chronic kidney disease W2

Question 1

case: 56 yr old man.
tiredness and itchy skin
BP 180/110
high urea
high creatinine
high potassium
low bicarbonate
low haemoglobin
low calcium
high phosphate

explain these results

Answer 1

poor tubule function = low bicarbonate, high potassium, high creatinine

fluid retention = hypertension

Question 2

diagnostic definition of chronic kidney disease

Answer 2

GFR of <50ml/min for >90 days

Question 3

causes of CKD?

Answer 3

most common = diabetes, hypertension

rarer = glomerulonephritis, cystic kidney disease, renovascular disease

Question 4

how do we estimate kidney function?

Answer 4

serum creatinine
creatinine clearance
isotope GFRs
formulae (often used)

Question 5

what is a normal GFR?

Answer 5

125ml/min/1.73m^2

Question 6

what formulae do we currently use to estimate GFR

Answer 6

MDRD or CKD-EPI equation
(CKD-EPI Cystatin C equation rarely used but more accurate)

Question 7

stages of CKD?

Answer 7

creatinine clearance (~GFR)
stage 1 = normal = 120-90
stage 2 = early CRF = 90-60
stage 3 = moderate CRF = 60-30
stage 4 = pre-ESRD = 30-15
stage 5 = ESRD = 15-0

Question 8

CRF? ESRD?

Answer 8

chronic renal failure
end stage renal disease

Question 9

when are you put on a renal transplant list!

Answer 9

GFR<15 (stage 5/ESRD)

Question 10

how to prevent progression of CKD

Answer 10

control blood pressure (RAS inhibition - ACE inhibitors)
reduce proteinuria (RAS inhibition)
if diabetes, optimise glycaemic control
SGLT2 inhibitors

Question 11

when do you have to worry about stage 1/2 CKD? (GFR>60)

Answer 11

when albuminuria is severely increased (>300mg/g or >30mg/mmol)

Question 12

is proteinuria a marker or cause of progressive renal disease

Answer 12

both!!

Question 13

how does proteinuria cause chronic interstitial fibrosis

Answer 13

proteinuria taken up into tubular cells, processed by lysosomes into amino acids, taken into tubular capillaries. system gets overloaded in patients with large amounts of proteinuria. cell gets overloaded and dies. fibroblasts/macrophages try remove cell, causes scarring (interstitial fibrosis)

Question 14

how do ACE inhibitors decrease proteinuria

Answer 14

cause efferent arteriole vasodilation. drop pressure in glomerulus therefore decrease amount of protein passing through.

Question 15

toxic drugs to the kidney?

Answer 15

NSAIDs/contrast/gentamicin
phosphate enemas

Question 16

drug dosing and CKD?

Answer 16

lower doses of blood pressure tablets, antimicrobials etc
especially chemotherapy agents
if in doubt check BNF!!

Question 17

hypertension and CKD?

Answer 17

cause and consequence of CKD

Question 18

BP treatment goals for CKD?

Answer 18

normal - 130/80
DM/proteinuria - 125/75

Question 19

treatment of hypertension in CKD?

Answer 19

low salt diet
lifestyle modifications (exercise/alcohol/smoking)
BP meds eg ACEi

Question 20

high potassium in CKD - when does this occur and how is it managed?

Answer 20

common once GFR<25
give dietary advice
give potassium binders (sodium zirconium) but expensive - only use short term

Question 21

what is much acidosis in CRF due to? why?

Answer 21

animal protein in food
because inability to acidify urine in CKD
phosphate/sulphates/other anions

Question 22

how to treat acidosis in CKD?

Answer 22

replace with NaHCO3 (sodium bicarbonate)
but beware fluid overload
aim to keep serum bicarbonate >22

Question 23

anaemia in CKD definition?

Answer 23

Hb<12 in males
Hb<11 in females

Question 24

anaemia in CKD features

Answer 24

generally normochromic normocytic anaemia
decreased response of EPO to a hypoxic stimulus (kidneys) and decreased red cell survival in most patients

Question 25

who should be on EPO and what is the target Hb?

Answer 25

all patients with Hb<100 and adequate iron stores should be on EPO target Hb = 100-120

Question 26

benefits of EPO therapy?

Answer 26

better quality of life less dyspnoea reduced left ventricular hypertrophy

Question 27

what to do if patient has poor response to EPO

Answer 27

check: iron stores inflammation B12 + folate PTH aluminium malnutrition malignancy

Question 28

why do CKD patients get renal osteodystrophy

Answer 28

kidneys activation of vitamin D reduced, vit D reduced, reduced calcium absorbed from gut, develop osteomalacia. in response to low Ca, PTH increases, causes osteitis fibrosa. PTH increases Ca and PO4 reabsorption from bone.

Question 29

another name for osteitis fibrosa?

Answer 29

parathyroid bone disease

Question 30

renal osteodystrophy treatment?

Answer 30

vegan diet (restrict phosphate) phosphate binders vit D therapy (alfacalcidol)

Question 31

what are the consequences of hyperphosphataemia

Answer 31

vessel calcification calciphylaxis

Question 32

cardiovascular disease in ESRD - increased risk factors?

Answer 32

diabetes hypertension L vent hypertrophy dyslipidaemia malnutrition

Question 32

what type of vessel calcification occurs in hyperphosphataemia? (explain)

Answer 32

medial calcification - calcification within the medial layer of vessel walls (makes vessels more visible in scans)

Question 33

cardiovascular disease in ESRD - unique risk factors?

Answer 33

anaemia hyperPTH uraemia hyperPO4

Question 34

malnutrition in CKD - why!

Answer 34

nauseous if eat meat/dairy, protein levels decrease decreased appetite

Question 35

features of malnourished CKD patients

Answer 35

low albumin relating to inflammation/infection malnourished patients do worse on dialysis

Question 36

who should you refer to the renal clinic?

Answer 36

anyone with rapid increase in creatinine/hypertension stage 3 CKD with hypertension/proteinuria/haematuria/rising creatinine any stage 4/5 CKD suitable for treatment

Question 37

options for dialysis?

Answer 37

haemodialysis - hospital 3 times a week, blood cleaned in machine for 4 hours. peritoneal dialysis - uses space between guts and abdominal wall, fill with fluid for 4-6 hours, drained out and repeated. waste products drift into fluid. transplantation - young, fit. history of malignancy is contraindication.

Question 38

when do you start dialysis?

Answer 38

creatinine clearance 9-14