Other manifestations

Other manifestations

Dehydration Dehydration is seen most commonly in small bowel obstruc tion because of repeated vomiting and fluid sequestration. It results in dry skin and tongue, poor venous filling and sunken eyes with oliguria. The blood urea level and haematocrit rise, giving a secondary polycythaemia. Hypokalaemia Hypokalaemia is not a common feature in simple mechanical obstruction. An increase in serum potassium, amylase or lactate dehydrogenase may be associated with the presence of strangulation, as may leukocytosis or leukopenia. Pyrexia Pyrexia in the presence of obstruction may indicate: /uni25CF the onset of ischaemia; /uni25CF intestinal perforation; /uni25CF inflammation or abscess associated with the obstructing disease. Hypothermia indicates septicaemic shock or neglected cases of long duration. Abdominal tenderness Localised tenderness indicates impending or established isch aemia. The development of peritonism or peritonitis indicates impending or established infarction and/or perforation. In cases of large bowel obstruction, it is important to elicit these findings in the right iliac fossa as the caecum is most vulnerable to ischaemia. - Bowel sounds High-pitched bowel sounds are present in the vast majority of patients with intestinal obstruction. Normal bowel sounds are of negative predictive value. Bowel sounds may be scanty or absent if the obstruction is longstanding and the small bowel has become inactive.

Figure 78.9 Skin discoloration over a strangulated incisional hernia. Figure 78.10 Ischaemic small and large bowel in a strangulated incisional hernia.