Intracerebral hemorrhage can affect any person, regardless of age, sex, or race, but it is most common in older individuals.

Hypertensive intracerebral hemorrhage is caused by chronic high blood pressure (hypertension). When blood pressure has remained high for a significant period of time, blood vessel walls can change in a process called lipohyalinosis. This can lead to blockage of the vessels and leakage of blood into the brain as the constant pressure wears away at the vessels' walls.

Intracerebral bleeding associated with hypertension most commonly occurs in the tissues of the basal ganglia, pons, cerebellum, and deep white matter of the brain. Blood irritates the brain tissues, causing swelling (cerebral edema).

The blood collects into a mass (hematoma). Both the swelling of the brain tissues and the presence of a hematoma within the brain put increasing pressure on brain tissue and can eventually destroy it.

Bleeding may occur into the ventricles of the brain or into the subarachnoid space (the space between the brain and the meninges, the membranes that cover the brain), causing symptoms of meningeal irritation.