Week 10

Question 1

What is AKI

Answer 1

Abrupt decline in renal function (GFR)

Question 2

Criteria for AKI

Answer 2

Serum creatinine increases by >1.5x baseline

Urine output <0.5ml/kg/hour for 6 hours

Question 3

Classification of AKI

Answer 3

Pre renal
Intrinsic
Post renal

Question 4

Broad causes of pre renal failure

Answer 4

Low effective circulating volume

Impaired renal auto regulation

Question 5

What can cause low ECV

Answer 5

Hypovolaemia - blood or fluid loss (D&V
Cardiac failure - LV dysfunction, cardiac tamponade, valve disease
Systemic vasodilation - sepsis, anaphylaxis, cirrhosis

Question 6

What can cause impaired renal auto regulation

Answer 6

Afferent vasoconstriction - sepsis, NSAIDs, hypercalcaemia

Efferent vasodilation - ACEi, AT2 receptor antagonists

Question 7

Treatment and outcome of pre renal failure

Answer 7

Aldosterone and ADH are released to restore blood flow
Responds well to fluid resuscitation
Will progress to ATN without treatment

Question 8

Causes of intrinsic renal failure

Answer 8

Renal artery/vein occlusion
Acute glomerulonephritis 
Acute tubular necrosis
Acute tubular interstitial nephritis 
Intra renal obstruction
Intra renal vascular disease

Question 9

Describe acute tubular interstitial nephritis

Answer 9

Inflammation of intersticium
Due to:
Infection - acute pyelonephritis
Toxin - antibiotics, PPIs, NSAIDs

Question 10

Do you give fluid resuscitation for ATN

Answer 10

No

Risks volume overload

Question 11

Causes of ATN

Answer 11

Ischaemia - usually secondary to pre renal failure
Nephrotoxins
Sepsis

Question 12

What is most affected in ATN and why

Answer 12

S3 segment

High metabolic acid and has a nearly hypoxic supply with normal perfusion

Question 13

Difference between pre renal failure and ATN

Answer 13

Urine Na is low in pre renal and high in ATN

Question 14

Endogenous nephrotoxins

Answer 14

Urate
Billirubin
Myoglobin (rhabdomyolosis)

Question 15

Exogenous nephrotoxins

Answer 15

Loop diuretics
Aminoglycosides 
ACE inhibitors
Endotoxins
XR contrast
NSAIDs 
Weedkiller
Antifreeze

Question 16

What must occur for post renal failure to occur

Answer 16

Obstruction blocking both kidneys or a single functioning kidney

Question 17

Causes of post renal failure

Answer 17

Lumen - stones, tumour, blood clot, papillary necrosis
Wall - neurogenic bladder, megaureter, pelivureteric neuromuscular dysfunction, bilateral Ureteric stricture
Pressure from outside - BPH, tumour, abdominal aneurysm, ligation of ureter

Question 18

What does post renal failure cause

Answer 18

Hydronephrosis

Question 19

Investigations for AKI

Answer 19

Urea
Creatinine
K, Na, Ca and PO4
(In serum and urine)

Question 20

Investigations for pre renal AKI

Answer 20

Look for shock and vascular disease

Question 21

Investigations for intrinsic AKI

Answer 21

Nephrotoxins
Parenchymal disease
Multi system diseases e.g UTI

Question 22

Investigations for post renal AKI

Answer 22

Anuria

Prostatism

Question 23

Signs of depleted volume

Answer 23

Cool peripheries
Tachycardia
Low BP
Low JVP
Low skin turgor
Dry axillae 
Sunken eyes

Question 24

Signs of volume overload

Answer 24

Gallop rhythm
High BP
Raised JVP
Pulmonary, ankle and sacral oedema

Question 25

Signs of urinary tract obstruction

Answer 25

``` Anuria Loin or suprapubic pain History of renal stones Previous pelvic or abdominal surgery Palpable bladder or kidney Prostatism ```

Question 26

Urine investigations for AKI

Answer 26

``` Urine dipstick - proteins and blood = intrinsic Microscopy: Normal = pre renal RBC casts = glomerulonephritis Muddy brown granular casts = ATN ```

Question 27

Imaging for AKI

Answer 27

Ultrasound within 24 hours if unknown cause or suspected post renal AKI Biopsy if pre and post renal have been ruled out CXR to look for fluid overload or infection

Question 28

Antibody detection in intrinsic AKI

Answer 28

Antinuclear antibody - SLE Anti neutrophil cytoplasmic antibody - vasculitis Collagen IV glomerular BM antibody - Good pastures syndrome

Question 29

Treatment of AKI

Answer 29

Volume overload - restrict dietary Na and water Hyperkalaemia - calcium gluconate, insulin, glucose Acidosis - NaHCO3 Nutrition Remove nephrotoxins (might need dialysis or chelation) Dialysis if no improvement

Question 30

First line investigation in asymptomatic glomerular disease picked up by urine dipstick (protein and bloods)

Answer 30

Flexible cystoscopy

Question 31

Appearance of macroscopic haematuria with glomerular disease

Answer 31

Brown | Episodic

Question 32

Reasons for brown urine

Answer 32

Glomerular disease Haemoglobinuria Myoglobinuria Consumption of food dyes

Question 33

Commonest cause if macroscopic haematuria

Answer 33

IgA nephropathy