Ministry of Health

NZ Government

Published: 09/12/2011

DIFFERENTIAL DIAGNOSIS

Must be excluded in anyone with suspected renal colic, especially the elderly.

• Aortic and iliac aneurysms
• Pyelonephritis
• Peritonitis, including appendicitis and diverticulitis
• Biliary colic
• Renovascular compromise, including renal artery or vein thrombosis
• Cancer esp renal
• Endometriosis
• Ovarian torsion

INVESTIGATIONS

MSU sent for microscopy and culture. Haematuria is present 85% of the time. !5 % of patients with renal colic will not have haematuria. If there are white cells or bacteria in the urine, consider infected stone.

FBC if there is a high fever T > 38 deg C with or without significant renal tenderness, infection maybe present. The WCC is often raised even when there is no infection therefore is not indicated in uncomplicated renal colic.

UREA / ELECTROLYTES & CREATININE is done in the elderly, impaired renal function, diabetes, and in those who are hypovolaemic. The young and previously healthy do not need renal function tests.

MANAGEMENT

Analgesia

• Morphine as per protocol for significant pain
• Metoclopromide 10mg IV for nausea and vomiting.
• Diclofenac sodium (voltaren) orally or rectally for moderate pain or with morphine for severe pain

Intravenous fluids

• Hydrate intravenously with 0.9 % saline.

Antibiotics

• Gentamicin 5 - 7mg/kg IV if co-existing urosepis is suspected.

FURTHER INVESTIGATION

In the young healthy patient in whom the diagnosis of renal colic is clinically not in question, and the pain has completely settled and there is no suspicion of any complication there is no need to obtain an immediate IVU.

If pain is severe and ongoing , if the diagnosis is in doubt, if another condition is suspected, or if the patient is elderly, some diagnostic imaging is essential.

Noncontrast helical CT

• Becoming the first line of imaging.
• Discuss with the radiologist on duty.
  Advantages
• Sensitivity 95 -97 % in detection of renal stones
• Specificity 96-98 % in detection of renal stones
• Faster than IVU
• Avoids intravenous contrast
  Limitations
• Will diagnose other conditions such as AAA and GIT disease but is not as sensitive or as specific as CT with contrast

Intravenous Urogram

• Comparable to CT in sensitivity and specificity for stones, but also shows renal function.
• Takes too long and exposes patient to contrast.
  Contraindications
  Serum creatinine > 0.2
  History of adverse (allergic) reaction to contrast.
• Contrast can be nephrotoxic in the following conditions
  Preexisting renal insufficiency
  Diabetics
  Dehydrated patients
  Hypotension
  Age> 60
  Multiple myeloma
  Hypertension
  Hyperuricemia
  Use of diuretics for cardiovascular system
  History of IV radiocontrast media within 72 hours

Ultrasound

• When IVU or CT is contraindicated, or when there is no haematuria.
• Will detect larger > 5 mm stones , particularly in the proximal and distal ureter but only poorly visualizes midureteric stones.
• Very sensitive for hydronephrosis (98%) but 22 % of hydronephroses detected on ultrasound do not represent obstruction.
  Advantages
• noninvasive, no contrast, no radiation, no side effects. Can give clues to other pathology, such as AAA.
• Obesity may reduce accuracy.

Plain X-ray KUB

• Limited use, but required by radiology prior to CT.
• 90 % of renal stones are radio-opaque but the sensitivity is only up to 22 to 58 % and the specificity 69 to 74 %. Negative predictive value is only 23 %. In patients in whom the diagnosis is already established, plain Xray is useful in following the passage of a radioopaque stone.

DISPOSITION OF PATIENT

Admit

1. Fever > 38 degrees, or septic as may require a nephrostomy.
2. Severe ongoing pain that does not settle with IV narcotic and NSAIDS.
3. Recurrent attacks of colic with repeated visits to the emergency department.
4. Ureteric stone more than 6 mm in diameter. These are unlikely to pass.
5. Any stone in a solitary kidney.
6. Creatinine > 0.2

Discharge

• Everyone else.
• Send a referral to the urology outpatients clinic. The patient will be seen in 4 weeks with an updated KUB film unless the stone is radiolucent when a limited IVU will be done.
• Advice patient to strain urine.
• Give the patient a script for voltaren unless there is a contraindication to the drug.
• The patient should return promptly if they develop a fever.

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