colonic disorders THAT CAUSE ACUTE ABDOMEN
Perforation of the Colon
Perforation of the colon allows leakage of fecal material containing massive numbers of anaerobic and gram-negative bacteria into the abdominal cavity.
This produces rapidly progressive bacterial peritonitis, sepsis, and endotoxemia. Death occurs in a matter of hours from septic shock. Colonic perforation may be caused by penetrating trauma (e.g., gunshot wounds), erosive tumors, complications of colonic surgery or biopsy procedures, and high doses of corticosteroids following neurosurgical procedures. Rectal perforation leads to retroperitoneal leakage of fecal material and may be caused by displaced bone fragments of a fractured pelvis or by iatrogenic puncture from a thermometer, enema infusor, or biopsy instrument.The clinical signs of colonic perforation are the result of septic peritonitis and include acute abdominal pain, severe depression, fever (hypothermia occurs terminally), vomiting, hemorrhagic diarrhea, and rapidly progressive signs of shock. A CBC usually reveals a neutropenia with a degenerative left shift and circulating toxic neutrophils. Serum electrolyte imbalances and prerenal azotemia are likely. Survey abdominal radiographs may indicate free air within the abdominal cavity or retroperitoneal space, loss of abdominal contrast due to peritoneal effusion, and gas-distended bowel loops due to ileus. Acute septic peritonitis (indicating probable bowel perforation) is confirmed by cytologic findings (toxic neutrophils and intracellular and extracellular bacteria), abdominocentesis, or peritoneal lavage.
Rapid recognition of colonic perforation as a life-threatening intraabdominal crisis in need of immediate surgical intervention is required. On the basis of signs of acute abdominal distress and radiographic or laboratory indication of perforation, the patient is treated for shock and emergency laparotomy is performed.
Parenteral antibiotics are initiated immediately to cover anaerobic and gramnegative enteric bacteria; for example, penicillin, ampicillin, or clindamycin combined with enro- floxacin, an aminoglycoside, or a cephalosporin. The colon is surgically repaired, the abdomen is copiously lavaged, and the septic peritonitis is treated vigorously postoperatively The prognosis for survival from colonic perforation is guarded to poor.Volvulus of the Colon
Torsion or volvulus of the colon results in complete distal bowel obstruction, rapidly progressive ischemic necrosis of the bowel, eventual septic peritonitis, and finally death from septic shock; thus early recognition and immediate surgical intervention are necessary. This is a rare condition in dogs and cats. When it occurs, the signs are those of acute abdominal distress with pain, vomiting, raspberry jam-like hemorrhagic diarrhea, and acute collapse. Radiographs generally reveal a gas-distended lower bowel, which, taken together with the clinical signs, is indication to proceed with emergency laparotomy. Measures to treat hypovolemic and septic shock also should be initiated immediately.