urinary stones Flashcards by Deema Baks

What are the causes of urinary stones?

Vitamin A deficiency
dehydration -> precipitation of solutes
reduction of urinary colloids
decreased urinary citrate (keeps calcium in solution in solution form)
renal infection -> streptococci
urinary stasis & inadequate urinary drainage
prolonged immobilization
hyperparathyroidism

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What are the etiologies of calcium oxalate stones?

hypercalcemia
hyperoxaluria
increased intake of ethylene glycol or vitamin C
inflammatory bowel disease due to malabsorption

will decrease urine pH
radio-opaque

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What are the types of urinary stones?

CALCIUM OXALATE -> irregular & sharp -> hard & radiodense
PHOSPHATE CALCULI -> stag horn calculus -> grows in alkaline urine (Proteus) -> presents with hematuria, urinary infection, or renal failure
URIC ACID & URATE CALCULI -> multifaceted -> CT to distinguish them
CYSTINE CALCULUS -> cystinuria (congenital) -> grow to form a cast of the collecting system -> radio-opaque & very hard

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What is the first indication if bilateral silent calculi?

Renal failure

- secondary infection produces symptoms

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Dull pain in the renal angle or the hypochondrium or both & radiates to the back, with movement making it worse is diagnostic for?

RENAL PAIN

- stretching of kidney capsule

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Agonizing colicky pain passing from the loin to groin that usually lasts for 8 hours & causes tachycardia is diagnostic for?

URETERIC COLIC

stone in ureter or stuck at pelviureteric junction
patients vomit from severity of pain

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What are the clinical features of urinary stones?

renal pain or ureteric colic
haematuria
pyuria -> dangerous when kidney is obstructed -> septicemia can develop quickly
- > could be caused by stones irritating the urothelium in the absence of infection

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What are the clinical features of renal destruction?

pyonephrosis
pyelonephritis
hydronephrosis

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What are the clinical features of pelvi-ureteric obstruction?

Renal colic
total hematuria
hydronephrosis
pyelonephritis

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What are the clinical features of bladder irritation?

terminal hematuria
frequency
suprapubic dull pain made worse by bladder filling

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What are the clinical features of vesico-ureteric obstructions?

Renal colic
total hematuria
hydronephrosis

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What the the clinical features of bladder outflow obstruction?

acute retention

- terminal hematuria

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What will be witnessed on the abdominal examination of a patient with a urinary stone?

during a ureteric colic attack -> rigidity MAY be present
tenderness on gentle deep palpation
hydronephrosis or pyonephrosis -> palpable loin swelling (rare)
renal punch (percussion over the kidney) -> stabbing pain

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How is the KUB film taken & what will it show?

Kidney, ureter, bladder x-ray

patient must be prepared well -> enema, laxative is given the previous day & patient is asked to fast to reduce bowel gas
an opacity relative to urinary tract (on lateral x-ray will be ON or POSTERIOR to vertebral body)
calcified mesenteric nodes & opacities within the gut is anterior to vertebral bodies on lateral x-rays

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What is the best method of investigation to detect a urinary stone?

CT (helical CTU)

- can identify other causes of non-stone flank pain

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How should renal colic be managed?

PAIN RELIEF
- NSAIDS

HYDRATION

WATCHFUL WAITING

if stone is 5mm or less
alpha-blockers (ZOSINS)

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What are the indications for intervention?

pain that fails to respond to analgesics
associated fever
renal function is impaired
obstruction unrelieved for 4 weeks
personal or occupational reasons

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What intervention provides temporary relief of obstruction?

surgical intervention

INSERTION OF JJ STENT
PERCUTANEOUS NEPHROSTOMY TUBE

What are the methods used to provide a definitive treatment?

Extracorporeal shockwaves lithotripsy (ESWL)
Ureteroscopy (URS)
Percutaneous nephrolithotomy (PCNL)
Open surgery

What are the indications for ESWL?

only if stone is in kidney or upper ureter

- stone must be less than 2cm

What are the limitations to ESWL?

may need multiple sessions
post ESWL ureteric colic is common -> needs NSAIDS
must use antibiotic cover due to fear of infection

What are the types of open surgery?

Pyelolithotomy -> incision directly on stone
Nephrolithotomy
Partial Nephrectomy -> stone in lower most calyx with infective damage
Nephrectomy -> functionless kidney

How should bilateral renal stones be treated?

Treat kidney with better function first UNLESS

the other kidney is more painful
pyonephrosis -> urgent decompression

What should be done to prevent recurrence of stone?

drink plenty of water
screen urine for infection
blood investigations -> serum calcium (hyperparathyroidism)
- > serum uric acid
- > urinary urate, calcium & phosphate in 24-hr collection

What are the normal ureteric anatomical narrowing that could cause stone impaction?

``` 1- uretero-pelvic junction 2- crossing the iliac artery 3- juxtaposition of vas deferens or broad ligament 4- entering bladder wall 5- ureteric orifice ```

What are the clinical features of ureteric calculi?

- intermittent attacks - agonizing loin pain -> referred to groin, external genitalia, & anterior surface of the thigh - when it enters the bladder -> referred to the tip of the penis

What features occur when the stone gets impacted?

- consistent dull pain in the iliac fossa | - increased by exercise & lessened by rest

What are the manifestations of ureteric obstruction?

- severe renal pain that subsides after a day | - if obstruction persists after 1-2 weeks -> calculus should be removed to avoid pressure atrophy or renal parenchyma

What will be observed in an abdominal examination of a patient with a ureteric stone?

- tenderness & some rigidity - hematuria (does not rule out appendicitis) - patient in severe pain

How can we confirm the diagnosis of a patient with a ureteric stone?

Spiral CT IVU while patient has pain -> little or no excretion on the affected side -> dilation of the ureter down to an obstructing calculus -> filling defect

How should a ureteric calculus be treated?

- NSAIDS (diclofenac & indomethacin) - removal of stone (it will likely pass naturally) - if it doesnt pass & the patient is not disabled by attacks -> follow progress by x-ray every 6-8 weeks

What are the indications for surgical removal of a ureteric calculus?

- repeated attacks of pain & the stone is not moving - stone is enlarging - complete obstruction of kidney - urine is infected - stone is too large to pass

What are the types of surgical removal of ureteric calculus?

ENDOSCOPIC STONE REMOVAL - Dormia Basket -> danger of ureteric injury - Ureteric meatotomy -> endoscopic incision with a diathermy knife URETEROSCOPIC STONE REMOVAL - transuretheral route -> remove impacted stone -> fragmented using electrohydraulic, percussive, or laser lithotripter PUSH BANG - stone in the middle of upper part of ureter -> flushed back into kidney -> J-stent secures calculus of kidney for subsequent ESWL LITHOTRIPSY IN SITU - stones fragmented in situ - not appropriate IF -> completely obstructed OR the stone has been impacted for a long time OPEN SURGERY - ureterolithotomy

What is the difference between a primary & secondary bladder stone?

Primary - develops in sterile urine - originates in kidney ``` Secondary occurs in presence of - infection - outflow obstruction - impaired bladder emptying - foreign body ```

What are the symptoms of bladder stones?

- frequency (initially) - sensation of incomplete bladder emptying - pain (strangury) -> at the end of micturition with oxalate calculus ---> referred to tip of penis or labia majora - terminal haematuria -> stone abrading the vascular trigone - interruption of urinary stream -> stone blocking internal meatus - urinary infection (most common)

What should be done for men with bladder outflow obstruction due to a bladder stone?

endoscopic resection of the prostate at the same time as the stone removal

How should a bladder stone be treated?

- cause of stone should be found & treated - treat bladder outflow obstruction - litholapaxy -> crush stone in bladder & wash out using catheter

what are the methods for non-operative conservative therapy?

- blind lithotirite | - lithotrite with ultrasound probe

What are the contraindications to peruretheral litholapaxy?

- urethral stricture -> can't be dilated sufficiently when a patient is below 10 - contracted bladder - very large stone

What should be used to remove the bladder stone if the urethra is too narrow?

percutaneous suprapubic litholapaxy

What are the etiologies of uric acid stones?

- gout - hyperuricemia - hyperuricosuria - high cell turnover (chemotherapy, leukemia) radioluscent decrease the acidity of urine

What is the cause of struvite stones?

- UTI with urease-producing bacteria (Proteus miribalis)

What is the cause of calcium phosphate stones

- hyperparathyroidism | - type 1 renal tubular acidosis