What are the key components of a comprehensive abdominal examination?

Comprehensive Abdominal Examination Components

A systematic abdominal examination should include inspection, auscultation, percussion, and palpation performed in that specific order, along with targeted laboratory and imaging studies when clinically indicated. 1

Inspection

• Observe for abdominal distension, visible peristalsis, pulsations, skin changes, surgical scars, and asymmetry 1
• Look for signs of peritonitis including guarding, rebound tenderness, or rigidity which may indicate perforation 1
• Note that clinical examination may be unreliable in patients with excess skin or flaccid abdomen (such as post-bariatric surgery patients) 1
• Assess the descent of the perineum during simulated evacuation and elevation during squeeze in the left lateral position when evaluating for defecatory disorders 2
• Observe the perianal skin for evidence of fecal soiling and test the anal reflex 2
• During simulated defecation, observe the anal verge for any patulous opening (suspect neurogenic constipation) or prolapse of anorectal mucosa 2

Auscultation

Auscultation should be performed BEFORE palpation and percussion, as traditional teaching that these maneuvers alter bowel sounds has been disproven. 3 However, the conventional order remains standard practice.

• Listen for bowel sounds in all four quadrants, noting character, frequency, and pitch 1
• Absent bowel sounds may suggest peritonitis or ileus 1
• Hyperactive, high-pitched bowel sounds may indicate early bowel obstruction 1
• Auscultate the abdomen and flank for bruits, which may indicate vascular pathology 2
• Auscultate both femoral arteries for the presence of bruits 2

The evidence shows acceptable rater agreement for detecting intestinal obstruction (94% for colonic obstruction), though agreement is lower for peritonitis. 4

Percussion

• Percuss all four quadrants to detect abnormal fluid, masses, or organomegaly 1
• Assess for shifting dullness and fluid thrill when ascites is suspected 1
• Percussion can help identify tympany associated with bowel distension or pneumoperitoneum 1

Palpation

• Begin with light palpation away from areas of reported pain, progressing to deeper palpation 1
• Assess for masses, organomegaly, tenderness, guarding, and rebound tenderness 1
• Palpate the abdomen and note the presence of aortic pulsation and its maximal diameter 2
• Palpate pulses at the brachial, radial, ulnar, femoral, popliteal, dorsalis pedis, and posterior tibial sites 2
• Record pulse intensity numerically: 0 (absent), 1 (diminished), 2 (normal), 3 (bounding) 2

Special Palpation Maneuvers

• Perform Murphy's sign, psoas sign, and obturator sign as clinically indicated 1
• Evaluate resting tone of the sphincter segment and its augmentation by squeezing effort during digital rectal examination 2
• Palpate the puborectalis muscle above the internal sphincter, which should contract during squeeze 2
• Assess for acute localized tenderness along the puborectalis (levator ani syndrome) 2
• Instruct the patient to "expel my finger" to evaluate expulsionary forces 2

Digital Rectal Examination

Digital rectal examination should be performed when indicated, especially for suspected lower GI pathology, constipation evaluation, or when assessing for blood. 1, 2

• Perform in left lateral position with buttocks separated 2
• Evaluate for rectocele or consider gynecologic consultation 2
• Note that a normal digital rectal examination does not exclude pelvic floor dysfunction 2

Additional Physical Examination Components

• Record pulse, blood pressure, temperature, weight, and height 2
• Assess for abdominal distension and tenderness 2
• Perform perianal inspection when appropriate 2
• Remove shoes and socks to inspect feet for color, temperature, skin integrity, and ulcerations 2
• Look for additional findings suggestive of severe peripheral arterial disease: distal hair loss, trophic skin changes, and hypertrophic nails 2

Mandatory Laboratory Assessment

Complete blood count, electrolytes, liver enzymes, and inflammatory markers (ESR, CRP) are mandatory when assessing acute abdomen. 1

• Obtain full blood count to assess for anemia, thrombocytosis, or leucocytosis 2
• Measure inflammatory markers (CRP) which broadly correlate with clinical severity in ulcerative colitis (except proctitis) 2
• Check electrolytes, liver function tests, and renal function 2
• Assess iron studies and vitamin B12 2
• Measure serum albumin and pre-albumin to assess nutritional status and degree of inflammation 1
• Obtain stool specimens for microbiological analysis including C. difficile toxin 2
• Measure faecal calprotectin as an accurate marker of intestinal inflammation 2
• In suspected infectious causes, rule out Clostridium difficile and Cytomegalovirus 1
• Check for leukocytosis, neutrophilia, elevated amylase levels, and lactic acidosis which may suggest perforation or necrosis 1

Imaging Studies When Indicated

CT scan with IV contrast is the recommended primary imaging study for suspected abdominal pathology, with superior sensitivity (93-96%) and specificity (93-100%). 1

• Abdominal ultrasound can be used as a screening test with moderate sensitivity (88%) when CT is unavailable 1
• Plain abdominal X-rays have limited sensitivity (74-84%) and specificity (50-72%) and should only be used when other modalities are unavailable 1
• For suspected bowel obstruction: CT scan is preferred; if unavailable, water-soluble contrast enema is a valid alternative 1
• For suspected perforation: CT scan is recommended for stable patients 1
• For pregnant patients: Ultrasound and MRI are recommended to limit radiation exposure 1
• MR enterography (or CT if unavailable) is recommended for baseline assessment of inflammatory bowel disease extent and severity 2
• Dedicated small bowel ultrasonography may be useful where expertise exists 2

Critical Pitfalls to Avoid

• Do not delay surgical exploration if there is high clinical suspicion and alarming signs/symptoms, even with negative radiological assessment 1
• Clinical examination may be unreliable in post-bariatric surgery patients due to excess skin and flaccid abdomen 1
• CT scan should never expose the patient to unsafe delays in appropriate treatment for conditions requiring immediate intervention 1
• Early involvement of a surgeon is required in cases of suspected perforation 1
• After a complete purge, it will take several days for residue to accumulate to form normal fecal mass—do not misinterpret this as ongoing constipation 2
• Many commonly used medications have constipation as a side effect (opiates, anticholinergics, calcium channel blockers)—obtain full medication history 2