg daily until CD4 >350 cells/mL for 6 months or lifelong

• Serial lumbar punctures to manage raised intracranial pressure

Prevention:

• Routine antifungal prophylaxis not recommended in CrAg-negative HIV-infected patients prior to ART, unless ART initiation is delayed

3. Viral Meningitis

Common Causes:

• Coxsackie virus, poliovirus, measles, mumps, influenza, herpes simplex, HIV

Signs and Symptoms:

• Similar to bacterial and cryptococcal meningitis: headache, fever, neck stiffness, photophobia, nausea, vomiting, altered mental state

Investigations:

• CSF analysis: clear appearance, lymphocytes 10–100, no polymorphs, protein 0.4–0.8 g/L

Treatment:

• Acyclovir 10–15 mg/kg IV three times daily for 7 days (for herpes simplex virus or suspected viral etiology requiring treatment)

General Management Principles

1. Early Recognition: Look for classic triad—fever, neck stiffness, altered mental state

2. Supportive Care: Airway, breathing, circulation stabilization, hydration, fever management, seizure control

3. Antimicrobial Therapy: Start empirically in suspected bacterial meningitis; adjust based on culture results

4. Neurological Monitoring: Monitor for raised ICP, cranial nerve deficits, or focal neurological signs

5. Infection Control: Isolation precautions for bacterial meningitis; notify public health authorities as required

6. Referral: Immediate specialist referral for complicated cases, immunocompromised patients, or failure to respond to therapy