Medical Perspectives | Infectious Diseases

February 24, 2020



Dr. Gwen Y. Reyes-Amurao, M.D.

Definition

The National Institute of Health defines an aneurysm as an enlargement or distention of an artery due to a weakness in the arterial wall. Arteries are essential to human life since they are responsible for delivering oxygenated blood to the different parts of the body. These arteries have the ability to withstand normal blood pressure through their thick walls, and any injury brought about by genetics, medical conditions, and trauma can result to its weakening and eventually lead to rupture or dissection. Both of which can be fatal.

 

Types

The most widely known type of aneurysm is that of the brain, but kinds do vary in terms of location.

 

Aortic aneurysm

As the name suggests, this is found in the largest artery of the body, the aorta and branches from the left ventricle of the heart, passing through the chest and abdominal cavities before branching out into smaller arteries. The normal diameter of the aorta is 2 to 3cm, but may distend to as much as 5 cm when an aneurysm is present. There are actually two different types of aortic aneurysms, thoracic (TAA) and abdominal (AAA). According to the Center for Disease Control and Prevention, the annual survival rate for an individual with abdominal aortic aneurysm over 6cm without surgery is a mere 20%. On the other hand, the survival rate of thoracic aortic aneurysms, or aneurysms found in the chest area, is 56% without surgery. Incidentally, it occurs only in 25% of cases of abdominal aneurysms, which makes it far less common than those found in the abdomen.

 

Cerebral aneurysm

More commonly known as brain aneurysms, these affect intracranial blood vessels and are also known as “berry” aneurysms because of their appearance. Sadly, this has the highest fatality rate among all the types of aneurysms and can be fatal within 24 hours of rupture.

 

Peripheral aneurysm

This type of aneurysm affects arteries that supply the periphery or other parts of the body aside from those mentioned above. There are aneurysms found in arteries supplying the area behind the knee (popliteal), near the spleen (splenic), the intestines (mesenteric), the groin (femoral), the neck (carotid), and the bowels and kidneys (visceral). The most common of which is the popliteal. Although these may be smaller in diameter, they also have a high risk of rupture or dissection.

 

Signs and Symptoms

Unfortunately, aneurysms are clinically silent and do not show any clear manifestations. In fact, the American Heart Association mentions that most aneurysms develop over many years undetected because no signs and symptoms are reported until they rupture.

 

When it comes to brain aneurysms, according to Dr. Kenny Seng, a Neurosurgeon who regularly sees these cases in the Philippine General Hospital, Asian Hospital and The Medical City, headaches are the most common complaint of his patients. These headaches occur in cases of sentinel leaks wherein the aneurysm bleeds into the wall of the blood vessel. If unruptured and if large enough (more than 2 centimeters in diameter), the aneurysm can cause doubling of vision (diplopia) or drooping of the eyelid (ptosis) due to nerve compression. If ruptured, there is almost always the classic thunderclap headache, which is severe and sudden in onset and which patients usually describe as the “worst headache of their life.”

 

As for abdominal aneurysms, especially those that progress rapidly, pain in the abdomen or low back pain and a pulsating sensation in that area may be observed.  Thoracic aneurysms because of its location in the chest, can compress on nearby nerves and structures which can lead to difficulties in swallowing and breathing, and radiating pain to the angle of the jaw, the upper back and the chest area. An aneurysm found near the surface of the skin will often be painful, swollen and can be seen as visibly throbbing.

 

Once an abdominal or thoracic aneurysm expands drastically then ruptures, the following are often reported:

  • Pain (in the affected area)
  • Cold, clammy skin
  • Dizziness
  • Nausea and vomiting
  • Rapid heart rate
  • Shock

On the other hand, once a brain or cerebral aneurysm ruptures, a person may experience what can be described as the “worst headache” ever experienced and may be accompanied by:

  • Neck pain
  • Blurring of vision
  • Nausea and vomiting
  • One-sided drooping of the face
  • Loss of consciousness
  • Confusion
  • Seizures
  • Loss of consciousness

Although these have been reported, it must be stressed that aneurysms can exist without the person experiencing any signs and symptoms.

 

Risk Factors

Despite having no direct causative factors, certain aspects have been associated with it. According to Dr. Seng, this is often detected between the ages of 40 and 60 and seems to be more commonly found in males than females.

The American Heart Association attributes an increased likelihood of having an aneurysm to the following factors, mainly because of the cumulative damage they have on arteries through time:

  • Poor diet, specifically a diet high in fats and cholesterol
  • Smoking
  • Obesity
  • Hypertension or high blood pressure

Conditions that lead to atherosclerotic disease such as having high cholesterol levels and hypertension have also been associated with increased incidence of aortic aneurysm in the general population, as mentioned in the European Heart Journal.

 

Smoking is by far the most common risk factor for having an aneurysm especially for AAA. In a study published by the American Journal of Vascular Surgery, they mention that with every year of smoking comes an increased relative risk of AAA by 4%. Fortunately, with the cessation of smoking, there was a very slow decline in the risk of the occurrence of AAA. Meaning, a person’s risk can decrease greatly, once he stops smoking.

 

When it comes to brain or cerebral aneurysm, some factors present at birth can lead to an aneurysm later on in life. Some of the more common conditions are:

  • Inherited connective tissue disorders
  • Polycystic Kidney Disease
  • Conditions affecting the aorta (ex. Coarctation of the Aorta)
  • Cerebral Arteriovenous Malformation or AVM wherein there is an abnormal connection between arteries and veins in the brain leading to an abnormal blood flow, which in turn leads to traumatic injuries on the blood vessels.

 

Diagnosis

Because aneurysms are relatively silent when it comes to clinical manifestations, diagnostic tools can help determine their presence with or without observable symptoms. These tools can be used to find arterial damage and would best be seen by a specialist a thoracic and cardiovascular surgeon (TCVS) or a neurosurgeon once it is detected.

  • Computed Tomography or CT scans are often used to diagnose the presence of aneurysms. Through these tests, they are able to determine the presence of irregularities such as bulges or weak spots within the blood vessels. In some cases, an injection of a dye is recommended to make it easier to visualize the aneurysm, its affected parts and how much blood flow is affected. This is more specifically called a CT angiography.
  • Magnetic Resonance Angiography is an MRI exam of the blood vessels for the brain, heart, abdomen, lungs, kidneys and legs, and can detect the presence of an aneurysm.
  • Cerebral Angiogram. If the doctor suspects the presence of a brain aneurysm, this procedure is performed by inserting a narrow flexible tube through a large artery, allowing it to course through the arteries of the heart and the brain. With a contrast or dye, more irregularities can be detected using this test. Although more invasive, an angiogram allows for more specific and more accurate results, if more information is needed.

 

Treatment

As with all other types of therapy, treatment will depend on the location and type of aneurysm. In an article published in the Medical News Today, where they thoroughly discuss treatment options for aneurysms, the decision is based on whether or not an aneurysm has ruptured. For those that have not, medications, preventive measures, and at times, active surgical treatment may be advised. Surgery may depend on several factors such as age, general health and the presence of other medical conditions. Other factors include:

  • The size and location of the aneurysm in the chest or abdomen, and the rate of its growth or progression
  • The presence of chronic abdominal pain or risk of thromboembolism, which may also require surgery.

Surgical repair can be done through open surgery with insertion of a graft or through endovascular stent graft surgery, a minimally invasive procedure that involves repairing and reinforcing damaged blood vessels through a small incision using a catheter. Since it is less invasive, complications are greatly reduced as compared to open surgery.

 

When it comes to brain aneurysms though, the option to operate may be considered only if there is a high risk of rupture since risk may outweigh the benefits in this case. For ruptured cerebral aneurysms, the Mayo Clinic mentions two common treatment options:

  • Surgical clipping. Once the neurosurgeon is able to access the aneurysm through open brain surgery, a tiny metal clip on the neck of the aneurysm is placed in order to stop blood flow towards it.
  • Endovascular coiling. With the use of a catheter, a guide wire is used to push a soft platinum wire through it and into the aneurysm. This wire coils up inside the aneurysm, disrupts the blood flow and seals off the aneurysm from the artery.

At present, there are newer forms of treatment such as flow diverters and tubular stent-like implants, both of which divert blood flow away from the aneurysm.

 

Once the aneurysm has ruptured, regardless of its location, emergency surgery is always indicated. Without it, the person suffering from the aneurysm may have very little chance of survival.  To help relieve symptoms of a ruptured aneurysm, pain relievers, calcium channel blockers, intravenous vasopressors, and anti-seizure medications may be given depending on what is present in the patient.

 

Whatever the treatment, it is best to discuss the risks and benefits of each procedure with a team of specialists to help alleviate any anxiety and address any concern or issue one may have.

 

Prevention

Technically speaking, Dr. Seng mentions that there is no foolproof way of preventing aneurysms, which all starts from the weakness in the blood vessel wall. There are actually 3 layers on the wall of our arteries, but in patients with aneurysm, one of the layers may be thin or completely absent. Contrary to what many people believe, aneurysms grow over time and do not just appear out of nowhere. Which is why, Dr. Seng advises to do what we can to avoid causing further damage to our blood vessels, which can be done by controlling factors, which can aggravate it, such as hypertension or high blood sugar.

 

With the recent cases of aneurysms leading to sudden and unexpected deaths, people have grown concerned over this condition. But we are left with these reassuring words, “out of 100 million Filipinos, 1 to 2 million will have an aneurysm. And out of this, only 10 thousand may rupture. So if someone does have an aneurysm, chances are, it won’t rupture in their lifetime”, says Dr. Seng, “and whatever concerns you may have, it is important to seek medical advice as soon as possible.”

 

As with any medical condition, maintaining a healthy lifestyle through proper diet, regular cardio exercises and elimination of tobacco can greatly decrease one’s risk for an aneurysm. Having an annual checkup can also help detect aneurysms without the presence of any signs or symptoms. Being proactive never really hurt anyone, especially when it comes to one’s health.

 

 

 

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