Renal Colic

Question 1

What are renal stones?

Answer 1

They consist of crystal aggregates, stones form in collecting ducts and may be deposited anywhere from the renal pelvis to the urethra

Question 2

What three places are stones most likely to be deposited?

Answer 2

3 narrowings:

• Pelviureteric junction
• Pelvic brim
• Vesicoureteric junction

Question 3

What are most stones composed of?

Answer 3

Calcium oxalate or phosphate (Calcium oxalate are the most common - 65%)

Question 4

Why do stones form?

Answer 4

Because solute concentrations exceed saturation, often in the context of a trigger that starts crystallisation

Question 5

What can hypercalciuria be caused by?

Answer 5

• Hyperparathyroidism resulting in hypercalcaemia
• Excessive dietary intake of Ca2+
• Idiopathic hypercalciuria - increased absorption in gut
• Primary renal disease such as polycystic kidneys or medullary sponge kidney

Question 6

What can hyperoxaluria be caused by?

Answer 6

• High dietary intake of oxalate rich food e.g. spinach, rhubarb, chocolate and tea
• Low dietary Ca2+ resulting in decreased binding of oxalate (by Ca2+) so increase oxalate absorption and urinary excretion
• Increased intestinal resorption due to GI disease e.g. Crohn’s

Question 7

What are the risk factors for renal stones?

Answer 7

• Anatomical abnormalities
• Dehydration
• Infection
• Hypercalcaemia, hyperoxaluria, hypercalciuria, -hyperuricaemia
• Primary renal disease e.g. polycystic kidneys or renal tubular acidosis
• Drugs e.g. diuretics, antacids, acetazolamide, corticosteroids, aspirin, allopurinol, vitamin C & D
• Diet e.g. chocolate, tea, strawberries, rhubarb - all increase oxalate levels
• Gout
• Family history

Question 8

What is the lifetime risk of developing renal stones?

Answer 8

10-15%

Question 9

What is the nature of the pain with renal stones?

Answer 9

• From loin to groin and comes and goes in waves as the ureters peristalise
• Has a rapid onset - may wake them from sleep
• Spasmodic pain
• The pain radiates to groin and ipsilateral testis/labia
• The patient will be very agitated and walking around and can’t lie still
• Bending over forwards can relieve the pain slightly
• The pain is very severe

Question 10

With the exception of pain what are some other signs of renal stones?

Answer 10

• Dysuria (difficulty peeing), strangury (burning when peeing), frequency
• Recurrent UTI’s - increased risk if voiding is impaired!
• Haematuria: Visible and nonviable (85%)
• Bowel sounds may be reduced
• BP may be low

Question 11

What are the symptoms of renal stones?

Answer 11

Nausea and vomiting

Question 12

What investigations would you do in renal colic?

Answer 12

• Urine dipstick
• Mid-stream-specimen of urine sent for microbiology culture and sensitivity
• Bloods: Serum urea, electrolyte, creatinine and calcium, FBC
• KUBXR - Kidney Ureter Bladder X-ray:
• NCCT-KUB (Non-contrast Computerised Tomography)
• Ultrasound

Question 13

What pharmacological treatments would you use in renal colic?

Answer 13

• Strong analgesics
• Antibiotics if there is an infection
• Anti-emetics to help the nausea
• Oral Nifedipine or alpha blocker e.g. Oral Tamsulosin can promote expulsion and reduce analgesia requirements

Question 14

What surgical treatment can be used?

Answer 14

• Extracorporeal shockwave lithotripsy (ESWL) - ultrasound fragments stone
• Endoscopy (uteroscopy) with YAG - laser for larger stones
• Percutaneous nephrolithotomy (PCNL) - keyhole surgery to remove stones that are large, multiple or complex

Question 15

What measures can be taken to avoid the formation of stones?

Answer 15

• Overhydration
• Normal low Ca2+ dietary intake
• Low salt (sodium) diet
• Reduce BMI
• Reduction in animal proteins
• Active lifestyle