Intracerebral hemorrhage (ICH) is a severe condition where a blood vessel within the brain ruptures, causing bleeding that destroys or compresses brain cells. The location of the bleeding significantly affects its cause, presenting symptoms, severity, and treatment plan. ICH is primarily classified into five types, ranging from Putaminal Hemorrhage, which is most frequent in Japan, to Pontine Hemorrhage, which has the highest fatality rate.
Main Types of Intracerebral Hemorrhage (by Location) and Details
| Type | Frequency (Japan) | Main Cause / Risk Factor | Typical Symptoms | Severity / Prognosis | Characteristic Image Findings (CT/MRI) |
| Putaminal Hemorrhage | Approx. 40–50% | Hypertension (90%+), vascular aging | Contralateral hemiparesis, sensory loss, aphasia (if dominant hemisphere) | Relatively good prognosis (10–20% mortality) | Hematoma in the putamen/internal capsule, sometimes breaking into the ventricle |
| Thalamic Hemorrhage | Approx. 15–25% | Mostly hypertension | Sensory loss (entire contralateral side), abnormal eye movements, reduced consciousness | Tends to be severe (20–40% mortality) | Hematoma in the thalamus, ventricular rupture can lead to hydrocephalus |
| Subcortical Hemorrhage(Cerebral White Matter) | Approx. 10–15% | Elderly: Cerebral Amyloid Angiopathy (CAA) / Young: AVM (Arteriovenous Malformation) | Severe headache, seizures, reduced consciousness, localized symptoms depend on location | Depends on bleeding volume (dangerous if large) | Hematoma near the brain surface (lobar hemorrhage) |
| Cerebellar Hemorrhage | Approx. 5–10% | Hypertension, vascular malformation | Severe headache & vomiting, dizziness, inability to walk, slurred speech (dysarthria) | Can deteriorate rapidly, often requires emergency surgery | Hematoma in the cerebellar hemisphere, compression of 4th ventricle →hydrocephalus |
| Pontine Hemorrhage(Brainstem) | Approx. 5–10% | Mostly hypertension | Quadriparesis (paralysis of all four limbs), pupillary abnormalities, reduced consciousness → coma, risk of respiratory arrest | Extremely high mortality (40–70%) | Hematoma in the pons (center of the brainstem) |
| Subarachnoid Hemorrhage (SAH)(Strictly extravascular) Often classified separately | N/A | Ruptured cerebral aneurysm (80–85%), vascular malformation, etc. | “Worst headache of life,” like being hit by a hammer, loss of consciousness | High risk of rebleeding, 30–50% mortality | High absorption area (blood) in the subarachnoid space on CT |
Detailed Explanation of Each Type
Putaminal Hemorrhage (Most Common)
- Caused by the rupture of the tiny Lenticulostriate arteries, which are damaged by long-standing high blood pressure.
- The classic presentation is contralateral hemiparesis + contralateral sensory loss + eye deviation towards the lesion.
- Prognosis tends to worsen if the hematoma volume exceeds 30 mL.
Thalamic Hemorrhage
- Characterized by sensory loss of the entire opposite body side because the thalamus is a major sensory relay center.
- Thalamic pain (a severe chronic pain syndrome) can occur as a sequela.
- Blood entering the ventricle can cause acute hydrocephalus, leading to a sudden decline in consciousness.
Subcortical Hemorrhage (Lobar Hemorrhage)
- In the elderly, it is often caused by Cerebral Amyloid Angiopathy (CAA), where amyloid deposits in the blood vessels, leading to recurrent bleeds.
- If it occurs suddenly in a young person, Vascular Malformation (AVM) is highly suspected (requires MRI investigation).
Cerebellar Hemorrhage
- The “6-hour rule” is critical: If the hematoma size increases within 6 hours of onset, emergency surgery (posterior fossa decompression) is required.
- Since the cerebellum is in a confined space, hematoma can compress the brainstem, leading to rapid respiratory arrest.
Pontine Hemorrhage (Brainstem Hemorrhage)
- Can result in “pinpoint paralysis” or Locked-in Syndrome.
- Even those who survive often have severe residual deficits.
Helpful Guidelines to Remember
- Caused by Hypertension → Common in the Putamen, Thalamus, Pons, and Cerebellum.
- Sudden onset in a young person → Suspect Vascular Malformation or Aneurysm.
- Multiple subcortical bleeds in the elderly → Suspect Amyloid Angiopathy.
- “Worst headache of my life” + Vomiting → First and foremost, suspect Subarachnoid Hemorrhage.
