Lecture 12: Imaging the Kidney Flashcards Preview

Phase 2: Reproduction, Nephrology and Urology > Lecture 12: Imaging the Kidney > Flashcards

Flashcards in Lecture 12: Imaging the Kidney Deck (42)
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1
Q

What is the gold standard imaging technique for kidney imaging

A

Ultrasound

2
Q

Can kidney stones be seen on a X-ray?

A

No

3
Q

What information can the ultrasound give regarding the kidney

A

•Can be used to gain information on:

–Kidney size

–Shape

–Location and number

–Structure

–Drainage / obstruction

–Renal blood flow

4
Q

What is the normal length of the kidney in ultrasound?

A

>10cm is normal

<9cm is abnormal and indicative of chronic disease

5
Q

Which is more echobright:

A) Liver

B) Kidney

A

A) Liver- appears a lot brighter in the ultrasound

Normal – Liver is more ‘echobright’ than kidney

Abnormal – Kidney more ‘echobright’ than liver – implies pathological change

6
Q

Why is CT with contrast is not recommended for imaging the kidneys?

A

–Potentailly nephrotoxic

~ weigh up risk v benefit with eGFR <30mL/min

Remember the kidneys needs to be able to excrete the contrast- toxic if patient has a low kidney function

7
Q

Which imaging technique will not show kidney stones?

A

X-ray

8
Q

What is the positives of using an MRI to image the kidney

A

•May be used in the assessment of:

–Renal structure (cysts / tumours)

–Renal vasculature (MRA)

9
Q

What are the possible problems of using MRI in imaging the kidney?

A

Can cause nephrogenic systemic fibrosis in patients with a low kidney function

NSF: disease of fibrosis of the skin and internal organs reminiscent but distinct from scleroderma or scleromyxedema. It is caused by gadolinium (Gd) exposure used in imaging in patients who have renal insufficiency.

10
Q

What are the positives of using a isotope scanning in imaging the kidneys?

A

•Gives information on:

–Structure

–Perfusion

–Excretion

–Differential Renal Function

11
Q

Plain CT should be used to image?

A

Kidney stones

12
Q

Plain MRI should be used to image?

A

Tumours

13
Q

Most renal stones are composed of

A

calcium oxalate and phosphate

14
Q

Define renal stone

A
  • A solid concretion of crystal aggregate formed within the urinary space.
  • Also known as •nephrolithiasis
  • Formed from the combination of excreted/secreted ions within the glomerular filtrate.
15
Q

Nephrolithiasis refers to

A

refers to the presence of crystalline stones within the kidneys

16
Q

Urolithiasis refers to

A

refers to the presence of stones originating anywhere in the ureter

17
Q

Cystolithiasis refers to

A

refers to the presence of crystalline stones within the bladder

18
Q

What are the types of kidney stones in regards to location

A
  • Nephrolithiasis - in the kidneys
  • Ureterolithiasis - in the ureters
  • Cystolithiasis - in the bladder
19
Q

What are the types of kidney stones in regards to their composition

A
20
Q

Struvite stones are more common in which gender

A
  • Mixed stones (struvite), accounting for about 15% of all calculi, are twice as common in women.
21
Q

Calcium oxalate and phosphate stones are more common in which gender

A

These types of stones are more common in men

22
Q

Describe the genetic risk factors for renal stones

A
  • Gender: calcium phosphate stones are more common in males. Mixed stones are more common in females
  • Family history
    *
23
Q

Describe the environmental risk factors for renal stones

A
  • BMI - greater than 27
  • Diet - high vegetarian diet, high fibre
  • Lifestyle - immobile or sedentary
  • Dehydration
  • Urinary tract infection
24
Q

80% of renal stones contain?

A

Calcium

25
Q

What are the two types of calcium containing renal stones

A

–Calcium Oxalate

–Calcium Phosphate

26
Q

Name the 6 types of renal stones

A

•Calcium containing (80%)

–Calcium Oxalate (40%)

–Calcium Phosphate (40%)

  • Struvite i.e. mixed stone (5-10%)
  • Uric Acid (5-10%)
  • Cystine (1-2%)
27
Q

Struvite (mixed stones) are composed of?

A
  • Magnesium
  • Ammonium
  • Phosphate
28
Q

Describe the specificity and sensitvity of:

A) X-ray

B) CT

C) Ultrasound

A
  • CT- most sensitive and specificity =95% sensitivity + 97% specificity
  • Ultrasound- 84% sensitivity + 53% specificity
  • X-ray- least sensitive and specificity= 60% sensitivity +75% specificity
29
Q

Which renal stones can be seen on X-rays?

A

Calcium containing: will be very bright (similar to bone as bone contains calcium too)

Struvite stones

30
Q

Define Medullary Sponge Kidney

A

A congenital disorder of the kidneys characterized by cystic dilatation of the collecting tubules, predisposing to stone formation

31
Q

Which conditions are associated with calcium renal stones

A
  • Primary Hyperparathyroidism
  • Hypercalcaemia (high calcium levels in the urine)
  • Idiopathic Hypercalciuria
32
Q

Which conditions are associated with High Oxalate / Urate / Cysteine renal stones

A
  • Primary/Secondary Hyperoxaluria (excessive urinary excretion of oxalate)
  • Hyperuricaemia (excess serum uric acid)
  • Cystinuria (high protein cysteine, in the urine)
33
Q

What conditions are associated increase the risk of calcium containing stones

A

Hypocitraturia (low levels of citrate in the urine). Marked in chronic metabolic acidosis – citrate is inhibitor of Calcium oxalate and calcium phosphate stone formatio

Renal Tubular Acidosis - alkaline urine – increased calcium phosphate stones -also may cause hypercalciuria and hypocitraturia

34
Q

____ and ____ stones precipitate pH >7.0

A

A) Calcium

B) Struvite

35
Q

_____ and _____ stones precipitate pH <6.0

A

A) Uric acid

B) Cystine

36
Q

Which renal stone is this?

A

Calcium oxalate crystals

37
Q

Which renal stones is this?

A

Uric acid crystals

38
Q

Which renal stones is this?

A

Struvite crystals

39
Q

Which renal stones is this?

A

Cysteine crystals

40
Q

Which renal stones is this?

A

Calcium phosphate

41
Q

What are the treatment options for nephrolithiasis

A

Stones in the kidney

< 2cm stone: May pass itself or lithotripsy

> 2cm or multiple stones: lithotripsy or nephrolithotomy

42
Q

How are recurrent cases of renal stones managed

A

–Increase fluid intake to >2.0L/day

–Treat the cause

–If struggling then consider citrate