Signs and symptoms
Three progressive phases of ischemic colitis have been described:
A hyperactive phase occurs first, in which the primary symptoms are severe abdominal pain and the passage of bloody stools. Many patients get better and do not progress beyond this phase. A paralytic phase can follow if ischemia continues; in this phase, the abdominal pain becomes more widespread, the belly becomes more tender to the touch, and bowel motility decreases, resulting in abdominal bloating, no further bloody stools, and absent bowel sounds on exam. Finally, a shock phase can develop as fluids start to leak through the damaged colon lining. This can result in shock and metabolic acidosis with dehydration, low blood pressure, rapid heart rate, and confusion. Patients who progress to this phase are often critically ill and require intensive care.Symptoms of ischemic colitis vary depending on the severity of the ischemia. The most common early signs of ischemic colitis include abdominal pain (often left-sided), with mild to moderate amounts of rectal bleeding. The sensitivity of findings among 73 patients were:
abdominal pain (78%)
lower gastrointestinal tract bleeding (62%)
diarrhea (38%)
Fever higher than 38 °C (100.4 °F) (34%)Physical examination
abdominal pain (77%)
abdominal tenderness (21%)

Causes
Ischemic colitis is often classified according to the underlying cause. Non-occlusive ischemia develops because of low blood pressure or constriction of the vessels feeding the colon; occlusive ischemia indicates that a blood clot or other blockage has cut off blood flow to the colon. Non-occlusive ischemia
In hemodynamically unstable patients (i.e. shock) the mesenteric perfusion may be compromised.
It is still available to physicians for patients in emergency situations that are life-threatening or require hospitalization.Prucalopride (brand name Resolor) is a current
drug approved for use in the EU since October 15, 2009, in Canada (brand name Resotran) since December 7, 2011, and in the United States since December 2018. Chloride channel activators
Lubiprostone is used in the management of chronic idiopathic constipation and irritable bowel syndrome. It causes the intestines to produce a chloride-rich fluid secretion that softens the stool, increases motility, and promotes spontaneous bowel movements (SBM). Comparison of available agents
Effectiveness
For adults, a randomized controlled trial found PEG (MiraLax or GlycoLax) 17 grams once per day to be superior to tegaserod at 6 mg twice per day. A randomized controlled trial found greater improvement from two sachets (26 grams) of PEG versus two sachets (20 grams) of lactulose. 17 grams per day of PEG has been effective and safe in a randomized controlled trial for six months. Another randomized controlled trial found no difference between sorbitol and lactulose.For children, PEG was found to be more effective than lactulose. Problems with use
Laxative abuse
Some of the less significant adverse effects of laxative abuse include dehydration (which causes tremors, weakness, fainting, blurred vision, kidney damage), low blood pressure, fast heart rate, postural dizziness and fainting; however, laxative abuse can lead to potentially fatal acid-base and electrolyte imbalances. For example, severe hypokalaemia has been associated with distal renal tubular acidosis from laxative abuse. Metabolic alkalosis is the most common acid-base imbalance observed.