In: Nursing
A 65-year-old man with a history of atrial fibrillation presents to his PCP’s office 2 months after suffering from a myocardial infarction. He declined anticoagulation due to fear he would bleed to death. He has had sudden-onset, moderately severe diffuse abdominal pain that began 18 hours ago. He has been vomiting, and he has had several episodes of diarrhea, the last of which was bloody. He has a fever of 100.9 ˚ F. CBC reveals WBC of 15,000/mm3.
What is the most likely mechanism behind his current symptoms?
The patient is experiencing ischemic colitis. It is said that the patient had a history of myocardial infarction and atrial fibrillation. But anticoagulation is not done.
Due to inadequate blood supply injury and inflammation has occurred to large intestine resulted in colitis.
Here the exact cause is referred as occlusive ischemia asca result of thromboembolism from myocardial infarction and atrial fibrillation. Colon receives blood from inferior and superior mesenteric arteries and also via collateral supply of marginal artery of colon . But there are weak points like splenic flexor and rectosigmoid junction which are very prone to get ischemic due to fewest collateral supply during crisis.
About 10 to 35 % of cardiac supply is received by colon. The arteries supplying colon are sensitive to vasoconstriction due to low blood pressure. It is also triggered by ergotamine, cocaine and vasopressors. During a stress heart and brain receives blood supplying by shunting away colonic supply.
3 phases
1. Hyperactive phase
Severe abdominal pain and bloody stools
2. Paralytic phase
Dull and severe abdominal pain, bloody diarrhea , decreased bowel sounds
3. Shock
Fluids leak ftom damaged colon
Metabolic acidosis
Hypotension
Tachycardia
Dehydration