Urinalysis: hematuria
Hematuria cannot be used to rule-out or rule-in stone (sensitivity 71-95%; specificity 18-49%)
The absence of pyuria cannot exclude a complicating UTI (sensitivity 86%; specificity 79%)
Urine culture :
Consider for all patients OR those at higher risk (female, pyuria, or cystitis symptoms)
Urine pregnancy
Chemistry
BUN/Cr to evaluate renal function
CBC: If concern for infection (>15k concerning)
Hematuria cannot be used to rule-out or rule-in stone (sensitivity 71-95%; specificity 18-49%)
The absence of pyuria cannot exclude a complicating UTI (sensitivity 86%; specificity 79%)
Consider for all patients OR those at higher risk (female, pyuria, or cystitis symptoms)
BUN/Cr to evaluate renal function
Consider tailoring your choice of imaging based upon the patient's age, clinical likelihood of stones, risk factors, and prior history of stones
In young patients, even with no prior history of kidney stones, reasonable approaches may be bedside ultrasound or no imaging
In middle aged patients with prior history of stones, it may be reasonable to perform a bedside ultrasound although no imaging can be appropriate as well
In middle aged patients with no prior history of stones, CT imaging is reasonable
In elderly patients, even with prior history of stones, CT is recommended in order to avoid missing alternative etiologies such as dissection, AAA, or diverticulitis.
In young patients, even with no prior history of kidney stones, reasonable approaches may be bedside ultrasound or no imaging
In middle aged patients with prior history of stones, it may be reasonable to perform a bedside ultrasound although no imaging can be appropriate as well
In middle aged patients with no prior history of stones, CT imaging is reasonable
In elderly patients, even with prior history of stones, CT is recommended in order to avoid missing alternative etiologies such as dissection, AAA, or diverticulitis.
Bedside Renal ultrasound
Consider non-contrast CT abdomen and pelvis (KUB protocol) for:
1st time stone
Older patients with other possible diagnosis
Avoid CT in young (<50 years old), health patients with known history of nephrolithiasis with presentation consistent with renal colic
Consider formal ultrasound for:
Pregnant pt
Repeat stone (to avoid CT)
In comparison of diagnosis by CT vs. U/S (by EP) vs. U/S (by radiologist):
No difference in rate of missed high-risk diagnoses that resulted in complications (pyelo/sepsis/diverticular abscess)
No difference in rate of serious adverse events, pain scores, return emergency department visits, or hospitalizations
1st time stone
Older patients with other possible diagnosis
Avoid CT in young (<50 years old), health patients with known history of nephrolithiasis with presentation consistent with renal colic
Pregnant pt
Repeat stone (to avoid CT)
No difference in rate of missed high-risk diagnoses that resulted in complications (pyelo/sepsis/diverticular abscess)
No difference in rate of serious adverse events, pain scores, return emergency department visits, or hospitalizations
CT Imaging
Hydronephrosis
Hydroureter
Hydrocalyx
Note: Hydronephrosis, hydroureter, hydrocalyx alone indicate obstructive uropathy, stone must be seen or collected (if passed) in order to diagnose nephrolithiasis as the etiology.
Perinephric Stranding
Location Landmarks
Renal: Does not cause pain, and usually considered an incidental finding
UPJ: Ureteropelvic Junction
UVJ Ureterovesicular Junction
Hydronephrosis
Hydroureter
Hydrocalyx
Note: Hydronephrosis, hydroureter, hydrocalyx alone indicate obstructive uropathy, stone must be seen or collected (if passed) in order to diagnose nephrolithiasis as the etiology.
Perinephric Stranding
Location Landmarks
Renal: Does not cause pain, and usually considered an incidental finding
UPJ: Ureteropelvic Junction
UVJ Ureterovesicular Junction
Renal: Does not cause pain, and usually considered an incidental finding
UPJ: Ureteropelvic Junction
UVJ Ureterovesicular Junction
Urolithiasis
Nephrolithiasis is most common misdiagnosis given to patients with rupturing AAA
Pyelonephritis
Vascular
Acute cystitis
Abdominal aortic aneurysm
Interstitial cystitis
Renal artery embolism