Diagnosing irritable bowel

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 http://en.citizendium.org/wiki/Irritable_bowel_syndrome

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

Frequency of Acute Coronary Syndrome in Patients with Normal Electrocardiogram Performed during Presence or Absence of Chest Pain

The presences of chest pain during EKG does not improve its negative predictive value.

The authors detail the findings of 387 consecutive patients with normal electrocardiograms admitted for a chief complaint of chest pain. The authors report that 17% (67/387) of patients had acute coronary syndrome ACS). However, the authors define ACS as:

• Unstable angina. Either:
  
  
  • 70% stenosis (38 patients)
  • positive stress test (1 patient)
• NSTEMI.
  
  
  • Positive troponin (28 patients)

The definition of unstable angina is unusual, differs from the definitions of the American Heart Association, and may include patients without acute ischemia who have a stable stenosis. Focusing on the patients with NSTEMI, the authors found:

• Among 261 patients with electrocardiogram taken during pain, 18 (7%) had NSTEMI.
  
• Among 126 patients with electrocardiogram not taken during pain, 10 (8%) had NSTEMI.
  

This study independently confirms the findings of an earlier study (PMID 16973638) that the presence of chest pain during a normal electrocardiogram does not adequately exclude NSTEMI among a group of patient that physicians chose to admit the hospital and had a 7% prevalence of NSTEMI.

This does not mean the electrocardiogram cannot help exclude acute coronary syndrome, but means that whether the electrocardiogram is taken during pain is not important.

This does not mean the electrocardiogram cannot exclude acute coronary syndrome in patients at lower risk such as those with unusual pain and no history of ischemic heart disease (PMID 3970650).

This has been added to http://en.citizendium.org/wiki/Acute_coronary_syndrome#Electrocardiogram

Citation:

Turnipseed, S., Trythall, W., Diercks, D., Laurin, E., Kirk, J., Smith, D., Main, D., & Amsterdam, E. (2009). Frequency of Acute Coronary Syndrome in Patients with Normal Electrocardiogram Performed during Presence or Absence of Chest Pain Academic Emergency Medicine, 16 (6), 495-499 DOI: 10.1111/j.1553-2712.2009.00420.x