What is chronic meningitis? What is treatment of tubercular meningitis?
Introduction
Tuberculous Meningitis signs and symptoms:
- Headache, malaise, mental confusion, and vomiting.
- Moderate increase in CSF cellularity, with mononuclear cells
- Protein level is elevated,
- Glucose content reduced or normal.
- Well circumscribed intraparenchymal mass – tuberculoma.
- Chronic tuberculous meningitis is a cause of arachnoid fibrosis, which may produce hydrocephalus.
Spirochetal infection of meninges:
Spirochetal Infections:
Neurosyphilis:
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| Types of meningitis and their fingdings |
Viral encephalitis causes, symptoms and management
Viral encephalitis is a parenchymal infection of the brain that is almost invariably associated with meningeal inflammation (better termed meningoencephalitis).
Causes of viral encephalitis:
- Arbo virus
- Herpes virus
- Rabies virus
- Poliovirus
- Cytomegalo virus
- HIV virus
Cerebrospinal fluid (CSF) findings in different types of meningitis
Here’s a comparison table summarizing the cerebrospinal fluid (CSF) findings in different types of meningitis:
| CSF Parameter | Bacterial Meningitis | Viral Meningitis | Tuberculous Meningitis | Fungal Meningitis |
|---|---|---|---|---|
| Opening Pressure | ↑↑ (elevated) | Normal or slightly ↑ | ↑↑ (elevated) | ↑ (elevated) |
| Appearance | Turbid or purulent | Clear | Clear or slightly cloudy | Clear or slightly cloudy |
| WBC Count | ↑↑ (100–10000/mm³) | ↑ (10–500/mm³) | ↑ (100–500/mm³) | ↑ (20–500/mm³) |
| Cell Type | Predominantly neutrophils | Predominantly lymphocytes | Lymphocytes | Lymphocytes |
| Protein | ↑↑ (100–500 mg/dL) | Normal or mild ↑ (50–100 mg/dL) | ↑↑ (100–500 mg/dL) | ↑ (100–200 mg/dL) |
| Glucose | ↓↓ (<40 mg/dL or <40% of serum) | Normal (>50% of serum) | ↓ (<45 mg/dL) | ↓ (low to normal) |
| Gram Stain | Positive in most cases | Negative | Negative | May show fungal elements (e.g. India ink for Cryptococcus) |
| Culture | Often positive | Usually negative | May be positive (Low yield) | May be positive |
| Other Tests | — | — | AFB stain, PCR, ADA ↑, TB culture | India ink, Cryptococcal antigen |
Notes:
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In bacterial meningitis, neutrophilic predominance and very low glucose are classic.
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In viral meningitis, lymphocytic predominance with normal glucose helps differentiate it.
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TB meningitis and fungal meningitis often resemble each other, but TB typically has more pronounced protein elevation and low glucose.
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Always correlate CSF findings with clinical context and other investigations like imaging and cultures.
Differences between subarachnoid hemorrhage (SAH) and meningitis
Here’s a comparison table highlighting the differences between subarachnoid hemorrhage (SAH) and meningitis:
| Feature | Subarachnoid Hemorrhage (SAH) | Meningitis |
|---|---|---|
| Cause | Ruptured cerebral aneurysm, AVM, trauma | Infection (bacterial, viral, fungal, TB) |
| Onset | Sudden (“thunderclap headache”) | Gradual or acute over hours to days |
| Headache | Severe, sudden, worst-ever headache | Gradual, diffuse headache |
| Fever | Usually absent or mild | Prominent feature, especially in bacterial meningitis |
| Neck Stiffness | Present | Present |
| Photophobia | Common | Common |
| Altered Consciousness | Common, especially with large bleed or raised ICP | May occur in severe cases |
| Seizures | May occur | May occur |
| Focal Neurological Deficits | May be present (due to vasospasm, infarct) | Less common; usually in complicated cases |
| CSF Appearance | Xanthochromia (after 12 hrs), bloody initially | Turbid in bacterial, clear in viral |
| CSF Opening Pressure | ↑ (variable) | ↑ in bacterial, TB, fungal; normal/mild ↑ in viral |
| CSF WBC | Mild ↑ or normal | ↑↑ in infection (type depends on etiology) |
| CSF RBC | High in all tubes if SAH; clears if traumatic tap | Usually absent |
| CSF Protein | ↑ | ↑↑ in bacterial/TB; mild ↑ in viral |
| CSF Glucose | Normal | ↓ in bacterial/TB/fungal; normal in viral |
| Imaging | CT head: hyperdensity in subarachnoid space | CT/MRI may show meningeal enhancement |
| Treatment | Neurosurgical (clipping/coiling), supportive | Antibiotics/antivirals/antifungals depending on cause |
Key Clinical Pearl:
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Both may present with headache and neck stiffness, but sudden onset without fever suggests SAH, while gradual onset with fever suggests meningitis.