WBR1113

Author	[[PageAuthor::Mugilan Poongkunran M.B.B.S [1]]]
Exam Type	ExamType::USMLE Step 3
Main Category	MainCategory::Emergency Room
Sub Category	SubCategory::Gastrointestinal
Prompt	[[Prompt::A 45 year old male is brought to the emergency department with complaints of sudden onset of severe abdominal pain for the past five hours. The pain is generalized and is increasing in severity since then. He also had two episodes of non-bloody vomiting on the way to the emergency department. On further review of his history, he reveals that he was having recurrent episodes of abdominal pain for the past three months, especially after meals that persisted for one to two hours. His past history is significant for valvular heart disease and is on ACE inhibitors and thiazide diuretics for that. He is a heavy smoker, but consumes alcohol occasionally. His family history is insignificant. On examination the patient is lethargic and his vitals are pulse: 120/min, BP: 80/70 mmHg and temperature: 38 degree Celsius. Abdominal examination reveals generalized tenderness with rebound tenderness and guarding. Other system examinations are normal except for a murmur at the mitral area. The patient is kept on NPO and started on intravenous fluids and broad spectrum antibiotics. Initial set of laboratory investigations and abdominal X-ray are ordered. Despite the initial aggressive fluid therapy, the patient’s pulse and blood pressure is dropping. Which of the following would be the most appropriate drug in the management of the patient’s vitals?]]
Answer A	AnswerA::Digitalis
Answer A Explanation	[[AnswerAExp::Digitalis is often avoided in acute mesenteric ischemia patients because of its vasoconstricting action.]]
Answer B	AnswerB::Epinephrine
Answer B Explanation	[[AnswerBExp::Epinephrine increases heart rate, contracts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. It should be avoided in acute mesenteric ischemia patients because of its vasoconstricting action on mesenteric circulation.]]
Answer C	AnswerC::Milrinone
Answer C Explanation	[[AnswerCExp::Milrinone is a phosphodiesterase III inhibitor and it potentiates the effect of cyclic adenosine monophosphate (cAMP). It has positive inotropic, vasodilating and minimal chronotropic effects. In acute mesenteric ischemia patients, milrinone are preferred since they have less of an effect on mesenteric perfusion compared with other vasopressor agents.]]
Answer D	AnswerD::Norepinephrine
Answer D Explanation	[[AnswerDExp::Norepinephrine increases blood pressure by increasing vascular tone through α-adrenergic receptor activation. It should be avoided in acute mesenteric ischemia patients because of its vasoconstricting action on mesenteric circulation.]]
Answer E	AnswerE::Dopamine
Answer E Explanation	[[AnswerEExp::Dopamine acts on the sympathetic nervous system, producing effects such as increased heart rate and blood pressure. It can be used in acute mesenteric ischemia patients at low doses but milrinone would be a better option in this patient.]]
Right Answer	RightAnswer::C
Explanation	[[Explanation::Acute mesenteric ischemia refers to the sudden onset of intestinal hypoperfusion, most commonly due to acute embolic or thrombotic occlusion of the superior mesenteric artery (SMA). The diagnosis of AMI depends upon a high clinical suspicion, especially in patients who develop severe and persisting abdominal pain that is disproportionate to their abdominal finding and with known risk factors such as atrial fibrillation, congestive heart failure, valvular heart disease, peripheral vascular disease, or a history of hypercoagulability. Rapid diagnosis is essential to prevent the catastrophic events associated with intestinal infarction and the goal of treatment is to restore intestinal blood flow as rapidly as possible. Initial management should include aggressive hemodynamic monitoring and support, correction of metabolic acidosis, initiation of broad spectrum antibiotics, and placement of a nasogastric tube for gastric decompression. Vasoconstricting agents and digitalis should be avoided if possible since they can exacerbate mesenteric ischemia. If vasopressors are required, dobutamine, low-dose dopamine, or milrinone are preferred since they have less of an effect on mesenteric perfusion compared with other vasopressor agents. Educational Objective: References: ]]
Approved	Approved::Yes
Keyword	[[WBRKeyword::Acute mesenteric ischemia]], [[WBRKeyword::mesenteric ischemia]]
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::