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Flashcards in Kidney Stones Deck (45)
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1
Q

What is urolithiasis?

A

Formation of stones in the urinary tract

2
Q

What is the commonest site of renal stone formation?

A

Renal pelvis

3
Q

What percentage of kidney stones occur as unilateral?

A

80%

4
Q

How can bladder stones form?

A

Can descend from the kidneys

Can form in the bladder

5
Q

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

A
Low protein diet 
Chronic diarrhoea 
Dehydration 
Increase oxalate consumption 
Vitamin A, B1, B6 deficiencies 
Magnesium deficiency
6
Q

What is a lithotomy?

A

Surgical removal of a calculus

From bladder, kidney or urinary tract

7
Q

What are the complications of kidney stones?

A
Haemorrhage 
Infection 
Fistulae
Incontinence
Erectile dysfunction
8
Q

Is it easier for men or women to pass stones?

A

Women

Have a shorter urethra

9
Q

Name some causes of bladder stones

A

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

10
Q

What are 2 other names of a kidney stone?

A

Renal calculus

Nephrolith

11
Q

Are stones more common in men or women?

A

Men (2:1)

12
Q

Which kidney stones are the only type commoner in women?

A

Struvite stones

13
Q

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

A

99%

14
Q

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

A

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

15
Q

Name some kidney stones that are not calcium based

A

Cysteine stones
Drug stones
Ammonium and urate stones
Urine stones

16
Q

When do urine stones form?

A

When there is a supersaturation of the urine with minerals

Minerals start to crystallise out of solution

17
Q

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

A

Hypercalcaemia -> hypercalciuria
Hyperoxaluria
Hyperuricaemia -> hyperuricosuria
Cysteinuria

18
Q

Acidic urine favours the formation of which stones?

A

Calcium oxalate

Uric acid

19
Q

Alkaline urine favours the formation of which stones?

A

Calcium phosphate

20
Q

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

A

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
Q

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

A

Hypercalcuria

Without hypercalcaemia

22
Q

Name the 3 substances that control calcium levels

A

PTH
Calcitriol (activated vit D)
Calcitonin

23
Q

In which organs are the most calcium sensing receptors located?

A

Parathyroid glands
Kidney
Brain

24
Q

Describe the effects of PTH

A
Increased osteoclastic resorption of bone
Increased intestinal absorption
Increased synthesis of calcitriol 
Increased tubular reabsorption 
Increased excretion of phosphate
25
Q

Describe the effects of calcitriol

A

Increased calcium absorption in gut

Increased calcification and resorption of bone - keeps bone turning over

26
Q

Describe the effects of calcitonin

A

Inhibits osteoclastic resorption of bone

Increased renal excretion of calcium and phosphate

27
Q

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

A

Hypercalcuria

28
Q

Name some causes of hypercalcuria

A

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

29
Q

Name some causes of hypercalcaemia

A

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

30
Q

Describe primary hypersecretion of PTH

A

Parathyroid hyperplasia

Tumour

31
Q

Name some reasons for destruction of bone tissue

A

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

32
Q

Give some clinical signs of hypercalcaemia

A

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

33
Q

Give some causes of hyperoxaluria

A

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

34
Q

Describe struvite stones

A

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

35
Q

Why are uric acid stones difficult to diagnose?

A

Radiolucent

Cannot see them on an xray

36
Q

Uric acid is the end point of which molecule metabolism?

A

Purine

37
Q

Give some causes of hyperuricaemia

A

Gout

Secondary consequence of increased cell turnover (malignancy, chemotherapy)

38
Q

Describe the presentation of kidney stones

A
Asymptomatic (most)
Renal colic
Dull ache in loins 
Recurrent UTIs
Haematuria 
Renal failure
UT obstruction
39
Q

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

A

Fluid is increased in kidneys

Increased pressure on stones

40
Q

What is renal colic?

A

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

41
Q

What symptoms often accompany renal colic?

A
Nausea/vomiting 
Pallor
Sweating
Restlessness
(Haematuria)
42
Q

What investigations would you do for renal stones?

A

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
Q

Stones under which diameter are usually passed?

A

< 5mm

44
Q

What are some severe complications of renal stones?

A
Acute pyelonephritis 
Pressure necrosis of renal parenchyma 
Urinary obstruction 
Hydronephrosis 
Ulceration
45
Q

Describe the treatment of urinary stones

A

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