8.5 Urolithiasis & Urogenital Trauma Flashcards
Factors that promote crystallisation of stones:
- consentration of urine
- stasis
- pH (acidic; alkaline)
- nidis (⬆️ crystallisation)
- other crystals (epitaxis)
- inhibitors
What are the 4 most common stones in order?
- Calcium oxalate
- Struvite (infec)
- Uric acid
- Cystine
Calcium stones
- calcium + oxalate (or phosphate)
- middle aged men
- visible in X-ray
Promoters: calcium, oxalate, uric acid
Inhibit: magnesium, citrate
Causes:
- Hypercalciuria, -oxaluria, -uricouria
- Hypocitrauria, -magnesuria
Hypercalciuria
- absorptive (absorb more from gut, calcium sup)
- resorptive (malignancy in bone)
- renal leak (kidneys can’t reabsorb urine)
Hyperoxaluria
- ⬆️ Ox diet
- ⬇️ Ca diet (less Ca, more free Ox {they bind together})
- bowel disease (leave fat in bowel; will bind to Ca)
- enzyme deficiency
Hyperuricosuria
- Epitaxis
- crystals form on a different type of crystal
Hypercitraturia
- bowel disease
- malabsorption
- renal tubular acidosis type 1
- high protein diet
Struvite stones / mg-ammonium-phophate / infective / staghorn / coral
Spesific organisms
- associated with stasis -> infec
- take on form of renal calyces
Specific organisms: urea-splitting organisms
- Proteus mirabilis
- Klebsiella aerogenes/mirabillis
- produce urease enzyme (urease breaks up urea -> NH4 {ammonium})
- makes urine more alkaline
- forms nidus
Uric Acid stones
- DNA cells contain purines (red meat, chicken , eggs)
- purines -> xanthine -> uric acid (by xanthine-oxidase)
Causes:
- diet (animal protein)
- urine pH (acidic)
- cell breakdown (malignancy)
- enzyme defects (Lesch-Nyhan syn: ⬆️ production of uric acid)
Cystine Stones
CONGENITAL STONES
- rare
- cystine = amino acid
- defect = amino acids not reabsorbed by kidney as they should be
- problem with reabsorption of COLA amino-acids
Cystine (causes most problems)
Ornithine
Lysine
Arginine
Medullary sponge kidney
- congenital
- cystic dilatation of collecting tubules of kidney
- predispose to calcification / stones
Bladder stones
- very different to kidney stones
- due to stasis (obstruction, strictures)
- infectious stones
- mostly secondary
- very rare that it is kidney stone that traveled down
Bladder stones in children
- primary
- malnutrition (low protein)
- bamboo sprouts for teething babies
Causes STASIS & OBSTRUCTION
- FB in bladder (catheter, suture, sling)
- benign prostatic hyperplasia
- urethral stricture
- bladder diverticulum
- neurogenic bladder dysfunction
- posterior urethral valves
Renal trauma
Kidneys protection
Mechanism
Grading system
- kidneys most injured UG organ
- rarely injured in isolation
- Large kidneys (hyponephronis/tumour) more easily injured
Kidneys protected by:
- retroperitoneal position
- visceral anteriorly
- ribs
- perinephric fast & fascia
Mechanism:
- penetrating
- blunt (acceleration / deceleration)
Grading system
- Minor - Grade 1-3: haemotomas, tears
- major - grade 4-5: urine leaks, vascular injuries
Ureteric injuries
Causes
Causes:
Iatrogenic
- urologist (ureteroscopy for stones)
- colectomy
- vascular surgery
Trauma
- penetrating
- blunt (rare; fracture of transverse process: massive force required)
Bladder injuries
Causes
Blunt trauma
- bladder contution (wall; no leaking of urine)
- extraperitoneal rupture (sides of bladder; pelvic fracture; no leaking of contrast)
- intraperotoneal rupture (rapture at top of bladder)
Penetrating trauma
- GSW’s / Stabs (intra-ab injury association)
- Iatrogenic
Atraumatic
- spontaneous bladder rupture (rare, underlying pathology: TB, cancer chronic retention
