**Tuberculous meningitis (TBM) with hydrocephalus** is a serious form of central nervous system (CNS) tuberculosis and is associated with high morbidity and mortality. Here's an overview of the **epidemiology** of **TBM-associated hydrocephalus**:

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### 🌍 **Global Epidemiology**
- **Prevalence**: TBM represents about **1% of all TB cases**, but it accounts for a significant proportion of **neurological TB**, especially in endemic regions.
- **Hydrocephalus** occurs in **up to 80% of TBM cases**, particularly in advanced stages.
- **High-burden regions**: South and Southeast Asia (e.g., India, Indonesia, Vietnam), Sub-Saharan Africa, and parts of Eastern Europe.
- **HIV co-infection** increases the risk of CNS TB, including TBM.

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### 👶 **Pediatric vs. Adult Populations**
- TBM is more **common in children** than adults.
- **Hydrocephalus** is a particularly frequent complication in **pediatric TBM**, occurring in **up to 85%** of cases.
- In adults, hydrocephalus occurs in **30–50%** of TBM cases, often as **communicating hydrocephalus**.

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### 🧠 **Types of Hydrocephalus in TBM**
- **Communicating hydrocephalus**: Most common; due to obstruction of CSF absorption in arachnoid granulations.
- **Non-communicating hydrocephalus**: Less common; results from blockage of ventricular system (e.g., at the aqueduct of Sylvius).

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### 📈 Risk Factors for TBM-Associated Hydrocephalus
- **Delayed diagnosis or treatment**
- **Advanced stage of TBM** at presentation (MRC Stage II or III)
- **Younger age**
- **HIV infection**
- **Drug-resistant TB**

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### ⚠️ Outcomes
- Hydrocephalus in TBM is associated with:
  - **Poorer neurological outcomes**
  - **Increased mortality**
  - **Higher rates of long-term disability**, especially if not promptly treated
- **Early detection and management** (e.g., medical vs. surgical interventions like VP shunt or ETV) are critical for prognosis.