Brief overview
- Course of disease and prognosis: Depending on location and extent, potentially life-threatening, sequelae possible such as movement disorders, cognitive impairment, paralysis, better prognosis with small hemorrhage and early therapy
- Examination and diagnosis: If necessary, history, family history, accident history, imaging procedures, computer tomography (CT), magnetic resonance imaging (MRI), vascular imaging with X-ray contrast medium (angiography)
- Symptoms: sudden severe headache, nausea, vomiting, loss of consciousness, coma.
- Treatment: Stop bleeding by surgery, surgical procedures such as clipping or coiling.
- Prevention: No general prevention, treat hypertension, avoid factors that increase blood pressure.
What is a subarachnoid hemorrhage?
In a subarachnoid hemorrhage, a vessel ruptures between the middle meninges (arachnoid) and the soft meninges that directly overlie the brain.
In Central Europe and the USA, approximately six to nine out of 100,000 people suffer a SAB each year. Subarachnoid hemorrhage usually occurs between the ages of 30 and 60, but the average age is 50. Women are affected slightly more often than men.
What are the chances of recovery from a subarachnoid hemorrhage?
In general, subarachnoid hemorrhage is potentially life-threatening. Overall, one in two people affected by SAB dies. About half of the survivors suffer from late effects of the subarachnoid hemorrhage, such as paralysis, coordination disorders or mental impairments, and one third remain dependent on outside help for the rest of their lives.
Early intensive medical treatment of subarachnoid hemorrhage improves the chances of recovery and prognosis.
Subarachnoid hemorrhage manifests as a crushing headache. It is potentially life-threatening. Therefore, anyone with a massive, sudden headache that they have never experienced before should go to a hospital emergency room or call 911.
Among other things, the physician inquires about family members with strokes and brain hemorrhages because subarachnoid hemorrhage sometimes runs in families.
Imaging techniques
To diagnose a subarachnoid hemorrhage, a CT (computed tomography) scan of the skull is particularly informative. In the so-called cranial computed tomography (cCT), the physician usually recognizes the subarachnoid hemorrhage as a two-dimensional, white area adjacent to the brain surface.
Magnetic resonance imaging (MRI) can also be used to detect a subarachnoid hemorrhage in the first few days after the event. If CT or MRI provide unremarkable findings, the collection of cerebrospinal fluid (CSF) through a lumbar puncture helps in the diagnosis. A bloody sample indicates SAB.
To identify the source of the bleeding (such as an aneurysm), the doctor sometimes produces an X-ray image of the vessels (angiography).
What is the cause of a subarachnoid hemorrhage?
Rupture of the aneurysm is not linked to a specific disease, but often occurs in full health without prior symptoms, often even at complete rest. Sometimes the subarachnoid hemorrhage is preceded by physical exertion, such as heavy lifting, difficult bowel movements (heavy pressing) or sexual intercourse.
The cause of the aneurysm bursting is sometimes also a sudden rise in blood pressure.
Sometimes no cause for subarachnoid hemorrhage can be found despite an intensive search.
Subarachnoid hemorrhage: risk factors
Preventable risk factors for subarachnoid hemorrhage include high blood pressure, smoking, excessive alcohol consumption, and cocaine use. Non-preventable risk factors for SAB include age, a history of SAB, a family history of SAB, genetic factors, or vascular changes such as an aneurysm.
The leading symptoms of subarachnoid hemorrhage are sudden, severe, never-before-experienced headaches that spread rapidly from the neck or forehead over the entire head and, within the following hours, also toward the back.
This so-called “annihilation headache” is often accompanied by nausea, vomiting, photophobia, and neck stiffness (meningismus). Depending on the extent of the subarachnoid hemorrhage, there are disturbances of consciousness up to deep coma.
Five degrees of subarachnoid hemorrhage
Experts divide the severity of a subarachnoid hemorrhage into five grades (Hunt and Hess classification). These are based on the severity of the symptoms and can be related to the score in the so-called Glasgow Coma Scale (GCS).
- Hunt and Hess grade I: no or only mild headache, possibly mild neck stiffness, GCS score 15
- Hunt and Hess grade II: moderate to severe headache, neck stiffness, no neurological deficits except cranial nerve disorders due to direct pressure of leaked blood on cranial nerves, no change in consciousness, GCS score 13-14
- Hunt and Hess grade IV: severe disturbance of consciousness/deep sleep (sopor), moderate to severe incomplete hemiparesis, autonomic disturbances (such as disturbances in breathing or temperature regulation), GCS score 7-12.
- Hunt and Hess grade V: deep coma, no light reaction of the pupils, evidence in the neurological examination of brain entrapment due to excessive pressure in the skull, GCS score 3-6
How is a subarachnoid hemorrhage treated?
Surgery to eliminate the aneurysm
If a ruptured aneurysm is the cause of the subarachnoid hemorrhage, it is separated from the bloodstream as quickly as possible. This can be done in two ways: either surgically by a neurosurgeon (clipping) or via the blood vessels by an experienced neuroradiologist (endovascular coiling).
If vasospasm is present or the patient is in poor neurological condition, doctors tend to wait before operating, otherwise there is a risk that the vasospasm will be exacerbated by the procedure.
Coiling is recommended when low-risk surgery is not possible. However, the aneurysm cannot be eliminated quite as effectively by coiling as by clipping. For this reason, all patients who have undergone coiling must be monitored after a few months by angiography (imaging of the vessels with the aid of an X-ray contrast medium).
Vascular spasms (vasospasms)
“Water head” (hydrocephalus)
Another possible complication of subarachnoid hemorrhage is “hydrocephalus” – a dilation of the cerebral ventricles caused by accumulated cerebrospinal fluid. In some cases, the hydrocephalus recedes spontaneously. In most cases, however, the accumulated cerebrospinal fluid must be drained to the outside via a tube for a few days.
How can subarachnoid hemorrhage be prevented?
The most common cause of subarachnoid hemorrhage – an aneurysm – cannot be prevented in general. However, certain risk factors for SAB can be avoided. These include all measures that contribute to healthy blood pressure, such as:
- Not smoking
- Treat and control high blood pressure
- Avoiding obesity
- Moderate alcohol consumption
- Do not use drugs
