Urine Pathologies - Stones, Bladder

Question 1

What are the different types of renal stones you can get?

Answer 1

• Calcium oxalate and phosphate
• Ammonium magnesium phosphate (struvite)
• Uric acid
• Cystine

Question 2

What stones may not be visible?

Answer 2

• Uric acid stones are radiolucent on X-ray (visible on CT)

- Cystine stones are faintly radiopaque on X-ray and moderately on CT

Question 3

What urine pH is associated with Uric acid and Cystine?

Answer 3

Low pH

Question 4

What urine pH is associated with Calcium PHOSPHATE, Ammonium magnesium phosphate (STRUVITE) stones?

Answer 4

Increased pH

Question 5

What are more common calcium oxalate or calcium phosphate stones?

Answer 5

Calcium oxalate

Question 6

What percentage of stones are Calcium?

Answer 6

80%

Question 7

What are causes of Calcium oxalate stones?

Answer 7

• Ethylene glycol (antifreeze)
• Vit C overuse
• Hypocitraturia (associated with decreased urine pH)
• Malabsorption (Crohn’s disease)

Question 8

What kind of stones are associated with hypocitraturia?

Answer 8

Calcium oxalate

Question 9

How are Calcium oxalate stones treated?

Answer 9

• Thiazides
• Citrate
• Low-Na+ diet

Question 10

How are calcium phosphate stones treated?

Answer 10

• Thiazides

- Low Na+ diet

Question 11

What do calcium oxalate crystals look like?

Answer 11

Envelope or dumbbell

Question 12

What do calcium phosphate crystals look like?

Answer 12

Wedge-shaped prism

Question 13

What do struvite (ammonium magnesium phosphate) look like?

Answer 13

Coffin lid

Question 14

What percentage of stones are struvite (ammonium magnesium phosphate)?

Answer 14

15%

Question 15

What are struvite (ammonium magnesium phosphate) stones caused by?

Answer 15

Infection with urease +ve bug

• Proteus mirabilis
• Staph saprophyticus
• Klebsiella

Question 16

How do urease positive bugs work?

Answer 16

Hydrolyse urea to ammnia -> urine alkalisation

Question 17

How are struvite (ammonium magnesium phosphate) stones treated?

Answer 17

• Eradication of underlying infection

- Surgical removal of stone

Question 18

What percentage of stones are uric acid?

Answer 18

~ 5%

Question 19

How are uric acid stones treated?

Answer 19

• Alkalization of urine (CA inhibitor -acetazolamide)

- Alopurinol

Question 20

What are uric acid stones associated with?

Answer 20

• Decreased urine volume
• Arid climates
• Acidic pH
• Gout
• Leukemia (high cell turnover)

Question 21

What do uric acid stones look like?

Answer 21

Rhomboid or rosettes

Question 22

What do cystine stones look like?

Answer 22

Hexagonal

-May form staghorn calculi

Question 23

What condition are cystine stones associated with?

Answer 23

Aut recessive condition

- Cystine reabsorbing PCT transporter loses function -> cystinuria

Question 24

What other amino acids are poorly reabsorbed in Cystinuria (aut recessive disorder)?

Answer 24

COLA

• Cystine
• Orthinine
• Lysine
• Arginine

Question 25

What test can confirm the presence of cystine stones?

Answer 25

+ve Sodium cyanide nitroprusside test

Question 26

What are cystine stones treated with?

Answer 26

- Low Na+ diet - Alkalinazation of urine - Chelating agents (tiopronin, penicillamine) if refractory

Question 27

What are the causes of hydronephrosis?

Answer 27

- Urinary tract obstruction (e.g. renal stones, BPH, congenital obstructions, cervical cancer, injury to ureter) - Retroperitoneal fibrosis - Vesicoureteral reflux

Question 28

What are the different classes of urinary incontinence?

Answer 28

- Stress incontinence - Urgency incontinence - Overflow incontinence

Question 29

What is stress incontinence due to?

Answer 29

- Urethral hypermobility or intrinsic sphincter deficiency - leak w. increased intra-abdo pressure - Associated w. obesity, pregnancy, vaginal delivery, prostate surgery

Question 30

How may stress incontinance be treated?

Answer 30

- Pelvic floor muscle strengthening (Kegel) exercises - Weight loss - Pessaries

Question 31

How can stress incontinence be diagnosed?

Answer 31

+ve bladder stress test | - Directly observed leakage from urethra upon coughing or Valsalva maneuver

Question 32

What is the mechanism behind urgency incontinence?

Answer 32

Detrusor overactivity | -> Leak w. urge to void immediately

Question 33

What is urgency incontinence associated with?

Answer 33

UTI

Question 34

How can Urgency incontinence be treated?

Answer 34

- Kegel exercises - Bladder training (timed voiding, distractionor relaxation techniques) - Antimuscarinics (e.g. oxybutynin for overactive bladder) - Mirabegron

Question 35

What is the mechanism of action behind overflow incontinence?

Answer 35

- Incomplete emptying (detrusor underactivity or outlet obstruction) - > Leak w. overfilling - > Increased postvoid residual on catherization or US

Question 36

What are the causes of overflow incontinence?

Answer 36

- Polyuria (e.g. diabetes) - Bladder outlet obstruction (eg BPH) - Spinal cord injury (eg MS)

Question 37

How can overflow incontinence be treated?

Answer 37

- Catherization | - Relieve obstruction (eg alpha-blockers for BPH)

Question 38

What does acute cystitis present with?

Answer 38

- Suprapubic pain - Dysuria - Urinary frequency - Urgency

Question 39

What are the common bugs to cause acute cystitis?

Answer 39

- E coli (most common always) - Staph saprophyticus - sexually active young women - Klebsiella - Proteus mirabilis - urine has ammonia scent

Question 40

What will labs show in acute cystitis?

Answer 40

- +ve leukocyte esterase - +ve nitrites (indicates presence of enterobacteriaceae) - Sterile pyuria (pyuria with -ve urine cultures) could suggest urethritis from STI

Question 41

What may UTI symptoms with negative urine cultures be suggestive of?

Answer 41

STI

Question 42

How are UTIs treated?

Answer 42

Antibiotics - TMP-SMX - Nitrofurantoin

Question 43

What will be seen on histology in acute pyelonephritis?

Answer 43

Neutrophils infiltrating renal interstitium | - Affects cortex with relative sparing of glomeruli/vessels

Question 44

What does acute pyelonephritis present with?

Answer 44

- Fevers - Flank pain (costovertebral angle tenderness) - N/V - Chills

Question 45

What will the urine contain in acute pyelonephritis?

Answer 45

WBCs in urine +/- WBC casts

Question 46

What will CT show in acute pyelonephritis?

Answer 46

Striated parenchymal enhancement

Question 47

What are risk factors for developing acute pyelonephrtitis?

Answer 47

- Indwelling urinary catheter - Urinary tract obstruction - Vesicouretral reflux - DM - Pregnancy

Question 48

What are complications of acute pyelonephritis?

Answer 48

- Chronic pyelonephritis - Renal papillary necrosis - Perinephric abscess - Urosepsis

Question 49

What is chronic pyelonephritis a result of?

Answer 49

Recurrent or inadequetly treated episodes of acute pyelonephrtitis - Typically requires predisposition to infection such as vesicouretral reflux or chronically obstructing kidney stones

Question 50

What will chronic pyelonephritis have in the kidney?

Answer 50

- Coarse asymmetric corticomedullary scarring, blunted calyces - Tubules can contain eosinophilic casts resembling thyroid tissue (thyroidisation of kidney)

Question 51

What is xanthogranulomatous pyelonephritis?

Answer 51

Rare - Grossly orange nodules that can mimic tumour nodules - Characterised by widespread kidney damage due to granulomatous tissue containing foamy macrophages - Associated with Proteus infection