Symptoms And Definition Of Aneurysm

Aneurysm

Introduction:

The term aneurysm is derived from the Greek word aneurysma meaning “a widening”.An aneurysm is a localized, abnormal, weak spot on a blood vessel wall that causes an outward bulging likened to a bubble or balloon. Aneurysms are a result of a weakened blood vessel wall and may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus for thrombosis and embolization. As an aneurysm increases in size, the risk of rupture increases leading to uncontrolled bleeding.

Although they may occur in any blood vessel particularly lethal examples include aneurysms of the Circle of Willis in the brain, aortic aneurysms affecting the thoracic aorta and abdominal aortic aneurysms.

Classification:

Aneurysms

o Medium aneurysms are 6–15 mm. o Large aneurysms are 16–25 mm . o Giant aneurysms are larger than 25 mm.

Brain Aneurysm

Four major blood vessel supply blood to the brain. They join together at the circle of willis at the base of the brain. Smaller arteries leave the circle and branch out to supply brain cells with oxygen and nutrients.Artery junction points may become weak causing a ballooning of the blood vessel wall to potentially form a small sac or aneurysm.Cerebral aneurysms are common but most are asymptomatic and are found incidentally at autopsy.

Causes of Brain Aneurysm:

Aneurysms have a variety of causes including high blood pressure and atherosclerosis, trauma, heredity and abnormal blood flow at the junction where arteries come together.There are other rare causes of aneurysms. Mycotic aneurysms are caused by infections of the artery wall. Tumors and trauma can also cause aneurysms to form. Drug abuse especially cocaine can cause the artery walls to inflame and weaken. Figure 2

Signs & Symptoms:

Symptoms can occur when the aneurysm pushes on a structure in the brain. Symptoms will depend on whether an aneurysm has ruptured or not. There may be no symptoms present at all until the aneurysm ruptures.For an aneurysm that has not ruptured the following symptoms can

 The history of the headache An acute onset of the headache of the patient’s life associated with a stiff neck. Figure 3

 CT-scan & MRI

An ill appearing patient on physical examination typically lead the health care practitioner to consider the diagnosis and order a CT (computerized tomography) scan of the head. If the CT scan is performed within 72 hours of the onset of the headache it will detect 93% to 100% of all aneurysms. Figure 4

 Lumbar Puncture

In the few cases that are not recognized by CT the health care practitioner may consider performing a lumbar puncture to identify blood in the cerebrospinal fluid that runs in the subarachnoid space.

 Angiography

If the CT or the LP reveals the presence of blood angiography is performed to identify where the aneurysm is located and to plan treatment. Angiography where a catheter is threaded into the arteries of the brain and dye is injected while pictures are taken can demonstrate the anatomy of the arteries and uncover the presence and location of an aneurysm. CT angiography or MR angiography may be performed without threading catheters into the brain as is the case with a formal