Abdominal Pain- Mesenteric Ischemia
A 65-year-old male with 1 week of progressive abdominal pain presented to a small hospital. Â His medical history is significant for a myelofibrosis with chronic portal vein thrombosis. He underwent CT scan and was urgently transferred to the surgical ICU at the nearby tertiary hospital.
CT abdomen and pelvis (coronal)
CT abdomen and pelvis (axial)
The abdomen pelvis CT showed chronic portal vein thrombosis with cavernous transformation as well as distal SMV thrombosis with inflammatory changes of the distal small bowel. There is a moderate amount of intra-abdominal fluid, including around the spleen and liver as well as in the pelvis. There is thickening of the small bowel wall as well as stranding and edema in the mesentery. There was also evidence of a splenorenal shunt.
Representative slice from CT, axial
Representative slice from CT, axial- labels
Representative slice from CT, axial
Representative slice from CT, axial- labels
Differential diagnosis?
Splenic injury secondary to splenomegaly (minor trauma can lead to splenic injury in the setting of splenomegaly).Â
Bowel ischemia.
Hollow viscus perforation.
On arrival to the ICU, his abdominal exam revealed diffuse rebound tenderness. He became disoriented during our interview. Concurrent with our evaluation, the images with reviewed with radiology who reported that the fluid was not consistent with hemoperitoneum from a splenic injury.
Based on our concern for bowel ischemia, he was taken to the operating room for abdominal exploration. He was noted to have a significant length of ischemic and necrotic bowel. This was resected and his bowel was left in discontinuity. He was returned to the ICU with an open abdomen and plan for second look laparotomy within 24 hours.
Evaluation and Management of Acute Mesenteric Ischemia
Causes
Arterial Embolism- from the left atria (atrial fibrillation), left ventricle (decreased function following cardiac ischemia) or heart valves.
Arterial Thrombosis- progression of underlying atherosclerotic disease leading to critical stenosis at the takeoff of the celiac or SMA from the aorta.
Venous Thrombosis- hypercoagulable states, acute inflammatory process around the SMV (pancreatitis), post-operative following splenectomy or bariatric surgery.
Non-occlusive mesenteria ischemia (NOMI)- low-flow through the SMA with vasoconstriction. Often having underying illness or cardiac failure, which is exacerbated by vasoconstrictive medications and hypovolemia.
Presentation
Severe abdominal pain, "pain out of proportion to exam" (report severe pain but abdominal exam doesn't elicit tenderness).
Arterial thrombosis may be acute on chronic, if there is underlying chronic mesenteric ischemia.
Diagnosis
Etiology can be suspected based on symptoms and medical/ surgical history.Â
Sudden onset is suggestive of arterial embolism.Â
Known hypercoagulable state is suggestive of venous thrombosis.
Chronic abdominal symptoms including pain with eating (food fear) and weight loss are suggestive of arterial thrombosis.
Imaging
Plain films may be non-specific, but may show free air or portal venous gas later in the course.
Angiography
Arterial thrombosis- often seen right at the takeoff of the celiac or SMA from the aorta.
Arterial embolism- typically an occlusion of the celiac or SMA at a branch (versus right at the takeoff).
Treatment
Volume resuscitation, antibiotics
Anticoagulation
Surgery consultation for assessment of bowel viability and treatment of vessel occlusion