Subarachnoid Haemorrhage

What Is a Subarachnoid Haemorrhage? A subarachnoid haemorrhage (SAH) is a serious and potentially life-threatening type of haemorrhagic stroke. It occurs when bleeding develops in the subarachnoid space—the area between the brain and the thin protective membranes (meninges) that cover it. This space normally contains cerebrospinal fluid (CSF), which cushions and protects the brain and spinal cord. When bleeding occurs in this area, it can rapidly increase pressure inside the skull, damage brain tissue, and disrupt normal brain function. Subarachnoid haemorrhage is a medical emergency and requires immediate diagnosis and treatment. Difference Between Subarachnoid Haemorrhage and Subdural Haematoma Although both conditions involve bleeding inside the skull, they occur in different locations: Subarachnoid haemorrhage (SAH): Bleeding occurs in the subarachnoid space, between the brain and the membranes covering it. Subdural haematoma: Bleeding occurs between the dura mater (the outermost membrane) and the arachnoid membrane. These differences are important because they affect symptoms, causes, and treatment approaches. Symptoms of Subarachnoid Haemorrhage Symptoms usually appear suddenly and are often severe. Common signs include: Sudden, intense headache often described as a “thunderclap headache” Nausea and vomiting Stiff neck due to irritation of the meninges Sensitivity to light (photophobia) Blurred or double vision Loss of consciousness, ranging from brief fainting to coma Seizures Confusion, disorientation, or difficulty thinking clearly Any sudden severe headache should be treated as a medical emergency. Causes of Subarachnoid Haemorrhage Primary Causes Ruptured cerebral aneurysm: The most common cause; occurs when a weakened blood vessel bulges and bursts Head trauma: Due to falls, road traffic accidents, or direct blows to the head Arteriovenous malformations (AVMs): Abnormal tangles of blood vessels that are prone to rupture Contributing Risk Factors Blood clotting disorders Use of blood-thinning medications Chronic high blood pressure (hypertension), which weakens blood vessels over time Complications and Related Conditions Subarachnoid haemorrhage can result in severe short- and long-term complications, including: Re-bleeding, particularly in the early period after the initial haemorrhage Cerebral vasospasm, where brain blood vessels narrow and restrict blood flow Hydrocephalus, an accumulation of cerebrospinal fluid that may require surgical drainage Seizure disorders Long-term disability, including paralysis, speech difficulties, memory loss, and emotional or behavioural changes The severity of complications depends on the extent and location of the bleeding and how quickly treatment is initiated. How Can Subarachnoid Haemorrhage Be Prevented? While not all cases are preventable, reducing risk factors can significantly lower the likelihood of a subarachnoid haemorrhage: Regular monitoring and control of high blood pressure Maintaining a healthy, balanced diet low in saturated and trans fats Engaging in regular physical activity Avoiding smoking and limiting alcohol consumption Proper management of chronic conditions such as diabetes and heart disease Routine medical check-ups and screenings, especially for individuals with a family history of aneurysms