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Stage 2: Inflammation > Chronic Kidney Disease > Flashcards

Flashcards in Chronic Kidney Disease Deck (54)
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1
Q

How many stages of CKD are there?

A

5

2
Q

What is pre-renal disease due to?

A

Problems with arterial supply and venous drainage

3
Q

What is intrinsic renal disease due to?

A

Problems within the renal interstitium/tubules

4
Q

What is post-renal disease due to?

A

Problems with the outflow tract of the the kidney (single drainage pathway)

5
Q

Why is the kidney susceptible to pre-renal insults?

A

Bc it has a single blood supply and drainage

6
Q

Describe renal artery stenosis

A
  • Problem if also have heart failure (common)
  • Renal artery on one side is narrower than the other one so the kidney on that side is smaller
  • Not always worth fixing bc can mostly survive with one kidney
  • But need to treat high BP
7
Q

What are causes of pre-renal kidney disease?

A

1) Pre-renal insults e.g. hypovolaemia, heart failure, vasodilation (sepsis/shock), arterial dissection
2) Renal artery stenosis e.g. atherosclerosis, fibromuscular dysplasia
3) Slinging and hyperviscosity
4) Large vessel vasculitis - giant cell/Takayasu’s arteritis
5) Venous thrombosis

8
Q

Why can’t you keep drinking in dehydration in sepsis/kidney failure?

A

It will lead to pulmonary oedema

9
Q

What are signs of mild to moderate dehydration?

A
  • Thirst
  • Dry mouth
  • Fatigue
  • Headache
10
Q

What are signs of severe dehydration?

A
  • Rapid breathing
  • High HR
  • Severe dizziness or lightheadedness
  • Unconsciousness or delirium
11
Q

How do BP and BP drugs affect the kidney?

A
  • The kidney is dependent one regulated BP to maintain health of the ‘sieve’ and GFR
  • It can be overwhelmed by sudden hypertension
  • Susceptible to injury from drugs that affect afferent and efferent BP e.g. ACEi, NSAIDs
  • ACE/ARB inhibition can be harmful acutely, but beneficial long term
12
Q

What is the effect of NSAIDs on the kidney?

A

1) Vasoconstriction of the afferent arteriole

2) Decreased GFR

13
Q

What is the effect of prostaglandins on the kidney?

A

1) Vasodilation of the afferent arteriole

2) Increased GFR

14
Q

What is the effect of ACE inhibitors/angiotensin receptor blockers on the kidney?

A

1) Vasodilation of the efferent arteriole

2) Decreased GFR

15
Q

What is the effect of angiotensin II on the kidney?

A

1) Vasoconstriction of the efferent arteriole

2) Increased GFR

16
Q

How can the glomeruli be injured?

A
  • They have a requirement for an intricate network of defined pore size and high SA
  • Can be injured by slugging and embedding of immune complexes
  • e.g. in SLE, cryoglobulinaemia, other immune complex GNs, microorganisms
17
Q

Describe the features of glomerular pathology

A

1) Limited capacity for healing, tends to scar easily, different histological patterns
2) Severe injury leads to rupture and thrombosis in the Bowman’s capsule i.e. crescent formation
3) Glomerular injury from systemic diseases is difficult to recover from
4) Often the aim is to preserve the less damaged glomeruli

18
Q

What are the clinical features of glomerular pathology?

A

1) Loss of function (usually consistent with AKI)
2) Heavy proteinuria
- If insidious, then proteinuria may be the only feature

19
Q

Describe what the glomerulus would look like in crescentic glomerulonephritis

A
  • Lots of proliferation of cells (inflammation)
  • Pushes glomerulus to one side, eventually reducing it completely
  • Usually scars
20
Q

What will tubular disease lead to?

A
  • Problems with electrolytes

- Or if they are not working, can’t get urine out at all, leading to AKI

21
Q

What are the characteristics of the kidney tubules?

A

1) Narrow convoluted tubular system with significant changes in osmolality and pH therefore susceptible to precipitation of solutes and luminal obstruction
2) Highly metabolically active with a dependence on oxygen supply therefore susceptible to acute tubular necrosis e.g. due to sepsis/dehydration

22
Q

What are the causes of tubular pathology?

A

1) Light chain disease light chain immunoglobulins, uric acid, myoglobin (rhabdomyolysis) sits in the tubules, causing inflammation, causing creatinine to shoot up bc of muscle breakdown and tubule disease
2) Hypoperfusion (pre-renal)
3) Tubular toxins e.g. aminoglycosides, cisplatin, ethylene glycol, IV contrast

23
Q

What are the features of tubular pathology?

A

1) Most commonly acute tubular necrosis (or acute tubular injury)
2) When it recovers, it starts to go into overdrive and produces so much urine which needs to be compensated for
3) More robust than glomeruli
4) Better capacity for recovery

24
Q

What are the clinical features of tubular pathology?

A

1) Loss of tubular function e.g. failure to absorb filtered solute esp. sodium with an AKI
2) Oligouria/anuria
3) Recovery usually accompanied by polyuria and saluria

25
Q

Describe the interstitial tissue in the kidney

A
  • Large volume fo interstitial tissue with intricate blood supply
  • Susceptible to inflammatory infiltration i.e. tubulo-interstitial nephritis
26
Q

What are causes of (tubulo-) interstitial nephritis?

A

1) Drugs - allergic like reaction e.g. due to penicillin, NSAIDs, herbal medicine
2) Infections e.g. pyelonephritis, CMV, HIV, fungal/parasitic
3) Autoimmune e.g. SLE, Sjogren, Sarcoid
4) Alloimmune = transplant rejection
5) Idiopathic

27
Q

Describe the features of acute interstitial nephritis

A

1) 10-15% of all cases of AKI
2) Important to establish the cause - often drug related
3) Inflammation and infiltration of immune cells into the interstitium
4) Steroids can aid recovery in some cases

28
Q

Describe the features of chronic interstitial nephritis

A

1) Insidious in onset
2) Less inflammation, more scarring
3) Important to establish cause but frequently idiopathic
4) Steroids unhelpful
5) Less capacity for recovery

29
Q

What are causes of obstruction to the outflow tract from the kidney causing post-renal disease?

A

1) Ureteric e.g. stones, retroperitoneal fibrosis (stops peristalsis of ureters), gynae malignancy
2) Bladder outflow e.g. stones, bladder cancer, prostatic (BPH/cancer)
3) Urethra e.g. stones, urethral stricture

30
Q

What imaging should you get for an AKI?

A

Ultrasound

31
Q

What might you see on an US of someone with a post-renal problem/blockage?

A

Hydronephrosis - back pressure of fluid causing dilation of pyramids

32
Q

At what age does GFR start declining normally and what does this mean?

A
  • 40
  • Lose one GFR point per year on average
  • Therefore have CKD by the age of 80 just normally
33
Q

What can cause severe AKI without recovery?

A

Severe sepsis (can end up of RRT, GFR can go to 0 v quickly or can get better and back to normal decline)

34
Q

What can uncontrolled hypertension in CKD lead to?

A
  • End stage renal failure (ESRF)
  • Causes a sudden much steeper decline in GFR
  • Goes unnoticed until ESRF
  • Due to gene and environment
35
Q

What is a common progression in CKD?

A

1) Normal decline in GFR at 1 mL/min/year
2) Severe sepsis
3) Rapid decline in renal function at 5mL/min/year
4) Renal referral decline at 2mL/min/year
5) Starts haemodialysis
6) Death

36
Q

What do you need to do to keep your GFR decline line as horizontal as possible?

A
  • Stop smoking
  • Look after co-morbidites
  • Take medication
  • Educate yourself
37
Q

What are the determinants of renal outcome?

A

1) Disease process itself
2) Site(s) of renal injury
3) Severity of renal injury
4) Amount of renal reserve
5) How long the pathology lasts/lag time to treatment
6) Developing hypertension
7) Whether the patient survives the underlying pathology

38
Q

What is necessary to interpret renal failure?

A
  • (A series of) previous creatinine/GFR

- Good history

39
Q

What is a typically presentation of someone with CKD?

A

1) Low GFR
2) Proteinuria
3) Pain
4) High BP

40
Q

Describe measurement of GFR (approx % kidney function)

A
  • Insulin clearance
  • Isotopic EDTA-GFR - injected with substance, get blood test after, line is measured, want to know exact kidney function e.g. for kidney donor
  • Creatinine
  • Creatinine clearance - (UCr x V)/PCr, 24h urine collections, overestimates GFR by 10-40%
  • GFR estimating equations
41
Q

Is urea or creatinine a better measure of GFR and why?

A

Creatinine

- More stable, urea is more variable depending on what you eat

42
Q

Which GFR measuring equation is better for ‘little old ladies’?

A

MDRD GFR (when < 60 ml/min)

43
Q

What is the other GFR equation better used in young fit men and not little old ladies?

A

C-G GFR

44
Q

What is stage 1 CKD?

A

Normal GFR > 90 with other evidence of chronic kidney damage

45
Q

What is stage 2 CKD?

A
  • Mild impairment

- GFR 60-89 with other evidence of chronic kidney damage

46
Q

What is stage 3 CKD?

A
  • Moderate impairment

- GFR 30-59

47
Q

What is stage 4 CKD?

A
  • Severe impairment
  • GFR 15-29
  • Damage to kidneys is generally beyond repair and should be preparing for RRT
48
Q

What is stage 5 CKD?

A
  • Established renal failure (ERF)
  • GFR < 15 or on dialysis
  • Need to start dialysis based on indications
49
Q

What are ‘other evidence of chronic kidney damage’?

A

1) Persistent microalbuminuria
2) Persistent proteinuria
3) Persistent haematuria (after exclusion of other causes e.g. urological disease)
4) Structural abnormalities of the kidneys e.g. polycystic kidney disease
5) Biopsy-proven chronic glomerulonephritis

50
Q

Describe features of a renal biopsy

A
  • Day case
  • Usually left kidney bc lower and right handed
  • Main complication is bleeding
  • Samples for light, immuno, histochemistry, EM
51
Q

What are indications for a renal biopsy?

A

1) Progressive or unexplained renal impairment regardless of urine sediment e.g. blood and protein in urine and kidney impairment
2) Nephrotic and diffuse nephritic syndrome
3) Significant proteinuria with normal BP (no diabetes)

52
Q

What are contraindications for a renal biopsy?

A

1) No likely change in management e.g. if they are v ill and won’t give immunosuppression even if find evidence of autoimmune case
2) Severe co-morbidity
3) Small kidneys - v scarred, difficult to do
4) Uncontrolled BP or coagulopathy

53
Q

What are the two most common causes of CKD in the UK?

A

1) Diabetes

2) Glomerulonephritides

54
Q

What is eGFR?

A
  • A value calculated from serum creatinine

- Is like a % of kidney function bc normal GFR is ~ 100