A 35-year-old male chef presents with a 4-hour history of acute right-sided loin pain radiating to the groin. He is otherwise fit and well, is a non-smoker, tee-total and gives a family history of renal stones. On examination, he is afebrile and haemodynamically stable and is tender over the right loin region with the remainder of the examination including external genitalia being normal. Routine blood tests are normal and urinalysis is positive for blood.
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1 What is the differential diagnosis in this case?
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Correct answer:
Given presentation with acute loin pain and urinalysis findings, ureteric stone disease should be considered. Other urological pathology would include urinary tract infection or tumours (unlikely given the patient’s age). Other causes of right-sided abdominal pain include hepatobiliary disease (e.g. gallstones), bowel pathology (appendicitis, obstruction), cardiac disease, pulmonary disease (lower lobe pneumonia) and referred pain.
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2 What is the imaging modality of choice for diagnosing urinary stones?
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A non-contrast CT (NCCT) scan of the urinary tract has become the standard imaging modality for acute flank pain. The sensitivity of this study in picking up urinary tract stones is 96–100% and specificity is 92–100%, and is superior to intravenous urography (IVU). A NCCT will show stone location, size and density while also potentially identifying alternative pathology in the absence of stones.
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3 Imaging shows a 4-mm right distal ureteric stone. How would you manage this patient initially?
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The patient should be given adequate analgesia (non-steroidal anti-inflammatory drugs are advocated for analgesia as they offer good analgesic efficacy) and monitored for any signs of sepsis (pyrexia, tachycardia, raised inflammatory markers). Provided the patient becomes comfortable and there are no signs of sepsis or renal function compromise then it may be appropriate to observe the stone for spontaneous passage (given the size and distal location of the stone the chance of spontaneous passage is over 90%).
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4 The imaging incidentally shows another 15 mm calculus in the lower calyx of the contralateral left kidney. What are the treatment options for this?
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Correct answer:
Treatment options generally include observation, extracorporeal shock wave lithotripsy (ESWL), flexible ureterorenoscopy with stone fragmentation (FURS) or percutaneous nephrolithotomy (PCNL). Observation is generally reserved for asymptomatic or patients unfit for intervention and may not be appropriate in this young patient’s case. ESWL has the advantage of being administered in an outpatient setting without the need for a general anaesthetic but success rates for lower calyceal stones are relatively lower (~50–70%) compared to other modalities. FURS is performed under general anaesthesia and while stone clearance rates are good (~70–80%), it may need repeated procedures (if access to the ureter is difficult or the stone has not been cleared in the first sitting). PCNL allows excellent clearance rates with a single procedure (~90%) but carries some morbidity related to the renal puncture (bleeding and injury to adjacent abdominal organs). Overall, the treatment options need to be discussed with the patient.
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5 What advice would you give the patient in order to reduce his risk of further stone formation?
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Correct answer:
He should be advised to drink enough fluid to produce a urine output of 2–2.5 L/day. He should consume a balanced diet rich in vegetables and limited in both animal proteins and salt. He should be advised not to restrict calcium intake below normal. Adequate physical activity is recommended and a healthy body mass index (BMI) should be maintained.
