Subarachnoid Haemorrhage - Symptoms & Causes

What is a subarachnoid haemorrhage?

A subarachnoid haemorrhage (SAH) is a type of haemorrhagic stroke, causing bleeding between the brain and the thin membranes covering it, otherwise known as the subarachnoid space. This space is usually filled with cerebrospinal fluid, which surrounds the brain and spinal cord.

Bleeding into this area can increase pressure on the brain, damage brain cells, and interfere with the brain's ability to function. Subarachnoid haemorrhages are often life-threatening and require immediate medical attention.

Difference between a subarachnoid haemorrhage and subdural haematoma

A subarachnoid haemorrhage (SAH) and a subdural haematoma are both types of bleeding within the cranium and brain.

• A subarachnoid haemorrhage refers to bleeding in the subarachnoid space, i.e., between the brain and the thin membranes covering it.
• A subdural haematoma refers to bleeding between the dura mater and the arachnoid membrane.

What are the symptoms of subarachnoid haemorrhage?

The symptoms of a subarachnoid haemorrhage can appear suddenly and can be severe. Common symptoms include:

• Sudden severe headache, sometimes called a "thunderclap headache."
• Nausea and vomiting frequently accompany the headache.
• Stiff neck due to irritation of the meninges (the membranes covering the brain and spinal cord).
• Sensitivity to light (photophobia).
• Blurred or double vision.
• Loss of consciousness, ranging from brief fainting to prolonged unconsciousness.
• Seizures.
• Difficulty thinking clearly, confusion, or disorientation.

What causes a subarachnoid haemorrhage?

Causes of subarachnoid haemorrhage:

• Aneurysm rupture. The most common cause, where a weakened blood vessel swells up like a balloon, then bursts.
• Trauma. Head injuries from falls, accidents, or blows to the head.
• Arteriovenous Malformations (AVMs). Abnormal tangles of blood vessels that can rupture.

Contributing factors:

• Blood clotting disorders. Conditions that affect the blood’s ability to clot properly.
• Use of blood thinners. Medications that reduce blood clotting can increase the risk of bleeding.
• Hypertension. Chronic high blood pressure can weaken blood vessels and increase the risk of rupture.

What are the complications and related diseases for a subarachnoid haemorrhage?

Subarachnoid haemorrhage can lead to several serious complications:

• Re-bleeding. The risk of further bleeding after the initial haemorrhage.
• Vasospasm. Narrowing of blood vessels in the brain, which can reduce blood flow and cause further brain damage.
• Hydrocephalus. Accumulation of cerebrospinal fluid in the brain, which may require surgical intervention.
• Seizures. Ongoing risk of convulsions following the haemorrhage.
• Long-term disability. Paralysis, physical disabilities, cognitive, and emotional impairments depending on the severity and location of the haemorrhage.

How do you prevent a subarachnoid haemorrhage?

Preventing a subarachnoid haemorrhage involves managing risk factors and leading a healthy lifestyle:

• Regular monitoring and management of hypertension.
• Eating a balanced diet low in saturated fats, trans fats, and cholesterol.
• Regular physical activity to keep the cardiovascular system healthy.
• Avoid smoking and excessive alcohol consumption, as both can increase the risk of aneurysm formation and rupture.
• Manage chronic conditions such as diabetes, heart disease, and other related conditions.
• Routine health screenings to monitor and manage risk factors.