Renal stones/Nephrolithiasis & Urinary Tract Trauma Flashcards
Renal stones aka nephrolithiasis are a cause of unilateral ureteric obstruction
What are other causes of unilateral ureteric obstruction?
- PUJ obstruction,
- extrinsic/intrinsic tumour,
- retroperitoneal fibrosis,
- AAA,
- calculi,
- ureteric stricture,
- congenital a-peristaltic segment
Renal stones aka nephrolithiasis are a cause of unilateral ureteric obstruction, there is also bilateral ureteric obstruction
What are other causes of bilateral ureteric obstruction?
- urethral stricture,
- BPH,
- prostate cancer (locally advanced),
- large bladder tumuor,
- gravid uterus
What is the definition of renal stones?
renal calculi consist of crystal aggregates - stones form in collecting ducts,
classically deposit at:
- pelvi-ureteric junction,
- pelvic brim,
- vesico-ureteric junction…
Which patient groups are more likely to get renal stones?
- hotter climates (dehydration)
- high protein & salt diets
- peak incidence 20-50yrs,
- M:F 3:1 (women have more citrate & less testosterone which may increase oxalate levels)
- 10% men by 70yrs,
- Women better at passing stones spontaneously
- Caucasians & Asians,
What types of renal stones are there & how prevalent are they?
Pathophysiology os stones = supersaturation –> cyrstallization –> aggregation / especially if abnormal surface
- calcium oxalate (85%)
- struvite (up to 20%)
- uric acid (5-10%)
- calcium phosphate (10%)
- cysteine (10%)
Calcium oxalate stones make 85% of renal stones AKA the most common type
where does the hypercalciruia / oxalate come from?
Oxalate
- in strawberries, rhubarb, tea, leafy veg, nuts,
- also hyperparathyroidism & IBD
Hypercalciuria but not hypercalcaemia (serum Ca - so don’t cut out diet); causes of hypercalciuria:
- Absorption: over absorption of Ca from gut
- Renal hypercalciura: defect in renal tubules impairing renal tubular absorption of calcium in proximal tubule
- Hypercalcaemia: usually due to primary hyperparathyroidism
STRUVITE renal stones make 20% of renal stones AKA the 2nd most common type
where do these come from?
- proteus infection (g-ve UTI, particularly from LT catheterisation)
- –> urease produced
- struvite = from –> urea + water –> ammonia + CO2 under effect of urease
- ammonia causes alkaline urine = mg, ammonium and phos precipitant
- –> struvite renal stones = radio-opaque!
Uric acid causes 5-10% of renal stones
how?
myeloproliferative disorders, acidic urine, gout & chemo
–> increase DNA breakdown = increase nulceic acid –> uric acid = stones
calcium phosphate causes 10% of renal stones.
How do these form?
- renal tubular acidosis,
- hyperchloraemic metabolic acidosis,
- hypokalaemia (assoc with alkalosis)
- alkaline urine (as acid is retained in kidneys?)
- [overall idk as both acid and alkalosis seem to cause this..]
cysteine causes 10% of renal stones.
How do these form?
associated with inherited metabolic disorders
cysteine renal stones are difficult to treat due to hard consistency
[- they are radioopaque]
What condition can kidney stones cause that gives
- reduced renal function and atrophy due to pressue
- –> development of UTI
hydronephrosis
What predisposing factors to renal stones are there and why?
- diet (Ca, oxylate, urate)
- dehydration (bus/taxi drivers)
- sedentary lifestyle seasons e.g. winter (vitamin D- PTH, hypercalcuria & ca oxalate stones)
- drugs (diuretics, antacids)
- recurrent UTIs (in Mg ammonium phosphate calculi akak Struvite)
- urinaty tract abnormalities (horseshoe kidney)
- foreign bodies
- family hx
- metabolic abnormalities
hyper - uric acid (gout), ca, oxylate (rhubarb, strawberries, tea , chocolate)
hypo = citrate
What are the SSx of renal stones?
- colicky loin pain (worst pain ever, stabbing, can’t get comfortable, loin to groin),
- N&V,
- tachycardia,
- fever,
- haematuria,
- PMH stones,
- comorbidities
- But often no signs on just renal angle tenderness
- Can predispose development of UTI
What are the RFs for renal stones?
- high protein/sald/oxalate diet (ca oxalate is commonest stone - formed with black tea & milk)
- infection (urease to breakdown urea + water–> ammonia)
- hot climate
- abnormal anatomy, foreign body
- poor mobility
- IBD
- chemotherapy
- gout
- high PTH
- low fluid intake, low citrate
What problems/complications can renal stones cause (if not treated etc)?
- infection/sepsis
- AKI
- obstruction
- hydronephrosis
- chronic inflammation & ulceration (viscus perforation, malignancy)
What Ix are used in renal stones for bloods?
(bloods, urine, imaging)
- FBC
- U&E
- Ca (ca oxalate)
- PO4 (ca phosphate / mg ammonium phosphate (struvite)
- glucose
- bicarb (renal rubular acidosis -> Ca phosphate)
- urate (uric acid stones from nucleic acids e.g. MPDs and chemo too)
- is there an infection above the stone?
What Ix are used in renal stones for urine?
(bloods, urine imaging)
- Urine dip (+ve for blood in 90%);
- MSU,
- MC&S
- Urine:
- urine pH, - alkaline urine
- 24h urine (ca, oxalate, urate, citrate, Na, creatiine),
- Stone biochem (sieve urine)
i
What Ix are used in renal stones for imaging?
(bloods, urine imaging)
- plain radiograph KUB,
- CT KUB (non-contrast, thick slices to reduce radiation),
- CT urogram (contrast);
- Intavenous Urogram, (Contrast w/XR)
- MRU (if pregnant) - magnetic resonance urography
- sometimes DMSA (radionuclide scan for split renal function, morphology & structure)
- renal US (hydronephrosis)
What is the Rx for renal stones?
There are conservative, medical expulsion therapy and surgical options, overall you should give:
- analgesia for the pain - PR diclofenac 100mg
- anti-emetic for N&V - metoclopramide 10mg
- fluid intake
- suveillance (95% stones <5mm pass spontaneously)
When is the conservative managment for stones appropriate?
stones <5mm
in the lower ureter
as up to 95% pass spontaneously
What is the medical expulsion therapy for renal stones?
- tamsulosin (alpha blocker)
- Calcium channel blockers
- (stops contraction of ureters/relaxes them on the stone –> reduce pain & pass them quicker)
What are the surgical options for the managment of renal stones?
the surgical management depends on if there is evidence of obstruction / high pressure system
if there IS evidence of obstruction or high pressure system = !!! :(
- TF –> nephrostomy to relieve pressure (urine diversion from kidney to skin) – radiology needle into kidney percutaneously - under LA for decompression
- (using a stent is possible but they can push up into kidneys)
- Go to HDU/ITU as can get septic shower…. look after them! - need abx etc
if there is no evidence of obstruction or high pressure system –>
- Ureteroscopy (basket removal) & fragmentation (laser)
- Extracorporeal shock wave lithotripsy (ESWL): outpatient procedure, often need more than one go, used to renal or upper reteric stones
- CIs’: pregnancy, anticoagulation
- Percutaneous nephrolithotomy (PCNL): large renal stones or staghorn calculi (via skin puncture under GA or spinal)
- Ureteric stents: for large ureteric stones causing ongoing pain & deranged U&Es/ creatinine
- Risks: bleeding, constant feeling of needing to pass urine (from stent), pain, infection
- Open nephrolithotomy/ ureterolithotomy: rare, for large staghorn calculi or complex stones
A patient has a kidney that is obstructed and infected by renal stones… what is the Rx?
- Infection AND obstruction is indication for urgent intervention (delay kills glomeruli)
- Percutaneous nephrostomy (drain) or ureteric stent to relieve obstruction, urosepsis, intractable pain or vomiting
- Nephrectomy(!) if staghorn calculi
How are renal stones best prevented?
- drink plenty,
- normal Ca (low increase oxlalate excretion)(also rememebr high Ca = stones, bones, psychic moans, thrones)
- treat hypercalciurea (thiazide),
- decrease oxalate intake (strawbetties, rhurbarb, tea, leafy veg, nuts,)
- allopruinol (urate stones),
- sodium bicarbonate to alkalize urine (for cystine & urate stones)
What are the different types of renal trauma that can occur?
What Ix do you do?
- blunt vs penetrating
- Trauma can be blunt abdo e.g. fall from height, RTA accel and decel injuries
- or blunt thoracic trauma - 9,10,11,12th ribs
- penetrating - stab or gunshot wounds
- Trauma can be blunt abdo e.g. fall from height, RTA accel and decel injuries
- may present w/ haematuria
- –> trauma CT - arterial phase shows the bleeding well but not renal damage
- 48 hrs later do CT urogram
What is the Rx for renal trauma?
- bed rest (majority of blunt 90% and penetrating renal injuries = conservative)
- (retroperitoneum can self-tamponade in blunt injury),
If pt is shock, decrease hb, extravation of urine
- embolisation of blood
- emergency nephrectomy (rare - do it if renal pedicle injury e.g. indicated by pulsatile retroperitoneal haematoma)
- ureteric stent & abx if leak (of urine from the renal trauma)
- difficult VTE prophylaxis
- can only really have TED stockings,
- otherwise LMWH would build up and cause 2o bleed
Pelvic trauma can cause pelvic fracture –> bladder or uretheral injury
What SSx can you get?
- Haematuria
- blood at meatus
- high riding prostate (is a CI for urethral catheterisation and incidation for urethrography)
in pelvic trauma do 1x gentle attempt at passing of urethral catheter by doctor before –> supra pubic catheter (US guidance)
A patient presents with haematuria, blood at urethral meatus and a high riding prostate. They have a hx of recent pelvic trauma.
What Ix do you do?
-
urethrogram
- dye in urethra, w/before and after images (retrograde and anterograde)
- cystogram
The Rx of pelvic trauma causing bladder or urethral injury depends on if it is urethral injury, intra-peritoneal bladder injury or extra-peritoneal bladder.
What is the rx for an intra-peritoneal bladder injury?
NB: it is more common for bladder rupture to be extraperitoneal than intraperitonal
- intraperitoneal ruptures need surgical repair
- supra pubic catheter
- drains
The Rx of pelvic trauma causing bladder or urethral injury depends on if it is urethral injury, intra-peritoneal bladder injury or extra-peritoneal bladder.
What is the rx for an extra-peritoneal bladder injury?
NB: it is more common for bladder rupture to be extraperitoneal than intraperitonal
Extra-peritoneal bladder injury: may heal with catheter drainage
AKA intraperitoneal is more severe, but less common –> needs catheter drainage
The Rx of pelvic trauma causing bladder or urethral injury depends on if it is urethral injury, intra-peritoneal bladder injury or extra-peritoneal bladder.
What is the rx for a urethral injury?
NB: it is more common for bladder rupture to be extraperitoneal than intraperitonal
- supra-pubic catheter,
- high risk of urethral stricture so delay repair
What was the condition this extensive surgical debridement was neccessary for?
What kind of conditon is this and what patient groups?
- Fourniere’s gangrene!
- is an EMERGENCY
- a necrotising fasciitis (commonly GroupAStrep), spreads rapidly from starting as a small back patch on cellultiis scrotum/perineum –> there is GAS IN TISSUES and it smells…
- often diabetic patients
- –> need immediate and extensive debridement
What would grey turners sign (sad pucker), haematuria and shock indicate?
Renal injury/trauma
Grey turners sign is caused by retroperitoneal haemorrhage
The pneumonis SAD PUCKER = retroperitoneal organs mneumonic
Suprarenal (adrenal glands, Aorta/inferior vena cava, Duodenum, Pancreas, Ureters, Colon (ascending and descending only), Kidneys, (o)Esophagus, Rectum
Ix into renal injuries depends if haemodynamically stable or unstable.
What Ix do you do if haemodynamically stable?
- Bedside: Hx and Exam
- urinalysis - haematuria
- Bloods: FBC, U&E
- Imaging: contrast-enhanced CT abdo pelvis
- macroscopic haematuria, microscopic haematuria and hypotensive, open wound
Ix into renal injuries depends if haemodynamically stable or unstable.
What Ix do you do if haemodynamically unstable?
surgery –> on-table intravenous urogram
indications: retroperitoneal haematoma - injury likely to need nephrectomy (removal of kidney)
How are renal injuries staged?
According to american association for the surgery of trauma
- G1 = CT normal, subcapsular haematoma w/no parenchymal laceration
- (e.g. under the fibrous capsule like a terrys chocolate orange in a wrapper)
- G2 = <1cm deep parenchhymal lesion, G3 >1cm
- (both NOT INVOLVING COLLECTING SYSTEM)
- G4 = lesion involves cortex, medulla, renal artery collecting system or vein w/haem
- (DOES affect the collecting system - get EXTRAVASION of urine)
- G5 = shattered kidney, avulsion of hilum
Ureteral injuries can be internal or external.
What aetiologies do these have?
Internal ureteral injury = due to pelvic or abdominal surgery (hysterectomy, colectomy, AAA repair, ureteoscopy) [uretera are thin walles and can quite easily be damaged by surgery]
external = due to trauma, RTA, penetrating trauma: stab or gunshot
[quite rare to have external injury as the ureters are quite mobile]
A patients presents with flank pain / vague abdominal pain, abdominal mass, ileus.
prolonged post operative fever or sepsis & persistent dainage of fluid from drains, wound or vagina, what is happening?
Ureteral injuries
ureteral injuries can cause an ileus due to urine in the peritoneal cavity irritating the bowel, this may also cause peritonitis and generalised abdo pain.
A collection of urine called a urinoma, can cause an abdominal mass
During a surgery it is suspected that a ureter has been injured. What should be done?
- pack the bowel out the way + control bleeding
- directly inspect the ureter
- extravasion (leakage of the fluid) after injection of melylene blue
- e.g. all to check/confirm suspicion of injury
- Intravenous urogram (inject contrast to veins so it is clearled by kidneys and take XR)
- NB: vs KUB is just plain
- On-table retrograde urethrography
- foley catherter into distal urethra and contrast through it and XR used to see where contrast leaks
Post operatively, it is suspected that a ureter has been injured. What should be done?
- Intravenous urogram (inject contrast to veins so it is clearled by kidneys and take XR)
- NB: vs KUB is just plain
- On-table retrograde urethrography [can be sone it iv pyelogram is CI e.g. probably in kidney injury as contrast is nephrotoxic]
- foley catherter into distal urethra and contrast through it and XR used to see where contrast leaks
What are 3 procedures for the management on ureteral injuries?
JJ stenting (3-6w)
[where both ends of the stent maybe coiled to prevent it moving out of place]
psoas hitch
(bladder is pulled up and secured to the psoas muscle to reduce the distance between the distal ureter and bladder)
Uretostomy
(is creating a stoma for a ureter (putting onto another) or kidney, diverting urine away from the bladder if not funcitoning or been removed)
Renal trauma is actually quite rare affecting 1.5-3% of individuals.
Why is renal trauma quite rare?
- Kidneys are protected by the ribs
- Kidneys are surrounded by wonderful layers of peri-nephric fat and are quite mobile vertically and anterior to posterior – which means they can avoid crush injuries a lot of the time. Renal trauma is actually more common in paediatric patients for this reason as there is less protection.
What are the main causes of bladder injuries?
blunt abdominal trauma (full bladder)
pelvic fractures
penetrating trauma
iatrogenic: TURBT, TURP, cytoscopy bladder biopsy, C- sections
What are the 2 types of bladder injury?
Extra-peritoneal rupture and intraperitoneal rupture
- extra = when the double membrnae peritoneum covering of the bladder is intact but bladder is injured = urine escapes into space outside peritoneal cavity
- alternatively intraperitoneal rupture = peritoneum is breeched and urine passes into the peritoneal cavity
What is the main 3 triad of bladder injury symptoms?
- suprapubic pain
- inability to pass urine
- haematuria
+ abdominal distention (due to urine collection)
+ absent bowel sounds
other features maybe ileus - usually if intraperitoneal causing absent bowel sounds.
What are retrograde cystography and CT cystography used for?
bladder injury diagnosis
intraperitoneal and extraperitoneal bladder injuries are Rx differently. What are the different Rx?
intraperitoneal = surgical repair (as is more severe) - the top of the bladder injury is intraperitoneal
extraperitoneal = drainage with urethral catheter for 2W & –> cystogram to confirm bladder has healed
NB: the bladder is highly vascularised and often repairs quite well
How ar urethral injuries divided?
Into Anterior and Posterior
- in males, anterior = penile and bulbar (base) urethral.
- in females, anterior = distal 1/3 of urethra
- in males, posterior = membranous and prostatic urethra
- in females, is proximal 2/3rds
- NB: (proximal to body centre)
Anterior and posterior urethral injuries can occur in different patterns.
How may anterior urethral injuries occur?
(distal 1/3 in females and penile and bulbar in males)
External:
- Straddle injury (characteristic)
- penetrating injury
Internal:
- object inserted inside the urethra
- catheter balloon insertion
- penile surgery
What is the mechanism of action for posterior urethral injuries?
- the prostatic and membranous urethra in men
- the proximal 2/3 in women (e.g. deeper inside proximal to body core) - NB: is rare to have posterior urethral injury in women due to shorter urethra & weaker attachments to pubic bone = less likely to rupture in pelvic bone fracture
External:
- pelvic fracture
- penetrating injuries
Internal:
- endoscopic surgery
- TURP
- foreign body insertion
What is a butterfly pattern of bruising (peri anal) and blood in scrotum indicative of?
anterior urethral injuries (e.g. in men) where the bucks fascia is disrupted (the deep layer of the superficial fascia of the penis) where blood tracks into the scrotum causing swelling
Anterior urethral injuries also present w/ difficulty passing urine, frank haematuria (as well as butterfly bruising)
How do you Ix and manage and anterior urethral injury?
- retrograde urethrography
Rx:
- partial rupture is Rx by suprapubic catheter, broad spectrum Abx, & cystogram in 2w & if healed, remove suprapubic catheter
- if complete rupture: surgical repair - immediately or wait with catheter in situ for 3M until oedema resolves
Difficulty passing using and frank hamaturia
vs
blood @ meatus, gross haematuria, inability to pass urine, peri-anal brusing & high riding prostate
Which is posterior and anterior urethral injury?
Ix of posterior?
blood @ meatus, gross haematuria, inability to pass urine, peri-anal brusing & high riding prostate = posterior urethral injury… a high riding prostate = where blood collects in the retro-pubic space causing the prostate to rise.
Ix = same as anterior urethral injury = retrograde urethrogram
Rx: for post urethral is same as anterior full rupture e.g. suprapubic catheter + delayed SURGICAL urethroplasty (as if partial anterior urethral rupture = suprapubic catheter and BS abx)
