Renal tract calculi

Question 1

What are the two types of renal tract stones?

Answer 1

Renal stones which are within the kidney and ureteric stones which are within the ureter

Question 2

What is urolithiasis?

Answer 2

Renal tract stones

Question 3

What are most urinary tract stones made out of?

Answer 3

Calcium oxalate

Question 4

What else can urinary tract stones be made out of?

Answer 4

Calcium phosphate, oxalate, phosphate, Magnesium ammonium sulphate (struvite) urate and cystine

Question 5

Where do struvite stones sit?

Answer 5

Usually fill the renal pelvis and this is called staghorn calculi

Question 6

Which type of stones are radiolucent?

Answer 6

Urate stones

Question 7

Why do renal tract stones form?

Answer 7

Over-saturation of urine

Question 8

Why do urate stones form?

Answer 8

high levels of purine in the blood

Question 9

What would cause high levels of purine in the blood?

Answer 9

red meats, haematological disorders such as myeloproliferative disease, causing increase in urate formation and crystallisation

Question 10

What are cystine stones associated with?

Answer 10

Hypocystinuria which is an inherited defect that affects the absorption and transport f cystine in the bowel and kidneys, citrate works as a stone inhibitor so reduced amounts causes stone formation

Question 11

Where are the three places stones are likely to impact?

Answer 11

PUJ, Crossing of the pelvic brim where the iliac vessels cross the ureter in the pelvis, VUJ

Question 12

What is the most common clinical feature of renal tract stones?

Answer 12

Pain- ureteric colic

Sudden, severe, radiating from flank to pelvis (loin to groin) with nausea and vomiting

Question 13

Why does pain occur with renal tract stones?

Answer 13

increased peristalsis from around the site of the obstruction

Question 14

What other clinical feature might you get in renal tract stones?

Answer 14

haematuria

Question 15

What would be present on examination with someone with renal tract stones?

Answer 15

tenderness in the affected flank, dehydration,

Question 16

What is a differential diagnosis for someone with renal tract stones?

Answer 16

Pyelonephritis, ruptured AAA, biliary pathology, bowel obstruction, lower lobe pneumonia or musculoskeletal pain

Question 17

What are the urine investigations for suspected renal tract stones?

Answer 17

Urine dip may show microscopic haematuria, and infection, if so then send urine culture

Question 18

What blood tests would you send for if there were suspected renal tract stones

Answer 18

FBC and CRP for infection, U and E to assess renal function, urate and calcium level can assess stone analysis

Question 19

What is the gold standard imaging for stones?

Answer 19

non-contrast CT scan of the renal tract CT KUB

Question 20

What other imaging can you do for stones?

Answer 20

plain film abdominal radiographs however not all stones are radiopaque, also ultrasound scans can be used to asses for hydronephrosis, can also detect renal stones but not usually ureteric stones, intravenous urograms

Question 21

what is a intravenous urogram?

Answer 21

a series of abdominal radiographs following injection of contrast to demonstrate any filling defects but these are rarely used due to high radiation exposure and superiority of CT imaging

Question 22

What is the initial management for renal stones?

Answer 22

Fluid resuscitation, if less than 5mm will pass spontaneously hopefully, analgesia such as NSAIDs per rectum, if infection then IV antibiotics

Question 23

Why would renal stones need to be admitted?

Answer 23

post obstructive AKI, uncontrollable pain from simple analgesia, infected stone stone >5mm

Question 24

Why would a stent be inserted or nephrostomy?

Answer 24

obstructive nephropathy or significant infection as the obstruction must be relieved immediately to avoid renal damage

Question 25

What is a retrograde stent insertion?

Answer 25

placement of a stent within the ureter approaching distal to proximal via cystoscopy, allows the ureter to be kept patent and temporarily relieve the obstruction

Question 26

What is a nephrostomy?

Answer 26

tube placed directly into the renal pelvis and collecting system, relieving the obstruction proximally, if needed a stent can be placed

Question 27

What are the methods of definitive management?

Answer 27

Extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy, flexible uretero-renoscopy

Question 28

What size stones is ESWL usually done?

Answer 28

less than 2cm, and not in pregnancy or if stone is positioned over a bony landmark

Question 29

What is PCNL used for?

Answer 29

renal stones

Question 30

What are the complications of renal stones?

Answer 30

infection, AKI, Recurrent stones can cause renal scarring and loss of kidney function

Question 31

What advice is given to patients with stones?

Answer 31

keep well hydrated, eat less salt, if oxalate avoid nuts, rhubarb, sesame and chocolate, check PTH levels, if Duarte acid red meat and shellfish while taking allopurinol

Question 32

When do bladder stones usually form?

Answer 32

when there is urine statuses within the bladder e.g. chronic urinary retention, after infections such as schistosomiasis

Question 33

What are the symptoms of bladder stones?

Answer 33

lower urinary tract symptoms

Question 34

How are bladder stones managed?

Answer 34

cystocopy and lithotripsy

Question 35

What can bladder stones predispose you to?

Answer 35

TCC bladder cancer