Lows, Highs, and Ureteric Calculi [QUIZ]

Posted on May 3, 2012

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Last week was a week of highs and lows.

Ward was super quiet. Low.

I went back home to see my good friend Sophie get married. High.

Only saw 20 minutes of surgery. Low.

Weather has been appalling all week. Low.

Well maybe mostly lows. But to top it off, my blog got 61 views yesterday! That might not sound a lot, but compared to usual it’s pretty darn good! And whilst it wasn’t quite as exciting as Sophie and Andy’s wedding, it came a close second.

Not my best work, I’ll grant you, but it’s getting late and I have to be up early.

I was worried at the start of the week that it might shape up to be much like the one before, but today I got to go into theatre and saw 3 laparoscopic cholecystectomies (“lap chole’s” to those of us in the trade), which if you don’t know involves having your gall bladder whipped out laparoscopically. You can watch one being done over at websurg (click HERE) and search for “cholecystectomy”. Laparoscopic procedures are always good to watch, because you can actually see what’s going on on the screen! (cf open procedures, like open hernia repair, where unless you’ve scrubbed in and are in the thick of it holding a retractor or something, in my (limited) experience you don’t get to see much over the surgeon’s shoulder).

Today I’m changing it up a bit, and writing about kidney stones. I know I said there’d be a post about pancreatitis coming soon, and there will be, but I’ve had just about enough of looking at that particular topic for the time being. So today, something new.

I’m actually going to kick things off with a little quiz about ureteric calculi, just to spice things up. Don’t forget to keep scrolling once you’ve finished the quiz, because there’s more information about renal and ureteric calculi!!

Amongst europeans, prevalence is about 3%.

THEORIES of CALCULI FORMATION

There are a few theories about kidney stone formation:

1: HYPERCALCIURIA: 65% of patients have idiopathic hypercalciuria

2: NUCLEATION THEORY: A crystal/foreign body acts as a nucleus for crystals to form from supersaturated urine.

3: STONE MATRIX THEORY: Renal tubular cells secrete a matrix of protein on which crystals from supersaturated urine are deposited.

4: REDUCED INHIBITION THEORY: Decreased levels of naturally occurring inhibitors of crystallisation lead to crystal formation

5: INFECTION: Staghorn (phosphate) caliculi are formed by urease producing organisms like klebsiella.

There are 3 types of urinary calculi: Oxalate, phosphate and urate stones, see the quiz to find out which type is the most common! Staghorn (phosphate) calculi are large, and fill the renal pelvis and calyces. This can lead to recurrent episodes of pyelonephritis and damage to the renal parenchyma. Other types of stone tend to be smaller, ranging from millimetres to a couple of centimetres. These cause problems by obstructing the urinary tract, usually the ureters. Stones in the calyces tend to result in haematuria, bladder stones cause infection. Chronic bladder stones can predispose patients to squamous cell carcinoma of the bladder.

CLINICAL FEATURES

Calyceal stones may be asymptomatic.

Staghorn calculi present with loin pain and upper urinary tract infection.

Stones in the ureters can cause ureteric colic, which is a severe colicky pain (meaning it comes and goes as the ureters contract and relax) that can radiate from the loin to the groin (and sometimes to the testes/labia). It may be associated with gross or microscopic haematuria.

Bladder calculi present with sudden interruption of urinary stream, perianal pain, and pain at the tip of the penis.

IMAGING

There are a few different types of imaging you might want to think about for investigating urinary calculi.

KUB radiograph, note the stones in the right ureter, indicated by the red arrows. Taken from medindia.net

KUB (Kindeys, Ureters, Bladder) radiograph– 90% of renal calculi are radio-opaque.

CT scanning: non-contrast helical CT scanning is more accurate than IVU in detecting urinary tract calculi. Gives no information about degree of obstruction or renal function.

Intravenous Urogram (IVU): confirms the presence and the position of the stone in the genitourinary tract.

Ultrasound Scan: USS may be indicated to exclude AAA. May show hydronephrosis or hydroureter if obstruction is present.

A renogram may be indicated with staghorn calculi to assess renal function.

PYELONEPHRITIS AND PYONEPHRITIS

Acute pyelonephritis: fever/rigors, dysuria, ispilateral loin pain usually supported by features of infection in the urine, and usually represents an ascending infection of the collecting system and renal parenchyma. When the obstructed renal system becomes infected by bacteria, infected urine cannot drain from the pelvi-calyceal region and forms pus (pyonephrosis).

Pyonephrosis is a life threatening condition, and patients usually develop sepsis, and may progress to septicaemic shock. With infection and obstruction, long term renal damage is likely.

 Management:

Treat infection with appropriate antibiotics and hydration.

Drainage is critical to reverse the clinical cause, and this is done usually by percutaneous nephrostomy, in which the pelvi-calyceal system if punctured by a nephrostomy needle under USS guidance. A tube is inserted to drain. Definitive treatment of urinary calculi can then be performed once the patient is stable.

INTERVENTIONAL PROCEDURES

External shock wave lithotripsy (ESWL) for small/medium stones.

Percutaneous nephrolithotomy for large kidney stones and staghorn calculi.

Uteroscopy and manipulation of stone back into the renal pelvis for ESWL or contact lithotripsy for upper uteric stones (above the pelvic brim)

Ureteroscopy with contact lithotripsy or extraction with a Dormia basket for lower ureteric stones.

Open surgery: uretolithotomy (rare now) or nephrolithotomy.

Mechanical lithotripsy or open surgery for bladder stones.

I hope that’s been useful to people, leave a comment and let me know if you liked the quiz format or not! If people enjoyed it maybe I’ll do more!

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