Spontaneous subarachnoid hemorrhage (SAH) is a severe medical emergency involving sudden bleeding into the space surrounding the brain. This type of stroke demands immediate medical attention due to its rapid onset and serious consequences.
What Spontaneous Subarachnoid Hemorrhage Is
Spontaneous subarachnoid hemorrhage involves bleeding into the subarachnoid space, the area between the brain and its membranes. This space contains cerebrospinal fluid, cushioning the brain and spinal cord. When blood enters this area without external trauma, it rapidly increases pressure around the brain, disrupting normal brain function and potentially reducing cerebral blood flow.
Identifying the Signs
The defining symptom of a spontaneous SAH is an abrupt, excruciating headache, often described as the “worst headache of life” or “like being kicked in the head.” This “thunderclap headache” reaches maximum intensity within seconds to a minute and differs significantly from typical headaches due to its suddenness and severity. Other symptoms include a stiff neck, sensitivity to light (photophobia), nausea, and vomiting. Individuals may also experience confusion, a decreased level of consciousness, or brief loss of consciousness. Seeking immediate emergency medical care is important.
Causes and Diagnosis
The most common cause of spontaneous SAH is the rupture of a brain aneurysm, accounting for approximately 80% to 85% of cases. A brain aneurysm is a weakened, bulging area in a brain blood vessel, often located at the base of the skull. Less common causes include abnormal tangles of blood vessels (arteriovenous malformations or AVMs), or other vascular abnormalities. Risk factors such as high blood pressure, smoking, excessive alcohol consumption, and a family history of aneurysms contribute to their development and rupture.
Diagnosing spontaneous SAH typically begins with a non-contrast computed tomography (CT) scan of the head, detecting blood in the subarachnoid space. This imaging test has high sensitivity, approaching 100% if performed within six hours of headache onset. If the CT scan is inconclusive or negative, a lumbar puncture (spinal tap) may analyze the cerebrospinal fluid for signs of bleeding, such as red blood cells or xanthochromia (a yellowish discoloration). Once SAH is confirmed, further imaging like CT angiography (CTA) or cerebral angiography is used to pinpoint the exact source of the bleeding.
Treatment and Management
Immediate medical and surgical interventions manage spontaneous SAH and prevent further complications. Blood pressure is carefully controlled to reduce the risk of re-bleeding from the ruptured vessel. Pain management is a priority. The two primary procedures for securing a ruptured aneurysm are surgical clipping and endovascular coiling.
Surgical clipping involves opening the skull in a craniotomy to access the aneurysm. A small metal clip is placed at its base to seal it off from blood circulation. Endovascular coiling is a less invasive procedure where a catheter is threaded through a blood vessel, usually in the groin, up to the aneurysm. Tiny platinum coils are then deployed into the aneurysm, filling it and promoting blood clot formation. The choice between clipping and coiling depends on factors including the aneurysm’s location, size, and the patient’s overall health, often made through a multidisciplinary discussion.
Management also addresses potential complications. Hydrocephalus, a buildup of cerebrospinal fluid, can occur from blood blocking fluid drainage pathways and may require a drain to relieve pressure. Vasospasm, a narrowing of brain blood vessels, is another serious complication that can lead to reduced blood flow and further brain injury. It typically occurs 3 to 14 days after the initial hemorrhage and is managed with medications and sometimes endovascular procedures.
Life After Spontaneous Subarachnoid Hemorrhage
Recovery from a spontaneous SAH can be a prolonged and challenging process, varying significantly among individuals depending on the hemorrhage’s severity and location. Rehabilitation often plays a significant role, involving specialists such as physiotherapists, speech and language therapists, and occupational therapists, to help regain lost functions.
Many survivors experience persistent challenges, including fatigue, headaches, and sleep difficulties. Cognitive changes, such as problems with memory, concentration, and information processing, are common. Emotional difficulties like anxiety, depression, and irritability can arise. Ongoing medical follow-up and support are important to manage these long-term effects and help individuals adapt to their “new normal.”