CKD

Question 1

What are the differences between acute CKD?

Answer 1

Long lasting (>3 months)
Less severe
Can progress to severe disease

Question 2

What are the functions of the kidney?

Answer 2

Remove waste products
Regulate ions in blood (K+, Ca2+, Na+)
Regulate water levels
Hormone production (EPO, vit D activation)

Question 3

What is the functional unit of the kidney?

Answer 3

Nephron - 10^6 - Glomerulus, PCT, LoH, DCT, Collecting duct

Question 4

What are the layers of the membrane between the glomerulus capillaries and bowmen capsule?

Answer 4

Fenestrated endothelium cells
Basesment membrane
Filtration slits in epithelial cells
Podocytes

Question 5

What controls the rate of filtration in the glomerulus?

Answer 5

Afferent and Efferent BP
Increase Efferent BP (vasoconstriction) causes build of up of pressure in the glomerular capillaries and increases the rate of ultrafiltration

Question 6

What can cause vasoconstriction in the efferent arteriole?

Answer 6

H20
Salt concentration
Prostaglandins
Angiotensin

Question 7

What are the components of the membrane that create the negative charge?

Answer 7

Fenestrated endothelium - Podocalyxin
Basesment - Heparin sulphate prostoglycans
Podocytes - Podocalyxin

Question 8

What is the rough limit of size of molecules to pass through the glomerulus?

Answer 8

50-60,000 mW

Question 9

What are some examples of molecules filtered?

Answer 9

H20
K+
Urea
Inulin
Creatinine

Question 10

What is not filtered?

Answer 10

Serum albumin

RBC

Question 11

What is the measurement for measuring kidney function?

Answer 11

GFR = ml/min/1.73m2

Question 12

How can we measure GFR?

Answer 12

Exogenous solutes - Inulin and Chromum51EDTA (Expensive, slow, exposure to radiation)

Endogenous solute - Creatinine

Question 13

What is creatinine?

Answer 13

Produced in the liver, converted from creatine
Muscle stores around 100g creatine (as creatine phosphate - high energy phosphate donor)
Rate of conversion depends on liver function, muscle mass and muscle catabolism
Freely filtered at the glomerulus

Question 14

What is the problem with measuring creatine clearance?

Answer 14

Requires measurement of urine over a 24 hour period – impractical

Question 15

What is the problem with using plasma creatine as a surrogate measure for GFR?

Answer 15

Poor at extreme measures
Doesnt take into account muscle mass
Creatine is secreted by the tubules so is not a direct measure of GFR
Affected by exercise and protein intake

Question 16

What are the validated formulas used to measure GFR?

Answer 16

Cockcroft-Gault - Gender, Age, Weight
MDRD (eGFR) - gender, age, ethnicity
CKD-EPI (Creatinine and CystatinC measurements)

Question 17

What other measurements can we use to determine kidney health?

Answer 17

Proteinuria (albumin/creatinine ratio)
Heamaturia
Albumuria (24 hour urine measurement)

Question 18

What defines CKD stages?

Answer 18

NKF-KDOQI (Kidney disease outcomes quality initiative)

Question 19

What are the stages of CKD?

Answer 19

Stage 1 - Haematuria, Proteinuria, normal GFR (>90)
Stage 2 - Haematuria, Proteinuria, slightly reduced GFR (60-89)
Stage 3a - reduced GFR (45-59), Stage 3b (31-44)
Stage 4 - vastly reduced GFR (16-30)
Stage 5 - kidney failure (>15ml/min/1.73m2)

Question 20

What are the stages of albuminuria?

Answer 20

A1 - <30
A2 - 31-299
A3 - >300

Question 21

What are the advantages of the introduction of the NKF-KDOQI?

Answer 21

Standaradise CKD diagnosis around the world - increased comparisons between epidemiology studies
Increase awareness
Increase need for early diagnosis

Question 22

What are the downside of the NKF-KDOQI?

Answer 22

Formula to calculate GFR not completely accurate - vary greatly with age, gender, ethnicity, pregnancy, extreme weights, diabetics
MDRD (eGFR) 30% of patients will get a result out by >30% - overestimation of CKD

Question 23

What are the prevalence stats for CKD in the UK?

Answer 23

10.6% women
5.8% men
around 3 mill have CKD
60,000 have Stage 5 and require treatment - 19 per day
RRT - Dialysis - 500 mil, Transplant - 225 mil (2010)

Question 24

What are the consequences of CKD?

Answer 24

Hyperkalaemia - High K - Arrthymia
Acidosis - Azotemia (urea) - weight loss, fatigue, nausea, asterixis
Hypocalcaemia - reduced activation of VitD - reduced calcium in blood - secondary hyperparathyroidism - calcium from bones - pain
Hyperphosphataemia - increased PO4 - leads to hypocalcaemia
Renal Anaemia - reduced EPO - fatigue, weight loss
Fluid retention - oedema
Hypertension - increased renin - increased BP