acute kidney injury

Question 1

what is AKI ?

Answer 1

a rapid deterioration of kidney function , which is a clinical consequence and not a diagnosis and is usually reversible
falling urine output
rising serum urea and creatinine

Question 2

what do the causes of AKI fall into ?

Answer 2

pre renal causes ( reduced kidney perfusion )
renal causes or intrinsic causes
post renal causes

Question 3

what are some of the pre renal causes of AKI ?

Answer 3

hypovolemia
hypotension
reduced kidney blood flow
severe oedema

Question 4

which patients are at higher risk of developing pre renal AKI ?

Answer 4

older patients
atherosclerotic patients
diabetics
patients with pre existing kidney disease

Question 5

what are the causes of hypovolemia ?

Answer 5

shock

Question 6

what are the causes of reduced kidney blood flow ?

Answer 6

NSAIDs
ACE inhibitors
angiotensin II receptor blockers
abdominal aortic aneurysm

ace inhibitors

Question 7

what effect do ace inhibitors have on the kidneys?

Answer 7

they inhibit efferent vasoconstriction

Question 8

what effect do NSAIDs have on the kidneys ?

Answer 8

NSAIDs inhibit prostaglandins which in turn allow for afferent vasodilatation

Question 9

what are the causes of renal AKI ?

Answer 9

glomerular disease which can either be :
inflammatory or thrombotic 
tubular injury 
interstitial injury 
vascular injury

Question 10

what are the causes of post-renal AKI ?

Answer 10

intrinsic and extrinsic

Question 11

what are the intrinsic causes of post renal AKI ?

Answer 11

stone
blood clot
papillary necrosis

Question 12

what are the extrinsic causes of post renal AKI ?

Answer 12

prostatic hypertrophy/malignancy
pelvic malignancy
retroperitoneal fibrosis

retroperitoneal fibrosis

Question 13

what does acute tubular necrosis happen as a result off ?

Answer 13

any pre renal cause of AKI that reaches a point where autoregulation is no longer working - this will most probably lead to ischemic ATN

Question 14

what are the four phases of AKI ?

Answer 14

onset phase
oliguric phase
diuretic phase
recovery phase

Question 15

when does the diuretic phase of AKI happen ?

Answer 15

when the cause of the AKI is corrected

Question 16

what is the clinical picture of each of the causes of AKI ?

Answer 16

1. pre-renal causes - evidence of dehydration and hypovolemia , low BP and a rapid pulse
2. post renal causes - evidence of renal colics with acute onset anuria and hematuria
3. renal cause - history of nephrotoxic drugs intake, sepsis

Question 17

what are the lab findings commonly found with hypovolemia ?

Answer 17

high levels of ADH , increased secretion from the pituitary gland
disproportionate rise in the plasma urea:creatinine ratio

disproportionate rise in plasma urea: creatinine ratio

Question 18

how would we differentiate between AKI and CKD using US ?

Answer 18

CKD shows a shrunken kidney
except in patients with diabetes- who have normal sized kidneys even in disease

Question 19

what investigation clues could indicate glomerulonephritis ?

Answer 19

hematuria
proteinuria
RBC casts

Question 20

in what cases may we find eosinophilia ?

Answer 20

acute interstitial nephritis
cholesterol embolism
vasculitis

Question 21

what does thrombocytopenia suggest ?

Answer 21

thrombotic microangiopathy

Question 22

what is the management for AKI ?

Answer 22

conservative management

Question 23

what is the management for hyperkalemia ?

Answer 23

urgently obtain a 12 lead ECG

• – if k> 7mmol give 10ml of 10% calcium gluconate IV and monitor every 10 minutes
• – if k>6.5mmol 10 units of actarapid in 100 ml of 20% dextrose over 15 minutes
• – if 6-6.5 mmol give calcium resonium 15g along with laxatives

Question 24

what is the management for acidosis ?

Answer 24

consider giving 300-600 ml of isotonic sodium bicarbonate if venous bicarbonate is <22 mmol

Question 25

what is the management for pulmonary oedema ?

Answer 25

give high flow oxygen if haemodynamically stablee give furosemide | if haemodynamically stable give furosemide

Question 26

if pulmonary oedema is very severe what is the best step in management ?

Answer 26

haemodialysis | haemofiltration

Question 27

what are the indications of dialysis in AKI ?

Answer 27

1- persistent hyperkalemia metabolic acidosis volume overload (pulmonary oedema) that are not responding to treatment 2- uremic manifestations 3- fear of volume overload 4- toxin induced AKI

Question 28

what is the mechanism of autoregulation of blood flow in the kidney ?

Answer 28

in cases of reduced blood flow to the kidney : afferent vasoconstriction occurs by prostaglandins efferent vasodilation occurs by action of angiotensin II

Question 29

what is the clinical application off the autoregulation mechanism ?

Answer 29

NSAIDs inhibit prostaglandins which in turn inhibit vasodilation of the afferent arteriole ACE inhibitors or ARBs inhibit angiotensin II which in turn inhibits the vasoconstrictive effect on the efferent arteriole both mechanisms may be overcome by hypovolemia kol dah under the umbrella off pre renal AKI

Question 30

what is the cut off value in which autoregulation cannot be maintained ?

Answer 30

70 mmHg

Question 31

what is oliguria ?

Answer 31

urine output less than 400 ml

Question 32

what is theRIFLE criteria

Answer 32

risk injury failure loss end stage uses an increase in serum creatinine or a decrease in urine output

Question 33

which stage ar RRT patient considered to be at according to the AKIN criteria ?

Answer 33

stage 3

Question 34

what are the LUTS ?

Answer 34

hesitancy frequency nocturia palpable bladder complete anuria

Question 35

what do different measures of urea:creatinine ratio indicate ?

Answer 35

BUN:C of more than 20:1 or U:C of more than 40:1 is indicative of pre-renal causes off AKI ratios more than those indicate renal causes - renal tubular acidosis

Question 36

What are the indications for a renal biopsy?

Answer 36

1: unexplained urine abnormalities 2: persistent ATN for more than 4 weeks 3: unclear etiology 4: suspicion of systemic disease

Question 37

What are the characteristic findings in the urine analysis of drug-induced nephritis?

Answer 37

proteinuria eosinophilia

Question 38

bilateral crepitatiions in a patient with AKI ?

Answer 38

pulmonary oedema due to volume overload

Question 39

what is the calcium homeostasis like in CKD ?

Answer 39

hypocalcemia hyperparathyroidism