week -1 kidney disease - AKI and CKD

Question 1

Define acute kidney injury (AKI) and which biomarkers are used in diagnosis

Answer 1

Abrupt decline in renal function > leads to increase in Sr urea and creatinine over a period of hrs to days

Question 2

what are risk factors for AKI:

a. Pt factors
b. medications factors
c. procedural factors

Answer 2

a. pre-existing renal function, sepsis, age, DM, liver failure, atherosclerosis, CHTN
b. NSAIDs, Angiotensin receptor blockers or converting enzyme inhibitors
c. liver, kidney transplant, cardiopulmonary bypass, ↑ abdo pressure

Question 3

What is the Australian criteria for diagnosis of AKI

Answer 3

• ↑ in Sr Cr ≥ 25 µmol/L w/i 48hrs
• ↑ in Sr Cr to ≥ 1.5x baseline w/i last 7 days
• significant redn in urine output compared with normal output

Question 4

Describe the 3 types of AKI pathophysiology

Answer 4

• Pre- Renal: most common; incident > renal HYPO-PERFUSION (tissues remain intact) > impaired function

Intra-Renal/Intrinsic: damage to renal tissue (parenchymal) > impaired function that will not return to baseline

Post-renal/obstructive: < 10% of cases; acute obstruction in ureter, bladder or prostate > ↑ pressure in kidney > impaired function

Question 5

Provide one example of a (a) Pre-renal and (b) Intrinsic AKI caused by medication

Answer 5

a. Triple whammy = ACE inhibitor/ARBs + Furosemide (diuretic) + NSAIDs
b. nephrotoxicity > aminoglycosides (GEN), AMP

Question 6

The ‘triple whammy’ is the most common cause of community acquired AKI. Describe the pathophysiology

Answer 6

• body is stressed, blood flow to kidney slowed > low GFR
• interruption by NSAID (stops prostaglandin > no afferent vasodilation)
• interruption by ACE/ARB (stops angiotensin II > prevents efferent artery vasoconstriction)
• furosemide > ↓ fluid volume
• GFR not maintained
• body senses something is wrong and shuts down kidneys