Types of Stroke
There are two main types of stroke – ischaemic and haemorrhagic.
Ischaemic stroke is due to a blockage of the blood vessels supplying to the brain tissues. Risk factors leading to ischaemic stroke include increasing age, hypertension, high cholesterol, diabetes, smoking and also atrial fibrillation (a condition where the heart beats irregularly).
Fig. CT scan showing
an ischaemic stroke
A transient ischaemic attack, commonly referred to as a TIA, is when patients present with symptoms of stroke, but the symptoms are short-lasting and resolve completely within 24 hours. It is important to recognise TIAs and seek early medical advice in these instances. While even though the symptoms seem to have resolved and the individual returned to previous health state, the underlying disease development would not be taken care of adequately if no medical attention was sought. If the underlying causes of a TIA have not been deciphered and appropriate treatment not timely initiated, there is a significant risk that a portion of the TIA patients may subsequently develop a disabling stroke with the silently advancing pathophysiological changes undetected. Therefore, it is crucial that individuals suffering from a suspected TIA episode recognizes the symptoms and seek medical attention timely.
Haemorrhagic stroke is where a blood vessel supplying the brain tissues suddenly bursts, resulting in bleeding within the brain and subsequently affecting the blood supply to the targeted normal brain cells.
Fig. CT scan showing a large haemorrhagic stroke
Risk factors include increasing age and hypertension; but it may also be due to an underlying blood vessel abnormality such as an aneurysm (where the blood vessel wall is weakened), underlying blood clotting disorders, use of blood thinners etc.