Meningitis

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This is inflammation of the meningeal covering of the brain or spinal cord. Both brain and meninges can be involved. This inflammation could be caused by bacteria, viral or fungal infections, malignancies, chemical reaction, intrathecal infections and also due to injury or trauma.

Clinical Features

Clinical presentation is the same despite different causative agents; but the commonest causative agent is bacteria and these include, Gram-negative organisms i.e. E. coli in children, H. influenzae type b, group B Streptococcus, Streptococcus pneumoniae, Neisseria meningitidis and Cryptococcus in immune-compromised patients. Factors such as age, head trauma, and compromised immunity may help predict causative agents.

The relative incidence of meningitis for children remains high in the first 2 years of life. The incidence of meningitis is high during the 1st month of life with most infections being due to gram-negative organisms i.e. E-Coli in children and group B Streptococcus.

Presentation of patients with meningitis varies according to age group.

Adults and older children  (**Common Presentations)

  • Headache  **
  • Neck stiffness/ache   **
  • Fever
  • Vomiting
  • Seizures
  • Confusion
  • Drowsiness
  • Loss of consciousness
  • Vascular collapse (Waterhouse - Friderichsen syndrome)

In infants

  • Fever
  • Vomiting
  • Irritability
  • Convulsions
  • High-pitched cry and
  • Bulging of the anterior fontanel is commonly present
  • Stiffness of the neck may be absent
  • There may be enlarging of head size

Signs of Meningitis
Other signs elicited during a physical examination that suggest meningitis include:

  • Neck stiffness
  • Positive kernig's sign
  • Brudzinski' s sign
  • Cranial nerves abnormality may occur (facial nerve palsy, oculomotor nerve palsy and occasional deafness).

Complications

These include:

  • seizures
  • loss of consciousness
  • hydrocephalus, thrombophlebitis
  • cranial palsies
  • hemiplegia and
  • death.

Long term complications include mental retardation, hearing loss, sometimes blindness, epilepsy.

Diagnosis

This is confirmed by laboratory investigations. Perform a lumbar puncture for gram-stain culture and sensitivity for glucose and protein.

Cerebral spinal fluid may be cloudy, indicating bacterial meningitis.

Bacterial Meningitis

Description

This is inflammation of the meningeal covering of the brain or spinal cord. Common causes include
Streptococcus pneumoniae, Group B Streptococcus, E. coli, H. influenzae type b, Neisseria meningitides

Signs and Symptoms

• Headache
• Neck stiffness/ache (common)
•Photophobia                                                      • Fever
• Vomiting
• Seizures
• Confusion, Drowsiness, Loss of consciousness
• Vascular collapse characterized low blood pressure (hypotension) and (Waterhouse - Friderichsen syndrome)
• Petechae skin rash
• Positive Kernig or Brudzinski’s sign
• Cranial nerve palsies (facial nerve, oculomotor nerve palsies and occasional deafness)

Investigations

  • Cerebral Spinal Fluid analysis
    • CSF color that is cloudy
    • Low CSF glucose
    • CSF positive gram stain
    • Positive culture and organism identification
    • Rapid antigen test for streptococcus
    • Multiplex PCR (if available)
  • Supportive tests
    • HIV testing should be offered to all patients whose HIV status in unknown
    • Full blood culture
    • Kidney function tests and electrolytes
    • Malaria parasite slide
    • Blood cultures
  • Imaging

A CT-scan should be done if available but should not delay starting therapy

Treatment

• Empiric: Benzylpenicillin 2.4 MU IV 4 times daily
PLUS
• Chloramphenicol IV 1g 4 times daily
OR
• Ceftriaxone IV 2g 12 hourly
OR
• Cefotaxime IV 2g 8 hourly

Specific treatment will vary depending on CSF-culture results

• Prevention
o Vaccination is recommended for those with hyposplenism
• Post exposure prophylaxis
o For those exposed or contacts of meningococcal. The contacts include:
o Sharing same household or dormitory
o More than 8 hours of contact or exposure
o Exposure to secretions
• Drug options AND dosages:
o Ceftriaxone 250 mg intramuscular as stat dose
o Ciprofloxacin (20 mg/kg) max 500 mg single dose
o Azithromycin 500 mg single dose
o Follow up for at least 10 day

Complications

• Seizures
• Loss of consciousness
• Hydrocephalus
• Thrombophlebitis
• Cranial palsies
• Hemiplegia and death.
• Mental retardation
• Hearing loss
• Blindness
• Epilepsy.

Referral Criteria

• Complications such as hydrocephalus
• Failure improves in 48-72 hours
• Suspected atypical infection based on history
• Resistant pathogen detected
• Suspected TB meningitis

Cryptococcal Meningitis

Description

The causative organism is Cryptococcal neoformans. The high-risk groups most affected are those with severe
immunosuppression such as Advanced HIV Disease (AHD) with low CD4 counts, and patients on cancer
treatment

Signs and Symptoms

• Headache
• fever
• Nausea and projectile vomiting
• Seizures
• Visual impairment
• Altered mental status with somnolence
• Photophobia
• Cranial nerve palsies
• Hemiplegia or hemiparesis

Investigations

  • Lumbar puncture with measurement opening pressure for CSF analysis as above in bacterial meningitis including the following:
    • Cryptococcal antigen (CrAg) assay
    • India Ink
    • Culture for Cryptococcus neoforman
  • 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 in 4 divided doses at 6hour intervals for 7 days

OR

  • Amphotericin B deoxycholate 7-1 mg/kg IV daily PLUS Flucytosine 25 mg/kg PO in 4 divided doses at 6 hour intervals for 7 days
  • Amphotericin B as above

PLUS

  • Fluconazole 800-1200 mg once daily for 14 days
  • Consolidation phase: Eight-week anti-fungal regimen
    • Fluconazole 400–800 mg/day after a two-week induction with Amphotericin B regimen (6–12 mg/kg/ day up to 400–800 mg/day, if below 19 years)
    • Fluconazole 800 mg/day after induction treatment with short-course Amphotericin B or Fluconazole- based induction (Fluconazole 12mg/kg/day up to 800 mg/day, if below 19 years)
  • Maintenance Phase:

Oral Fluconazole 200 mg daily (6 mg/kg/day up to 200 mg/day, if below 19 years) until CD4 >350 cells/mL for more than 6 months or lifelong

Serial lumbar puncture is recommended to manage raised intracranial pressure

Prevention of Cryptococcal Disease
The routine use of antifungal primary prophylaxis for Cryptococcal disease in HIV-infected with a CD4 count
less than 100 cells/μL and who are CrAg negative or where CrAg status is unknown is not recommended
before ART initiation, unless a prolonged delay in ART initiation is likely

Viral Meningitis

Description

This is inflammation of the meningeal covering of the brain or spinal cord. Common causes include coxsackie, polio, Measles, Mumps, Influenza, Herpes simplex and HIV

Signs and Symptoms

• As for bacterial and cryptococcal meningitis

Investigations

Cerebral Spinal Fluid analysis
• Clear appearance
• Lymphocytes: 10 to 100
• Polymorphs: none
• Protein: 0.4 to 0.8 g/l

Treatment

Acyclovir 10-15mg/kg IV 3 times per day for 7 days