History and exam

Key diagnostic factors

common

intermittent abdominal pain

Ask about abdominal pain. It may be intermittent cramping or constant pain, often described as severe.[5] 

  • Assess pain at presentation and throughout the admission.[6][23] 

  • Establish whether there is continuous pain - this may indicate bowel ischaemia.[3]  

  • Bear in mind that cessation of pain may be an indication of deterioration. There is anecdotal evidence that the bowel muscle becomes overstretched to a point that the muscle contractions causing the colicky pain cease.

abdominal distention

Look for abdominal distention on examination.[5]

nausea

A classical symptom of bowel obstruction.[3] Less frequent than in small bowel obstruction.[5]

vomiting

A classical symptom of bowel obstruction.[3] 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 faeculent in nature.

change in bowel habit

Ask about a change in bowel habit, such as complete failure to pass faeces or flatus.[5] This usually occurs suddenly and is a dramatic change for the patient. Some patients can continue to pass small volumes of stool or flatus in the early stages. Stay vigilant for the combination of a dramatic reduction in stool volume associated with colicky abdominal pain. 

A longer history of symptoms, accompanied by a change in bowel habit, might indicate a malignant cause.[3] 

presence of risk factors

See risk factors above.

hard faeces

Note the presence of hard faeces on digital rectal examination. This may indicate faecal impaction.

soft stools

Note the presence of soft stools on digital rectal examination. This may indicate a partial obstruction.

empty rectum

An empty rectum may indicate a proximal obstruction when noted on digital rectal examination.

recent weight loss

May suggest an underlying malignancy.

rectal bleeding

May suggest an underlying malignancy.

palpable rectal mass

Palpate for a mass on digital rectal examination.[5] This may indicate a rectal carcinoma.

palpable abdominal mass

Palpate the abdomen for a mass. May indicate a malignancy or diverticular mass. Hernial orifices should be examined to detect an obstruction secondary to an irreducible hernia.

tympanic abdomen

Percuss the abdomen.

abnormal bowel sounds

May be normal initially, and then increase in frequency with absent sounds found in more advanced stages of obstruction.

uncommon

fever

May indicate an urgent complication of bowel obstruction, such as sepsis or impending perforation.

May arise from concurrent illness or be implicated in a rarer cause of obstruction such as pelvic abscess or inflammatory bowel disease.

abdominal tenderness

Palpate for tenderness.[5] Significant right iliac fossa tenderness may indicate impending perforation. The caecum is the commonest site of perforation through back pressure. Look for localised tenderness in the right iliac fossa as a sign that the underlying caecum is tearing. If found, investigate and treat urgently.

abdominal rigidity

Implies peritonitis secondary to perforation.

Other diagnostic factors

common

tenesmus

Can imply rectal malignancy, inflammatory bowel disease, or radiotherapy-induced strictures.

Use of this content is subject to our disclaimer