Question

A 59-year-old man presents to the emergency department with abdominal pain. He states that it seemed to come on abruptly, though he does endorse feeling pain the past several days. He has been experiencing bloody diarrhea as well as a subjective fever. His past medical history is notable for an ST elevation myocardial infarction (STEMI) treated 1 year ago, an abdominal aortic aneurysm (AAA) treated 1 week ago, chronic obstructive pulmonary disease (COPD), asthma, obesity, hypertension, stroke treated 5 years ago, an atrial arrhythmia, diabetes, constipation, and post-traumatic stress disorder (PTSD). His temperature is 102.0°F (39°C), blood pressure is 197/128 mmHg, pulse is 135/min, respirations are 22/min, and oxygen saturation is 92% on room air. On physical exam, you note an obese man in distress. Cardiopulmonary exam is notable for bilateral wheezes and a systolic murmur. There is bilateral lower extremity pitting edema and venous stasis ulcers. Abdominal exam reveals diffuse tenderness which the patient describes as 10/10 in severity. Laboratory values are ordered as seen below.

Hemoglobin: 14 g/dL
Hematocrit: 42%
Leukocyte count: 15,500/mm^3 with normal differential
Platelet count: 199,000/mm^3

Serum:
Na+: 139 mEq/L
Cl-: 100 mEq/L
K+: 4.4 mEq/L
HCO3-: 22 mEq/L
BUN: 32 mg/dL
Glucose: 189 mg/dL
Creatinine: 1.9 mg/dL
Ca2+: 10.2 mg/dL
Lactate: 4.5 mg/dL
AST: 12 U/L
ALT: 10 U/L

Which of the following is the most likely explanation for this patient's presentation?

a. Abdominal aortic aneurysm repair complication
b. Atheromatous plaque rupture
c. Atrial fibrillation
d. Obstruction of the small bowel
e. Ruptured appendix

Answer 1

A complication from the abdominal aortic aneurysm (AAA) repair is the most likely explanation for the patient's acute symptoms, which include severe abdominal pain, bloody diarrhea, fever, and elevated lactate levels, given his recent medical history.

Step-by-step explanation:

Explanation for the Patient's Presentation

The most likely explanation for the 59-year-old man's presentation, who is experiencing abrupt abdominal pain, bloody diarrhea, and a subjective fever, is a complication from the abdominal aortic aneurysm repair he underwent a week ago. Considering his recent AAA repair, his symptomatology of a high fever, hypertension, and diffuse abdominal tenderness, combined with elevated lactate levels, suggest an infectious or ischemic postoperative complication. This is more likely than the other options given, such as atheromatous plaque rupture, atrial fibrillation, obstruction of the small bowel, or a ruptured appendix, primarily because they do not align as closely with his recent medical history and current symptoms.

Patients with recent vascular surgical procedures are at risk for complications including graft infection or aortic graft enteric fistula, which could present with these symptoms. Additionally, his elevated blood pressure and tachycardia could be secondary responses to severe pain and infection. His history of COPD, stroke, and diabetes also increase his risk for postoperative complications.

A differential diagnosis and further imaging studies would be required to confirm the suspicion and plan for appropriate management which could involve antibiotics for infection or surgery for any mechanical complication related to the AAA repair.