STONES Flashcards
Causes of UT Stones
idiopathic calcium urolithiasis hypercalcaemic disorders renal tubular syndromes uric acid lithiasis enzyme disorders secondary urolithiasis
Hypercalcaemic disorders
PRIMARY HYPERPARATHYROIDISM
-increased intestinal calcium absorption, renal tubular reabsorption and bone resorption
PROLONGED IMMOBILISATION
EXCESSIVE INTAKE OF CALCIUM, VIT D & ALKALI
SARCOIDOSIS
RENAL TUBULAR SYNDROMES
RENAL TUBULAE ACIDOSIS TYPE 1
-hypercalciuria and low urinary citrate excretion
CYSTINURIA
Uric acid lithiasis
EXCRETE EXCESSIVE URIC ACID
DIETARY PURINE & PROTEIN
LOW URINE VOLUME
Enzyme disorders
PRIMARY HYPEROXALURIA
-def of alanine:glyoxalate aminotransferase, D-glycerate dehydrogenase
XANTHIURIA
-def in xanthine oxidase
2,8 DIHYDROADENINURIA
-def in adenine phosphoribosyl transferase
Secondary urolithiasis
SECONDARY HYPEROXALURIA -increased oxalate absorption dt: -- after small bowel resection -- IBD -- Chronic pancreatitis -- hx of jejunoileal bypass -reduce the calcium available to bind oxalate DIETARY EXCESS -rhubarb, spinach, tea, cocoa, chocolate and pepper INFECTION -Proteus, Pseudomonas, Staphylococcus -- urea break down into ammonia and CO2, which leads to urine become alkaline and promotes formation of struvite calculi (Mg,NH3, PO4), forming staghorn calculus -E.coli never produce struvite stones OBSTRUCTION AND STASIS -delayed cyrstal washout
Other risk factors
URINARY DIVERSION DRUGS - Acetazolamide (renal tubular acidosis) - Allopurinol (xanthine stones) - Thiazide diuretics (uric acid stones) LOW WATER INTAKE DIET HOT ENVIRONMENT OCCUPATION
Clinical features
URETERIC COLIC ACUTE URINARY RETENTION HAEMATURIA - Non visible haematuria DEHYDRATION VOMITING
Investigations
FBC -leucoytosis (infection) -CRP BUSE & CREATININE - renal function SERUM CALCIUM & URATE
Differential diagnosis
PYELONEPHRITIS RUPTURED ABDOMINAL AORTA ANEURYSM BILIARY PATHOLOGY BOWEL OBSTRUCTION LOWER LOBE PNEUMONIA
Common site of STONES
the PUJ
point which the ureter corsses the bifurcation of the common iliac artery
distal ureter/ vesico-ureteric junction
Emergency Management
- NSAIDS, diclofenac for pain relief
- monitor pain, temperature, pulse, blood pressure and white blood count for signs of infection
- monitor the estimated glomerular filtration rate (eGFR) to look for decline in renal function
Urgent treatment of pain
- in situ extracorporeal shockwave lithotripsy (ESWL)
- Cystoscopy and insertion of a ureteric stent
- Primary ureteroscopic stone retrieval usually treated with lasertripsy
Septic secondary to obstruction of STONES
- insertion of a percutaneous nephrostomy under local anaethesia
- Cystoscopy and insertion of a ureteric stent
PCN is more preferred to stent insertion which it can adequately drain pus from a kidney and lower risk of septicaemia
Extracorporeal shockwave lithotripsy
generate shockwaves outside the body and focused on the stones.
stones can be localised for treatment using either fluoroscopy or USS
prophylatic antibiotics used to prevent infection as stones are often colonised by bacteria
complications: haematuria, parenchymal haemorrhage and even perirenal haematoma
contraindications: obese, pregnant, anticoagulants
Ureteroscopy
semi-rigid ureteroscopes are used to directly visualised ureteric calculi
- the stones are retrieved by using wire retrieval baskets or more commonly using lithotripsy employing diff enery (US, electrohydraulic)
- stones can also be fragmented using mechanical disintegration using the lithoclast
Complications: injury to the ureteric mucosa or wall and include ureteric perforation and extravasation, avulsion of the ureter and ureteric stricture
Cystoscopy
For distal ureteric stones
Percutaneous Nephrolithotomy (PCNL)
To treat larger stones in the renal pelvis or calyces but is sometimes also employed to deal with stones in the proximal ureter
- tract is established into the renal collecting system using US or fluoroscopic guidance
- dilators used followed by placement of a working sheath into the collecting system through which the stone is visualised and fragmented
- nephrostomy tube is left in the kidney for 24/48hrs
Indication:
- obstruction at PUJ, calyceal diverticula or ureteric
- obese patient whom ESWL contraindicated
- lower calyceal stones
- struvite stones as ass with infections
Complications:
- injury to spleen, pleura and colon
- haemorrhage from renal parenchyma
- sepsis
- extravasation dt rupture of the collecting system
- retained stone fragments
- open surgery to the kidney
