Cholecystitis - Diagnostic tests

JAMA Clinical Rational Examination Series: Meta-analysis of 17 studies which evaluated role of history, physical, and lab tests in working up cholecystitis

History and Physical Exam

Finding	(+) LR	(-) LR
Anorexia	1.1-1.7	0.5-0.9
Emesis	1.1-2.1	0.3-0.9
Fever (>35C)	1.0-2.3	0.8-1.0
Guarding	1.1-2.8	0.5-1.0
Murphy sign	0.8-8.6	0.2-1.0
Nausea	1.0-1.2	0.6-1.0
Rebound	0.6-1.7	0.8-1.4
Rectal tenderness	0.5-2.3	1.0-1.3
Rigidity	0.3-0.7	1.0-1.2
RUQ mass	0.5-1.2	0.9-1.1
RUQ pain	0.9-2.5	0.3-1.6
RUQ tenderness	1.0-2.5	0.2-1.1

Laboratory tests

Finding	(+) LR	(-) LR
Alkaline phosphatase (AP) >120 U/L	0.4-1.6	0.6-2.0
ALT >40 U/L or AST >48 U/L	0.5-2.0	0.8-1.4
Total bilirubin >2 mg/dL	0.7-2.3	0.7-1.2
All 3 elevated: Total bili, AST, AP	1.0-2.8	0.8-0.9
Any 1 elevated: Total bili, AST, AP	1.0-1.5	0.6-0.9
WBC >10K	1.2-1.9	0.5-1.8
WBC >10K and fever (>35°C)	0.9-2.8	0.8-1.0
WBC ≤10K and no fever (≤35°C)	0.4-0.7	1.4-1.8

Use the Fagan nomogram

Note:

• All likelihood ratios (LR) cross or almost cross 1.0.
• This is no history, physical exam, or lab test that would comfortably allow you to rule- out or rule-in cholecystitis.
• Murphy’s sign is perhaps the most useful sign because the +LR has been shown to be as high as 8.6.

Bottom line

Have a low threshold to perform a RUQ abdominal bedside ultrasonography for patients with upper abdominal pain or a fever from an unclear source (especially elder patients). Look for indirect signs of cholecystitis:

• Murphy sign
• Distended gallbladder
• Pericholecystic fluid
• Thickened gallbladder wall
• Gallstones

Fagan nomogram

Draw a connecting your pre-test probability and your likelihood ratio. This provides you with your post-test probability.

References

• Trowbridge RL et al. Does this patient have acute cholecystitis? JAMA. 2003, 289(1): 80-6. [PubMed]