AKI / RRT/ Acid base

Question 1

Features of AIN

Answer 1

The eosinophilia and active urinary sediment (red cells and white cells) with minimal proteinuria
clinical features include a rash and fever. The triad of a rash, fever and eosinophilia is seen in about 10% of cases.
commonly drug-induced, though it can also be caused by autoimmune disease (Sjögren’s, SLE and others) and infections (Legionella, CMV and others)
Can cause polyuria and low BP

Question 2

How to determine pre renal AKI from ATN

Answer 2

AKI - High urine osmolarity, low urine Na

ATN - low urine osmolarity, high urine Na (>60), urine plasma osmolarity <1.1

Fractional excretion (Fe) of Na and Mg = <2% if kidneys working normally. >2% if there are renal losses / urinary / salt wasting wasting

Question 3

Blood tests associated with Rhabdomyolysis

Answer 3

Low Ca
Raised K+, phosphate, LDH, CK
Deranged LFTs - raised ALT
AKI

Question 4

Kt/v and URR aim in dialysis

Answer 4

Aim for >1.7
Anything <1.2 is failing

Aim URR>70%

Question 5

Features of PD high and low transporter

Answer 5

D/P ratio - dialysate/ plasma ratio -

High transporter - <0.8 D/P ratio, APD preferred, achieve poor UF - Increase number exchanges to improve clearance
Low transporter <0.5 D/P ratio, CAPD preferred, get good UF - Increase dwell volumes to improve clearance

Question 6

Ultrafiltration failure on PD

Answer 6

Standard test = Rule of 4’s = If after 4 hour dwell, less than 400ml UF with 4% bag = UF failure

PET Test = If after 4hr dwell with 2.27% bag , <100ml UF = UF failure

Question 7

Concentrations of PD bags

Answer 7

Weak = 1.36%, Orange
Medium = 2.27%, green
Strong 3.36%, red

Extraneal
Isodextrin - Not glucose based, good for high transporters, can maintain osmotic gradient to achieve UF

Question 8

How to manage intradialytic hypotension

Answer 8

Reduced temperature
Increase calcium concentration

Question 9

Difference between HD, CVVH, HDF

Answer 9

Hemodialysis - HD - diffusion across dialysate, fluids moving in opposite directions, poor large molecule clearance

Hemofiltration -CVVH - Clearance by convection, no dialysate needed, uses pressure and large volumes. Good for large molecule clearance

Hemodiafiltration - combines convection and diffusion, increased middle molecule clearance, need dialysate and large volumes of fluid. This is done most often in centers - best for patients with haemodynamic instability

Question 10

Dialysis water treatment thresholds

Answer 10

HDF - requires ultra pure water = bacteria count <0.1, endotoxin level <0.03
Standard dialysis = Bacteria count <100 and endotoxin level <0.25

Question 11

What to check before giving Rasburicase in TLS

Answer 11

Check G6PD test prior to giving as rasburicase as it can induce haemolysis and worsen renal failure.

Question 12

How to calculate anion gap and normal range

Answer 12

(Na + K) - (Cl +HCO3-)
Normal range 3-11

Question 13

Causes of raised Anion Gap acidosis

Answer 13

ketones / lactatic acidosis / metformin
Uremia
Salicylates / alcohol / isoniazid

Question 14

Causes of normal anion gap acidosis

Answer 14

Diarrhoea / GI losses
RTA
Carbonic anhydrase inhibitors - acetazolamide
Excessive saline
Addison’s

Question 15

Pathophysiology of HRS

Answer 15

Vasodilation of splanchnic circulation
Rise in cardiac output causing portal hypertension
Reduced systemic vascular resistance = activates RASS
Causes renal vasoconstriction = sodium and water retention - leads to ascites and hyponatremia

Question 16

Cuase of port wine changes on dialysis

Answer 16

If blood becomes dark ‘port wine’ colour - then suggests severe intravascular hemolysis

Question 17

Autosomal recessive versus dominant PKD

Answer 17

AR PKD - tends to present earlier and associated with congenital liver fibrosis
AD PKD - deteriorate later in life

Question 18

Acid base disturbance in short gut syndrome

Answer 18

Low bicarb
Increased anion gap metabolic acidosis
Raised D-Lactic acidosis

Question 19

TB effect on the urinary tract

Answer 19

Preferentially affects the renal medulla
Can cause progressive scarring, calcification and fibrosis
urethral strictures can cause hydronephrosis and obstruction
CT KUB = calyceal tip erosions, pelvic distortion and filling defects

Question 20

Normal anion gap range

Answer 20

4-12

Question 21

Renal prognosis for CKD patients in pregnancy

Answer 21

1/3 will become dialysis dependent if pre pregnancy renal function is CKD 4-5
If UPCR >1g daily then risk of needing dialysis is 50%