-IBIS-1.5.0-
tx
cardiovascular system
myocardial infarction sequelae
diagnoses
definition and etiology
myocardial infarction is a medical emergency requiring immediate hospitalization
definition:
permanent myocardial damage due to myocardial infarction
etiology:
The most common cause is coronary artery disease, following the many attendant risk factors for atherosclerosis. Occlusion may be gradual or thrombotic, and involve coronary spasm or emboli. Lesions may be transmural or subendocardial.
Curiously, Traditional Chinese Medicine considers excessive joy as a potential contributing factor. This contrasts sharply with the emerging Western understanding of suppression of anger and other emotions, or the more familiar implication of 'type A' behavior as etiologic factors.
signs and symptoms
complications:
pericarditis
mural thrombi (subject to rupture)
peripheral artery embolism
frank rupture
cardiac tamponade (intrapericardial hemorrhage)
ventricular aneurysm
signs and symptoms:
classic symptoms of an MI include:
deep, severe substernal pain referred to the left arm, jaw, or back; the pain is refractory to nitroglycerin; it may be preceded by one of the angina variants
fear, sweating, great anxiety
shortness of breath
other associated symptoms are:
hypotension, poor peripheral blood flow, pulmonary edema, arrhythmias, fever, leukocytosis
lab findings:
elevated levels of CPK, LDH, and AST, depending on timing
elevated levels of alkaline phosphatase
CPK-MB isoenzyme returns to normal after 3 days
LDH increases 10-12 hours after MI, peaks @ 48-72 hours; LDH isoenzymes flip so LDH1/LDH2 ratio >1
AST level increases @ 6-8 hours, peaks @ 24 hours, normal in 4-6 days
leukocytosis invariable by day two
ESR increased 2nd-3rd day
glycosuria in 50% of patients
course and prognosis
Damage to the heart muscle results in coagulative necrosis of the muscle fibers and loss of normal contractile and conductive responses of the myocardium. In the post infarction phase, scar tissue is the primary consideration. There can be many complications (listed under signs and symptoms) but the depth, extent, and health of the scar tissue determines the length and quality of life after an MI. Early intervention with tissue plasminogen activator (TPA) has been shown to reduce mortality by causing early dissolution of vessel obstruction.
differential diagnosis
indigestion, peptic ulcer, hiatal hernia, gall bladder disease
angina pectoris
abdominal emergency
aortic aneurysm
pneumonia, pleuritis, pneumothorax, pulmonary embolism
costochondritis
anxiety
footnotes