Diagnostic Approach to Lower Abdominal and Back Pain

Immediate Clinical Assessment

The American College of Radiology recommends checking vital signs to exclude shock or systemic infection in patients with lower abdominal and back pain 3
The British Medical Journal suggests assessing for urinary retention by measuring post-void residual volume, as retention has 90% sensitivity for cauda equina syndrome and can present with lower abdominal pain 4
The British Medical Journal recommends examining the abdomen for peritoneal signs, masses, or pulsatile abdominal aortic aneurysm, particularly if patient is over 60 years old 3, 4
The Annals of Internal Medicine suggests performing straight-leg raise testing and brief neurological exam to assess for radiculopathy if back pain radiates to legs 4
The British Medical Journal recommends excluding ectopic pregnancy with β-hCG testing in women with delayed menses, even if urinalysis is negative 3

The American College of Radiology recommends CT abdomen and pelvis with IV contrast as the preferred initial imaging modality because it provides comprehensive evaluation of both abdominal and retroperitoneal structures 1
The Journal of the American College of Radiology suggests that contrast-enhanced CT identifies clinically significant non-urological diagnoses in 15% of cases in patients with flank/back pain and negative urinalysis without history of kidney stones 1, 2
The American College of Radiology recommends using IV contrast when urinalysis is negative, as it better characterizes alternative diagnoses beyond urolithiasis 2, 5

The American College of Radiology suggests considering appendicitis, which can present with atypical pain patterns and negative urinalysis 1
The Journal of the American College of Radiology recommends evaluating for gynecological pathology in women, such as ovarian torsion, tubo-ovarian abscess, or endometriosis 1
The Annals of Internal Medicine suggests considering musculoskeletal causes, including vertebral compression fracture, particularly in older patients or those with osteoporosis risk 4
The British Medical Journal recommends evaluating for vascular causes, such as aortic aneurysm, in patients over 60 years 3, 4

The American College of Radiology warns against assuming negative urinalysis excludes urological pathology, as early obstruction or anatomical abnormalities may not produce hematuria initially 2
The British Medical Journal recommends not delaying imaging in patients with severe pain, and immediate hospital admission and imaging are warranted if pain fails to respond to analgesia within 1 hour 3
The Annals of Internal Medicine suggests not overlooking red flags, such as history of cancer, unexplained weight loss, age over 50 years, fever, or progressive neurological deficits, which require urgent evaluation 4

The Journal of Urology recommends follow-up ultrasound in 1-6 months to ensure resolution if CT shows minimal hydronephrosis 2
The Annals of Internal Medicine suggests managing musculoskeletal causes according to low back pain guidelines with conservative therapy unless red flags are present 4, 7