A subarachnoid hemorrhage (SAH) occurs when a blood vessel in the brain ruptures, causing blood to flow rapidly into a space between the brain and the skull known as the subarachnoid space. A subarachnoid hemorrhage is usually the result of a ruptured intracranial aneurysm, but an SAH also can be caused by head trauma or an arteriovenous malformation.
Signs and Symptoms
Signs and symptoms of a subarachnoid hemorrhage include: a sudden and severe onset of headache, often described as the “worst headache of my life,” a stiff or painful neck, vision loss, inability to move an arm or leg, numbness, tingling, speech difficulty, and/or loss of consciousness.
The first diagnostic test typically performed is a noninvasive CT scan, which will show blood in the subarachnoid space and help physicians determine the cause of the bleeding. The CT scan will be followed by a CT angiogram, a noninvasive study that produces 3D images. If the SAH is caused by an aneurysm, this test will show where the aneurysm is located, its size and shape, and its relationship to other structures of the brain. A cerebral angiogram also may be performed in patients who present with an SAH.
Subarachnoid Hemorrhage Treatment
Treatment for SAH depends on the cause.
If the SAH was caused by an Intracranial Aneurysm, treatment is typically initiated within 24 to 48 hours via either surgical clipping or endovascular coiling. This is done to prevent re-bleeding of the aneurysm.
If the SAH was caused by an Arteriovenous Malformations (AVM), a cerebral angiogram with embolization followed by surgical resection may be necessary.
If the SAH was caused by a traumatic injury, the patient will be observed and managed in the neuroscience intensive care unit (NSICU).
Related Conditions of SAH
After a SAH, the major risk that patients face is vasospasm. Vasospasm narrows the artery and reduces the blood flow to the region of the brain that the artery feeds. If left untreated, vasospasm can cause a stroke. Vasospasm can occur three to 30 days after SAH, appearing most commonly between the third and fourteenth day.
In the NSICU, patients are monitored every hour for signs of vasospasm which include: weakness in an arm or leg, confusion, sleepiness, or restlessness. The arteries are also monitored using a test called Transcranial Doppler Study (TCD), a special ultrasound machine that is able to measure the velocity of the artery- or the amount of narrowing. To control vasospasm, patients are given the drug Nimodipine for 14 days, combined with Triple H therapy.
Triple H therapy includes:
Hypertension: increasing the blood pressure to force blood through the narrowed arteries.
Hypervolemia: increasing IV fluids to make more blood volume.
Hemodilution: making the blood thin and watery so that it flows more easily through narrowed arteries.
If Triple H therapy is ineffective, different medications can be injected into the artery to make it relax and open. Patients will be taken to the interventional radiology suite for a cerebral angiogram. A catheter is threaded into the groin and up to the cerebral vasculature. Once the vessel in vasospasm is identified, a medication called Verapamil is injected directly into the vessel. This medication will relax the vessel and allow for increased blood flow.
Balloon angioplasty can also be used to reduce vasospasm. This procedure is preformed in the interventional radiology suite during a cerebral angiogram. A catheter is fed up through the groin to the vessel in vasospasm. A balloon around the catheter is inflated, stretching the vessel and allowing for increased blood flow. The balloon is deflated and removed, but the stretched vessel remains open.
Hydrocephalus is an abnormal accumulation of cerebrospinal fluid (CSF) in the ventricles or cavities in the brain. In an SAH, this occurs when blood interferes with the normal outflow of CSF from the brain. A CT scan will reveal enlarged ventricles and trapping of CSF in the brain. Patients with hydrocephalus will have a decreased level of consciousness. Hydrocephalus can be acute (typically lasting the duration of hospitalization) or chronic (if there is a permanent obstruction of CSF).
There are several treatment options for acute hydrocephalus after SAH. A lumbar drain can be placed in the lower back to allow CSF to be drained manually as the blood dissipates from the brain. A second option involves placing an intraventricular catheter (IVC) directly into the ventricle of the brain to manually drain CSF. If an IVC is placed, a trial run is conducted to determine if the hydrocephalus is acute or chronic. In acute cases, the drain is raised, clamped and then discontinued. In these situations, CSF will freely flow out of the ventricles. If the patient does not tolerate the raising or clamping period, a permanent internal shunt may need to be placed for long-term CSF drainage.