Dr Health-shared Official
topic by Dr Health-shared Official

Diabetes and Stroke

Diabetes and Stroke

Those diagnosed with diabetes are at greater risks of suffering from a stroke (also known as a cerebrovascular accident). The inability to control the blood sugar levels causes damage to both the large and small blood vessels in the body. A high blood sugar level causes carbohydrate molecules (known as sugars) to stick to the enzymes and molecules in the body. This has a variety of effects but it importantly increases the amount of inflammation in the body. This aids a process known as atherosclerosis - the narrowing and hardening of the arteries. Atherosclerosis is an inflammatory process in which certain cell types move into the artery wall and begin a chemical process which changes its structure. This process leads to infiltration of the artery wall with fat-like substances which are then chemically changed and harden over time. The artery wall is then vulnerable to plaque formation in which the inner surface of the artery is broken and fissured – this means it is more susceptible to narrowing and blockage. There is a wealth of research into this process and certain medications are targeted at halting and reversing it.

Diagram showing the progression of atherosclerosis, causing the narrowing of arteries over time

The brain itself requires nutrients and oxygen to function. A stroke occurs when the brain is deprived of these nutrients and oxygen. The most common cause of stroke is unclear. Approximately half of all strokes are caused by a small blood clot forming in the general circulation and passing up to the blood vessels supplying the brain, causing a blockage. Around 1 in 4 strokes are caused by the plaque breaking off from the sides of the blood walls which then travels within the vessel towards the brain until the blood vessel is too small for the plaque to pass through, there it becomes lodged and causes a complete blockage. This prevents the supply of the oxygen and nutrients required by brain cells hence causing them to die. This type of stroke is known as an Ischemic stroke. There are other types of stroke, which are less common, that occur when high blood pressure weakens the walls of the arteries in the brain and causes them to burst. This is known as a haemorrhagic stroke. In both types of strokes, the damage to the brain cells is irreversible.

An Ischaemic stroke caused by a blockage to the blood vessels supplying that part of the brain, thus depleting it of the required oxygens and nutrients and causing the cells in that part of the brain to die as a result
A haemorrhagic stroke caused by the weakening of the walls of arteries in the brain, causing them to burst

Surviving a stroke is time critical – the faster one gets treatment, the greater the chances of survival. The treatment for strokes depends on the cause and time taken to intervene. For ischaemic strokes, which are the most common, if treated within 4.5 hours, interventions can be given to break the plaque blocking the artery. However, even if the supply to the brain is re-established, since the damage to cells is irreversible, patients can develop further complications dependant on the part of the brain that was affected, such as the inability to move arms and legs.

Find out more about stroke here. (Hyperlink stroke page on health shared)