Subarachnoid hemorrhage

Generality

Subarachnoid hemorrhage is a blood spill in the space between the arachnoid and the pia mater (two of the three membranes - or meninges - that cover and protect the brain). Bleeding can occur spontaneously or derive from a head injury or from the rupture of a brain aneurysm.

Symptoms of subarachnoid hemorrhage include: sudden and severe headache, vomiting, confusion, unconsciousness and convulsions. Diagnosis is generally confirmed by computerized tomography (CT) of the head. If not treated appropriately, a subarachnoid hemorrhage can induce permanent brain damage or the patient's death. The therapeutic approaches involve neurosurgery and drugs, useful to prevent the recurrence of bleeding and the onset of other complications. Subarachnoid hemorrhage is a medical emergency and can lead to irreversible disability, even when it is recognized and treated at an early stage.

Causes

Subarachnoid hemorrhages are mainly caused (85% of cases) by the rupture of a cerebral aneurysm (pathological dilation of a cerebral artery with weakening of its wall and greater ease of rupture). Sometimes, the bleeding episode can be triggered by an increase in blood pressure.

Other less common causes include:

• Arteriovenous malformations;
• Head trauma;
• Brain tumors;
• Encephalitis;
• Vasculitis.

Diagnosis

To diagnose a subarachnoid hemorrhage, the doctor evaluates the symptoms and can prescribe a series of tests to determine the cause of the condition:

• Computed tomography: it is a minimally invasive scan (it provides exposure to a small dose of ionizing radiation) which allows us to examine the anatomical structures within the brain and confirms (or excludes) the presence of a blood effusion.
• MRI: provides a detailed view of the soft tissues of the brain and is used to monitor the condition in the days following onset.
• Cerebral angiography : accurately determines the origin of subarachnoid hemorrhage. A catheter is inserted into an artery and passed through the blood vessels of the brain, then a contrast medium is injected which allows the acquisition of radiographic images.

Treatment

Subarachnoid hemorrhage is a medical emergency and requires immediate treatment. Once the cause and location of the bleeding has been identified, medical or surgical therapy is performed to stop the bleeding, remove a possible clot and relieve intracranial pressure.

The treatment is aimed at controlling symptoms and managing any complications that may occur, including:

• rebleeding;
• Cerebral vasospasm (involves narrowing of the arteries, with reduced blood supply to the brain);
• Accumulation of fluid in the brain (hydrocephalus).

The surgical approach aims to repair the origin of subarachnoid hemorrhage, including arteriovenous malformations, cerebral aneurysm or injuries due to trauma. The prognosis of subarachnoid hemorrhage has improved in recent decades and most patients survive. However, recovery can be a slow and often frustrating process.

How to reduce risk

To prevent subarachnoid hemorrhage, three effective measures can be taken:

• Stop smoking;
• Moderate alcohol consumption;
• Take measures to maintain blood pressure within normal parameters (such as, for example, exercising regularly and respecting a healthy, balanced diet).