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
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.
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 of Meningitis
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
Bacterial Transmission: Through respiratory droplets, close contact (kissing, coughing), or invasive medical procedures.
Viral Transmission: Often via fecal-oral route, respiratory droplets, or direct contact with infected fluids.
Fungal Transmission: Inhalation of fungal spores, typically affecting those with weakened immune systems.
Parasitic Transmission: Usually contracted through contaminated water, entering through the nasal passages.
Pathogenesis
1) Bacterial Meningitis
Bacteria enter the bloodstream, cross the blood-brain barrier, and infect the meninges, leading to inflammation and increased intracranial pressure.
2) Viral Meningitis
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 Meningitis
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.