What is SAH?

Subarachnoid haemorrhage (SAH) takes place when a cerebral artery ruptures and blood leaks out into the space between the membranes that cover the brain and spinal cord, i.e., the subarachnoid space. SAH is most commonly the result of a cerebro-arterial aneurysm, in 75% of cases, and in 5% of cases, it is the result of an arteriovenous malformation (AVM). Despite examinations, the cause is not established in 20% of cases. The latter SAH patients’ prognosis is good and new leaks do not occur.

SAH is a life-threatening disease. Symptoms are usually severe: sudden and acute headache, nausea and vomiting, stiffness of the neck, and eyes that are sensitive to light. A third of patients lose consciousness in connection with the leak. Other symptoms that may occur are one-sided paralysis of varying degrees, lingual problems (aphasia), double vision and sagging of the upper eyelid.

Non-leaking aneurysms can cause symptoms by applying pressure to the optic nerve or the occulomotor nerve that controls eye-movement muscles and the muscles that lift the eyelid. Hereby, an ophthalmologist can detect an aneurysm by looking for symptoms of pressure on these nerves: loss of part of the visual field, eye movement problems, squinting, double vision or sagging of the upper eyelid.

The incidence of SAH in Finland is unusually high, as much as 3 to 4 times higher than elsewhere in the world. In Finland about a thousand patients a year get SAH, which is a severe disease. The mortality rate is high, i.e. 50% of patients die within the first month.

Aneurysms do not appear to be clearly hereditary, even though, in dealings with patients, families with accumulations of SAH are encountered. Such families are screened for the prevention of SAH. About 10% of aneurysms are identified as familial occurrences.

Untreated arterial hypertension (high blood pressure) and smoking significantly increase the risks of SAH. High blood pressure can be prevented or controlled by the moderate use of alcohol and salt, weight control and sufficient exercise. It is always worthwhile to stop smoking.

How is SAH treated?

Once a patient has been diagnosed with SAH, before neurosurgery, medicinal treatment is prescribed in order to prevent new haemorrhages and cerebro-arterial contractions or vasospasms that cause cerebral ischemia.

The goal is to operate on the first day, but at least within three days of the haemorrhage. Neurosurgical treatment is the microsurgical closure of the neck of the aneurysm, i.e. ligation. The objective is to confine the aneurysm from the circulatory system, so that it does get to leak again. In certain cases an aneurysm may, alternatively, be filled with a thin platinum wire, i.e. a coil, in a neuroradiological operation. The form of treatment is selected with reference to the extent of the haemorrhage, the site and shape of the aneurysm and the age of the patient. The permanent tissue damage already caused by a SAH is, nonetheless, not treatable by surgery or by inserting coil.

Drug treatment is prescribed post-operatively to prevent vasospasms and other subsequent complications, still later. The patient’s condition permitting, the patient is transferred from the intensive care unit to the normal ward, where the emphasis of care is on rehabilitation and the promotion of independent function. In principle, non-haemorrhaging aneurysms in all under 65 year-olds should be treated, either by surgery or by the insertion of a coil. The problem is their diagnosis. More often than not, they are found by accident while carrying out imaging for other reasons.