Epidemiology of Aortic Dissection

Call to: Patient is 65-year-old Stephen Jones. He is found seated on the couch clutching his chest with Angela, his wife in attendance.

PMHx

• High Cholesterol
• Hypertension
• Depression

Family Hx

• Nil family Hx of cardiovascular disease
• Current Medication
• Atorvastatin (Lipitor)
• Atenolol (Tenormin)
• Aspirin
• Citalopram

Vital Signs

Provisional Diagnosis

Provisional diagnosis: Aortic dissection
Differential diagnosis: Acute coronary syndrome

Epidemiology/ Etiology/ Pathophysiology

Etiology

Aortic dissection occurs in a weakened section of the aortic wall. According to Criado (2011), the occurrence of aortic dissection (AD) is due to the occurrence of an intimomedial tear that allows entry of blood flow to the aortic wall. The effect is the creation of a secondary channel called the false lumen (FL) which propagates distally. The true lumen is compressed by the FL which is pressurized and could lead to a collapse causing ischemic complications. The occurrence of such events are attributed to the weakening of vessels rendering the aorta vulnerable if it is exposed to uncontrolled hypertension. Stephen Jones has a history of high cholesterol and hypertension. The vulnerability of the aorta can be attributed to high blood pressure. The hypertension could be causing a strain on the arterial walls resulting in a dissection.

Epidemiology

Epidemiological studies on AD have been conducted in the past to help in understanding its prevalence. LeMaire and Russell (2011) report that AD occurs at the rate of 3 to 4 cases in 100,000 persons every year, associated with increased mortality rates. However, increased cases of the condition continue to be reported with the disease prevalent in men and older individuals. Indeed, Stephen Jones, a 65-year-old male patient has been diagnosed with the condition. Studies were conducted by Howard et al., (2013) that sought to determine the incidence of the disease in a population. In particular, the researchers investigated a total of 155 patients with more than 50% having the disease. In particular, 54 patients had an AD.
Graphical Representation of the prevalence of aortic dissection in each age group.

Pathophysiology

The wall of the aorta has three primary layers including inner intima, middle media, and outer adventitia. AD depicts a pathological condition that is characterized by the presence of an intimal tear, with blood flowing from the entry site to a false lumen (Nienaber, & Clough, 2015). The condition can equally occur due to intramural hemorrhage. The weakening of the medial layers causes an increase in wall stress and eventual dilatation of and formation of an aneurysm. The effect is a rupture. The condition is depicted by an intimal flap in the aorta. Following medial wall degeneration, blood re-enters the true lumen resulting in a communication dissection. Intimal tears occur at sections of the aorta which are under stress or experiencing fluctuation pressures. Hypertension and aortic dilations increase the risk of dissections (Baliga et al., 2014). The chronic hypertension causes progressive changes at the wall of the artery and extracellular matrix. The elevation of intimal thickening and adventitial fibrosis causes smooth muscle necrosis, in addition to fibrosis of elastic structures of vessels. The effect is stiffening and vulnerability of the pulsatile forces. The impact of the changes is In particular, hypertension causes mechanical stress arising from the pressure. Also, the dissection is due to an initial transverse tear through curvature of the aorta. In the case of Stephen Jones, his past medical history shows hypertension and high cholesterol levels. It is an indication of increased blood pressure through the arterial walls. The extreme pressure could have increased the likelihood of a tear taking place. Also, tearing which occurs at the innermost part of the arterial wall causes blood to be channeled inside weakening it and increasing the chance of rupture. The effect is presence of abrupt and excruciating chest pain. In the case depicted, Stephen Jones complained of acute pain which travels as a dissection proceeds along the aorta. The pain could radiate to the back as witnessed by Mr. Jones. Furthermore, the condition causes compression preventing blood from going back to the heart.

Assessments and Investigations to be conducted

The assessment of AD by the healthcare professional should be guided by the patient’s past medical history. However, the symptoms presented by the patient should help in determining whether or not the patient has AD. The assessment needs to be guided by evaluation of vital signs including poor breathing, abnormality in the pulse, blood pressure and presence or absence of chest pain. A physical examination can be done to check for possible complications including an aortic aneurysm (Baliga et al., 2014). In the process of assessment, the dissection should be evaluated to monitor the location. Following the physical evaluation, the patient can be subjected to tests such as electrocardiogram and chest X-ray. Presence of an abnormal shape of the aorta and wide media can indicate the presence of AD. However, the angiogram utilizing computerized tomography of the abdomen and chest can be used. The test entails a contrast injection of dye followed by visualization of the aorta and blood vessels. The examiner can equally use magnetic resonance imaging, but it has the challenge of time wastage.

Treatment

The first response to help Stephen Jones in dealing with the condition is performing an ABC resuscitation before reaching the hospital. Upon reaching the emergency department, it could be vital to place intravenous lines, attachment of monitors for both heart rate and rhythm. Also, supplemental oxygen should be provided. The patient should also be given medication to help in lowering the blood pressure to reduce the tear and prevent damage of aorta. Common medications that can be used includes labetalol, metoprolol which help in reducing adrenaline action (Fisker, Grimm, & Wehland, 2015). Nitroglycerin can be administered to help in dilation of blood vessels and reduce pressure.

Transport

The cardiac emergency requires the need to have the patient transported to the hospital in a timely manner. The patient will be admitted to a facility having appropriate equipment to deal with the emergency.

References

Baliga, R. R., Nienaber, C. A., Bossone, E., Oh, J. K., Isselbacher, E. M., Sechtem, U., ... & Eagle, K. A. (2014). The role of imaging in aortic dissection and related syndromes. JACC: Cardiovascular Imaging, 7(4), 406-424.
Criado, F. J. (2011). Aortic Dissection: A 250-Year Perspective. Texas Heart Institute Journal, 38(6), 694–700.
Fisker, F. Y., Grimm, D., & Wehland, M. (2015). Third‐Generation Beta‐Adrenoceptor Antagonists in the Treatment of Hypertension and Heart Failure. Basic & clinical pharmacology & toxicology, 117(1), 5-14.
Howard, D. P., Banerjee, A., Fairhead, J. F., Perkins, J., Silver, L. E., & Rothwell, P. M. (2013). Population-based study of incidence and outcome of acute aortic dissection and pre-morbid risk-factor control: 10-year results from the Oxford Vascular Study. Circulation, CIRCULATIONAHA-112.
LeMaire, S. A., & Russell, L. (2011). Epidemiology of thoracic aortic dissection. Nature reviews cardiology, 8(2), 103-113.
Nakashima, Y. (2010). Pathogenesis of Aortic Dissection: Elastic Fiber Abnormalities and Aortic Medial Weakness. Annals of Vascular Diseases, 3(1), 28–36. http://doi.org/10.3400/avd.AVDsasvp10002
Nienaber, C. A., & Clough, R. E. (2015). Management of acute aortic dissection. The Lancet, 385(9970), 800-811.
Yeh, T. Y., Chen, C. Y., Huang, J. W., Chiu, C. C., Lai, W. T., & Huang, Y. B. (2015). Epidemiology and medication utilization pattern of aortic dissection in Taiwan: a population-based study. Medicine, 94(36).

Case Study Two: Acute Abdomen Emergency

Call to: Patient is 52-year-old Emma Smith. He is found seated on the couch clutching his chest with Angela, his wife in attendance.

PMHx

• Migraine Headaches
• Left Hip Replacement
• Chronic Bronchitis

Family Hx

• None that is of relevance
• Current Medication
• Panadeine as needed
• Prednisolone
• Asmol Inhaler as needed

Vital Signs

Provisional Diagnosis

Provisional diagnosis: Acute abdominal pain
Differential diagnosis: Cholecystitis

Epidemiology/ Etiology/ Pathophysiology

Etiology

The cause of acute abdominal pain is varied. The possible cause of the condition could be appendicitis, diverticulitis, biliary tract disease, abdominal aortic aneurysm, malignancy, gastroenteritis or peptic ulcer disease. Other causes can be due to intestinal obstruction. In Emma’s case, she has a history of chronic bronchitis which may be the cause of the condition. The patient experiences right lower quadrant pain which could be attributed to appendicitis.

Epidemiology

The development of acute abdominal pain is widespread in a population. Studies conducted by Cervellin et al. (2016), have demonstrated that the condition accounts for 7-10% of all cases reported to the Emergency Department. However, the researchers equally indicate that there is scarcity regarding knowledge of the epidemiology of AAP. In Kendall and Moreira (2011), abdominal pain contributes to 5-10 of all the cases that are reported to the emergency department. The researchers equally indicate that older patients have a six- to the eightfold higher chance of mortality as compared to the younger patients. Further, 20% of all the patients who are admitted to the emergency department comprise the elderly with 3-4% complaining of acute abdominal pain. Chiu et al., (2007) conducted retrospective reviews of 158 patients, the mean age of 50.6 +/-15 years, to determine the epidemiology of abdominal pain. The findings of the researchers indicate that 61.7% of patients reported the acute abdominal pain. The NIDDK Gastroparesis Clinical Research Consortium (GpCRC), (2013) evaluated clinical data in 393 patients in 7 centers to assess cases of abdominal pain. In general, findings from the study indicate that 66% of patients reported moderate-severe abdominal pain with 44% experiencing vomiting and nausea. In general, the results of the study indicate that acute abdominal pain remains to be a disease of fundamental concern because of the prevalence reported in the population.

Pathophysiology

The understanding of the pathophysiology of the pain is dependent on the comprehension of mechanisms that cause the pain. In Emma’s case, the focus is on the evaluation of the presenting symptoms and past medical history since they offer an in-depth understanding of the pathophysiology. The development of acute abdominal pain is followed by the Pain receptors responding to both the mechanical and chemical stimuli (Martinez, & Mattu, 2014). In particular, in the process of stretching, mechanical stimulation is elicited. In the case presented, Emma complains of the pain and lifts her legs in a bid to stretch. The stimuli could be involved in the contraction, compression or distention. It is essential to understand that mechanisms that cause acute abdominal pain remain to be elusive. However, their detection relies on the type of the stimulus and interpretation of visceral inputs at the central nervous system. In general, pain forms the basis of acute abdominal disease. The occurrence of the pain is attributed to various factors. For example, it could be due to ischemia, distention of organs, inflammation of peritoneal lining due to infectious substance and mechanical stretch (Bhangu, Søreide, Di Saverio, Assarsson, & Drake, 2015). In Emma’s case, she was able to identify the source of the pain. In particular, she notes that the pain began from her right lower quadrant. Based on the identification, it could be that she was having somatic pain since it was more localized (Bellini, Gambaccini, Stasi, Urbano, Marchi, & Usai-Satta, 2014). The result is due to the traveling of nerve fibers along specific peripheral nerves entering the spinal cord. The pain could also be perceived as being parietal since Emma described it as increasing in severity. She had her knees pulled up to help in easing the pain. The infection of the appendix causes filling up of a purulent fluid resulting in the visceral pain. The intensity of the pain explains the decision by Emma to pull up her knees.

Assessments and Investigations to be conducted

The first evaluation is based on checking the airway, breathing, and monitoring of the circulation. It is essential to do a history to determine the chief complaints, previous surgery, medications or tobacco use. Following determination of history, physical examination can be performed with a focus on the evaluation of scars, peripheral pulses, pulsatile mass and checking of lower and upper pulses. Emma should equally undergo laboratory assessment to check the electrolytes, cardiac enzymes and amylase. The examination should similarly involve palpation which can be done on the abdomen gently starting far from the pain and moving toward it. It could be accompanied by an assessment of tenderness.

Treatment

Emma should be treated to help in the relief of pain prior to diagnosis. In particular, it could be vital to providing doses of analgesics such as fentanyl 50-100 mcg or morphine 4-6mg (Di Saverio et al., 2014). However, the choice of treatment depends on the findings of the diagnosis. For example, the patient can be admitted if there is need to perform surgery. In Emma’s case, she has not been able to take oral fluids. It could be vital to arrange for surgical intervention to address the situation. Provision of intravenous fluids may be helpful in helping the patient.

Transport

Following the outcome of the assessment, transportation should be arranged in a timely manner to have Emma reach the hospital. Prior to accessing the health facility, efforts should be made to ensure that supportive care is provided along the way with adequate oxygenation and ventilation.

References

Bellini, M., Gambaccini, D., Stasi, C., Urbano, M. T., Marchi, S., & Usai-Satta, P. (2014). Irritable bowel syndrome: a disease still searching for pathogenesis, diagnosis and therapy. World journal of gastroenterology: WJG, 20(27), 8807.
Bhangu, A., Søreide, K., Di Saverio, S., Assarsson, J. H., & Drake, F. T. (2015). Acute appendicitis: modern understanding of pathogenesis, diagnosis, and management. The Lancet, 386(10000), 1278-1287.
Cervellin, G., Mora, R., Ticinesi, A., Meschi, T., Comelli, I., Catena, F., & Lippi, G. (2016). Epidemiology and outcomes of acute abdominal pain in a large urban Emergency Department: retrospective analysis of 5,340 cases. Annals of Translational Medicine, 4(19), 362. http://doi.org/10.21037/atm.2016.09.10
Chiu, D. Y., Whiteside, A. M., Hegarty, J., Wood, G., O'donoghue, D. J., Waldek, S., ... & Kalra, P. A. (2007). Epidemiology and investigation of acute abdominal presentations in autosomal dominant polycystic kidney disease. Nephrology Dialysis Transplantation, 22(5), 1483-1484.
Di Saverio, S., Sibilio, A., Giorgini, E., Biscardi, A., Villani, S., Coccolini, F., ... & Catena, F. (2014). The NOTA Study (Non Operative Treatment for Acute Appendicitis): prospective study on the efficacy and safety of antibiotics (amoxicillin and clavulanic acid) for treating patients with right lower quadrant abdominal pain and long-term follow-up of conservatively treated suspected appendicitis. Annals of surgery, 260(1), 109-117.
Kendall, J. L., & Moreira, M. E. (2011). Evaluation of the adult with abdominal pain in the emergency department. UpToDate.(level 5).
Martinez, J. P., & Mattu, A. (2014). Abdominal pain in the elderly. Geriatric Emergency Medicine, 94.
The NIDDK Gastroparesis Clinical Research Consortium (GpCRC). (2013). FACTORS RELATED TO ABDOMINAL PAIN IN GASTROPARESIS: CONTRAST TO PATIENTS WITH PREDOMINANT NAUSEA AND VOMITING. Neurogastroenterology and Motility : The Official Journal of the European Gastrointestinal Motility Society, 25(5), 427–e301. http://doi.org/10.1111/nmo.12091