Meningitis is an inflammation of the protective membranes covering the brain and spinal cord, known as the meninges. It is a medical emergency because swelling around the brain can quickly become life-threatening. Meningitis may be caused by bacteria, viruses, fungi, or parasites, but bacterial meningitis is the most dangerous and requires immediate treatment.
Types of Meningitis
- Bacterial meningitis – Most severe; requires urgent antibiotics.
- Viral meningitis – Usually mild and self-limiting.
- Fungal meningitis – Seen in immunocompromised patients.
- Tuberculous meningitis – Slow onset; needs long-term therapy.
Common Causes
Bacterial Causes
- Streptococcus pneumoniae (most common)
- Neisseria meningitidis
- Haemophilus influenzae type b
- Group B Streptococcus (newborns)
- Listeria monocytogenes (elderly, pregnant women, immunocompromised)
Viral Causes
- Enteroviruses
- Herpes simplex virus
- Mumps virus
Symptoms of Meningitis
- High fever
- Severe headache
- Neck stiffness
- Nausea and vomiting
- Sensitivity to light
- Confusion or altered mental state
- Seizures (in severe cases)
In infants, symptoms may include irritability, poor feeding, bulging fontanelle, or abnormal cry.
Diagnosis
Diagnosis must be rapid to avoid complications.
- Lumbar puncture (CSF analysis) – gold standard
- Blood cultures
- CT scan (if raised intracranial pressure suspected)
- CSF PCR for viruses
CSF Findings in Bacterial Meningitis
- High protein
- Low glucose
- High neutrophils
- Positive Gram stain
Treatment of Bacterial Meningitis
This condition requires immediate empirical antibiotic therapy before lab results arrive.
Empirical Therapy
- Adults: Ceftriaxone or cefotaxime + vancomycin
- Age >50 or immunocompromised: Add ampicillin (for Listeria)
- Neonates: Ampicillin + gentamicin or cefotaxime
Specific Therapy Based on Culture
- S. pneumoniae: Ceftriaxone or cefotaxime
- N. meningitidis: Ceftriaxone
- H. influenzae: Ceftriaxone
- Listeria: Ampicillin + gentamicin
Corticosteroids
Dexamethasone is recommended before or with the first antibiotic dose in suspected pneumococcal meningitis. It helps reduce inflammation and neurological complications.
Management of Viral Meningitis
- Usually self-limiting
- Supportive care: fluids, rest, analgesics
- If HSV suspected: Acyclovir
Complications
- Hearing loss
- Seizures
- Hydrocephalus
- Brain damage
- Shock (in meningococcal sepsis)
Prevention
- Vaccination: Hib, pneumococcal, and meningococcal vaccines
- Prophylaxis for close contacts (rifampicin for meningococcal exposure)
- Avoid overcrowded environments during outbreaks
Patient Counseling
- Seek emergency care for severe headache, fever, or stiff neck
- Complete full antibiotic course
- Monitor for neurological symptoms
- Encourage vaccination for children and at-risk adults
Detailed Notes:
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