While not always present and often overlapping, three progressive phases of<unk>  have been described: * A hyper active stage 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<unk>  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. Clinical findings Symptoms of<unk>  vary and can be acute (especially if embolic), subacute, or chronic. Case series report prevalence of clinical findings and provide the best available, yet biased, estimate of the sensitivity of clinical findings. In a series of 58 patients with<unk>  due to mixed causes: * abdominal pain was present in 95% (median of 24 hours duration). The other three patients presented with shock and metabolic acidosis. * nausea in 44% * vomiting in 35% * diarrhea in 35% * heart rate > 100 in 33% * rectal bleeding in 16% (not stated if this number also included occult blood – presumably not) * constipation in 7% Diagnostic heuristics In the absence of adequate quantitative studies to guide diagnosis, various heuristics help guide diagnosis: *<unk> " should be suspected when individuals, especially those at high risk for acute<unk> , develop severe and persisting abdominal pain that is disproportionate to their abdominal findings"., or simply, pain out of proportion to exam. * Regarding intestinal arterial thrombosis or embolism: "early symptoms are present and are relative mild in 50% of cases for three to four days before medical attention is sought". * Regarding intestinal arterial thrombosis or embolism: "Any patient with an arrhythmia such as atrial fibrillation who complains of abdominal pain is highly suspected of having embolization to the superior mesenteric artery until proved otherwise." * Regarding nonocclusive<unk> : "Any patient who takes digitalis and diuretics and who complains of abdominal pain must be considered to have nonocclusive<unk>  until proved otherwise."
Intestinal ischemia
Bowel obstruction
Bowel infarction
Intestinal pseudo-obstruction
Splenic infarction
Short bowel syndrome
Gallstone ileus
Vesicointestinal fistula