A 58-year-old man with a 15-year history of poorly controlled hypertension (BP usually 160–180/100–110 mmHg) presents to the emergency department with sudden-onset severe occipital headache, neck stiffness, and photophobia. His wife reports he was watching television when he suddenly cried out in pain and collapsed. On examination, he is drowsy (GCS 13/15), has a stiff neck, and focal neurological deficits are absent. CT head (non-contrast) shows a hyperdense lesion in the basal ganglia with intraventricular extension. What is the most likely mechanism of this hemorrhage?

Explanation

## Clinical Presentation Analysis The patient presents with the classic triad of **hypertensive intracerebral hemorrhage (ICH)**: - Sudden-onset severe headache - Neck stiffness and photophobia (meningeal irritation from blood) - Basal ganglia location with intraventricular extension ## Pathophysiology of Hypertensive ICH **Key Point:** Chronic hypertension causes lipohyalinosis of small penetrating arteries (diameter 50–200 μm), leading to formation of Charcot–Bouchard microaneurysms. These are the hallmark of hypertensive ICH. **High-Yield:** The distribution of hypertensive ICH follows the territory of penetrating arteries: - **Basal ganglia/putamen** (35–50%) — rupture of lenticulostriate arteries - **Thalamus** (15–25%) - **Pons** (5–10%) - **Cerebellum** (5–10%) - **Lobar** (10–20%) — typically subcortical white matter ## Mechanism: Charcot–Bouchard Aneurysms | Feature | Charcot–Bouchard (Hypertensive) | Berry Aneurysm | AVM | |---------|----------------------------------|----------------|-----| | **Location** | Penetrating arteries (basal ganglia, thalamus, pons, cerebellum) | Circle of Willis (AComm, MComm, tip of basilar) | Cortical or subcortical, can be anywhere | | **Pathology** | Lipohyalinosis from chronic HTN | Congenital defect in tunica media | Abnormal vascular malformation | | **Risk Factor** | Hypertension (>90% of cases) | Family history, polycystic kidney disease, connective tissue disorders | Genetic syndromes (HHT), family history | | **Typical Age** | 50–70 years with HTN history | 40–60 years (often younger) | Any age; can present in childhood | | **Intraventricular Extension** | Common (due to deep location) | Possible (depends on location) | Rare | **Clinical Pearl:** The **basal ganglia location with intraventricular extension** is pathognomonic for hypertensive ICH from Charcot–Bouchard rupture. This patient's 15-year history of uncontrolled hypertension is the smoking gun. ## Why This Patient's Hemorrhage Is Hypertensive 1. **Age and risk factor**: 58 years old with chronic, poorly controlled hypertension 2. **Location**: Basal ganglia (putamen) — classic for hypertensive ICH 3. **Intraventricular extension**: Indicates deep brain origin (penetrating artery territory) 4. **Absence of focal deficits initially**: Suggests deep midline hemorrhage rather than cortical (berry aneurysm or AVM) [cite:Harrison 21e Ch 435]