Aortic dissection most often happens because of a tear or damage to the inner wall of aorta leading to bleeding into and along the wall of the aorta. When a tears occurs it creates two channels- .1)one in which blood continues to travel 2) another where blood stays still.
If the channel with nontravelling blood gets bigger it can push on other branches of the aorta.This can narrow the other branches and reduce blood flow through them.
The exact cause is unknown but more common risks include-
2)atherosclerosis 3) blunt trauma to the chest such as hitting the steering wheel of a car during an accident.4)high blood pressure 5)bicuspid aortic vulve 6) coarctation of aorta 7) heart surgery 8) marfan syndrome
1) Usually presents with severe tearing chest pain- the onset of pain is typically very abrupt, pain follows the path of dissection migrating from its point of origin and along the dissection tract.
• if ascending aorta involved – anterior chest pain
• if descending aorta involved – intrascapular pain
PHYSICAL FINDINGS ;
1) HTN 2) Asymmetry of brachial , carotid or femoral pulses 3) loss of pulses 4)features of aortic regurgitation 5)pulmonary edema 6)neurologic findings due to carotid artery obstruction 7)bowel ischemia 8)haematuria 9) MI 10) Sign of compression of adjacent structures
1) Chest x –ray ( to observe broadening of upper mediastinum, distortion of aortic knuckle , left sided pleural effusion)
2) ECG (to observe left ventricular hypertrophy in HTN, features of acute myocardial infarction rarely)
3) Doppler ( for aortic regurgitation. Dilated aortic root, flap of dissection)
Urgent management is required –1)initial management; pain control,treatment of HTN. 2)Type A Dissection;Require emergency surgical repair (replacing ascending aorta with Dacron graft) 3) Type B aneurysms; can be treated medically unless there is actual or impending external rupture or vital organ or limb ischaemia 4) percutaneous or minimal access endoluminal repair ; involves either- fenestrating the intimal flap so that blood can returr from the false to the true lumen or implanting a stent graft placed from the femoral artery.