Meningitis

Meningitis

 

Meningitis is an inflammation of the meninges, the protective membranes covering the brain and spinal cord. It can be caused by various pathogens or non-infectious factors, and its severity ranges from mild to life-threatening. Below are concise notes on meningitis, covering its causes, types, symptoms, diagnosis, treatment, and prevention.

1. Causes

• Infectious:
  • Bacterial: Common pathogens include Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae type b, and Listeria monocytogenes. Bacterial meningitis is often severe and requires urgent treatment.
  • Viral: Enteroviruses (e.g., echovirus, coxsackievirus), herpesviruses, and others. Typically milder than bacterial but can be serious.
  • Fungal: Caused by fungi like Cryptococcus or Histoplasma, often in immunocompromised individuals.
  • Parasitic: Rare, caused by organisms like Naegleria fowleri (from contaminated water).
• Non-infectious: Caused by cancer, autoimmune diseases, head trauma, or drug reactions.

2. Types

• Bacterial Meningitis: Rapid onset, potentially fatal without prompt treatment.
• Viral Meningitis: Generally self-limiting, less severe.
• Fungal Meningitis: Chronic, often in immunocompromised patients.
• Aseptic Meningitis: Non-bacterial causes (viral, drug-induced, or other).
• Tuberculous Meningitis: Caused by Mycobacterium tuberculosis, often in endemic areas.

3. Symptoms

• Common Symptoms (may vary by age):
  • Fever
  • Severe headache
  • Stiff neck (nuchal rigidity)
  • Nausea and vomiting
  • Photophobia (light sensitivity)
  • Altered mental status (confusion, lethargy)
• In Infants:
  • Irritability, poor feeding, lethargy
  • Bulging fontanelle, abnormal reflexes
• Severe Cases:
  • Seizures, coma, or shock
  • Rash (e.g., petechial rash in meningococcal meningitis)

4. Diagnosis

• Clinical Assessment: History and physical exam (e.g., Kernig’s or Brudzinski’s signs for neck stiffness).
• Lumbar Puncture (LP): Cerebrospinal fluid (CSF) analysis for:
  • Cell count, glucose, protein levels
  • Gram stain, culture, or PCR for specific pathogens
• Blood Tests: Cultures, inflammatory markers (e.g., C-reactive protein, white blood cell count).
• Imaging: CT/MRI to rule out brain swelling or other complications before LP.
• Other Tests: Antigen tests or serology for specific pathogens (e.g., cryptococcal antigen).

5. Treatment

• Bacterial Meningitis:
  • Immediate IV antibiotics (e.g., ceftriaxone, vancomycin) based on suspected pathogen.
  • Corticosteroids (e.g., dexamethasone) to reduce inflammation in some cases.
  • Supportive care (IV fluids, oxygen, seizure management).
• Viral Meningitis:
  • Supportive care (rest, hydration, pain relief).
  • Antiviral drugs (e.g., acyclovir) for herpes-related cases.
• Fungal Meningitis:
  • Antifungal therapy (e.g., amphotericin B, fluconazole) for weeks to months.
• Other:
  • Treat underlying causes (e.g., TB treatment for tuberculous meningitis).
  • Manage complications (e.g., hydrocephalus, seizures).

6. Prevention

• Vaccinations:
  • Neisseria meningitidis: MenACWY, MenB vaccines.
  • Streptococcus pneumoniae: PCV13, PPSV23.
  • Haemophilus influenzae type b: Hib vaccine.
• Prophylactic Antibiotics: For close contacts of meningococcal meningitis cases (e.g., rifampin, ciprofloxacin).
• Hygiene and Public Health:
  • Avoid sharing utensils or drinks.
  • Practice good hygiene to reduce viral transmission.
  • Avoid contaminated water sources (for parasitic meningitis).
• Immunocompromised Patients: Antifungal prophylaxis in high-risk individuals.

7. Complications

• Hearing loss
• Seizures or epilepsy
• Cognitive impairment or developmental delays
• Hydrocephalus
• Sepsis or multi-organ failure (in severe cases)
• Death (especially in untreated bacterial meningitis)

8. Epidemiology

• At-Risk Groups:
  • Infants, young children, adolescents, and young adults.
  • Immunocompromised individuals (e.g., HIV, cancer patients).
  • People in crowded settings (e.g., dormitories, military barracks).
• Geographic Variation: Higher incidence in the "meningitis belt" of sub-Saharan Africa for meningococcal meningitis.

9. Key Points for Awareness

• Early recognition is critical, especially for bacterial meningitis, due to rapid progression.
• Seek immediate medical care for symptoms like fever, neck stiffness, and altered mental status.
• Vaccination and public health measures significantly reduce incidence.