Archive for the ‘Gastroenterology’ Category

Carnett’s test for excluding intra-abdominal origins of abdominal tenderness

May 26, 2011

Interpretation of this study is difficult since the authors excluded patients with functional gastrointestinal disorders. I will continue to use Carnett’s sign as one vote among components of the evaluation of abdominal pain.


Patients and examiners

130 consecutive outpatients with abdominal tenderness. “Patients who had functional
gastrointestinal disorders such as functional dyspepsia or irritable bowel syndrome were excluded from the analysis because of the potential for comorbidity by psychiatric disorders.”

Two of 8 generalist physicians with a mean of 7 years in practice examined each patient. One examiner knew the patient’s medical history and one was blinded.

Description of the test

“After routine examination of the abdomen, the site of maximum
tenderness is determined. The patient is then asked to
contract the abdominal muscles by raising his/her head from
the examination table while the examiner continues to apply
pressure to the tender site. The test is positive if tenderness
becomes more severe or is unchanged. A positive test suggests
that the abdominal wall is the source of pain. On the
other hand, the test is negative when tenderness is reduced,
which suggests that the pain has an intra-abdominal source.”

Reference standard

Final diagnosis after clinical evaluation.


Results are in the Figure. 86% of patients with abdominal wall or psychogenic pain had a positive test. 13% of patients with intra-abdominal causes of pain had a positive test.

The reproducibility was high, κ=0.81.


Takada T, Ikusaka M, Ohira Y, Noda K, & Tsukamoto T (2011). Diagnostic usefulness of Carnett’s test in psychogenic abdominal pain. Internal medicine (Tokyo, Japan), 50 (3), 213-7 PMID: 21297322


Diagnosing irritable bowel

September 18, 2009 JAMA. 2009 PMID: 18854541
This comprehensive systematic review by the Rational Clinical Examination is very helpful after a few adjustments. First, the review allows source studies to place patients with symptoms of irritable bowel who are found to have diverticulosis or polyps into the category of underlying organic illness. Patients with diverticulosis who have symptoms of irritable bowel probably have irritable bowel syndrome.(PMID: 3717113) Likewise, polyps seem very unlikely to cause symptoms of irritable bowel and these patients also probably irritable bowel syndrome and coincidental polyps. Now that the USPSTF recommends screening for polyps starting at age 50, the presence of polyps among patients with irritable bowel syndrome is less important.(PMID: 18838716)
The review cites the study of Bellentani (PMID: 2289644) to conclude that 60% of patients in primary care with symptoms of irritable bowel have irritable bowel syndrome. However, if you group the patients with polyps or diverticulosis with the patients with irritable bowel, the prevalence becomes 87%.
Diagnosing irritable bowel syndrome
Likelihood ratio + Likelihood ratio –
History alone (Manning criteria) 2.9 0.29
History and physical examination (Rome criteria) 4.8 0.34
History, physical examination, and laboratory tests (Kruis score) 8.6 0.26
Thus, the Kruis score seems good enough to diagnose irritable bowel among patients in primary care (remember that patients over age 50 probably need endoscopy to screen for polyps). The composition of the Kruis score is:
Kruis score. Abnormal is < 44
Finding Score
Abdominal pain or flatulence or bowel irregularity 34
Duration of symptoms >2 y 16
Abdominal pain is “burning, cutting, very strong, terrible, feeling of pressure, dull, boring, not so bad” 23
Alternating constipation and diarrhea 14
History of blood in stool -98
Physical examination or history pathognomonic for an alternative diagnosis -47
ESR > 10 mm/hr -13
WBC > 10k -50
Hemoglobin < 12 g/dL for females or < 14 g/dL for males -98
This has been added to

Ford, A., Talley, N., Veldhuyzen van Zanten, S., Vakil, N., Simel, D., & Moayyedi, P. (2008). Will the History and Physical Examination Help Establish That Irritable Bowel Syndrome Is Causing This Patient’s Lower Gastrointestinal Tract Symptoms? JAMA: The Journal of the American Medical Association, 300 (15), 1793-1805 DOI: 10.1001/jama.300.15.1793