A 58-year-old hypertensive man presents with acute onset severe headache, vomiting, and right-sided weakness. CT head shows a hyperdense lesion in the basal ganglia with intraventricular extension. What is the most common site of hypertensive intracerebral hemorrhage?

Explanation

## Most Common Sites of Hypertensive ICH **Key Point:** Hypertensive intracerebral hemorrhage has a characteristic distribution pattern based on the location of lipohyalinosis in penetrating vessels. ### Site Distribution in Hypertensive ICH | Site | Frequency | Vessel Involved | Clinical Features | |------|-----------|-----------------|-------------------| | **Putamen/External Capsule** | **50–60%** | Lenticulostriate arteries | Contralateral hemiparesis, hemisensory loss, homonymous hemianopia | | Thalamus | 15–25% | Thalamoperforating arteries | Contralateral sensory loss, vertical gaze palsy, altered consciousness | | Pons | 5–12% | Pontine penetrating branches | Pinpoint pupils, locked-in syndrome, respiratory failure | | Cerebellum | 5–10% | Superior cerebellar artery | Ataxia, headache, hydrocephalus (mass effect) | | Lobar/Subcortical | 10–20% | Cortical branches | Variable, often associated with amyloid angiopathy in elderly | **High-Yield:** The **putamen and external capsule** account for >50% of all hypertensive ICH. This is because the lenticulostriate arteries (branches of the middle cerebral artery) are the most common sites of lipohyalinosis in chronic hypertension. ### Pathophysiology 1. Chronic hypertension → lipohyalinosis of small penetrating arteries 2. Weakening of vessel wall → microaneurysm formation (Charcot-Bouchard aneurysms) 3. Rupture → hemorrhage in distribution of affected vessel 4. Lenticulostriate territory most vulnerable due to high pressure exposure **Clinical Pearl:** When you see a hypertensive patient with acute ICH on imaging, **always look at the basal ganglia first**—this is where >50% of cases will be found. Thalamic involvement is the second most common site. **Mnemonic:** **PTTCL** — Putamen (most common), Thalamus (second), Thalamus again, Cerebellum, Lobar (least common in hypertensive ICH). ### Why Other Sites Are Less Common - **Cerebellum (5–10%):** Lower frequency of lipohyalinosis; when it occurs, risk of obstructive hydrocephalus is high and may require urgent decompression. - **Pons (5–12%):** Relatively rare; when present, carries poor prognosis due to brainstem involvement. - **Lobar/Subcortical (10–20%):** More common in elderly patients with cerebral amyloid angiopathy (CAA) rather than pure hypertensive disease; typically superficial location. [cite:Harrison 21e Ch 435]