What is a stroke?

A stroke is defined as the sudden onset of neurological deficits – for example, paralysis of one side of the body – that last at least 24 hours. In about five out of six cases, a stroke is caused by a disturbance in circulation (ischaemic stroke), and in the remaining cases by bleeding in the brain (haemorrhagic stroke).


An ischemic stroke occurs when an artery supplying a specific area of the brain becomes permanently blocked by a blood clot. After about 10 seconds, the affected area of the brain becomes divided into two zones with different prognoses: the region in the centre receives the least blood and contains irreversibly damaged nerve tissue. The area surrounding the core is the slightly better-perfused penumbra. Like the core zone, it is functionally inactive but not damaged irreversibly.

Intracerebral hemorrhage (ICH), also known as cerebral bleed, is a type of intracranial bleed that occurs within the brain tissue or ventricles. Symptoms can include headache, one-sided weakness, vomiting, seizures, decreased level of consciousness, and neck stiffness. Often symptoms get worse over time. In many cases bleeding is present in both the brain tissue and the ventricles. Causes include brain trauma, aneurysms, arteriovenous malformations, and brain tumours. The largest risk factors for spontaneous bleeding are high blood pressure and amyloid deposits in aging blood vessels. Other risk factors include heavy alcohol use, low cholesterol, blood thinners and illicit drug use, in particular cocaine. Diagnosis is typically by CT scan.


Immediately after admission, a blood sample is taken, infusions are placed, ECG measurements are taken and monitoring set up, and an oxygen meter placed on the stroke patient’s finger. Afterwards, the doctor collects the patient’s medical history and examines the patient. Finally, the brain is investigated using nuclear magnetic resonance (MR) and the cerebral arteries with MR angiography to determine if the cause of the stroke is a blood clot or bleeding. This is significant in the determination of further treatment.

Patients rushed to hospital with a suspected stroke are pre-registered with the Mediclinic City Hospital Stroke Centre by the emergency services. The initial inquiries and referral for imaging are completed within a matter of minutes.

Initial examinations and the arrival of a neurologist the Stroke Centre also take place swiftly for patients who come directly to the emergency department of Mediclinic City Hospital.