Ischaemic enteritis is considered a transitional condition between abdominal angina and mesenteric infarction.1
As in other mesenteric ischaemic diseases, the central abnormality of ischaemic enteritis is an inadequate blood supply to the abdominal viscera; there are two types that have been described: occlusive and non-occlusive. Embolism or thrombosis of the superior mesenteric artery is the cause of occlusion in the majority of patients.2
Non-occlusive ischaemic enteritis occurs in 25% of all patients with ischaemic enteritis, and this entity usually manifests in the setting of haemodynamic decompensation superimposed on a severely stenosed mesenteric vasculature.2 3
Patients with ischaemic enteritis usually complain of diffuse abdominal pain, which subsequently localizes to the approximate site of involvement. Nausea, vomiting and diarrhoea with or without melena or haematochezia may be seen. Peritoneal signs may also be present along with paralytic ileus, which can be seen on a simple abdominal x-ray.1
The diagnosis of ischaemic enteritis is difficult because of the non-specific symptoms and laboratory investigations. In this setting, imaging procedures can offer some clues to the diagnosis. Dilated intestinal loops and thickening of the intestinal wall with an intraluminal collection of fluid can be observed on ultrasound, x-ray and CT scans.4
With the introduction of contrast-enhanced MR angiography (MRA) it became feasible to generate high-quality and high-resolution images of the mesenteric vasculature. In comparison with CT and ultrasound, the MRA is more time-consuming and, similar to other non-invasive methods, it provides no therapeutic options. Therefore, MRA is not considered a diagnostic tool in critically ill patients or patients with severe acute abdominal disorders, including patients with suspected mesenteric ischaemia.5
Angiography findings may confirm the diagnosis of arterial occlusion and indicate non-occlusive mesenteric ischaemia with the findings of the ‘defoliated tree’ sign that refers to the absence of contrast dye in the smaller mesenteric vessels.4 6
However, a definite diagnosis of ischaemic enteritis requires histopathology evaluation as the differential diagnosis includes other bowel diseases such as inflammatory bowel disorders, intestinal tuberculosis and carcinoma.1 2
In patients with chronic renal failure, various ischaemic conditions involving the stomach, small bowel and large intestine can be present.7
Similar to other gastrointestinal abnormalities found in patients with chronic renal failure, ischaemic enteritis may be among the clinical manifestations of uraemia. The dialysis population is especially prone to the development of non-occlusive mesenteric ischaemia. This is particularly common in haemodialysis patients but occurs in patients on peritoneal dialysis. In the latter group there can be difficulty differentiating this entity from peritonitis.8
The increased susceptibility of dialysis patients to non-occlusive ischaemic enteritis is likely due to the fact that they have many of the predisposing risk factors for bowel ischaemia. Diabetes, hypertension and ischaemic heart disease are common predisposing factors both for renal failure and ischaemic enteritis.1
Other risk factors include wide-spread atherosclerosis, smoking, advanced age, hyperlipidaemia, secondary hyperparathyroidism, use of digoxin (a drug with potential vasoconstrictive effects on mesenteric vessels), bleeding diatheses and mechanical problems such as volvulus and an incarcerated hernia.3 6 9
In addition, vasculitis, fibromuscular dysplasia and arterial dissection may also present with ischaemic enteritis.2 10
The fact that patients on chronic dialysis have more cardiovascular comorbidity compared to the general population may explain the higher frequency of non-occlusive mesenteric ischaemia.6
An aggressive ultrafiltration protocol and increased time on haemodialysis can cause a hypotensive episode during haemodialysis. This hypotension, especially when recurrent, is a significant risk factor for non-occlusive mesenteric ischaemia in patients on dialysis.3 6
Although mesenteric ischaemia appears more frequently among dialysis patients than in the non-dialysis population, ischaemic enteritis can occur in non-dialysed patients with chronic renal failure. The actual incidence of ischaemic enteritis in patients with chronic renal failure and who are not on dialysis is not known, but may be similar to the general population. Of note is the higher incidence of this condition in women, especially those presenting with mesenteric ischaemia, including those who are on dialysis and not on dialysis.11
The present patient had risk factors for mesenteric ischaemia such as generalised atherosclerosis, hypertension and smoking. In addition, optimising patient blood pressure and controlling oedema, with antihypertensive and diuretic agents, may have been important factors in triggering the mesenteric hypoperfusion and ischaemic insults. The subsequent oliguria after the development of ischaemic enteritis, in this patient, was likely precipitated by a severe reduction in renal perfusion resulting from overuse of diuretics and antihypertensive drugs, combined with the ischaemic enteritis-related diarrhoea.
Although early diagnosis remains the cornerstone of successful treatment, the management of ischaemic enteritis remains challenging and controversial. The treatment of ischaemic enteritis depends on the evolution of the disease, the extent of the vessel(s) compromised and the available collateral circulation.1
In general, early surgery or endovascular therapy is advised. In cases with transient reversible ischaemia, the patient can be treated conservatively with analgesics and total parenteral nutrition. If the bowel is seen to progressively dilate, associated with clinical deterioration, a presumption of impending gangrene is made, and immediate resection is indicated.1 2
If ischaemic enteritis resolves and progresses to stricture formation over the course of 3–4 weeks, without evolving to gangrene, such patients can be observed and surgery performed only if bowel obstruction develops.1
Continuous and selective infusion of substances such as vasodilator or thrombolytic agents via angiography has also been suggested for revascularisation;12
however, no significant improvement in survival has been demonstrated, and the mortalities are reported to be as high as 80–95%.13
Although the recent recommendations tend to prefer prompt laparotomy,12 13
the general condition of patients, cause of mesenteric ischaemia and intraoperative findings of the extent of bowel involvement can affect decision making. Our patient was initially treated with total parenteral nutrition and improved both clinically and radiographically. However, as the haemodialysis treatment was continued, ischaemic enteritis rapidly progressed to intestinal necrosis. The haemodialysis procedure to remove large volumes of fluid from the intravascular space likely led to relative hypovolemia, even without significant hypotension, and this must have been the main factor affecting the clinical course of the ischaemic enteritis. Furthermore, in our case, the advanced age and multiple other problems influenced the decision of whether to perform an early surgical procedure. Especially, COPD with FEV1
<50% of predicted value and FEV1
/FVC <75%, current smoking history, and resistance to multimodal treatments, including chest physical therapy, bronchodilators, smoking cessation, antibiotics and corticosteroids, raised the risk of development of postoperative pulmonary complications.14
In summary, ischaemic enteritis is an uncommon but potentially fatal condition that usually requires an aggressive diagnostic and therapeutic approach. The general condition of patients remains the main issue for surgical decision making. Appropriate guidelines for the decisions regarding surgical or supportive treatment of patients with both ischaemic enteritis and chronic renal failure need to be further defined.
- Ischaemic enteritis in patients with chronic renal failure is a rare but a potentially fatal disorder.
- Hypotension is considered the most important and precipitating factor for non-occlusive mesenteric ischaemia in patients on dialysis.
- Perioperative morbidity should be taken into consideration because the majority of these patients have poor general health secondary to underlying disorders.