Aneurysm 101

What is an aneurysm?

A brain (cerebral) aneurysm is a bulging or blister that arises at a weak area in the wall of an artery that supplies blood to the brain. In most cases, a brain aneurysm causes no symptoms and goes unnoticed. In certain cases, the brain aneurysm ruptures, releasing blood into the spinal fluid and brain causing a stroke and brain injury.

When a brain aneurysm leaks or ruptures, it causes bleeding into the brain (hemorrhagic stroke). Most often this bleeding occurs in the space between the brain and the thin tissues covering the brain. This type of hemorrhagic stroke is called a subarachnoid hemorrhage. A ruptured aneurysm is life-threatening and requires prompt medical treatment.

Many brain aneurysms, however, don’t rupture, create health problems or cause symptoms. Such aneurysms are often detected during tests for other conditions and are termed “an incidental finding.” Despite this, treatment of an “incidental” aneurysm may be appropriate in some cases to prevent a rupture in the future.

How do aneurysms form, and what causes them?

Brain aneurysms develop as a result of a weakness in the muscular layer of the artery wall. At the site of this weakness the artery wall initially bulges which then can enlarge to form an aneurysm. Aneurysms often form at forks or branches in arteries because those sections of the vessel are weaker. Although aneurysms can appear anywhere in the brain, they are most common in arteries at the base of the brain.

The exact cause or reason for the arterial wall weakness and aneurysm development is unknown, but researchers have concluded that there are factors; both at birth and that can develop over time, which may increase the risk of developing an aneurysm. While some of these risk factors can be controlled, other cannot.

Risk factors present at birth

  • Inherited connective tissue disorders, such as Ehlers-Danlos syndrome, that weaken blood vessels
  • Polycystic kidney disease, an inherited disorder that results in fluid-filled sacs in the kidneys and usually increases blood pressure
  • Abnormally narrow aorta (coarctation of the aorta), the large blood vessel that delivers oxygen-rich blood from the heart to the body
  • Cerebral arteriovenous malformation (brain AVM), an abnormal connection between arteries and veins in the brain that interrupts the normal flow of blood between them
  • Family history of brain aneurysm, particularly a first-degree relative, such as a parent,  sibling or child
  • Gender and race have been linked to higher risk of aneurysms. For example, women are more likely to develop a brain aneurysm or to suffer a subarachnoid hemorrhage. Also, African Americans are more likely than whites to have a subarachnoid hemorrhage.

Risk factors that develop over time

  • Older age
  • High blood pressure (hypertension). The risk of subarachnoid hemorrhage is greater in people with a history of hypertension.
  • Smoking. In addition to being a cause of hypertension, the use of cigarettes may greatly increase the chances of a brain aneurysm rupturing or increasing in size.
  • Hardening of the arteries (arteriosclerosis)
  • Drug abuse, particularly the use of cocaine and amphetamines
  • Head injury
  • Heavy alcohol consumption
  • Certain blood infections
  • Lower estrogen levels after menopause

Are there any symptoms to make me aware that I might have an aneurysm?

Unfortunately, most brain aneurysms cause little or no symptoms, and may only be discovered during tests for another, usually unrelated, condition. In some instances, an unruptured aneurysm may cause problems if it is pressing on areas in the brain; and that usually occurs in larger aneurysms that are big enough to cause pressure.

Potential symptoms of an unruptured aneurysm

  • Pain above and behind an eye
  • A dilated pupil
  • Change in vision or double vision
  • Numbness, weakness or paralysis of one side of the face
  • A drooping eyelid
  • Facial pain
  • Vertigo
  • Imbalance
  • Extremity weakness
  • Trouble swallowing
  • Speech impairment
  • Trouble with tongue motility

In the case of a ruptured or “leaking” aneurysm, symptoms often come swiftly and harshly. A sudden, severe headache is the key symptom of a ruptured aneurysm, one that many patients have described as the “worst headache” ever experienced. However, a bleeding aneurysm can also have many other symptoms, including those below.

Potential symptoms of a ruptured aneurysm

  • Sudden, extremely severe headache
  • Nausea and vomiting
  • Stiff neck
  • Blurred or double vision
  • Sensitivity to light
  • Seizure
  • A drooping eyelid
  • Loss of consciousness
  • Confusion
  • Sudden language or speech abnormality

If you have any of these symptoms or notice them in someone you know, call 911 or other emergency services immediately.

If there are few, if any, symptoms, how is a brain aneurysm diagnosed?

Oftentimes, brain aneurysms are detected after they’ve ruptured and become medical emergencies. However, a brain aneurysm may also be detected when you’ve undergone head-imaging tests for another condition. Regardless of the clinical situation, imaging tests to diagnosis and evaluate a brain aneurysm are very similar.

If such test results indicate you have a brain aneurysm, you may have the following tests:

  • Computed tomography (CT).A CT scan is a study that evaluates the brain tissue and possible bleeding. This study is the best test to see if a patient has suffered bleeding within the brain. However, this study does not image the blood vessels so it is not the best test to find an aneurysm. In some instances, very large aneurysms can be seen on a CT scan but even then the scan just suggests an aneurysm.
  • Computed tomography angiogram (CTA) scans. CTA is a more precise method of evaluating blood vessels than a standard CT scan, and uses a combination of CT scanning, special computer techniques, and dyes injected into the blood to produce images of blood vessels. In this study the arteries of the brain are imaged and an aneurysm can be detected with greater sensitivity.
  • Magnetic resonance angiography (MRA). Similar to a CTA, MRA uses a magnetic field and pulses of radio wave energy to provide pictures of blood vessels inside the body. The advantages of MRA are that it avoids the radiation and iodine dye needed for a CTA scan. The disadvantages are that the study takes a longer time to perform (so more difficult in a sick patient) and the resolution is less than CTA. However, it is rare to need both a CTA and MRA since they provide very similar information.
  • Cerebral angiogram. This is the gold-standard test to evaluate the blood vessels of the brain. During this X-ray test, a catheter is inserted through an artery in the groin or arm and moved up through the vessel into the neck. A dye is then injected into the carotid or vertebral arteries. After the dye is injected an x-ray movie is made of the dye moving through the blood vessels in the brain – from arteries to capillaries to veins. Although this test is more invasive and carries more risk than the above tests, it is the most sensitive test and best way to locate small (less than 5 mm) brain aneurysms. In addition, because this test follows the dye in motion further information regarding the blood flow pattern is obtained.

If a hemorrhage is detected on the CT or an aneurysm is seen on one of the non-invasive tests (CTA or MRA) most times the next step would be to perform a cerebral angiogram. This is because this is the most sensitive test and the information from a cerebral angiogram allows for the neurosurgeon to plan the best treatment course. The cerebral angiogram allows for more definite assessment as to whether an aneurysm is present; and if one is present will give the most accurate information regarding size, shape, location and relationship to the normal vessel. This information is crucial in determining the treatment options.

If I am diagnosed with an aneurysm, how is it treated?

Your doctor will consider several factors before deciding the best treatment for you. Things that will determine the type of treatment you receive are listed below:

Factors that doctors consider in making treatment recommendations include:

  • The size and location of the aneurysm. Because the risk of a small (less than 7 mm) aneurysm rupturing is low and surgery for a brain aneurysm is often risky, your doctor may want to continue to observe your condition rather than perform surgery.
  • Symptoms caused by the aneurysm – ruptured, headaches, pressure on the brain
  • Your age and general health
  • Family history of ruptured aneurysms
  • Congenital conditions that increase the risk of a ruptured aneurysm
  • Past history of aneurysm rupture

Surgical options

All surgical procedures carry some risks. The most significant risks of the treatment options listed below include stroke and bleeding in the brain. Your neurosurgeon will make a recommendation based on the size and shape of the brain aneurysm, location of the aneurysm, your ability to undergo surgery and other factors. Overall the risks and consequences of aneurysm rupture will be weighed against the risks of a procedure to treat the aneurysm.

  • Coil embolization. During this procedure, a small catheter is inserted into the affected artery and positioned into the aneurysm. Tiny platinum coils are then passed through the catheter and positioned within the aneurysm. The platinum coils fill up the inside of the aneurysm, diverting blood flow away from the aneurysm and causes the aneurysm to clot off. This clotting essentially seals off the aneurysm from the artery, thereby eliminating blood flow into the aneurysm which relieves the pressure on the arterial wall making it less likely to rupture. Coil embolization (also referred to as endovascular coiling) is less invasive and is believed to be safer than surgical clipping. The hospital stay and length of recovery is also significantly shorter than an open surgical procedure. However, this procedure in some aneurysms may be less effective at reducing the risk of a later rupture and may have a higher risk of recurrence. Therefore, it is important that an experienced team perform an evaluation to minimize these risks.
  • Surgical clipping. This is also termed open craniotomy or micro-surgical clipping. During this type of procedure, meant to close off an aneurysm, a neurosurgeon opens a section of your skull to access the aneurysm by locating the blood vessel that feeds the aneurysm. He or she then places a small metal clip across the base of the aneurysm to isolate it from normal blood circulation. This decreases the pressure on the aneurysm and prevents it from rupturing. The risks of this surgery depends on the location of the aneurysm, its size, and your general health.

Non-surgical treatments

While surgical clipping or Coil embolization can be used to seal off an unruptured brain aneurysm and help prevent a future rupture, the known risks of these procedures may outweigh the potential benefit. In some instances, non-surgical treatments aimed at relieving symptoms might be used, followed by observation to assess for aneurysm growth or development of new symptoms.

There are a variety of medical treatments used following and during recovery from a ruptured brain aneurysm. These medical treatments are used to reduce or minimize the risk of further brain injury and maximize the chances of neurological recovery. These treatments include:

  • Pain relievers, such as acetaminophen (Tylenol, others), may be used to treat headache pain.
  • Calcium channel blockers prevent calcium from entering cells of the blood vessel walls preventing the muscle in the vessel wall from contracting. These medications may lessen vasospasm, the erratic narrowing of blood vessels that may be a complication of a ruptured aneurysm. One of these medications, nimodipine, has been shown to reduce the risk of delayed brain injury caused by insufficient blood flow after subarachnoid hemorrhage of a ruptured aneurysm.
  • Interventions to prevent stroke from insufficient blood flow include intravenous injections of a drug called a vasopressor, which elevates blood pressure to overcome the resistance of narrowed blood vessels. An alternative intervention to prevent stroke is angioplasty. In this procedure, a surgeon uses a catheter to inflate a tiny balloon that expands a narrowed blood vessel in the brain. A catheter may also be used to deliver to the brain a drug called a vasodilator, which causes blood vessels to expand.
  • Anti-seizure medications may be used to treat seizures related to a ruptured aneurysm. These medications include levetiracetam (Keppra), phenytoin (Dilantin, Phenytek, others) and valproic acid (Depakene).
  • Ventricular or lumbar draining catheters and shunt surgery can lessen pressure on the brain from excess cerebrospinal fluid (hydrocephalus) associated with a ruptured aneurysm. A catheter may be placed in the spaces filled with fluid inside of the brain (ventricles) or surrounding your brain and spinal cord to drain the excess fluid into an external bag. Sometimes, it may then be necessary to introduce a shunt system — which consists of a flexible silicone rubber tube (shunt) and a valve — that creates a drainage channel starting in your brain and ending in your abdominal cavity.
  • Rehabilitative therapy. Damage to the brain from a subarachnoid hemorrhage usually results in the need for physical, speech and occupational therapy to relearn skills.

Can I prevent aneurysms from developing?

Since there is no exact cause for the development of aneurysms, there is no tried-and-true way for the prevention of their development. However, there are some simple lifestyle changes that one can make to help lower the risk of aneurysms from rupturing.

  • Don’t smoke or use recreational drugs. Smoking and recreational drug use has been shown to greatly increase the likelihood of an aneurysm rupturing. If you smoke or use recreational drugs, talk to your doctor about strategies or an appropriate treatment program to help you quit.
  • Eat a healthy diet and exercise. Proper control of blood pressure may lower the risk of rupture, and changes in diet and exercise can help lower blood pressure. Talk to your doctor about changes appropriate for you.
  • Limit caffeine. Caffeine is a stimulant that can cause a sudden increase in blood pressure.
  • Avoid straining. Sudden, forceful and sustained exertion of the type you expend when you lift heavy weights can cause a sudden increase in blood pressure.
  • Be cautious of aspirin use. Talk to your doctor before taking aspirin or other drugs that inhibit blood clotting, because they may increase blood loss if you do have a ruptured aneurysm.

What is the recovery process for an aneurysm? How long until I fully recover?

Unfortunately, there is no way to predict the length of time it will take to improve or even how much improvement will actually occur.

Recovery differs from patient to patient, as well, depending on the location and extent of the damage done by your aneurysm.

Mood changes are common, anger and depression over losing the life one had before are frequent reactions to this life-altering event. There are several principles that are essential for an aneurysm survivor to understand:

  • Recovery is a robust process that occurs for the rest of your life
  • There are no deadlines for learning new skills
  • Patience is critical to the process of your recovery

There are a couple of different therapy routes those dealing with aneurysm recovery can undertake:

  • Hospital rehabilitation Mild-to-severe cognitive, behavioral and physical symptoms require specialized care in an acute rehabilitation hospital. Typically, the rehabilitation team works with the patient to facilitate safe walking, personal care skills, basic communication and problem solving skills. Hospital stays can last up to three weeks, depending how the patient progresses towards independence. The rehabilitation team works closely with the family, providing education about the recovery process and preparing patient and caregivers for the transition home.
  • Home rehabilitation This setting is best for patients who have transitioned back to their homes but need constant assistance. The patient’s team of caregivers develops strategies for managing home-related tasks, including safety and personal care. The goal is to help the patient begin to resume normal activities.
  • Outpatient rehabilitation Patients graduate to this level of care when they are ready to resume typical daily tasks. The outpatient rehabilitation team’s focus is to help the patient resume real-life activities (driving, shopping, returning to work, leisure activities, etc.). This level of care refocuses the patient on regaining the skills for prior role resumption.
  • Alternative Therapies Alternative therapies include yoga, acupuncture, massage therapy, EEG biofeedback, and hydrotherapy. Some aneurysm patients find these alternative therapies help in the healing process.

For more information on recovering from aneurysms, please visit The Brain Aneurysm Foundation.