Intestinal ischemia resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mugilan Poongkunran M.B.B.S [2]

Definition

Intestinal ischemia are a heterogeneous group of diseases characterized by hypoxia of the small bowel and/or colon, which most commonly arises from occlusion, vasospasm, and/or hypoperfusion of the mesenteric vasculature. Intestinal ischemic disorders have been classified into the following three major types.

Clinical subgroups	Definitions
Acute mesenteric ischemia (AMI)	It includes superior mesenteric artery embolism (SMAE) (50%); nonocclusive mesenteric ischemia (NOMI) (20% to 30%); superior mesenteric artery thrombosis (SMAT) (15% to 25%); and superior mesenteric vein (SMV) thrombosis (5%). It is most commonly associated with compromise of the blood flow in the superior mesenteric artery (SMA) distribution affecting all, or portions of, the small bowel and right colon.
Chronic mesenteric ischemia (CMI)	It usually refers to intestinal angina, where the splanchnic circulation is insufficient in meeting the functional demands of the gut, but there is no loss of tissue viability.
Colonic ischemia (CI)	It is the most common vascular disorder of the gut that includes reversible ischemic colopathy, transient ulcerating ischemic colitis, chronic ulcerating ischemic colitis, colonic stricture, colonic gangrene, and fulminant universal ischemic colitis.

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Intestinal ischemia itself may present or complicate as a life-threatening condition and must be treated as such irrespective of the causes.

Common Causes

• Arterial embolism
• Arterial thrombosis
• Hypercoagulable states
• Non-occlusive ischemia
• Cardiogenic shock
• Vasculitis
• Vasoconstrictors: Cocaine, ergot, vasopressin, or norepinephrine.
• Venous thrombosis

Management

The algorithm is based on the American College of Gastroenterology guidelines for management of Intestinal Ischemia in adults.

Management of Acute Mesenteric Ischemia

Characterize the symptoms: ❑ Abdominal pain: ❑ Onset (sudden or insidious) ❑ Duration (persistent for more than 2-3 hours) ❑ Location (localized or generalized) ❑ Severity (often out of proportion to findings on physical examination) ❑ Nausea and vomiting ❑ Abdominal distention ❑ Bloody stools ❑ Mental status change Inquire about risk factors for AMI: ❑ Cardiovascular: ❑ Congestive heart failure ❑ Cardiac arrhythmias ❑ Recent myocardial infarction ❑ Valvular heart disease ❑ Previous H/O DVT, PVD, PE, vasculitis ❑ Recent hypovolemia ❑ Recent hypotension ❑ Cardiac surgery and dialysis ❑ Hypercoagulable states: ❑ Protein C deficiency and Protein S deficiency ❑ Antithrombin III deficiency ❑ Activated protein C resistance (APC) ❑ Paroxysmal nocturnal hemoglobinuria ❑ Myeloproliferative disease ❑ Intestinal angina: ❑ Chronic postprandial pain ❑ Aversion to eating ❑ Weight loss ❑ Sepsis, abdominal infections ❑ Blunt abdominal trauma ❑ Pancreatitis, splenectomy, and malignancy in the portal region ❑ Familial history of atheroembolism

Assess volume status: ❑ General condition ❑ Thirst ❑ Pulse ❑ Blood pressure ❑ Eyes ❑ Mucosa Examine the patient: ❑ Abdomen: ❑ Abdominal distension ❑ Occult blood in the stool ❑ Signs of peritoneal inflammation (rebound tenderness and guarding) ❑ Bowel sounds (absent in bowel infarction) ❑ Cardiovascular system (murmur) ❑ Respiratory system ❑ Anorectal (bleeding) ❑ Signs of vasculitis

High clinical suspicion with known risk factors Resuscitate the patient: ❑ NPO ❑ Intravenous fluids ❑ Avoid vasoconstrictors ❑ Correct predisposing or precipitating factors: ❑ Relieving acute congestive heart failure and hypotension ❑ Correction of hypovolemia ❑ Correction of cardiac arrhythmias ❑ Antibiotics for sepsis ❑ Monitor vitals every 1/2 to 1 hour Order tests (urgent): ❑ CBC: Leukocytosis ❑ Serum electrolytes ❑ ESR: Elevated ❑ D dimer: Elevated ❑ Serum lactate: Elevated ❑ Serum amylase ❑ ABG: Metabolic acidosis or metabolic alkalosis ❑ Serum alpha-glutathione S-transferase (alpha-GST): Elevated ❑ Urinary and plasma intestinal fatty acid-binding protein (I-FABP): Elevated ❑ Total serum protein and albumin ❑ Urinalysis ❑ BUN ❑ Creatinine ❑ Serum glucose

Plain abdominal X-ray (urgent)

Other causes ❑ Perforated peptic ulcer Or ❑ Gallbladder disease Or ❑ Pancreatic pathology Or ❑ Intestinal obstruction

History of DVT or familial hypercoagulable state

Treat accordingly

Yes

No

Dynamic CT scan

Peritoneal signs

No

Yes

Mesenteric angiography

Laprotomy

Specific diagnosis ❑ Mesenteric venous thrombosis Or ❑ Major arterial occlusion (non-embolic) Or ❑ Minor arterial occlusion or embolic Or ❑ Major embolus Or ❑ Splanchnic vasoconstriction (no occlusion)

Normal findings

Look below for specific management

No persistent peritoneal findings

Persistent peritoneal findings

Observe

Laprotomy

References

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