Makindo Medical Notes

Related Subjects: |Metabolic acidosis |Lactic acidosis

Early diagnosis and timely surgical intervention are the cornerstones of modern treatment and are essential to reduce the high mortality associated with this entity.

About

• Superior mesenteric artery is most vulnerable

Aetiology

• Embolism from AF or LV thrombus
• Thrombosis in situ
• Hypotension
• Venous thrombosis

Anatomy

• Superior mesenteric artery (SMA) is the primary blood supply for the small bowel with some collateral flow from the coeliac arterial system
• This is via the superior and inferior pancreaticoduodenal arteries, as well as from the inferior mesenteric artery
• The SMA is particularly vulnerable because of its relatively large diameter and low takeoff angle from the aorta.
• The majority of emboli lodge 3 to 10 cm distal to the origin of the SMA, thus classically sparing the proximal jejunum and colon

Clinical

• Acute severe abdominal pain but can be minimal
• Older patients or those on steroids may present atypically
• Some may have acute on chronic ischaemia with food induced abdominal pain
• Peritonism suggests irreversible intestinal ischaemia with bowel necrosis

Investigations

• FBC: WCC rise. U&E may see AKI
• ABG: Metabolic acidosis with elevated lactate level. Indeed lactic acidosis in a combination of abdominal pain when the patient may not otherwise appear clinically ill should lead to consideration for early CTA.
• ECG : ? AF? MI? LVH
• AXR: only becomes positive when bowel infarction has developed an intestinal perforation manifests as free intraperitoneal air.
• CT/Angiogram Abdomen: irreversible ischaemia (intestinal dilatation and thickness, reduction or absence of visceral enhancement, pneumatosis intestinalis, and portal venous gas) and free intraperitoneal air

Pathology

Management

• ABC, Oxygen. IV fluids. Correct electrolytes. NBM and NG suction
• Broad-spectrum antibiotics should be administered immediately.
• Unless contraindicated, patients should be anticoagulated with intravenous unfractionacted Heparin
• Prompt laparotomy should be done for patients with overt peritonitis.
• Mesenteric venous thrombosis can often be successfully treated with a continuous infusion of unfractionated Heparin
• Close cooperation between acute care surgeons, radiologists, anesthetists, and the vascular surgeons is essential.

References

• Article on Mesenteric infarction