Renal stones/Nephrolithiasis & Urinary Tract Trauma

Question 1

Renal stones aka nephrolithiasis are a cause of unilateral ureteric obstruction

What are other causes of unilateral ureteric obstruction?

Answer 1

• PUJ obstruction,
• extrinsic/intrinsic tumour,
• retroperitoneal fibrosis,
• AAA,
• calculi,
• ureteric stricture,
• congenital a-peristaltic segment

Question 2

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?

Answer 2

• urethral stricture,
• BPH,
• prostate cancer (locally advanced),
• large bladder tumuor,
• gravid uterus

Question 3

What is the definition of renal stones?

Answer 3

renal calculi consist of crystal aggregates - stones form in collecting ducts,

classically deposit at:

1. pelvi-ureteric junction,
2. pelvic brim,
3. vesico-ureteric junction…

Question 4

Which patient groups are more likely to get renal stones?

Answer 4

• 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,

Question 5

What types of renal stones are there & how prevalent are they?

Answer 5

Pathophysiology os stones = supersaturation –> cyrstallization –> aggregation / especially if abnormal surface

1. calcium oxalate (85%)
2. struvite (up to 20%)
3. uric acid (5-10%)
4. calcium phosphate (10%)
5. cysteine (10%)

Question 6

Calcium oxalate stones make 85% of renal stones AKA the most common type

where does the hypercalciruia / oxalate come from?

Answer 6

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

Question 7

STRUVITE renal stones make 20% of renal stones AKA the 2nd most common type

where do these come from?

Answer 7

• 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!

Question 8

Uric acid causes 5-10% of renal stones

how?

Answer 8

myeloproliferative disorders, acidic urine, gout & chemo

–> increase DNA breakdown = increase nulceic acid –> uric acid = stones

Question 9

calcium phosphate causes 10% of renal stones.

How do these form?

Answer 9

• 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..]

Question 10

cysteine causes 10% of renal stones.

How do these form?

Answer 10

associated with inherited metabolic disorders

cysteine renal stones are difficult to treat due to hard consistency

[- they are radioopaque]

Question 11

What condition can kidney stones cause that gives

• reduced renal function and atrophy due to pressue
• –> development of UTI

Answer 11

hydronephrosis

Question 12

What predisposing factors to renal stones are there and why?

Answer 12

• 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

Question 13

What are the SSx of renal stones?

Answer 13

• 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

Question 14

What are the RFs for renal stones?

Answer 14

• 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

Question 15

What problems/complications can renal stones cause (if not treated etc)?

Answer 15

• infection/sepsis
• AKI
• obstruction
• hydronephrosis
• chronic inflammation & ulceration (viscus perforation, malignancy)

Question 16

What Ix are used in renal stones for bloods?

(bloods, urine, imaging)

Answer 16

• 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?

Question 17

What Ix are used in renal stones for urine?

(bloods, urine imaging)

Answer 17

• 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

Question 18

What Ix are used in renal stones for imaging?

(bloods, urine imaging)

Answer 18

1. plain radiograph KUB,
2. CT KUB (non-contrast, thick slices to reduce radiation),
3. CT urogram (contrast);
4. Intavenous Urogram, (Contrast w/XR)
5. MRU (if pregnant) - magnetic resonance urography
6. sometimes DMSA (radionuclide scan for split renal function, morphology & structure)
7. renal US (hydronephrosis)

Question 19

What is the Rx for renal stones?

Answer 19

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)

Question 20

When is the conservative managment for stones appropriate?

Answer 20

stones <5mm

in the lower ureter

as up to 95% pass spontaneously

Question 21

What is the medical expulsion therapy for renal stones?

Answer 21

• tamsulosin (alpha blocker)
• Calcium channel blockers
• (stops contraction of ureters/relaxes them on the stone –> reduce pain & pass them quicker)

Question 22

What are the surgical options for the managment of renal stones?

Answer 22

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

Question 23

A patient has a kidney that is obstructed and infected by renal stones… what is the Rx?

Answer 23

• 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

Question 24

How are renal stones best prevented?

Answer 24

• 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)

Question 25

What are the different types of renal trauma that can occur? What Ix do you do?

Answer 25

* 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 * may present w/ ***haematuria*** * --\> **trauma CT** - arterial phase shows the bleeding well but not renal damage * **48** hrs later do **CT urogram**

Question 26

What is the Rx for renal trauma?

Answer 26

* 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

Question 27

Pelvic trauma can cause pelvic fracture --\> bladder or uretheral injury What SSx can you get?

Answer 27

* 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 cathete**r by doctor before --\> **supra pubic** catheter (**US** guidance)

Question 28

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?

Answer 28

* **urethrogram** * dye in urethra, w/before and after images (retrograde and anterograde) * **cystogram**

Question 29

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

Answer 29

* intraperitoneal ruptures need **surgical repair** * **supra pubic catheter** * **drains**

Question 30

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

Answer 30

Extra-peritoneal bladder injury: **may heal with catheter drainage** AKA intraperitoneal is more severe, but less common --\> needs catheter drainage

Question 31

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

Answer 31

* **supra-pubic catheter,** * high risk of urethral stricture so delay repair

Question 32

What was the condition this extensive surgical debridement was neccessary for? What kind of conditon is this and what patient groups?

Answer 32

* 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

Question 33

What would grey turners sign (sad pucker), haematuria and shock indicate?

Answer 33

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

Question 34

Ix into renal injuries depends if haemodynamically stable or unstable. What Ix do you do if haemodynamically stable?

Answer 34

* Bedside: Hx and Exam * urinalysis - haematuria * Bloods: FBC, U&E * Imaging: contrast-enhanced CT abdo pelvis * macroscopic haematuria, microscopic haematuria and hypotensive, open wound

Question 35

Ix into renal injuries depends if haemodynamically stable or unstable. What Ix do you do if haemodynamically unstable?

Answer 35

surgery --\> on-table intravenous urogram indications: retroperitoneal haematoma - injury likely to need nephrectomy (removal of kidney)

Question 36

How are renal injuries staged?

Answer 36

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

Question 37

Ureteral injuries can be internal or external. What aetiologies do these have?

Answer 37

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]

Question 38

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?

Answer 38

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

Question 39

During a surgery it is suspected that a ureter has been injured. What should be done?

Answer 39

1. pack the bowel out the way + control bleeding 2. directly inspect the ureter 3. extravasion (leakage of the fluid) after injection of melylene blue * e.g. all to check/confirm suspicion of injury 4. Intravenous urogram (inject contrast to veins so it is clearled by kidneys and take XR) * NB: vs KUB is just plain 5. On-table retrograde urethrography * foley catherter into distal urethra and contrast through it and XR used to see where contrast leaks

Question 40

Post operatively, it is suspected that a ureter has been injured. What should be done?

Answer 40

* 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

Question 41

What are 3 procedures for the management on ureteral injuries?

Answer 41

**_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)

Question 42

Renal trauma is actually quite rare affecting 1.5-3% of individuals. Why is renal trauma quite rare?

Answer 42

* 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.

Question 43

What are the main causes of bladder injuries?

Answer 43

blunt abdominal trauma (full bladder) pelvic fractures penetrating trauma iatrogenic: TURBT, TURP, cytoscopy bladder biopsy, C- sections

Question 44

What are the 2 types of bladder injury?

Answer 44

_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

Question 45

What is the main 3 triad of bladder injury symptoms?

Answer 45

1. suprapubic pain 2. inability to pass urine 3. haematuria + abdominal distention (due to urine collection) + absent bowel sounds other features maybe **ileus** - usually if intraperitoneal causing absent bowel sounds.

Question 46

What are retrograde cystography and CT cystography used for?

Answer 46

bladder injury diagnosis

Question 47

intraperitoneal and extraperitoneal bladder injuries are Rx differently. What are the different Rx?

Answer 47

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

Question 48

How ar urethral injuries divided?

Answer 48

_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)

Question 49

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)

Answer 49

External: * **Straddle** injury (characteristic) * penetrating injury Internal: * object inserted inside the urethra * catheter balloon insertion * penile surgery

Question 50

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

Answer 50

_External_: * pelvic fracture * penetrating injuries _Internal_: * endoscopic surgery * TURP * foreign body insertion

Question 51

What is a butterfly pattern of bruising (peri anal) and blood in scrotum indicative of?

Answer 51

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)

Question 52

How do you Ix and manage and anterior urethral injury?

Answer 52

* 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

Question 53

**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?

Answer 53

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)