I have been writing a series of blogs devoted to common and not-so-common causes of back pain, some of which cause devastating and catastrophic injury. Aneurysms of the aorta, either in the chest or abdominal cavity, can present as back pain, and these can often be fatal if not diagnosed or treated in a short period of time.
Considering that 1 in every 50 males over the age of 55 have an abdominal aneurysm, this is a more common pathologic diagnosis than some others. Men also corner the market at an 8-to-1 ratio as compared to women with abdominal aneurysms. Thoracic aneurysms make up only 10% of the total number of aneurysms of the aorta, but these have a much poorer prognosis.
What is an aneurysm?
An aneurysm is a localized dilatation (i.e. the widening or stretching of an opening or a hollow structure in the body) of a blood vessel or even the heart, itself, due to some induced weakness in the wall of the vessel. The aorta is the largest blood vessel leaving the heart and transporting blood, oxygen and nutrition to every cell in the human body. It has the highest pressures and the thickest walls.
Should the weakness in the wall of the vessel rupture, blood will be released in such quantities and at such high pressures that the rapid blood loss causes a rapid death in most patients. There are a few exceptions, depending on which side of the blood vessel ruptures. If the rupture occurs on the side facing the abdominal cavity, the blood loss tends to be rapid since no opposing structures obstruct the flow. If the rupture occurs on the side facing the spinal column, structures in the near vicinity can actually slow the flow of blood allowing for a small time frame for diagnosis and intervention to occur. Sometimes, there is a slow “leak” of blood prior to a massive rupture, and this blood causes irritation and pain, allowing for a “window-of-opportunity” for a diagnosis to be made and intervention to occur.
I’ve provided a link at the end of this article to a well done video explaining aneurysms.
Real Case Scenario:
Patient M was a 62-year-old, moderately obese female, who came to the ER when I was working one day, complained of some vague low back pain and several episodes where she briefly lost consciousness that morning while trying to get up and move around. No injuries were sustained, but she felt very weak and light-headed. Her blood pressure was 109/68 while lying flat with a heart rate of 96. An attempt was made to obtain a blood pressure while sitting, but Patient M became near-syncopal and sweaty. A quick examination of her abdomen revealed a pulsatile aneurysm in her abdomen measuring 6cm (almost 2 1/2 inches wide). I was able to contact the vascular surgeon, have nurses place appropriate IV lines and obtain labs, and I notified the nursing supervisor regarding the need for an operating room. Patient M actually went for a CT scan on her way to the OR; the CT verified a “leaking” abdominal aortic aneurysm. Patient M was in the OR within 20 minutes of my evaluation. Upon opening the abdomen, the bleeding worsened, but the surgical team was prepared. They did have to resuscitate Patient M once, but a repair of the aorta was effective, and she went home within one week of her life-saving operation!
How is an aortic aneurysm diagnosed?
Most are actually diagnosed incidentally when patients undergo various diagnostic studies for other, unrelated complaints.These are the luckiest patients, because aneurysms can be detected early, monitored and then the patient can be offered elective intervention before an acute rupture occurs. It seems that 5cm (about 2 inches) is the “magic number” when it comes to an indication for repair since an aneurysm larger than that significantly increases the risk of rupture. Now, with endovascular (i.e. procedures in which a catheter is placed inside the blood vessel) repair options (“stenting procedures”), some of these aneurysm repairs can be done in a minimally invasive manner, offered even earlier, and have very good outcomes with only 2-to-3 day hospital stays.
Routine but thorough physical exams by a conscientious practitioner can ofter detect aneurysms in the abdomen simply by feeling the abdomen by hand. The chest cavity is more difficult for obvious reasons. Chest x-rays can sometimes suggest a problem if calcifications are present in the vessel wall (high-lighting the vessel contour) or if abnormalities are detected in the mid-line structures that overlap in this 2-dimensional picture. These patients can then undergo subsequent imaging studies to determine the existence and extent of the aneurysm.
When aneurysms go undetected, the acute presentation can also vary depending on the location of the aneurysm both in relation to the distance from the heart and the side of the vessel. Because of the position of the aorta anatomically (close to the spine), patients often experience back pain due to impingement of the spine and spinal nerves. If the aneurysm is in the chest cavity (thoracic), one often will feel upper to mid-back pain that can range from dull and aching to searing and excruciating; this may or may not accompany chest pain and other symptoms. If the aneurysm is in the abdomen (most often below the arteries that supply the kidneys), a patient will often complain of low back pain that could extend into the groin, and again, this pain can be dull and aching or sharp and excruciating.
What causes aortic aneurysms to occur?
The most common cause of aortic aneurysms is atherosclerotic vascular disease, commonly called cholesterol-plaqueing of the arteries. There are a multitude of other causes such as genetic conditions, fungal infections, bacterial infections, and other collagen-vascular diseases. Those individuals who have abnormal cholesterol panels, high blood pressure, perhaps a history of coronary artery disease or peripheral vascular disease, and diabetes are at risk for aortic aneurysms as they age.
So, a person who is a little older with perhaps some of these notable risk factors who develops unusual back pain with no apparent precipitating cause (excessive physical activity/labor, fall, etc.) should be evaluated for a possible aneurysm. If present and detected, it is often a treatable condition; left untreated, it will ultimately lead to death, which is often sudden. Medical technology even offers minimally invasive procedures that are quite effective if treated early enough and located in an accessible region. Keep in mind that thoracic aneuryms do have a worse prognosis than abdominal aneurysms.
Here’s the link to the video explaining aneurysms.
Image from aorticstents.com