Aneurysm, intracranial berry

Intracranial Berry Aneurysm

An intracranial berry aneurysm is a type of cerebral aneurysm characterized by a saccular outpouching of a cerebral artery. These aneurysms are often found at the bifurcations of the major arteries of the brain and are a common cause of subarachnoid hemorrhage.

Pathophysiology

Intracranial berry aneurysms are typically located at the circle of Willis, a circulatory anastomosis that supplies blood to the brain and surrounding structures. The most common sites for these aneurysms include the anterior communicating artery, the posterior communicating artery, and the middle cerebral artery.

The development of a berry aneurysm is thought to be due to a combination of genetic and environmental factors. The wall of the aneurysm is thinner than that of a normal artery, making it prone to rupture. The rupture of a berry aneurysm leads to bleeding into the subarachnoid space, which can cause a subarachnoid hemorrhage, a life-threatening condition.

Risk Factors

Several risk factors are associated with the development of intracranial berry aneurysms, including:

• Hypertension: High blood pressure can weaken arterial walls, increasing the risk of aneurysm formation.
• Smoking: Tobacco use is a significant risk factor for the development and rupture of aneurysms.
• Genetic Predisposition: A family history of aneurysms can increase the risk.
• Age and Gender: Aneurysms are more common in adults over the age of 40 and are more prevalent in females.
• Connective Tissue Disorders: Conditions such as Ehlers-Danlos syndrome and Marfan syndrome can predispose individuals to aneurysm formation.

Symptoms

Unruptured berry aneurysms are often asymptomatic and may be discovered incidentally during imaging for other conditions. However, if an aneurysm ruptures, it can cause a sudden and severe headache, often described as "the worst headache of one's life." Other symptoms of rupture may include:

• Nausea and vomiting
• Stiff neck
• Sensitivity to light (photophobia)
• Loss of consciousness
• Neurological deficits

Diagnosis

The diagnosis of an intracranial berry aneurysm is typically made using imaging studies. Common diagnostic tools include:

• Computed Tomography (CT) Scan: A CT scan can quickly identify bleeding in the brain.
• Magnetic Resonance Imaging (MRI): An MRI provides detailed images of the brain and can detect aneurysms.
• Cerebral Angiography: This is the gold standard for diagnosing cerebral aneurysms and involves injecting a contrast dye into the cerebral arteries to visualize the aneurysm.

Treatment

The treatment of intracranial berry aneurysms depends on the size, location, and risk of rupture. Options include:

• Surgical Clipping: This involves placing a clip at the base of the aneurysm to prevent blood flow into it.
• Endovascular Coiling: A less invasive procedure where coils are inserted into the aneurysm to induce clotting and prevent rupture.
• Observation: Small, asymptomatic aneurysms may be monitored with regular imaging studies.

Prognosis

The prognosis for individuals with an intracranial berry aneurysm varies. Unruptured aneurysms have a better prognosis, especially if treated before rupture. The prognosis after rupture depends on the severity of the hemorrhage and the timeliness of treatment.

Also see

• Subarachnoid hemorrhage
• Cerebral aneurysm
• Circle of Willis
• Hypertension
• Endovascular coiling