Page 127 - Registrar Orientation Manual 2016

Reference:
1257
Effective date:
7 July 2015
Expiry date:
6 July 2018
Page:
10 of 35
Title:
Imaging Guidelines
Type:
Clinical Guideline
Version:
02
Authorising initials:
Renal Colic (Suspected)
In older patients it is important to consider and exclude an abdominal aortic aneurysm.
This is best done in with a bedside USS but some patients may require a contrast CT.
A non-contrast enhanced CT scan is the most accurate way of detecting calculi in the renal tract.
An ultra-low dose CT scan gives an acceptably low radiation exposure and is of acceptable accuracy for detecting calculi and/or most alternative causes of pain.
In young patients with typical symptoms of renal colic, plain x-ray and ultrasound is an acceptable initial combination and in pregnant patients, ultrasound is the investigation of choice.
Ultrasound has high specificity (90%) but low sensitivity (10-50%) for the diagnosis of ureteric stones and >90% sensitivity and specificity for the detection of urinary tract obstruction.
Plain film in combination with US has a sensitivity of 77-79% and specificity of 90-92.7% for stones.
The ‘Choosing Wisely’ recommendations include:
Avoid requesting CT KUB in otherwise healthy ED patients, age <50 years, with a history of kidney stones, presenting with symptoms and signs consistent with uncomplicated renal colic
Suspected Renal Colic
Age > 50
Age < 50
Exclude AAA
First presentation
Repeat presentation of patient with known stones
Pregnant
Unstable
Stable
Low-dose non- contrast MDCT
Stone visible on previous imaging
Stone NOT visible on previous imaging
Ultrasound
CT Abdomen with IV contrast
Plain KUB+/- USS
Low-dose non- contrast MDCT
Renal tract calculus seen
Renal tract calculus NOT seen
Plain KUB
Consider alternative diagnosis
Resuscitate Vascular Consult