Nephrolithiasis -Melani

Question 1

What is the most common type of kidney stone ?

Answer 1

Calcium oxalate

Question 2

What is the second most common kidney stone ?

Answer 2

Calcium phosphate

Question 3

Calcium oxalate stone and Calcium phosphate stone accounts for what % of kidney stones ?

Answer 3

80%

Question 4

What % kidney stones are struvite stones ?

Answer 4

15%

Question 5

What % of kidney stones are uric acid stones ?

Answer 5

5%

Question 6

what is the rarest type of kidney stones ?

Answer 6

Cysteine stones

Question 7

What are the main locations of kidney stones ?

Answer 7

renal pelvis, ureter, and bladder.

Question 8

What are the causes of calcium oxalate stones ?

Answer 8

High level of Ca2+ in serum or urine due to primary hyperparathyroidism, chronic academia from tubular acidosis. It can also be idiopathic. It can also occur due to low level of citrate in the urine due to chronic metabolic acidosis or high animal protein intake. High level of oxalate in the blood or urine poor GI absorption of fat, Ingestion of antifreeze, and excessive vitamin C can also cause the formation of calcium oxalate stone.

Question 9

What are the causes of calcium phosphate stone ?

Answer 9

High level of calcium in urine or blood, low level of citrate in urine. High urine PH due to RTA, kideny failure UTI or GI issues such as emesis.

Question 10

What are the causes of Struvite stones ?

Answer 10

It is a mixture of Mg+, ammonium, phosphate, &
calcium carbonate. It typically occurs after infection with amonia producing bacteria.Ammonia increases pH of urine and promotes the formation of ‘Coffin-lid’ crystals into staghorn calculi.

Question 11

What are the causes of uric acid stones ?

Answer 11

Low urine volume &/or high protein metabolism causes increase in uric acid with decrease in PH.Low urine pH (consistently < 5.5) favours polymorphic uric acid crystal formation. They don’t show up on X-ray, but on CT.

Question 12

What is the epidemiology of kidney stones.

Answer 12

• It is 3 times more common in males than female. peak age is 20-40 years. Higher rates in areas
  with high humidity and high temperature.

Question 13

What are the risk factors for kidney stones ?

Answer 13

• Previous hx of stones
• Family hx of stones
• HTN
• Hx of gastric bypass or other
  bariatric surgery

Question 14

What are the drugs that increase the risk fo kidney stones ?

Answer 14

– Antivirals (acyclovir)
– Antibiotics (ceftriaxone)
– K+-sparing diuretics

Question 15

What are the dietary factors that increase the risk of kidney stones ?

Answer 15

– Low fluid intake
– Low calcium
– High animal protein
– High salt
– High intake of vitamin C (men only)

Question 16

What is the clinical presentation of kidney stones ?

Answer 16

Excruciating flank pain – 10/10+ ‘Renal Colic: which is paroxysm of severe pain that lasts for 20-60 minutes. The pain typically radiates to the groin and Relief occurs after passage of stone. In some patients the stones can be incidental imaging finding.

Question 17

What does the flank tenderness on PE indicates ?

Answer 17

pyelonephritis

Question 18

What does a palpable kidney on PE indicates ?

Answer 18

hydronephrosis

Question 19

What does abdominal tenderness implies on PE ?

Answer 19

It warrants investigating other issues such as Ovarian torsion / Cholecystitis / Peritonitis / Ectopic
pregnancy / Biliary colic / Intestinal obstruction /
Hepatitis.

Question 20

Hematuria + Flank pain =

Answer 20

Kidney stones.

Question 21

What are the diagnostic work-ups in kidney stone?

Answer 21

*Urine analysis: to check for PH and rule out hematuria and UTI.
*Uria and electrolytes: To Assess kidney function
*Serum calcium- To rule out hyperparathyroidism.
* Non-contrast CT of the abdomen
* Ultrasound if pregnant.

Question 22

What is the size of kidney stone that can pass on its on

Answer 22

<5 mm

Question 23

What is the management of kidney stone patients ?

Answer 23

*Pain control: NSAIDs, if pregnant Paracetamole, avoid opioids if possible.
* IV hydration and PO intake at home.
* Treat fever with broad spectrum anti-biotic.
* If possible catch stone to analyse composition.

Question 24

What is the Tx relative to stone size ?

Answer 24

– < 5mm will likely pass without intervention
– 5-10 mm  medical expulsive therapy. Use alpha blocker tamsulosin and CCB Nefidepine for relaxation of smooth muscles.
– > 10mm  surgical management

Question 25

What are the surgical options for kidney stones?

Answer 25

For stones >10mm or after 4 weeks of MET
* Shockwave Lithotripsy (SWL): first line therapy
* Ureteroscopy (URS) with lithotripsy: First line therpay. \
If the stones are too large:
* Percutaneous nephrolithotomy (PNL)
* Laparoscopic stone removal
* Open surgical stone removal

Question 26

what are the prevention and patient education in kidney stones ?

Answer 26

• Address any underlying diseases
  increasing risk of stone formation.
• Endocrine referal for hyperparathyroidism.
• Increase water intake 3 L/day and protein <50gm /day. salt <2 g/day.
• Reduce intake in oxalate-rich foods for Calcium oxalate stones.
• UTI prevention in Struvite stone.