Abdominal Aortic Aneurysm - Case Study Example

Abdominal Aortic Aneurysm Lafi 9/17 A brief case study: A 74-year-old retired man consulted a doctor of chiropractic for chronic low back pain. The history and physical examination confirmed chronic sacroiliac and a lumbar facet dysfunction. After 5 weeks, the patient stated he had stomach cramps. After this, a more thorough abdominal examination was done. The doctor of chiropractic detected an enlarged pulsatile mass upon abdominal palpation. (10). Lateral lumbosacral weight bearing view. The AAA anterior to L3—L4 was measured at 4.2 cm. Also note the degenerative changes, most prominent at L5/S1 with almost complete loss of disc height, osteophytosis and juxta articular hemispherical spondylosclerosis. History: The first historical records about AAA are from Ancient Rome in the 2nd century AD, when Greek surgeon Antyllus tried to treat the AAA with proximal and distal ligature, central incision and removal of thrombotic material from the aneurysm. However, attempts to treat the AAA surgically were unsuccessful until 1923. In this year, Rudolph Matas performed the first successful aortic ligation on a human. Other methods that were successful in treating the AAA included wrapping the aorta with polyethene cellophane, which induced fibrosis and restricted the growth of the aneurysm. Albert Einstein was operated on by Rudolf Nissen with use of this technique in 1949, and survived five years after the operation. (2). Endovascular aneurysm repair was first performed in the late 1980s and has been widely adopted as a treatment option in the subsequent decades. In recent decades approximately 40,000 patients underwent aneurysm each year. In the United States, 15,000 deaths per year are attributed to abdominal aortic aneurysms. (8) Anatomy: The aorta is the largest artery in the body. Arteries are vessels that carry blood away from the heart. Aorta arises from the left ventricle of the heart, forms an arch, and then extends down to the abdomen, where it branches off into two smaller arteries. Aorta is only 5 - 6cm. long and 16-20 mm. in diameter. Branches of the Aorta •Ascending aorta • Aortic Arch • Thoracic (descending) aorta • Abdominal aorta AAA: Is focal enlargement of the abdominal aorta usually involving the infra-renal portion of the vessel to more than 50% larger in diameter than the normal aorta or to greater than 3.0 cm in its largest true transverse dimension. Type of AAA: – suprarenal (dilatation of the infra-renal aorta up to or above the level of renal artery osmium), – juxta-renal (origin of aneurysm less than 15 mm below the renal arteries), or – infra-renal (aneurysm extends cranially more than 15 mm below the renal arteries) depending on their relation to the renal artery origin (1). Epidemiology: – AAA primarily affects elderly males (sex ratio 4:1) with prevalence up to 9%, – Smoking, Greater than 90% of people who develop AAA have smoked at some point in their life. – Coronary artery disease, or peripheral vascular disease, – Those with first-degree relatives who have aneurysms are at increased risks for developing atherosclerotic AAA Nonaneurysmal abdominal aortas normally increase their diameter by 0.05-0.08 mm/year, – Aneurysms less than 4.0 cm increase by 2.0-5.3 mm/year, – Aneurysms between 4.0 and 5.0 cm grow at a rate of 3.0-6.9 mm/year, – Aneurysms of 5.0 cm or more enlarge by 4.0-8.0 mm/year. Natural history: – the risk of rupture is 0% after 8 years for aneurysms that are initially less than 3.5 cm, – 5% after 9 years for aneurysms between 3.5 and 4.9 cm, – 25% after 8 years for aneurysms 5 cm or more in maximum diameter (1, 3,4). Etiology and risk factors – The vast majority of AAA develops as a result of atherosclerosis, – Less commonly, AAA is seen after blunt or penetrating abdominal trauma – In patients with infections, Marfan syndrome, cystic medial necrosis, or syphilis, – Established factors include tobacco use, hypertension, male sex rate to female 4:2, and hyperlipidemia. The main purpose is to prevent rupture through placement of the dilated segment of aorta with a prosthetic graft. Pathology summary Aortic dissections occur when a tear forms in the intimal layer of the aorta creating a subintimal collection of blood (15). The pulsing high pressures in the aorta then force more blood into this space causing the hematoma to grow distally from its origin (7). The dissection commonly occupies approximately half of the circumference of the aorta and rarely includes the whole vessel wall. There are two types of aortic dissection. Thoracic is broadly documented as type 1 while abdominal is largely noted as type 2.The signs of aortic dissection ascend on to the patient rapidly. It has a rapid onset of signs that can be used to differentiate this life threatening condition from other simple pathologies. (6). The primary indicator is severe chest pain which the patient describes as acute stabbing firstly located posterior to the sternum which then moves to the shoulders, neck, arm, abdomen and hips (6). Other symptoms can be confusion, intense anxiety, pallor, a rapid weak pulse, profuse sweating, dry skin, dry mouth, nausea, dizziness, fainting and shortness of breath. Not every patient will experience all of the same symptoms as it depends on the location of the dissection and the arterial branches involved (7). Diagnosis: An abdominal aortic aneurysm is usually diagnosed by physical examination, ultrasound, or CT. Plain abdominal radiographs may show the outline of an aneurysm when its walls are calcified. However, this is the case in less than half of all aneurysms. Ultrasonography is used to screen for aneurysms and to determine the size of any aneurysms present. Additionally, free peritoneal fluid can be detected. It is noninvasive and sensitive, but the presence of bowel gas or obesity may limit its usefulness. CT scan has a nearly 100% sensitivity for aneurysms and is also useful in preoperative planning, detailing the anatomy and possibility for endovascular repair. In the case of suspected rupture, it can also reliably detect retroperitoneal fluid. Alternative less often used methods for visualization of the aneurysm include MRI and angiography (6, 11). Role of imaging modalities in the diagnosis: Imaging modalities Chest and abdomen x ray Plain radiograph can demonstrate calcification in the wall of an aneurysm. a patient with an abdominal aortic aneurysm US – Initial screening examination to confirm the diagnosis and assess the size and involvement of iliac arteries, Ultra sonogram of a patient with an abdominal aortic aneurysm Is useful to follow-up small aneurysms (5cm). • CT angiography allows evaluation of the anatomy of the abdominal aortic aneurysm and associated structures prior to elective surgical repair. Endovascular repair first became practical in the 1990s and although it is now an established alternative to open repair, its role is yet to be clearly defined. It is generally indicated in older, high-risk patients or patients unfit for open repair (14). Abdominal aortic end prosthesis, CT scan, original aneurysm marked in blue. Main article: Endovascular aneurysm repair Summary and conclusion: An abdominal aortic aneurysm has specific symptoms and associated risk factors. If known risk factors are present, a clinical examination needs to be carried out, even though sensitivity of the clinical examination may be low. It should be a differential diagnosis in every male patient older than 50 years with low back pain that should be referred for advanced imaging. Moreover, occur in patients with hypertension, others include trauma, or a genetic defect (Marfan’s syndrome). Imaging appearances widening of aortic shadow on chest radiograph also can diagnosis the AAA by Angiography as acts as a pre-surgical road map to define the extent of the lesion, whether renal arteries or other branches are involved. It is can be treated by surgery and by interventional radiography (9, 10, 13, 14,) References: 1. Abdominal Aortic Aneurysm; Studies from Institute of Technology provide new data on abdominal aortic aneurysm. 2010. Medical Devices & Surgical Technology Week, September 5, 3711.  http://www.proquest.com.dbgw.lis.curtin.edu.au (accessed Aug. 29, 2010). 2. Albert, B. 2002. Famous Patients, Famous Operations, 2002 - Part 3: The Case of the Scientist with a Pulsating Mass http://www.medscape.com/viewarticle/436253 (accessed Aug. 31, 2010). 3. Aortic Dissection. 2005. http://www.emedicine.com/med/topic2784.htm (accessed Aug, 11, 2010). 4. Aortic dissection. 2005. http://www.cnn.com/HEALTH/library/DS/00605.html (accessed Aug, 27, 2010). 5. Aortic dissection. 2005. http://www.mayoclinic.com/health/aortic-dissection/DS00605 (accessed Aug, 27, 2010). 6. Aortic dissection. 2006. http://www.nlm.nih.gov/medlineplus/ency/article/000181.htm (accessed Aug, 27, 2010). 7. Aortic dissection. 2007. http://www.americanheart.org/presenter.jhtml?identifier=3005390 (accessed Aug, 27, 2010). 8. Ballard DJ, Filardo G, Fowkes G, Powell JT. (2008). "Surgery for small asymptomatic abdominal aortic aneurysms". Cochrane Database Syst Rev (4): 9. Khan, N., K. Lerrick. A, Kypson, and P, Saha. 2004. Pitfalls of Coronary Angiography in Aortic Dissection – A case. International Journal of Angiography 13 (2). http://www.springerlink.com/content/m9m1l53u52qx9967/ (accessed Sep, 11, 2010). 10. Nathan J. de Boer, Simone F.C. Knaap, Annemarie de Zoete. 2010. Clinical detection of abdominal aortic aneurysm in a 74-year-old man in chiropractic practice. Journal of Chiropractic Medicine, Volume 9, Issue 1, March 2010, Pages 38-41. 11. Pathway of diagnosis AAA http://www.imagingpathways.health.wa.gov.au/includes/dipmenu/aaa/chart.html (accessed Sep, 1, 2010). 12. THE AORTIC DISECTION. [Image]. 2006. http://www.heart-vessels.com/cardiovascular-diseases/aortic-dissection4.php (accessed Sep, 11, 2010. 13. U.S. Preventive Services Task Force (2005). "Screening for abdominal aortic aneurysm: recommendation statement". Ann. Intern. Med. 142 (3): 198–202. 14. What’s the treatment for aortic dissection? 2005. http://heart-disease.health-cares.net/aortic-dissection-treatment.php (accessed Aug, 27, 2010). 15. Wiesenfarth, J. 2005. Dissection, Aortic. www.emedicine.com/emerg/topic28.htm (accessed Aug, 21, 2010). Read More