Ischemic bowel disease

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Key Recommendations

Treatment for ischemic bowel disease depends on the anatomical location and severity of ischemia, its underlying pathophysiology and time course. Thorough assessment and prompt, appropriate intervention are essential to alleviate symptoms and improve outcome.[46] Surgical consultation should not be delayed if ischemia of the bowel is suspected or verified.

Acute mesenteric ischemia

Resuscitation and supportive measures

Adequate fluid resuscitation and supplemental oxygen should be administered to optimize tissue perfusion and oxygenation.[37]

Inotropic support may be required. Consult a specialist for guidance on suitable inotrope regimens.

Selection of appropriate vasoactive agents should only take place under critical care supervision, and may vary according to the type of shock, clinician preference, and local practice guidelines.
Vasopressors should be avoided where possible as they may cause further splanchnic vasoconstriction.[11][24]
Continuous monitoring of cardiac rhythm is recommended during infusion of inotropes.

Initial resuscitation should also aim to relieve any acute heart failure and correct any cardiac arrhythmias. Invasive monitoring may be appropriate. Nothing by mouth (NPO) status should be enforced, with nasogastric tube decompression for symptomatic relief.[11]

Antibiotics

Empiric antibiotics suitable for enteric coverage (e.g., a third-generation cephalosporin or fluoroquinolone plus metronidazole) are administered to all patients according to local antimicrobial guidelines, as ischemia can lead to significant bacterial translocation due to damage to the normal intestinal mucosal barrier.[11]

Systemic fluoroquinolone antibiotics may cause serious, disabling, and potentially long-lasting or irreversible adverse events. This includes, but is not limited to: tendinopathy/tendon rupture; peripheral neuropathy; arthropathy/arthralgia; aortic aneurysm and dissection; heart valve regurgitation; dysglycemia; and central nervous system effects including seizures, depression, psychosis, and suicidal thoughts and behavior.[47]

Prescribing restrictions apply to the use of fluoroquinolones, and these restrictions may vary between countries. In general, fluoroquinolones should be restricted for use in serious, life-threatening bacterial infections only. Some regulatory agencies may also recommend that they must only be used in situations where other antibiotics that are commonly recommended for the infection are inappropriate (e.g., resistance, contraindications, treatment failure, unavailability).
Consult your local guidelines and drug information source for more information on suitability, contraindications, and precautions.

Revascularization

With the emergence of interventional radiology, endovascular treatment may be considered for hemodynamically stable patients where available. Research suggests that outcomes of endovascular treatment are favorable.[48] Options depend on the underlying cause of ischemia, and include aspiration embolectomy, transcatheter thrombolysis, transjugular intrahepatic portosystemic shunt (TIPS), and thrombectomy.[11][12][17][24] Endovascular therapy for acute mesenteric ischemia has been shown to be associated with a reduced mortality and reduced risk of small bowel resection.[17][49][50][51][52]

If there are clinical signs of peritonitis, or radiographic or laboratory evidence suggestive of infarction or perforation, revascularization should be the primary goal, followed by urgent surgical intervention to assess the extent and severity of the ischemia and need for resection and reconstruction.[17][37] Ideally, revascularization procedures should be completed prior to any bowel resection, as borderline ischemic bowel may recover satisfactorily after revascularization. Second-look operations may be necessary to evaluate progression of ischemia or reperfusion injury resulting in more nonviable intestine requiring resection. Anastomosis can at times be delayed until the second-look laparotomy, especially if the patient is clinically unstable.

Depending on the underlying pathology and findings at surgery, several interventions may be appropriate:

Proximal embolisms may be amenable to revascularization with embolectomy at the level of arterial occlusion.[17] This can be performed with surgical or endovascular intervention.[12][17][24]
Acute superior mesenteric artery thrombosis may be treated with endovascular interventions.[17][51] However, if arterial occlusion is due to severe and widespread atherosclerotic disease and the patient is stable enough to tolerate increased operative duration, systemic-mesenteric bypass may be considered.
Nonocclusive mesenteric ischemia may be treated with transcatheter infusion of a vasodilator (e.g., papaverine, alprostadil).[53] In addition, the underlying medical cause should be corrected. Papaverine is not available as a Food and Drug Administration (FDA)-approved proprietary formulation in the US. In practice, alprostadil (prostaglandin E1) may be considered.[17] The American College of Radiology recommends alprostadil for patients without evidence of peritoneal signs.[17] However, in practice it is also used for those with evidence of infarction, perforation, or peritonitis. Other vasodilatory agents to be considered in the treatment of nonocclusive mesenteric ischemia include nitroglycerin.[54][55][56]
If mesenteric venous thrombosis is identified, anticoagulation is first-line treatment.[17][57] Endovascular management may be used if anticoagulation is unsuccessful.[17][58] Surgery is only indicated if there are signs of infarction or peritonitis.[58]
External compression of the proximal celiac artery by the median arcuate ligament (MAL) is usually managed with surgical release of the MAL.[17] Further intervention with either endovascular stent placement or surgical bypass may be required for reconstruction of the celiac artery; a multidisciplinary approach is required.[17] However, select patients may be managed using supportive measures only, which include counseling, analgesia, and dietary modifications.[17]
If a source of sepsis is identified, appropriate swabs and cultures allow identification of causative organisms and subsequent targeting of antibiotic therapy.
If vasculitis is identified as a contributory cause (e.g., by thickened blood vessels on CT scan, or the presence of other vasculitic symptoms, or a previous diagnosis) postoperative corticosteroid therapy may be considered.

In the case of nonocclusive mesenteric ischemia, intra-arterial vasodilator infusions may be used as an adjunctive therapy during selective mesenteric angiography.[17][53] Infarcted bowel should be resected following infusion of vasodilators.[24]

Anticoagulation is also generally recognized as being beneficial, although timing of treatment is controversial. Some authorities recommend a delay of 48 hours following surgery because of the risk of intraluminal bleeding from damaged bowel, while others advocate immediate anticoagulation. Another suggested approach has been immediate anticoagulation if no infarction is present at surgery, but delayed anticoagulation if intestinal infarction is found. Good data supporting any of these approaches are lacking.[32]

In patients with a superior mesenteric artery (SMA) embolus where there is no evidence of infarction, perforation, or peritonitis requiring urgent surgical intervention, endovascular intervention should be performed.[17]

Endovascular intervention includes aspiration embolectomy and transcatheter thrombolysis; choice of intervention is guided by local preference.[17] Transcatheter thrombolysis may be used instead of, or in addition to, aspiration embolectomy.[12][17][59][60][61] Anticoagulation should also be started.[17]
If endovascular intervention is unsuccessful, patients should undergo surgical embolectomy.[17] Indications that endovascular intervention has been unsuccessful include lysis of the embolus not demonstrated within 4 hours, and evidence of ischemia progression.

Patients with an SMA thrombosis and no evidence of infarction, perforation, or peritonitis should be treated with endovascular intervention (which may include thrombolysis, angioplasty, or stent placement) first line.[17] Anticoagulation should be given before, during, and after this procedure in order to prevent clot propagation.[17] Surgical intervention (with endarterectomy or bypass) may be used in certain circumstances, but this has generally been replaced by endovascular management.[17]

Chronic mesenteric ischemia

If chronic mesenteric ischemia is due to atherosclerotic disease, endovascular revascularization is the primary treatment of choice.[17] Surgical bypass or endarterectomy may be considered, but endovascular treatment is generally preferred for initial management.[17]

Endovascular revascularization has largely replaced open surgical revascularization because it is associated with lower perioperative risk, especially in patients with severe malnutrition.[17][62][63][64][65]
However, endovascular management is associated with higher risk of peripheral vascular complications, restenosis, recurrent symptoms, and requirement for additional interventions.[17]

If chronic mesenteric ischemia is due to celiac compression syndrome (external compression of the proximal celiac artery by the median arcuate ligament), this is usually managed initially with surgical release of the MAL.[17]

Further intervention with either endovascular stent placement or surgical bypass may be required for reconstruction of the celiac artery; a multidisciplinary approach is required.[17]
However, some patients may be managed using supportive measures only (instead of surgery), which include counseling, analgesia, and dietary modifications.[17] In particular, one retrospective study showed that patients with mesenteric collateralization on mesenteric angiography were less likely to benefit from surgical release of the MAL than those without mesenteric collateralization.[66]

Colonic ischemia

This is the most common form of intestinal ischemia and comprises a spectrum of disorders covering:[67]

Reversible colopathy
Transient colonic ischemia
Chronic colonic ischemia
Stricture
Gangrene
Fulminant pancolitis.

Most patients with colonic ischemia do not have any identifiable, specific, and precipitating cause, and treatment varies with severity of presentation.[7] Most cases resolve spontaneously (reversible ischemic colopathy or transient colonic ischemic changes). Severe or continuing symptoms necessitate hospitalization, supportive measures, bowel rest, and investigation and correction of precipitants.

Patients with moderate or severe acute presentations of colonic ischemia routinely receive antibiotic therapy, although good evidence of benefit is lacking. The practice is based on a number of old studies and the theoretical protection it gives against the bacterial translocation that occurs with loss of mucosal integrity.[11]

Indications for surgery in colonic ischemia include:[7]

Acute indications:
- Peritoneal signs, suggestive of necrosis or perforation
- Massive bleeding (rare): may require subtotal colectomy
- Universal fulminant colitis with or without toxic megacolon.
Subacute indications:
- Failure of an acute segmental ischemic colitis to respond within 2 to 3 weeks, with continued symptoms or a protein-losing colopathy
- Apparent healing but recurrent bouts of sepsis.
Chronic indications:
- Symptomatic colon stricture: may be treated with endoscopic balloon dilation or segmental resection
- Symptomatic segmental ischemic colitis.

Transient or mild ischemia with no evidence of infarction, perforation, or peritonitis

Patients with acute transient or mild ischemia have physical findings without peritonitis, a computed tomography scan or mesenteric angiography demonstrating intestinal perfusion, and no evidence of full thickness necrosis. If colonoscopy and imaging suggest mucosal or submucosal involvement only, conservative measures may be employed. These include:[11]

NPO status
Fluid resuscitation and possible inotropic support
Antibiotics for enteric coverage
Nasogastric tube decompression for symptomatic relief.

Antibiotics suitable for enteric coverage (such as a third-generation cephalosporin or quinolone plus metronidazole) should be given to all patients, as bacterial translocation may be significant due to the loss of the normal intestinal mucosal barrier.[11]

The underlying cause should be treated promptly. Initial management should include:

Correction of underlying medical cause and vasodilator infusion for nonocclusive mesenteric ischemia[11][24][53]
Anticoagulation for mesenteric venous thrombosis[17][58]
Tailored antibiotic therapy when an infectious cause is identified
Corticosteroids for vasculitis
Fluid resuscitation and cardiac optimization for shock.

Diligent and frequent reassessment of the patient must be undertaken to detect those patients for whom conservative management fails and who then require operative intervention due to evidence of peritonitis or infarction.

Central venous catheter insertion: animated demonstration

Ultrasound-guided insertion of a non-tunnelled central venous catheter (CVC) into the right internal jugular vein using the Seldinger insertion technique.

Peripheral intravascular catheter: animated demonstration

How to insert a peripheral intravascular catheter into the dorsum of the hand.

Female urethral catheterization: animated demonstration

How to insert a urethral catheter in a female patient using sterile technique.

Male urethral catheterization: animated demonstration

How to insert a urethral catheter in a male patient using sterile technique.

Nasogastric tube insertion animated demonstration

How to insert a fine bore nasogastric tube for feeding.

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