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Explore the challenging diagnosis and management of acute aortic dissection, a potentially fatal condition. Learn about key risk factors, diagnostic strategies, outcomes, and long-term care.
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JCM 4th June 2014
History • M/28 Chinese • Police Cadet • History of back pain treated conservatively 2011 • Severe upper back pain after firing a pistol in Cadet School • No SOB, no weakness, no radiation
Examination • Triage Cat 4 • BP 124/66 mmHg, P63/min • Temp 35.7C, SpO2 100% • Mild tenderness at the paraspinal area of T-spine • Chest clear • Abdomen soft and no tenderness
Our management • CXR: no pneumothorax, pneumomediastinum • Ketorolac IMI given • Pain decreased after IMI • Advised to avoid physical exercise • Discharged with NSAIDs and sick leave for 1 day
4 days later • Noticed right leg pain and numbness • Feeling coldness of right leg • Patient worried about side effects related to the previous IM Ketorolac • Circulation normal • No neurological deficit • Lower limb power full
DDx? • Sprain back? • PID with radiculopathy? • Right leg DVT? • Other possibilities? • ……
Outcome • Admitted to Ortho QMH in view of pain • Suspected T9 collapse at lateral X-ray by Ortho • Private MRI spine referred • Noticed type B aortic dissection on MRI • Both leg warm and abdomen soft • Vascular team consulted and agreed to takeover
CT Aortogram • Type B aortic dissection from distal aortic arch down to right iliacs/ CFA • No coronary artery stenosis • Both kidneys perfused symmetrically • False lumen compressing true lumen leading to decreased blood flow to both lower limbs
Management • BP controlled with beta-blockers • Pain well controlled • Discharged home D13 after admission
2 months later, endovascular stenting was done in QMH in view of young age and involvement of the right iliacs/ CFA
Long term management • Follow up with contrast CT in 6 months • BP control with home BP monitoring • Advised light duty and to avoid competitive sports/ collision
Acute aortic dissection (AAD) • A potentially catastrophic disease that remains difficult to diagnose in the emergency department • Circulation 2010 • Mortality 40% for immediate death • 1% per hour for incremental death thereafter • 20% for perioperative death • 50% to 70% reported survival rate after initial surgery
Epidemiology • True incidence is unknown • Population-based prevalence studies have estimated the incidence to be about 3 cases per 100000 people per year • Higher incidence in men (65%) and with increasing age
Significant medicolegal issues surrounding missed diagnosis of AAD • Common misdiagnoses • Acute coronary syndrome (19%) • Musculoskeletal pain (20%) • Pneumonia/ pulmonary embolism (20%) • Pericarditis (12%) • Gastrointestinal pain (9%) • Other causes (20%)
Consider the diagnosis of AAD in situations of • Sudden severe chest pain • Accompanying visceral symptoms (nausea, vomiting, pallor, diaphoretic) • Normal/ minimally abnormal ECG findings • Inappropriate reliance on classic features
Clinical assessment in the ED • Risk factors • Presentations • Physical findings • End-organ presentations
Presentations • Sudden-onset severe chest pain (91%) • Visceral symptoms – pallor, vomiting, diaphoresis (78%) • Intermittent pain (75%) • Radiation to back/ neck/ arms/ jaw (69%) • Pleuritic/ positional pain (44%) • Pyrexia (22%) • Syncope (9%) • Tearing quality (3%)… CMPA case review series of missed AAD (n = 32 patients)
Poor reliance on the presence or absence of these features • High level of suspicion is needed
Physical findings • Peripheral pulses in the upper extremities/ blood pressure differentials • New aortic regurgitation murmurs • Complications of acute aortic regurgitations • Congestive heart failure, cardiogenic shock, pericardial tamponade, • Mass compression effects on adjacent structures • SVC, sympathetic chain, recurrent laryngeal nerve, tracheobronchial tree, esophagus…
End-organ presentations • Cardiovascular: AR and related disorders, pulse deficits, BP differentials, syncope, MI, CHF, cardiogenic shock, conduction abnormalities… • Syncope: cardiovascular, neurologic • Neurologic: intracranial, brainstem, spinal cord, lower extremities • Ears/ nose/ throat: mass effects on trachea, esophagus, RLN, sympathetic chain • Respiratory: mass effects on tracheobronchial tree, hemorrhage into lung tissue/ pleural space, pleural effusions • GI: mesenteric ischemia, aortoenteric fistula
Diagnostic tests • ECG (non-specific change) • Laboratory markers (currently no sensitive/ specific test) • Soluble elastin fragments, smooth muscle myosin heavy chain, WBC, hsCRP, fibrinogen, D-dimer
Diagnostic images • Chest X-ray • Abnormal aortic contour, mediastinal widening, pleural effusion, displacement of intimal calcifications, abnormal aortic knob, displacement of trachea or NG tube deviation to the right…
Mediastinal widening • Widening of aortic contour
Diagnostic images (continued) • CT • Transesophageal echocardiography • MRI
Management of type B AD • Mainly Medical treatment in form of BP control • Maintain PR <60/min by Beta blockers and SBP <120mmHg [Class I; level C] • 1 month survival 89% • 1 year survival 84% • But poor long term outcome: Mortality 30-50% at 5 year • Surgical Intervention • Indicated in complicated AD: malperfusion, rupture, rapid expansion esp false lumen, extension, severe pain, failed to control BP [Class I; level B] • Open Surgery: High mortality in the past • Endovascular Stenting: Maybe more superior but lacking evidence on long term survival Circulation 2010
Follow up • Close follow-up visits • Long-term medical therapy with beta-blockers • Serial imaging • 1, 3, 6 and 12 months post-dissection • Annually thereafter if stable
Summary for AAD • Rare but potentially catastrophic • Presentation and initial assessment findings are always non-specific • High index of suspicion is needed • CT is the most common diagnostic modality initially used • Initial management with BP, heart rate and pain control important • Subsequent definitive surgical consultation
Failure to consider AAD in these situations (and document risk assessments accordingly) can lead to clinically adverse outcomes for patients and medicolegal liability for physicians
References • Upadhye S, Schiff K. Acute aortic dissection in the emergency department: diagnostic challenges and evidence-based management. Emerg Med Clin North Am. 2012 May;30(2):307-27, viii. • De Leon Ayala IA, Chen YF. Acute aortic dissection: an update. Kaohsiung J Med Sci. 2012 Jun;28(6):299-305. • Hiratazka LF, Bakris GL, Beckman JA, et al. 2010 ACCF/AHA/AATS/ACR/ASA/SCA/SCAI/SIR/STS/SVM guidelines for the diagnosis and management of patients with thoracic aortic disease. Circulation 2010;121:e266-369.
References (continued) • http://www.medinterestgroup.com/portfolio-items/aortic-dissection-cxr-findings/ • http://www.wikiradiography.com/page/Calcium+Sign