A 56-year-old man presented to surgery with new-onset urinary tract symptoms over the preceding week. These consisted of urgency and frequency associated with suprapubic pain. There was no frank haematuria. He had no significant past medical history and no history of STIs.
Clinically he was afebrile and his abdomen was soft with no palpable bladder. There were no testicular abnormalities. A provisional diagnosis of UTI was made and the patient was prescribed a seven-day course of ciprofloxacin 500mg daily.
His symptoms improved over the week and the urine microscopy report revealed no growth but large quantities of white and red blood cells.
The patient was reviewed at 10 days and was asymptomatic. A repeat urine microscopy was normal. At the review appointment, digital rectal examination revealed a non-tender benign prostatic enlargement.
Biochemical tests including a PSA, glomerular filtration rate and U+Es were normal.
Three weeks later he presented with frank haematuria and incontinence with lower abdominal and left-sided loin pain. He had a palpable bladder and a large stone trapped at the urethral entrance. He was admitted as a surgical emergency and underwent a meatotomy and stone removal under anaesthetic. A cystoscopy was normal and there was no evidence of further calculi in the renal tract.
The stone was calcium oxalate and thought to have originated from the ureter. A coexistent UTI had caused urethral impaction secondary to epithelial slough and an element of BPH.
He has been well since.
The overall prevalence of renal calculi in the UK is 3 per cent. Males are more affected with peak age incidences in the mid-twenties and mid-fifties.
The majority arise in the upper urinary tract and most are radio opaque. Smaller stones are more likely to migrate causing pain while larger stones may remain within the kidney.
Many calculi form in the absence of obvious precipitating factors but recognised causative factors include:
- An excess of a normal constituent in blood or urine, for example hypercalcaemia or hyperuricaemia.
- Impaired drainage causing chronic urethral obstruction, for example, benign prostatic hypertrophy.
- The presence of abnormal constituents, for example coexistent urinary infection.
Kidney stones cause flank pain that spreads around the abdomen as the stone migrates.
There is often associated microor macroscopic haematuria.
There may be an associated UTI with pyrexia and septicaemia. An acute pyelonephritis associated with urinary obstruction requires emergency urological review.
Ureteric stones present with colicky pain radiating from the flank into the scrotum or the labia majora. There is commonly associated haematuria and symptoms of urinary infection. Abdominal examination may elicit tenderness along the course of the ureter but this is usually milder than the pain reported.
In the lower urinary tract stones may cause pain in the lower abdomen or genitalia.
This may be worse on standing or at the end of micturition if the stone is lying on the trigone.
Around 90 per cent of stones will pass spontaneously. The patient should be kept hydrated and appropriate analgesia given.
If the patient is unwell, febrile or in severe pain, hospital admission is indicated with consideration of IV fluids and antibiotics to treat associated infection.
When the stone is passed, it is important to retain it for further histological examination.
Larger stones may require surgical management. Open surgery has now been largely replaced by endoscopic and percutaneous techniques to remove stones. Lithotripsy is also readily used.
Once the acute phase has passed, the patient should remain under urological follow-up to ensure there are no further residual stones.
- Dr Croton is a GP in Birmingham