ANEURYSM

What is an Aneurysm?

An aneurysm is a localized abnormal dilatation or ballooning of a blood vessel caused by weakness or damage in the blood vessel wall. Some aneurysms may be small and cause no problem. Usually all the layers of the blood vessel wall are involved in the aneurysm. Aneurysms are also caused by disease such as (arteriosclerosis and hypertension), injury or defect present at birth.

Types of Aneurysms:

· Dissecting aneurysm - A dissecting aneurysm is bleeding within the layers of the blood vessels- separation in the aortic wall, usually within the medial wall.
· Saccular aneurysm - A saccular aneurysm is an outpouching of the wall of the blood vessel with a narrow neck.
· Fusiform aneurysm - A fusiform aneurysm (spindle shaped) is the enlargement of the complete circumference of the blood vessel.

Locations of Aneurysms:
· Cerebral
· Subclavian
· Thoracic
· Abdominal
· Femoral and Popliteal
· Peripheral

Cerebral aneurysms

Cerebral aneurysm is a common cerebrovascular disorder caused by a weakness in the wall of an artery or vein of the brain (mostly in the circle of Willis). This disorder may be the result of congenital defects, arteriosclerosis, infection or head injury.

What are the symptoms of cerebral aneurysms?

A cerebral aneurysm may cause symptoms ranging from severe headaches, vision impairment, drowsiness, neck stiffness, nausea and vomiting to more severe symptoms such as mental confusion, vertigo (dizziness) and loss of consciousness, or the individual may experience no symptoms at all (asymptomatic).
Ruptured of a cerebral aneurysm is dangerous and usually results in bleeding in the brain or in area surrounding the brain, leading to an intracranial haematoma (clotted blood within the skull). This is most often accompanied by severe headache needing urgent medical attention.

What is the prognostic?

A ruptured aneurysm can lead to bleeding inside the head. Often, the aneurysm heals, bleeding stops and the patient survives. In more serious cases, the bleeding may cause brain damage with paralysis or coma (stroke). In some severe cases, a ruptured cerebral aneurysm can lead to death. Early diagnosis and treatment are important, the danger from an aneurysm is that it will continue to bulge and may burst. If an aneurysm in a large blood vessel or in the heart bursts, a person could bleed to death.

Investigations

In addition to a complete medical history and physical examination, diagnostic for cerebral aneurysms, can be detected by MRI scan (magnetic resonance imaging), CT scan (computed axial tomography) and angiograms.

• Angiogram--X-rays are used to produce pictures of the inside of blood vessels.
  
• CT scan (computed axial tomography)-is a diagnostic imaging procedure using a combination of x-rays and computer technology to produce cross- sectional images of the brain. CT scans are more detailed than general x-rays.
  
• Lumbar puncture--A needle is inserted under local anaesthetic into the spinal cavity and used to extract spinal fluid for testing.
  
• Ultrasound--high-frequency sound waves are transmitted through body tissues. The echoes from the sound waves are recorded and transformed into video or photographic images.
  
• MRI scan (magnetic resonance imaging)--a large magnet, radio waves and a computer are used to produce very clear detailed pictures of organs and structures within the body.

How are cerebral aneurysms treated?

Emergency treatment for ruptured cerebral aneurysm is to restore deteriorating respiration and to reduce intracranial pressure. Surgery is usually performed as soon as possible to clip the ruptured aneurysm and to reduce the risk of further bleeding or to repair the aneurysm with microsurgery. If surgery is considered too risky, microcoil thrombosis or balloon embolization may be an alternative. Other treatments may include intensive care, drug therapy and as little stress as possible.

Subclavian aneurysms

Aneurysms of the subclavian artery (under the clavicle) are less common and account for less than 1% of all peripheral aneurysms.
The most common causes are arteriosclerosis (hardening of the arteries), thoracic outlet obstruction (a mechanical, poststenotic dilation), post-traumatic (i.e. gun-shot, blunt trauma), aberrant (malposition) right subclavian artery and miscellaneous. Rare causes include: syphilis, tuberculosis and abnormalities of the vessel wall (fibromuscular dysplasia).

What are the symptoms?

In most cases an asymptomatic pulsatile mass is detected either above or below the clavicle (collar bone). Symptoms such as dysphagia (difficulty swallowing), stridor (difficulty breathing), chest pain, hoarseness, upper extremity fatigue, numbness/tingling and gangrene or ulceration of the fingers may develop with progressive enlargement of the aneurysm. These result from compression of adjacent structures (i.e. nerves, veins, trachea or esophagus), thromboembolism (blood clots breaking off from the wall of the aneurysm) or rupture into the soft tissues of the neck.