History and exam
Key diagnostic factors
common
colicky abdominal pain
Common to all causes of mechanical obstruction.
Increasing constant or intermittent pain, and pain on movement, coughing, or deep breathing, may imply perforation or impending perforation.
abdominal distention
Found with most causes.
nausea
A classical symptom of bowel obstruction. Less frequent than in small bowel obstruction.[5]
vomiting
A classical symptom of bowel obstruction. Less frequent than in small bowel obstruction.[5] This typically occurs later in large bowel compared with small bowel obstruction. In later stages it may be feculent in nature.
change in bowel habits
Either failure to pass feces (complete obstruction) or successful passing of some flatus or feces (partial obstruction).[5]
History of reduction in stool caliber/diameter and loose motions may be associated with a diverticular stricture or colorectal malignancy.
hard feces
May indicate fecal impaction when noted on digital rectal exam.
soft stools
Suggests partial obstruction when noted on digital rectal exam.
empty rectum
In the setting of suspected large bowel obstruction, it implies proximal obstruction when noted on digital rectal exam.
recent weight loss
Suggests an underlying malignancy, especially if in conjunction with a change in bowel habit or rectal bleeding.
rectal bleeding
Suggests an underlying malignancy, particularly when mixed with stool.
palpable rectal mass
May be possible to palpate a mass on digital rectal exam in patients with a rectal carcinoma.
palpable abdominal mass
May indicate malignant disease or diverticular mass. Hernial orifices should be examined to detect an obstruction secondary to an irreducible hernia.
tympanic abdomen
Common to all causes.
abnormal bowel sounds
May be normal initially, and then increase in frequency with absent sounds found in more advanced stages of obstruction.
uncommon
fever
Implies perforation or impending perforation, but may arise from concurrent illness or be implicated in a rarer cause of obstruction such as pelvic sepsis or inflammatory bowel disease.
abdominal tenderness
Mild tenderness may be present with any cause.
Significant right iliac fossa tenderness or localized peritonitis may indicate impending perforation.
Severe tenderness implies peritonitis secondary to perforation.
abdominal rigidity
Implies peritonitis secondary to perforation.
Other diagnostic factors
common
tenesmus
In the setting of large bowel obstruction, it implies distal colonic or rectal malignancy.
Occurs due to a small volume of feces repeatedly entering the rectum.
Tenesmus is more usually associated with inflammatory bowel disease, though can be related to pelvic radiotherapy and radiotherapy-induced strictures.
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