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Flashcards in Kidney Stones Deck (45):
1

What is urolithiasis?

Formation of stones in the urinary tract

2

What is the commonest site of renal stone formation?

Renal pelvis

3

What percentage of kidney stones occur as unilateral?

80%

4

How can bladder stones form?

Can descend from the kidneys
Can form in the bladder

5

Give some dietary conditions that increase a patient's risk of kidney stones

Low protein diet
Chronic diarrhoea
Dehydration
Increase oxalate consumption
Vitamin A, B1, B6 deficiencies
Magnesium deficiency

6

What is a lithotomy?

Surgical removal of a calculus
(From bladder, kidney or urinary tract)

7

What are the complications of kidney stones?

Haemorrhage
Infection
Fistulae
Incontinence
Erectile dysfunction

8

Is it easier for men or women to pass stones?

Women
Have a shorter urethra

9

Name some causes of bladder stones

Bladder outflow obstruction (stricture, BPH)
Presence of a foreign body
Some are passed down from upper urinary tract

10

What are 2 other names of a kidney stone?

Renal calculus
Nephrolith

11

Are stones more common in men or women?

Men (2:1)

12

Which kidney stones are the only type commoner in women?

Struvite stones

13

What percentage of kidney stones are a type of calcium stone?

99%

14

Name the different types of calcium stones starting from the most prevalent

Calcium oxalate (with calcium phosphate)
Calcium phosphate
Struvite (infection)
Uric acid

15

Name some kidney stones that are not calcium based

Cysteine stones
Drug stones
Ammonium and urate stones
Urine stones

16

When do urine stones form?

When there is a supersaturation of the urine with minerals
Minerals start to crystallise out of solution

17

What pathologies can lead to increased mineral content in the urine?

Hypercalcaemia -> hypercalciuria
Hyperoxaluria
Hyperuricaemia -> hyperuricosuria
Cysteinuria

18

Acidic urine favours the formation of which stones?

Calcium oxalate
Uric acid

19

Alkaline urine favours the formation of which stones?

Calcium phosphate

20

How do the majority of calcium oxalate stones seem to form?

Appear to grow like stalactites
Attached to exposed interstitial deposits of calcium phosphate
(Randall's plaque)
Core of calcium phosphate surrounded by calcium oxalate

21

55% of calcium oxalate stones are associated with which plasma/urine abnormalities?

Hypercalcuria
Without hypercalcaemia

22

Name the 3 substances that control calcium levels

PTH
Calcitriol (activated vit D)
Calcitonin

23

In which organs are the most calcium sensing receptors located?

Parathyroid glands
Kidney
Brain

24

Describe the effects of PTH

Increased osteoclastic resorption of bone
Increased intestinal absorption
Increased synthesis of calcitriol
Increased tubular reabsorption
Increased excretion of phosphate

25

Describe the effects of calcitriol

Increased calcium absorption in gut
Increased calcification and resorption of bone - keeps bone turning over

26

Describe the effects of calcitonin

Inhibits osteoclastic resorption of bone
Increased renal excretion of calcium and phosphate

27

What is the most common metabolic abnormality in calcium stone formers?

Hypercalcuria

28

Name some causes of hypercalcuria

Idiopathic
Hypercalcaemia
Increased dietary intake of calcium
Excessive resorption of calcium from skeleton

29

Name some causes of hypercalcaemia

Hypersecretion of PTH
Destruction of bone tissue
Excessive vit D ingestion
Thiazides

30

Describe primary hypersecretion of PTH

Parathyroid hyperplasia
Tumour

31

Name some reasons for destruction of bone tissue

Primary tumour of bone marrow
Diffuse skeletal metastases
Paget's disease of bone
Immobilisation

32

Give some clinical signs of hypercalcaemia

Severe muscle weakness
Painful bones
Renal stones
Abdominal groans - constipation, ulcers, gallstones etc
Psychic moans - depression, lethargy, seizures

33

Give some causes of hyperoxaluria

Rare autosomal recessive genetic disorder of oxalate synthesis
Increased intestinal absorption of oxalate
High oxalate diet
Low calcium intake

34

Describe struvite stones

More common in women
Mixed infective stones
Composed of magnesium ammonium phosphate
Usually secondary to infection of organisms with urease
Often large

35

Why are uric acid stones difficult to diagnose?

Radiolucent
Cannot see them on an xray

36

Uric acid is the end point of which molecule metabolism?

Purine

37

Give some causes of hyperuricaemia

Gout
Secondary consequence of increased cell turnover (malignancy, chemotherapy)

38

Describe the presentation of kidney stones

Asymptomatic (most)
Renal colic
Dull ache in loins
Recurrent UTIs
Haematuria
Renal failure
UT obstruction

39

Why does drinking water often make the pain in real stones worse?

Fluid is increased in kidneys
Increased pressure on stones

40

What is renal colic?

Excruciating pain
Bouts of 20-60 minutes
Peristaltic contractions/spasms
Loin to groin pain

41

What symptoms often accompany renal colic?

Nausea/vomiting
Pallor
Sweating
Restlessness
(Haematuria)

42

What investigations would you do for renal stones?

Mid stream urine: blood, culture etc
Serum: urea, creatinine, electrolytes, calcium
Plain abdominal x-ray (can see 60% of stones)
CT of kidneys, ureter and bladder

43

Stones under which diameter are usually passed?

< 5mm

44

What are some severe complications of renal stones?

Acute pyelonephritis
Pressure necrosis of renal parenchyma
Urinary obstruction
Hydronephrosis
Ulceration

45

Describe the treatment of urinary stones

Analgesia, warmth to site and bed rest
Ureteroscopy
Percutaneous nephrolithotomy
ESWL (extracorporeal shock wave lithotripsy)