1. Primary intracerebral haemorrhage (ICH): bleeding directly into brain tissue, commonly related to hypertension, anticoagulants, cerebral amyloid angiopathy in older adults, vascular malformation, tumour, or drugs such as cocaine.
2. Haemorrhagic transformation of an ischaemic infarct: bleeding into an area of prior ischaemic stroke, more likely with a large infarct or after reperfusion treatment.

Imaging

• Non-contrast CT is usually the first test to confirm blood and assess mass effect or hydrocephalus. ICH is initially hyperdense; its appearance changes as the clot ages.
• MRI better characterizes the age of blood products and can help identify an underlying lesion. In subacute haemorrhage, methaemoglobin makes the bleed bright on T1 imaging. Frameworks for Internal Medicine, p. 576.

Clinical priorities in the subacute phase

• Repeat neurological examination and imaging if there is deterioration.
• Identify the cause: hypertension, antithrombotic medication, vascular lesion, venous thrombosis, tumour, or haemorrhagic transformation.
• Maintain carefully controlled blood pressure.
• Review antiplatelet and anticoagulant treatment with a stroke specialist. Restarting these is individualized and should not be done without specialist advice.
• Treat complications such as raised intracranial pressure, hydrocephalus, swallowing impairment, venous thromboembolism risk, seizures when present, and begin rehabilitation early.
• Plan secondary prevention, especially sustained blood-pressure control. The AHA/ASA ICH guideline addresses adult spontaneous ICH management and prevention.