Urology: Renal Colic

Question 1

Outline the pathophysiology of renal colic

Answer 1

Primarily caused by dilation, stretching, and spasm because of the acute ureteral obstruction

Waves = ureteric peristalsis

Question 2

What causes renal colic

Answer 2

Stones = most common calcium oxalate

Dehydration

Question 3

Describe the signs and symptoms of renal colic

Answer 3

Sudden onset of severe pain originating in the flank and radiating inferiorly and anteriorly – comes in waves

Nausea

Vomiting

Haematuria

Cannot lie still (differentiate from peritonitis)

Question 4

What investigations should be performed for renal colic?

Answer 4

Urine dipstick = demonstrate RBCs, nitrite

Urine culture

Urine analysis = microscopy

Bloods = FBC, U+Es, amylase

Pregnancy test

Serum and urinary pH level = may provide insight regarding patient’s renal function and type of calculus

Serum Ca - if high check PTH (parathyroidectomy = increased calcification)

CT KUB without contrast

Renal US = determine presence of stones

Question 5

How should emergency renal colic be managed?

Answer 5

Stent – so the kidney can drain urine into bladder

Nephrostomy – drain kidney

Question 6

What makes renal colic an emergency?

Answer 6

Pain that won’t recede after treatment, obstructive/infective, renal impairment

Question 7

How should renal stones be managed?

Answer 7

1. Conservative = hydration = Increase oral fluid, IV. NSAIDs = diclofenac (anti-spasmodic), ibuprofen. PO/IV analgesics = codeine, morphine (can raise urethral pressure). Alpha blockers = tamsulosin. Antiemetics = ondansetron
2. ESWL (Extracorporeal Shockwave Lithotripsy) = <2cm, won’t work through bone in the mid ureter
3. URS (Ureteroscopy) = painful, laser or basket
4. PCNL (Percutaneous Nephrolithotomy) = >2cm, near pelvic region of kidney, needle through back
5. Open pyelotomy = open surgery
6. Nephrostomy = if the kidney is dead, DMSA scan

• Abx = if infection present
• Stone prevention = allopurinol

Question 8

What is a DMSA scan?

Answer 8

Assess function of kidney – active nephrons

Radioactive DMSA is taken up by kidney tissue = active tissue parts will emit more gamma rays

Question 9

What is the mechanism of allopurinol?

Answer 9

Xanthine oxidase inhibitor that decreases uric acid production

Question 10

Where do stones commonly cause obstruction in the urinary tract?

Answer 10

Pelvic-ureteric junction

Pelvic brim (passes external iliac artery)

Vesico-ureteric junction

Question 11

Name the risk factors for renal stones

Answer 11

Low fluid intake

Previous stones

FHx

Diet – salt, fatty food

Question 12

What is a DDx for renal colic?

Answer 12

Biliary colic

Appendicitis

Ectopic pregnancy

Acute pancreatitis

AAA

Gynae pathology