Meningitis

• Meningitis is the inflammation of the membranes (meninges) surrounding the brain and spinal cord.
• It is a medical emergency due to the potential for rapid progression and severe complications, including death.

Signs and Symptoms

1. General Symptoms:

   • Severe Headache: A hallmark of meningitis, often described as the worst headache of one’s life.
   • Fever: High temperature, often sudden onset.
   • Stiff Neck: Difficulty in bending the neck forward due to inflammation of the meninges.
   • Photophobia: Sensitivity to light, causing discomfort or pain.
   • Confusion or Altered Consciousness: Can range from mild confusion to complete unresponsiveness.
   • Vomiting: Often occurs due to increased intracranial pressure.
   • Seizures: In severe cases, due to inflammation affecting the brain tissue.

2. Infants and Young Children:

   • Irritability: Excessive crying and difficulty soothing the child.
   • Poor Feeding: Refusal to eat or drink.
   • High-pitched Crying: Especially when the infant is handled.
   • Bulging Fontanel: Soft spot on the head may appear swollen.

Types

1. Bacterial Meningitis:

   • Neisseria meningitidis: Common in adolescents and young adults, spread through respiratory droplets.
   • Streptococcus pneumoniae: Common in all age groups, particularly young children and elderly.
   • Haemophilus influenzae type b (Hib): Less common now due to vaccination.

2. Viral Meningitis:

   • Enteroviruses: Most common cause, spread through fecal-oral route.
   • Herpes Simplex Virus: Can cause severe encephalitis as well.
   • Mumps Virus: Now rare due to vaccination.

3. Fungal Meningitis:

   • Cryptococcus: Common in immunocompromised individuals, especially those with HIV/AIDS.

4. Parasitic Meningitis:

   • Naegleria fowleri: Rare, often fatal, contracted through contaminated water entering the nose.

5. Non-infectious Meningitis:

   • Causes: Cancer, autoimmune diseases (like lupus), certain drugs, head injury.

Etiology

1. Bacterial Transmission: Through respiratory droplets, close contact (kissing, coughing), or invasive medical procedures.
2. Viral Transmission: Often via fecal-oral route, respiratory droplets, or direct contact with infected fluids.
3. Fungal Transmission: Inhalation of fungal spores, typically affecting those with weakened immune systems.
4. Parasitic Transmission: Usually contracted through contaminated water, entering through the nasal passages.

Pathogenesis

1. Bacterial:

   • Bacteria enter the bloodstream, cross the blood-brain barrier, and infect the meninges, leading to inflammation and increased intracranial pressure.

2. Viral:

   • Viruses enter the body through the respiratory or gastrointestinal tracts, spread to the central nervous system, causing inflammation of the meninges.

3. Fungal and Parasitic:

   • Similar to bacterial meningitis, fungi and parasites invade the central nervous system, causing inflammation.

Treatment

1. Bacterial Meningitis:

   • Antibiotics: Immediate intravenous antibiotics like ceftriaxone, vancomycin, or ampicillin.
   • Corticosteroids: Reduce inflammation (e.g., dexamethasone).
   • Supportive Care: Includes fluids, pain management, and monitoring for complications.

2. Viral Meningitis:

   • Supportive Care: Rest, hydration, and pain relief.
   • Antiviral Medications: Acyclovir for herpes simplex virus.

3. Fungal Meningitis:

   • Antifungal Medications: Amphotericin B, flucytosine, fluconazole.
   • Supportive Care: Addressing symptoms and supporting organ functions.

4. Parasitic Meningitis:

   • Antiparasitic Treatment: Depending on the specific parasite.
   • Supportive Care: Includes managing symptoms and supporting vital functions.

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