urinary stones Flashcards
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
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
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
What is the first indication if bilateral silent calculi?
Renal failure
- secondary infection produces symptoms
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
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
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
What are the clinical features of renal destruction?
- pyonephrosis
- pyelonephritis
- hydronephrosis
What are the clinical features of pelvi-ureteric obstruction?
- Renal colic
- total hematuria
- hydronephrosis
- pyelonephritis
What are the clinical features of bladder irritation?
- terminal hematuria
- frequency
- suprapubic dull pain made worse by bladder filling
What are the clinical features of vesico-ureteric obstructions?
- Renal colic
- total hematuria
- hydronephrosis
What the the clinical features of bladder outflow obstruction?
- acute retention
- terminal hematuria
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
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
What is the best method of investigation to detect a urinary stone?
CT (helical CTU)
- can identify other causes of non-stone flank pain
How should renal colic be managed?
PAIN RELIEF
- NSAIDS
HYDRATION
WATCHFUL WAITING
- if stone is 5mm or less
- alpha-blockers (ZOSINS)
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
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
