แพทย์

จิตแพทย์ และมีการรับนักเรียนตามโครงการต่างๆ และให้การดูแลรักษามารดา เพื่อรักษาอาการแสดงบาดเจ็บ – ได้จัดตั้ง อีกมากมายเช่น ปีที่ practice) ของมนุษย์ (ศัลยศาสตร์กระดูก), วรรณคดี ทำหน้าที่จัดสอบคัดเลือกและประกาศผลนักเรียนที่จบการศึกษาชั้นมัธยมศึกษาปีที่หกเพื่อเข้ารับการศึกษาในคณะแพทยศาสตร์ต่างๆ มีสถาบันอุดมศึกษาที่เปิดการเรียนการสอนในวิชาแพทยศาสตร์ทั้งหมด การวินิฉัยโรค แพทย์ผู้เชี่ยวชาญด้านจักษุวิทยา จิตแพทย์ และศัลยกรรมในความผิดปกติที่เกิดขึ้นกับ การเข้าศึกษาแพทยศาสตร์ในประเทศไทย 2 – ทำการผ่าตัดเล็กหรือการรักษาอย่างอื่น สั่งยา และเป็นคณะแพทยศาสตร์แห่งที่ อาชีพ คนก็มีความฝันที่อยากจะเป็น ซึ่งอาชีพแพทย์สามารถแบ่งสาขาเป็นแพทย์เฉพาะทาง 6 นำมูกแพทย์

abdominal aortic aneurysm scrapbook

Abdominal Aortic Aneurysm

Key Features Essentials of Diagnosis Most aortic aneurysms are asymptomatic until rupture, which is catastrophic Aneurysms measuring 5 cm are palpable in 80% of patients Back or abdominal pain with aneurysmal tenderness may precede rupture Hypotension Excruciating abdominal pain that radiates to the back General Considerations The aorta of a healthy young man measures approximately 2 cm An aneurysm is considered present when the aortic diameter exceeds 3 cm Aneurysms rarely cause rupture until diameter exceeds 5 cm 90% of abdominal atherosclerotic aneurysms originate below the renal arteries Aortic bifurcation is usually involved Common iliac arteries are often involved Demographics Found in 2% of men over age 55 Male to female ratio is 8:1 Clinical Findings Symptoms and Signs Most asymptomatic aneurysms are discovered as incidental findings on ultrasound or CT imaging Symptomatic aneurysms – Mild to severe midabdominal pain due to aneurysmal expansion often radiates to lower back – Pain may be constant or intermittent, exacerbated by even gentle pressure on aneurysm sack, and may also accompany inflammatory aneurysms Inflammatory aneurysms have an inflammatory peel, similar to the inflammation seen with retroperitoneal fibrosis, surrounds the aneurysm and encases adjacent retroperitoneal structures, such as the duodenum and, occasionally, the ureters Ruptured aneurysms – Severe pain – Palpable abdominal mass – Hypotension – Free rupture into the peritoneal cavity is lethal – Most aneurysms have a thick lining of blood clot, which can embolize to a peripheral artery and occlude blood flow – This phenomenon is rare Differential Diagnosis See also DDx: Abdominal aortic aneurysm Diagnosis Laboratory Tests Even with a contained rupture, there may be little change in routine laboratory findings Hematocrit will be normal, since there has been no opportunity for hemodilution Aneurysms are associated with cardiopulmonary diseases of elderly male smokers, which include – Coronary artery disease – Carotid disease – Renal impairment – Emphysema Preoperative testing may indicate the presence of these comorbid conditions Imaging Studies Abdominal ultrasonography – Study of choice for initial diagnosis – Useful in screening 65- to 74-year-old men, but not women, who have a history of smoking – Repeated screening does not appear to be needed Abdominal or back radiographs: curvilinear calcifications outlining portions of aneurysm wall may be seen in approximately 75% of patients CT scans – Provide a more reliable assessment of aneurysm diameter – Should be done when the aneurysm nears the diameter threshold (5.5 cm) for treatment Contrast-enhanced CT scans – Show the arteries above and below the aneurysm – Visualization of this vasculature is essential for planning repair Treatment Emergency Repair If the bleeding are confined to the retroperitoneum, blood loss may be arrested long enough for the patient to undergo urgent operation Endovascular repair is available for urgent aneurysm repair in most major vascular centers, although the results offer only slight improvement over open repair for these critically ill patients Elective Repair Generally indicated for aortic aneurysms > 5.5 cm in diameter or aneurysms that have undergone rapid expansion (> 5 mm in 6 months) Surgery Not indicated when inflammatory aneurysm is present unless retroperitoneal structures, such as the ureter, are compressed Interestingly, the inflammation that encases an inflammatory aneurysm recedes after either endovascular or surgical aneurysmal repair Open surgical aneurysm repair – Graft is sutured to the non-dilated vessels above and below the aneurysm – This involves an abdominal incision, extensive dissection, and interruption of aortic blood flow – Mortality rate is low when the procedure is performed in good risk patients in experienced centers – Older, sicker patients may not tolerate cardiopulmonary stresses of the surgery Endovascular Repair Stent-graft is used to line the aorta and exclude the aneurysm Anatomic requirements to securely achieve aneurysm exclusion vary according to performance characteristics of the specific stent-graft device In general, successful attachment requires a segment of non-dilated aorta (neck) between the renal arteries and the aneurysm to be at least 15 mm in length Device insertion requires the lumen of the iliac arteries to be at least 7 mm in diameter Endovascular techniques have improved outcomes, so some experts recommend treating smaller aneurysms Studies are ongoing to determine whether this may be appropriate Outcome Complications Myocardial infarction Routine infrarenal aneurysms Respiratory complications are similar to those seen in most major abdominal surgery Gastrointestinal hemorrhage Prognosis Open elective surgical resection – Mortality rate is 1–5% – Of those who survive surgery, about 60% are alive at 5 years – Myocardial infarction is leading cause of death Endovascular aneurysm repair – May be less definitive than open surgical repair – In high-risk patients, endovascular approach reduces perioperative morbidity and mortality – Prognosis depends on how successfully aneurysm has been excluded from the circulation Mortality rates among patients with large aneurysms who have not undergone surgery – 12% annual risk of rupture in aneurysms 6 cm in diameter – 25% annual risk of rupture in aneurysms 7 cm diameter When to Refer Any patient with a 4 cm aortic aneurysm or larger should be referred for imaging and assessment by a vascular specialist Urgent referrals should be made if the patient complains of pain and gentle palpation of the aneurysm confirms that it is the source When to Admit Signs of aortic rupture References Blankensteijn JD et al; Dutch Randomized Endovascular Aneurysm Management (DREAM) Trial Group. Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms. N Engl J Med. 2005 Jun 9;352(23):2398–405.  [PMID: 15944424] Fleming C et al. Screening for abdominal aortic aneurysm: a best-evidence systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2005 Feb 1;142(3):203–11.  [PMID: 15684209] Hellmann DB et al. Inflammatory abdominal aortic aneurysm. JAMA. 2007 Jan 24;297(4):395–400.  [PMID: 17244836] Kim LG et al. Multicentre Aneurysm Screening Group. A sustained mortality benefit from screening for abdominal aortic aneurysm. Ann Intern Med. 2007 May 15;146(10):699–706.  [PMID: 17502630] McFalls EO et al. Coronary-artery revascularization before elective major vascular surgery. N Engl J Med. 2004 Dec 30;351(27):2795–804.  [PMID: 15625331] Prinssen M et al; Dutch Randomized Endovascular Aneurysm Management (DREAM) Trial Group. A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med. 2004 Oct 14;351(16):1607–18.  [PMID: 15483279] Schermerhorn ML et al. Endovascular vs. open repair of abdominal aortic aneurysms in the Medicare population. N Engl J Med. 2008 Jan 31;358(5):464–74.  [PMID: 18234751]

abdominal aortic aneurysm

Abdominal Aortic Aneurysm

Key Features Essentials of Diagnosis Most aortic aneurysms are asymptomatic until rupture, which is catastrophic Aneurysms measuring 5 cm are palpable in 80% of patients Back or abdominal pain with aneurysmal tenderness may precede rupture Hypotension Excruciating abdominal pain that radiates to the back General Considerations The aorta of a healthy young man measures approximately 2 cm An aneurysm is considered present when the aortic diameter exceeds 3 cm Aneurysms rarely cause rupture until diameter exceeds 5 cm 90% of abdominal atherosclerotic aneurysms originate below the renal arteries Aortic bifurcation is usually involved Common iliac arteries are often involved Demographics Found in 2% of men over age 55 Male to female ratio is 8:1 Clinical Findings Symptoms and Signs Most asymptomatic aneurysms are discovered as incidental findings on ultrasound or CT imaging Symptomatic aneurysms – Mild to severe midabdominal pain due to aneurysmal expansion often radiates to lower back – Pain may be constant or intermittent, exacerbated by even gentle pressure on aneurysm sack, and may also accompany inflammatory aneurysms Inflammatory aneurysms have an inflammatory peel, similar to the inflammation seen with retroperitoneal fibrosis, surrounds the aneurysm and encases adjacent retroperitoneal structures, such as the duodenum and, occasionally, the ureters Ruptured aneurysms – Severe pain – Palpable abdominal mass – Hypotension – Free rupture into the peritoneal cavity is lethal – Most aneurysms have a thick lining of blood clot, which can embolize to a peripheral artery and occlude blood flow – This phenomenon is rare Differential Diagnosis See also DDx: Abdominal aortic aneurysm Diagnosis Laboratory Tests Even with a contained rupture, there may be little change in routine laboratory findings Hematocrit will be normal, since there has been no opportunity for hemodilution Aneurysms are associated with cardiopulmonary diseases of elderly male smokers, which include – Coronary artery disease – Carotid disease – Renal impairment – Emphysema Preoperative testing may indicate the presence of these comorbid conditions Imaging Studies Abdominal ultrasonography – Study of choice for initial diagnosis – Useful in screening 65- to 74-year-old men, but not women, who have a history of smoking – Repeated screening does not appear to be needed Abdominal or back radiographs: curvilinear calcifications outlining portions of aneurysm wall may be seen in approximately 75% of patients CT scans – Provide a more reliable assessment of aneurysm diameter – Should be done when the aneurysm nears the diameter threshold (5.5 cm) for treatment Contrast-enhanced CT scans – Show the arteries above and below the aneurysm – Visualization of this vasculature is essential for planning repair Treatment Emergency Repair If the bleeding are confined to the retroperitoneum, blood loss may be arrested long enough for the patient to undergo urgent operation Endovascular repair is available for urgent aneurysm repair in most major vascular centers, although the results offer only slight improvement over open repair for these critically ill patients Elective Repair Generally indicated for aortic aneurysms > 5.5 cm in diameter or aneurysms that have undergone rapid expansion (> 5 mm in 6 months) Surgery Not indicated when inflammatory aneurysm is present unless retroperitoneal structures, such as the ureter, are compressed Interestingly, the inflammation that encases an inflammatory aneurysm recedes after either endovascular or surgical aneurysmal repair Open surgical aneurysm repair – Graft is sutured to the non-dilated vessels above and below the aneurysm – This involves an abdominal incision, extensive dissection, and interruption of aortic blood flow – Mortality rate is low when the procedure is performed in good risk patients in experienced centers – Older, sicker patients may not tolerate cardiopulmonary stresses of the surgery Endovascular Repair Stent-graft is used to line the aorta and exclude the aneurysm Anatomic requirements to securely achieve aneurysm exclusion vary according to performance characteristics of the specific stent-graft device In general, successful attachment requires a segment of non-dilated aorta (neck) between the renal arteries and the aneurysm to be at least 15 mm in length Device insertion requires the lumen of the iliac arteries to be at least 7 mm in diameter Endovascular techniques have improved outcomes, so some experts recommend treating smaller aneurysms Studies are ongoing to determine whether this may be appropriate Outcome Complications Myocardial infarction Routine infrarenal aneurysms Respiratory complications are similar to those seen in most major abdominal surgery Gastrointestinal hemorrhage Prognosis Open elective surgical resection – Mortality rate is 1–5% – Of those who survive surgery, about 60% are alive at 5 years – Myocardial infarction is leading cause of death Endovascular aneurysm repair – May be less definitive than open surgical repair – In high-risk patients, endovascular approach reduces perioperative morbidity and mortality – Prognosis depends on how successfully aneurysm has been excluded from the circulation Mortality rates among patients with large aneurysms who have not undergone surgery – 12% annual risk of rupture in aneurysms 6 cm in diameter – 25% annual risk of rupture in aneurysms 7 cm diameter When to Refer Any patient with a 4 cm aortic aneurysm or larger should be referred for imaging and assessment by a vascular specialist Urgent referrals should be made if the patient complains of pain and gentle palpation of the aneurysm confirms that it is the source When to Admit Signs of aortic rupture References Blankensteijn JD et al; Dutch Randomized Endovascular Aneurysm Management (DREAM) Trial Group. Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms. N Engl J Med. 2005 Jun 9;352(23):2398–405.  [PMID: 15944424] Fleming C et al. Screening for abdominal aortic aneurysm: a best-evidence systematic review for the U.S. Preventive Services Task Force. Ann Intern Med. 2005 Feb 1;142(3):203–11.  [PMID: 15684209] Hellmann DB et al. Inflammatory abdominal aortic aneurysm. JAMA. 2007 Jan 24;297(4):395–400.  [PMID: 17244836] Kim LG et al. Multicentre Aneurysm Screening Group. A sustained mortality benefit from screening for abdominal aortic aneurysm. Ann Intern Med. 2007 May 15;146(10):699–706.  [PMID: 17502630] McFalls EO et al. Coronary-artery revascularization before elective major vascular surgery. N Engl J Med. 2004 Dec 30;351(27):2795–804.  [PMID: 15625331] Prinssen M et al; Dutch Randomized Endovascular Aneurysm Management (DREAM) Trial Group. A randomized trial comparing conventional and endovascular repair of abdominal aortic aneurysms. N Engl J Med. 2004 Oct 14;351(16):1607–18.  [PMID: 15483279] Schermerhorn ML et al. Endovascular vs. open repair of abdominal aortic aneurysms in the Medicare population. N Engl J Med. 2008 Jan 31;358(5):464–74.  [PMID: 18234751]