Meningitis: Causes, Transmission Routes, and Prevention

Meningitis = inflammation of the meninges. Etiology determines transmission, severity, and prevention.

Bacterial (Most Severe)

• S. pneumoniae, N. meningitidis, H. influenzae type b
• Spread: respiratory droplets, saliva (cough, kiss, close contact)
• Vaccines: PCV13/PPSV23, MenACWY/MenB, Hib

Viral (Most Common, Usually Self-Limited)

• Enteroviruses (most common), HSV, VZV, mumps, measles, influenza, arboviruses (West Nile, EEE)
• Spread: fecal-oral, respiratory, vector-borne (mosquito/tick)

Fungal

• Cryptococcus neoformans (inhaled spores from soil/bird droppings)
• Affects immunocompromised primarily

Parasitic (Rare)

• Naegleria fowleri (warm freshwater → nasal entry → PAM)

Non-Infectious

• Autoimmune (SLE, sarcoid), drugs, malignancy, post-neurosurgery

Prevention

• Vaccination (on schedule)
• Hand hygiene, respiratory etiquette
• Avoid warm freshwater nasal exposure
• Prompt antibiotics for close contacts of meningococcal cases

Symptoms = Emergency: Fever, severe headache, stiff neck, photophobia, altered mental status, petechial rash → ER immediately.