Meningitis : Definition, Etiology, Types, Signs, Symptoms, Differential Diagnosis, Management, & Prevention
Definition
- Meningitis is defined as inflammation of the meninges covering the brain & spinal cord.
Etiology
Causative organisms:
- Bacteria
- Viruses
- Mycobacterium tuberculosis
Types
1. Acute Pyogenic (Bacterial) Meningitis
- Acute inflammation of leptomeninges due to bacterial infection.
- Age Most common cause < 2 Months Group B Streptococcus (Strep. agalactiae), Klebsiella, Listeria 2 Months – 2 Year World: Pneumococcus
India: Haemophilus influenzae 2-12 Year World: Pneumococcus
India: Neisseria meningitidis > 12 Year Pneumococcus
2. Aseptic or Viral Meningitis
- Most common causative organisms: Enterovirus > Herpes simplex virus > Mumps virus > Japanese encephalitis virus
3. Tubercular Meningitis (Tuberculous or TB Meningitis)
- Causative organism: Mycobacterium tuberculosis
- Age group: Any age but most common between 6-24 months of age
- Hallmark feature: Basal cistern exudates
- Increased intracranial pressure is more common & more severe than other type of meningitis.
Differential Diagnosis
1. Lumbar puncture
CSF analysis
| Type | Cells | Protein | Glucose | Others |
| Normal | 0-5 : All lymphocytes | 20-40 mg/dl | 50-70 mg/dl | Clear, Sterile |
| Pyogenic meningitis | ↑↑ (100-10000) : Mostly neutrophil | ↑ (100-200 mg/dl), Usually below 500 mg/dl | ↓ (<40 mg/dl) | Clear/Turbid, Culture may be positive |
| Tubercular meningitis | ↑ (100-1000) : Mostly lymphocytes | ↑↑ (100-500 mg/dl) Even upto g/dl | ↓ (<40 mg/dl) | Pellicle or Cobweb formation |
| Aseptic meningitis | ↑ (100-200) : Mostly lymphocytes | ↑ (50-200 mg/dl) | Normal | Culture is always sterile |
2. CT scan
3. ELISA
4. Latex agglutination test
Treatment
Acute pyogenic type
Empirical IV antibiotics × 10-14 days
Steroids ⇒ ↓ Complication rate
Supportive therapy
- Anticonvulsants
- Raised intracranial pressure: Lumbar puncture, osmotic diuresis
- Fluid & electrolyte maintenance
- Hypotension: IV fluids, vasopressors
- Nursing care
Tubercular type
Antituberculosis therapy (ATT) × 9-12 months
Steroids × Daily for 2-3 months during intensive phase
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