Renal

Question 1

3 equations for eGFR

Answer 1

1. Cockcroft-Gault equation (tend to overestimate patients)
2. MDRD equation (tend to underestimate normal subjects)
3. CKD-EPI (recommended)

Question 1

Reference interval of GFR

Answer 1

90~120 ml/min/1.73m^2

Question 2

Cockcroft-Gault equation

Answer 2

(140 - age) ⨉ weight / (P_Cr ⨉ 72) , times 0.85 for female

Question 3

Parameters in CKD-EPI

Answer 3

Cr, age, gender, race

Question 4

Reference interval of creatinine

Answer 4

70~150 µmol/L

Question 5

creatinine clearance equation

Answer 5

Clearance ⨉ P_Cr = U_Cr ⨉ V_U
(ml/min)

Question 6

Limitation of creatinine

Answer 6

FP: drugs
FN: lower muscle mass

Question 7

FP & FN of urea (4+4)

Answer 7

FP: high protein diet, catabolic state, GI bleed, dehydration
FN: low protein diet, fasting, liver disease, over-hydration

Question 8

Urea:Creatinine ratio range indicating pre-renal failure

Answer 8

> 80:1

Question 9

Oliguric definition

Answer 9

urine output <400 ml/day
OR <0.5 ml/kg/hr

Question 10

Anuric definition

Answer 10

urine output <50 ml/day

Question 11

Acute kidney injury definition in KDIGO definition

Answer 11

(any one of the following)
a. Urine output <0.5 ml/kg/h for 6h
b. Serum Cr ↑ 1.5x baseline in 7d
c. Serum Cr ↑ >26.5 µmol/L in 48h

Question 12

Clinical staging of acute kidney injury

Answer 12

Stage 1: serum Cr ↑ 1.5~2x, oliguric for 6h
Stage 2: serum Cr ↑ 2~3x, oliguric for 12h
Stage 3: serum Cr ↑ >3x, anuric for 12h

Question 13

Causes of pre-renal failure

Answer 13

↓ ECV: dehydration, GI bleed, third spacing…
↓ cardiac output: CHF, MI…
Shock
Renal vascular disease: RAS, MAHA
Drugs: NSAID, ACEI

Question 14

Which region is most vulnerable in acute tubular necrosis?

Answer 14

proximal convoluted tubule

Question 15

Causes of acute tubular necrosis

Answer 15

ischaemia / toxins

Question 16

Nephrotoxins that cause acute tubular necrosis (8)

Answer 16

Iatrogenic: aminoglycosides, amphotericin B, cisplatin, contrast
Metabolic: haemoglobin, myoglobin, urate
heavy metal

Question 17

Natural history of acute tubular necrosis

Answer 17

oliguric phase –> anuric phase –> recovery phase, each lasts for one week

Question 18

How to differentiate pre-renal injury and acute tubular necrosis with urine electrolyte?

Answer 18

FENa: (<1%; >2%)
Urine Na: (<20; >40)
Urine:plasma Cr ratio: (>40; <20)
Urine osmolality: (>500; <350)
Plasma UCR: (>80;<80)

Question 19

Equation for fraction of Na excretion

Answer 19

(U_Na/P_Na) ➗ (U_Cr/P_Cr) ⨉ 100%

Question 20

Definition of chronic kidney disease

Answer 20

progressive irreversible impairment of renal function >3m, as evidenced by
a. eGFR <60 ml/min/1.73m^2
b. albuminuria
i. albumin excretion rate >30 mg/day, or
ii. urine albumin: creatinine ratio >3 mg/mmol

Question 21

Aetiology of chronic kidney disease (4)

Answer 21

1. DM nephropathy (30%)
2. Hypertension (25%)
3. Glomerulonephritis (15%)
4. Polycystic kidney disease (5%)
   …

Question 22

What is secreted in adaptation in chronic kidney disease to ↑ phosphate secretion?

Answer 22

FGF23 (fibroblast growth factor 23)

Question 23

Pathogenesis for impaired concentrating ability in chronic kidney disease (3)

Answer 23

1. ↓ medullary hypertonicity
2. medullary fibrosis
3. collecting duct resistance to ADH

Question 24

Renal osteodystrophy (3)

Answer 24

Osteomalacia Osteitis fibrosa cystica Osteosclerosis

Question 25

Renal replacement therapy indications

Answer 25

- eGFR <5 ml/min; or <10ml/min with ESRF s/s - uraemic encephalopathy --- - declining nutritional status - persistent volume overload - refractory acidosis / hyperkalaemia / hyperphosphataemia

Question 26

Advantages of haemodialysis compared with peritoneal dialysis

Answer 26

- more efficient in small molecules - much shorter period of dialysis - lower dextrose & osmolality required

Question 27

Proteinuria definition

Answer 27

>0.15 g/day (Nephrotic range: >3.5g/day)

Question 28

Microalbuminruia deinition

Answer 28

30~300mg /day or ACR 3~30mg/mmol

Question 29

Macroalbuminuria definition

Answer 29

>300 mg/day

Question 30

Pathological proteinuria exclusion criteria (4)

Answer 30

UTI, fever, heavy exercise in 24h, menstruation

Question 31

Aetiology of proteinuria

Answer 31

1. Orthostatic proteinuria 2. Transient proteinuria 3. Overflow proteinuria 4. Glomerular proteinuria 5. Tubular proteinuria

Question 32

Size of protein that are not filtered through glomerular ultrafiltration

Answer 32

>40kDa

Question 33

MC isolated proteinuria in teenagers

Answer 33

Orthostatic proteinuria

Question 34

MC proteinuria cause

Answer 34

Glomerular proteinuria

Question 35

Limitations of urine dipstick for detecting proteinuria

Answer 35

1. only detect >300mg protein 2. only detect albumin (do two times)

Question 36

Compare severity of acidaemia of 3 types of RTA

Answer 36

type 1 > type 2 > type 4

Question 37

Which type of RTA gives hypercalciuria, nephrolithiasis, and osteomalacia? What is the pathogenesis?

Answer 37

type 1 Severe acidaemia —> buffering of H+ from bones

Question 38

Which type of RTA gives hypoK and hyperK?

Answer 38

hypoK: type 1, 2 hyperK: type 4

Question 39

Which type of RTA gives -ve UAG?

Answer 39

type 2

Question 40

Pathogenesis of type 1 RTA (relation to K)

Answer 40

impaired distal tubule to secrete H+ ⨉ secrete H+ --> K+ is secreted in compensation

Question 41

Management of type 1 RTA

Answer 41

Oral NaHCO3

Question 42

Pathogenesis of type 2 RTA (relation to K)

Answer 42

↓ proximal HCO3- reabsorption ↑ HCO3 loss --> ↑ Na loss --> ↑ aldosterone & distal flow --> ↑ K secretion

Question 43

Which RTA is associated to Fanconi syndrome?

Answer 43

type 2

Question 44

Diagnosis of type 2 RTA

Answer 44

HCO3- loading test FE of >15% HCO3

Question 45

Management of type 2 RTA

Answer 45

IV NaHCO3 + K supplements

Question 46

Pathogenesis of type 4 RTA

Answer 46

mieralocorticoid deficiency / resistance

Question 47

Which 2 ions have serum concentrations normal until GFR <50% of normal in CKD patient?

Answer 47

H, phosphate

Question 48

Effect of CKD on Ca metabolism

Answer 48

↓ phosphate excretion --> ↑ phosphate concentration --> hypocalcaemia --> secondary hyperPTH --> tertiary hyperPTH ↓ 1α-hydroxylation --> vitamin D resistance