Last updated date: 07-Jun-2023

Originally Written in English

The Harmful Effects of Subarachnoid Hemorrhage (SAH)


    Subarachnoid hemorrhage (SAH) refers to bleeding that occurs in the subarachnoid space, the area between the arachnoid membrane and the pia mater surrounding the brain. Early mortality is a significant concern, but with prompt medical attention and appropriate treatment, outcomes can be improved.


    What is Subarachnoid Hemorrhage (SAH)?

    Subarachnoid Hemorrhage (SAH)

    Subarachnoid hemorrhage (SAH) is a type of bleeding that occurs in the subarachnoid space, which is the area between the brain and the thin tissues that cover it. It is a medical emergency that can cause severe brain damage, stroke, and even death. SAH typically occurs as a result of a ruptured cerebral aneurysm, which is a weak spot in the wall of a blood vessel in the brain. When an aneurysm ruptures, blood leaks into the subarachnoid space and causes pressure on the brain and surrounding tissues, leading to a range of symptoms such as sudden and severe headache, neck pain and stiffness, nausea and vomiting, confusion, seizures, and loss of consciousness.


    How common is Subarachnoid Hemorrhage (SAH)?

    Subarachnoid hemorrhage (SAH) is relatively rare compared to other types of strokes. Its annual incidence varies depending on geographic location and population demographics. On average, the incidence of SAH is estimated to be around 6 to 16 cases per 100,000 people per year.

    SAH can occur at any age, but it is more common in adults, with the highest incidence observed in individuals between the ages of 40 and 60. There is also a slightly higher incidence in women compared to men.

    While SAH is considered relatively uncommon, it is a serious medical condition that requires prompt medical attention. It is essential to recognize the symptoms of SAH and seek immediate medical care if any signs of a potential hemorrhage are present, as early intervention is crucial for the best possible outcome.


    What causes subarachnoid hemorrhage?

    Causes subarachnoid hemorrhage

    A subarachnoid hemorrhage (SAH) is typically caused by the rupture of an aneurysm, which is a weakened area in the wall of a blood vessel within the brain. However, there can be other less common causes of SAH as well. Here are the primary causes:

    1. Aneurysm Rupture: The most common cause of subarachnoid hemorrhage is the rupture of a cerebral aneurysm. Aneurysms are abnormal bulges or sacs that form in weakened areas of blood vessels, often at the branching points. When an aneurysm ruptures, blood leaks into the space between the arachnoid membrane and the pia mater, which is called the subarachnoid space.
    2. Traumatic Brain Injury: Severe head trauma, such as a car accident or a fall, can lead to subarachnoid hemorrhage. The impact causes blood vessels to rupture, resulting in bleeding into the subarachnoid space.
    3. Arteriovenous Malformation (AVM): An arteriovenous malformation is an abnormal tangle of blood vessels in the brain. These tangled vessels can rupture and cause subarachnoid hemorrhage. AVMs are usually present at birth, but symptoms may not occur until later in life.
    4. Blood Disorders: Certain blood disorders that affect the clotting ability of blood, such as hemophilia or sickle cell anemia, can increase the risk of spontaneous bleeding, including subarachnoid hemorrhage.
    5. Vascular Abnormalities: Other vascular abnormalities, such as vascular tumors or vascular infections, can also cause subarachnoid hemorrhage, although these are relatively rare.


    What are the Symptoms of Subarachnoid Hemorrhage?

    Symptoms of Subarachnoid Hemorrhage

    Symptoms of a subarachnoid hemorrhage (SAH) can vary depending on the severity and location of the bleeding. The onset of symptoms is often sudden and intense, resembling a severe headache. Here are some common symptoms associated with SAH:

    1. Sudden and severe headache: Described as the worst headache of one's life, often referred to as a "thunderclap" headache. It can occur suddenly, without any apparent cause.
    2. Neck stiffness and pain: Stiffness in the neck and pain, commonly referred to as a "stiff neck," may be present. It can be difficult to touch the chin to the chest due to the stiffness.
    3. Nausea and vomiting: These symptoms are often accompanied by the severe headache and can persist even after vomiting.
    4. Sensitivity to light (photophobia): Bright lights or even normal indoor lighting may cause discomfort and sensitivity to the eyes.
    5. Altered consciousness: SAH can cause a decrease in consciousness levels, ranging from mild confusion to loss of consciousness.
    6. Seizures: Some individuals may experience seizures, which can manifest as uncontrolled movements or convulsions.
    7. Vision problems: Blurred or double vision, visual disturbances, or even temporary loss of vision in one or both eyes may occur.
    8. Loss of coordination and balance: Difficulty with coordination, balance, and walking may be present.


    How is Subarachnoid Hemorrhage (SAH) Diagnosed?

    Subarachnoid Hemorrhage (SAH) Diagnosed

    The diagnosis of subarachnoid hemorrhage (SAH) typically involves a combination of medical history assessment, physical examination, imaging studies, and, in some cases, additional tests.

    Here is an overview of the diagnostic process for SAH:

    1. Medical history and physical examination: The healthcare provider will gather information about the patient's symptoms, medical history, and any risk factors for SAH. They will perform a thorough neurological examination, checking for signs of neurological deficits, neck stiffness, and other physical indicators.
    2. Imaging tests:
      • Computed Tomography (CT) scan: This is often the initial imaging test used to diagnose SAH. A CT scan can detect the presence of blood in the brain and determine the location and extent of bleeding. If performed within a few hours after the onset of symptoms, it has a high sensitivity for detecting SAH.
      • Magnetic Resonance Imaging (MRI): An MRI scan may be performed if the initial CT scan is inconclusive or to provide more detailed information about the brain and blood vessels. MRI can help identify underlying causes, such as aneurysms or vascular malformations.
      • Cerebral Angiography: In some cases, a cerebral angiogram may be performed. It involves the injection of a contrast dye into the blood vessels to visualize the cerebral arteries and identify any abnormalities, such as an aneurysm or arteriovenous malformation.
    3. Lumbar puncture (spinal tap): A lumbar puncture may be performed if the initial imaging is inconclusive, but SAH is still suspected. In this procedure, a needle is inserted into the lower back to collect a sample of cerebrospinal fluid (CSF). If blood is present in the CSF, it indicates a subarachnoid hemorrhage.
    4. Other tests: Additional tests may be conducted to assess the patient's overall condition and to evaluate any complications or related issues. These may include blood tests, electrocardiogram (ECG) to check for cardiac abnormalities, and other investigations as deemed necessary.

    Early and accurate diagnosis of SAH is crucial for prompt treatment and improved outcomes. If you suspect a subarachnoid hemorrhage or experience severe symptoms, it is important to seek immediate medical attention.


    How is Subarachnoid Hemorrhage (SAH) Treated?

    Subarachnoid Hemorrhage (SAH) Treated

    The treatment of subarachnoid hemorrhage (SAH) involves a multidisciplinary approach and aims to address the underlying cause, manage complications, prevent rebleeding, and provide supportive care. Here are the primary components of SAH treatment:

             1. Emergency Care: SAH is a medical emergency, and immediate medical attention is necessary. The patient will be stabilized to ensure adequate oxygen supply, blood pressure control, and management of any life-threatening complications.

             2. Aneurysm Repair: If an aneurysm is identified as the cause of the SAH, it will require treatment to prevent rebleeding. The two main treatment options are:

        • Surgical Clipping: This involves a neurosurgical procedure to place a metal clip at the base of the aneurysm, effectively sealing it off from the circulation.
        • Endovascular Coiling: In this minimally invasive procedure, a catheter is threaded through the blood vessels to the site of the aneurysm. Small platinum coils are then inserted into the aneurysm, promoting clotting and sealing it off.

              3. Medications:

        • Nimodipine: This medication is commonly prescribed after SAH to prevent vasospasm, which is a narrowing of blood vessels in the brain that can occur after the hemorrhage.
        • Pain medications: Analgesics and other pain medications may be prescribed to manage the severe headache associated with SAH.

              4. Management of Complications:

      • Vasospasm management: If vasospasm occurs despite nimodipine treatment, additional interventions may be needed to improve blood flow, such as intravenous medications, angioplasty, or the administration of medications directly into the blood vessels (intra-arterial therapy).
      • Hydrocephalus: If there is a buildup of cerebrospinal fluid in the brain, a drainage system (ventriculostomy) may be inserted to alleviate pressure.
      • Seizure management: Medications may be administered to prevent and control seizures if they occur.

              5. Rehabilitation and Supportive Care: Following the acute treatment, the patient will require a comprehensive rehabilitation program, including physical therapy, occupational therapy, and speech therapy if needed. Supportive care will focus on managing pain, preventing complications, and addressing psychological and emotional needs.

    SAH treatment can vary depending on the severity of the hemorrhage, the location of the aneurysm, the patient's overall health, and other individual factors. It is essential to consult with a neurologist or neurosurgeon for a thorough evaluation and personalized treatment plan.


    What are the Complications of Subarachnoid Hemorrhage (SAH)?

    Complications of Subarachnoid Hemorrhage (SAH)

    Subarachnoid hemorrhage (SAH) can lead to various complications, which may arise from the initial bleeding or occur during the treatment and recovery process. The complications can range from immediate life-threatening conditions to long-term effects.

    Here are some common complications associated with SAH:

    1. Rebleeding: One of the most significant risks after an SAH is the potential for rebleeding. The risk is highest in the first 24-48 hours but can persist for up to two weeks. Rebleeding carries a high mortality rate and requires immediate medical attention.
    2. Vasospasm: Vasospasm refers to the narrowing of blood vessels in the brain that can occur after an SAH. It typically peaks between the fourth and fourteenth day after the initial bleeding. Vasospasm can reduce blood flow to the brain, leading to cerebral ischemia (lack of oxygen and nutrients) and potentially causing stroke or brain damage.
    3. Hydrocephalus: SAH can disrupt the normal flow and absorption of cerebrospinal fluid (CSF), leading to the accumulation of fluid in the brain. This condition is known as hydrocephalus. Hydrocephalus can cause increased pressure within the skull and may require the placement of a ventriculostomy or shunt to drain the excess fluid.
    4. Seizures: Some individuals who experience SAH may develop seizures. Seizures can be a result of the initial bleeding, blood irritating the brain tissue, or subsequent brain damage. Antiseizure medications may be prescribed to prevent or control seizures.
    5. Cognitive and Neurological Deficits: Depending on the severity and location of the SAH, individuals may experience cognitive impairments, memory problems, difficulty with concentration, and other neurological deficits. Rehabilitation therapy, including physical, occupational, and speech therapy, may be necessary to address these deficits.
    6. Emotional and Psychological Effects: SAH can have a significant emotional and psychological impact on patients. They may experience anxiety, depression, post-traumatic stress disorder (PTSD), or other emotional disturbances. Psychosocial support and counseling can be beneficial in managing these effects.
    7. Other complications: Other possible complications include infections, respiratory problems, cardiac abnormalities (such as arrhythmias), deep vein thrombosis (DVT), pulmonary embolism (PE), and pressure ulcers in individuals with limited mobility.


    How can I reduce my risk for Subarachnoid Hemorrhage (SAH)?

    While subarachnoid hemorrhage (SAH) cannot always be prevented, there are certain lifestyle modifications and measures you can take to reduce your risk. Here are some strategies that may help lower the risk of SAH:

    1. Manage Blood Pressure: Hypertension (high blood pressure) is a significant risk factor for SAH. It's important to maintain healthy blood pressure levels through lifestyle changes, such as adopting a balanced diet low in sodium, engaging in regular physical activity, and reducing stress. If necessary, consult your healthcare provider for appropriate blood pressure management and medication.
    2. Avoid Smoking: Cigarette smoking increases the risk of SAH. Quitting smoking or avoiding exposure to secondhand smoke can significantly reduce your risk. Seek support from healthcare professionals, smoking cessation programs, or support groups to help you quit smoking successfully.
    3. Limit Alcohol Consumption: Excessive alcohol consumption can raise blood pressure and increase the risk of SAH. Limit your alcohol intake to moderate levels or consider avoiding it altogether. Moderation typically means up to one drink per day for women and up to two drinks per day for men.
    4. Exercise Regularly: Engaging in regular physical activity can help maintain a healthy cardiovascular system and reduce the risk of SAH. Aim for at least 150 minutes of moderate-intensity aerobic exercise or 75 minutes of vigorous-intensity exercise each week. Consult your healthcare provider before starting any exercise program, especially if you have pre-existing health conditions.
    5. Eat a Healthy Diet: Adopting a balanced and nutritious diet can promote overall cardiovascular health. Focus on consuming a variety of fruits, vegetables, whole grains, lean proteins, and healthy fats. Reduce the intake of processed foods, saturated and trans fats, and excessive salt.
    6. Maintain a Healthy Weight: Obesity is associated with an increased risk of SAH. Maintain a healthy weight through a combination of a healthy diet and regular physical activity. Consult a healthcare professional for guidance on achieving and maintaining a healthy weight.
    7. Treat Underlying Medical Conditions: If you have underlying medical conditions such as diabetes, high cholesterol, or atrial fibrillation, ensure they are properly managed and controlled with the help of your healthcare provider. Following the recommended treatment plan and attending regular check-ups can reduce the risk of complications.
    8. Be Mindful of Family History: A family history of aneurysms or SAH may increase your risk. If there is a history of SAH or aneurysms in your family, consider discussing it with your healthcare provider to determine if any additional screening or preventive measures are recommended.

    Remember, these strategies can help reduce the risk of SAH, but they do not guarantee prevention. If you have concerns or specific risk factors, it is advisable to consult with a healthcare professional for personalized advice and appropriate risk assessment.


    What is the Prognosis for Subarachnoid Hemorrhage (SAH)?

    The prognosis for subarachnoid hemorrhage (SAH) can vary widely depending on several factors, including the severity of the hemorrhage, the location of the bleeding, the age and overall health of the individual, and the timely management of complications. Here are some key points regarding the prognosis of SAH:

    1. Early Mortality: SAH is a medical emergency associated with a significant risk of early mortality. Approximately 10-15% of individuals with SAH die before reaching the hospital, often due to the severity of the bleeding or complications during the acute phase.
    2. Rebleeding: The risk of rebleeding is highest within the first 24-48 hours after the initial hemorrhage and decreases over time. Rebleeding carries a high mortality rate and can have a severe impact on the prognosis. Prompt treatment to secure the aneurysm or the source of bleeding is crucial in preventing rebleeding.
    3. Vasospasm and Delayed Ischemic Deficits: Vasospasm, which is the narrowing of blood vessels in the brain after SAH, can lead to delayed ischemic deficits. These deficits, resulting from reduced blood flow and oxygen supply to the brain, can cause further neurological damage and impact prognosis. Aggressive management of vasospasm, including monitoring, blood pressure control, and interventions such as angioplasty or intra-arterial therapy, can improve outcomes.
    4. Neurological Deficits and Functional Recovery: SAH can result in varying degrees of neurological deficits depending on the extent of brain damage caused by the hemorrhage or subsequent complications. Recovery from these deficits can be a lengthy process, and the extent of functional recovery can vary from individual to individual. Rehabilitation programs, including physical therapy, occupational therapy, and speech therapy, can aid in maximizing functional recovery and improving quality of life.
    5. Long-Term Outcomes: The long-term prognosis for SAH survivors can be influenced by various factors, including the presence of cognitive impairments, emotional and psychological effects, and the development of other medical conditions or complications. 

    It's worth noting that SAH is a complex condition, and outcomes can be unpredictable. The management of SAH requires a multidisciplinary approach, involving neurosurgeons, neurologists, critical care specialists, and rehabilitation teams. Early diagnosis, prompt treatment, and comprehensive care can positively impact the prognosis and improve the chances of favorable outcomes. The individual's overall health, age, and ability to access appropriate medical care and rehabilitation services also play a significant role in determining the prognosis.


    What is the difference between Subarachnoid Hemorrhage and Subdural Hematoma?

    Subarachnoid hemorrhage (SAH) and subdural hematoma are both types of bleeding that can occur within the skull, but they differ in terms of the location and the mechanism of bleeding. Here are the key differences between SAH and subdural hematoma:

    • Location of Bleeding:
        • SAH: In SAH, the bleeding occurs in the subarachnoid space, which is the area between the arachnoid membrane and the pia mater, the delicate innermost layer covering the brain. The subarachnoid space is filled with cerebrospinal fluid (CSF), and SAH involves blood accumulating within this space.
        • Subdural Hematoma: In a subdural hematoma, the bleeding occurs between the dura mater (the tough outermost layer covering the brain) and the arachnoid membrane. Blood accumulates in the potential space between these layers.
    • Mechanism of Bleeding:
        • SAH: SAH is commonly caused by the rupture of an intracranial aneurysm, which is a weakened area in the wall of a blood vessel in the brain. Other causes can include head trauma, arteriovenous malformations (AVMs), or bleeding disorders.
        • Subdural Hematoma: Subdural hematoma typically occurs due to trauma, such as a blow to the head or a fall, which causes the bridging veins between the brain and the dura mater to tear or rupture. This leads to blood accumulating in the subdural space.
    • Clinical Presentation and Symptoms:
        • SAH: The primary symptom of SAH is a sudden, severe headache often described as the worst headache of one's life. Other symptoms include neck stiffness, nausea, vomiting, altered consciousness, sensitivity to light, and neurological deficits.
        • Subdural Hematoma: Symptoms of a subdural hematoma can vary depending on the size and rate of bleeding. They can include headache, confusion, drowsiness, dizziness, nausea, vomiting, seizures, weakness, and focal neurological deficits specific to the affected area of the brain.
    • Imaging Findings:
      • SAH: SAH is often diagnosed using a computed tomography (CT) scan, which can detect the presence of blood in the subarachnoid space.
      • Subdural Hematoma: A CT scan or magnetic resonance imaging (MRI) is typically used to diagnose a subdural hematoma, which shows the accumulation of blood between the dura mater and the brain.

    The management and treatment of SAH and subdural hematoma also differ, depending on the severity and individual patient factors. Prompt medical attention and appropriate diagnostic imaging are essential in determining the specific type of bleeding and guiding the appropriate treatment approach.



    Subarachnoid hemorrhage (SAH) is a medical condition characterized by bleeding in the subarachnoid space, which is the area between the arachnoid membrane and the pia mater covering the brain. It most commonly occurs due to the rupture of an intracranial aneurysm, although other causes, such as head trauma or arteriovenous malformations, can also lead to SAH.

    While it is not always possible to prevent SAH, certain lifestyle modifications, such as managing blood pressure, avoiding smoking, limiting alcohol consumption, engaging in regular exercise, maintaining a healthy weight, and treating underlying medical conditions, can help reduce the risk.