Acute Kidney Injury (AKI) Stages and Causes

Questions and Answers

What are the three main categories of AKI classified based on the location of the underlying cause?

Prerenal AKI, Renal AKI, and Post-renal AKI

What is the main cause of Prerenal AKI?

Decreased blood flow into the kidneys

What is the mechanism of action of NSAIDs in decreasing renal blood flow?

Inhibiting COX and lipoxygenases, leading to decreased prostaglandin production

What is the role of prostaglandins in maintaining renal blood flow?

Prostaglandins increase renal blood flow by vasodilating the afferent arteriole Signup and view all the answers

What are the common risk factors for AKI?

Advanced age, Diabetes, CKD, Sepsis, Hypotension/shock, Dehydration, burn trauma, and UTI Signup and view all the answers

What is the pharmacological role of a pharmacist in managing AKI?

Discontinuing nephrotoxic drugs, treating infections early, monitoring blood pressure, and adjusting doses Signup and view all the answers

What is the non-pharmacological role of a pharmacist in managing AKI?

Recognizing high-risk patients, accessing fluid status/balance, and checking renal functions Signup and view all the answers

What are the limitations of the Cockcroft-Gault equation?

It is only suitable for elderly people and those with muscle mass changes, and it requires the use of ideal body weight (IBW) for obese patients Signup and view all the answers

What is the effect of ACEi/ARBs on renal blood flow?

ACEi/ARBs decrease renal blood flow by inhibiting the conversion of angiotensin I to angiotensin II, leading to less vasoconstriction of the efferent arteriole Signup and view all the answers

What is the purpose of monitoring serum creatinine in AKI?

To indicate increased or excessive production of urine, exacerbating hypovolaemia, and associated with a sharp decrease in kidney function Signup and view all the answers

Study Notes

Acute Kidney Injury (AKI)

AKI is diagnosed by an absolute increase in serum creatinine (sCr)
Classified into three main categories based on the location of the underlying cause:

Prerenal AKI
- Causes: decrease blood flow into the kidneys
- Examples: hypovolaemia (low volume of fluid), loss of peripheral resistance, reduced cardiac output, renovascular obstruction
- Examples of causes: dehydration, burning trauma, hypotension, heart failure, thrombosis
Renal AKI
- Causes: damage to nephrons or surrounding factors
- Examples: pre-glomerular (small arteries), glomerular (capillary network), post-glomerular (tubules)
- Examples of causes: hypertension, glomerulonephritis, tubular necrosis
Post-renal AKI
- Causes: obstruction of urinary outflow
- Examples: ureteric obstruction, bladder outflow obstruction, infections
- Examples of causes: kidney stones, benign prostatic hyperplasia, inflammation of the kidney

Risk Factors for AKI

Advanced age
Diabetes
Chronic kidney disease (CKD)
Sepsis
Hypotension/shock
Dehydration, burn trauma
Urinary tract infection (UTI)

Pharmacist's Role in Managing AKI

Pharmacological management:
- Discontinue nephrotoxic drugs
- Treat infections early
- Monitor blood pressure
- Adjust doses
Non-pharmacological management:
- Recognize high-risk patients
- Assess fluid status/balance
- Monitor renal function

Medications Affecting Renal Function

NSAIDs:
- Decrease renal blood flow and eGFR
- Promote fluid retention
- Inhibit prostaglandin synthesis
ACEIs/ARBs:
- Decrease renal blood flow and eGFR
- Cause hyperkalemia
Diuretics:
- Cause increased urine production, exacerbating hypovolaemia
Iodine-based contrast media:
- Decrease renal blood flow and eGFR

Mechanism of Action (MoA)

NSAIDs: inhibit COX and lipoxygenases, leading to decreased prostaglandin release and inflammation
ACEIs/ARBs: inhibit conversion of angiotensin I to angiotensin II, reducing vasoconstriction and aldosterone production

Prostaglandins

Produced in the kidney: PGI2, PGE1, PGE2
Increase renal blood flow and eGFR by vasodilating afferent arteriole
Released in response to dehydration, acute stress, angiotensin II, and sympathetic nervous system (SNS) stimulation
Used to treat renal ischemia by preventing excessive reduction in GFR and renal blood flow

Renal Function Calculations

Cockcroft-Gault equation:
- Calculates estimated creatinine clearance in micromol/L
- Used for elderly patients, bodybuilders, and obese individuals
- Requires ideal body weight (IBW) and dose determining weight (DDW) formulation
MDRD equation:
- Calculates eGFR
- Affected by muscle mass (reduced muscle mass leads to overestimation, increased muscle mass leads to underestimation)

Description

Learn about the three stages of Acute Kidney Injury (AKI) and its causes, including Prerenal, Renal, and Post-renal AKI. Understand the factors that lead to AKI, such as hypovolaemia, loss of peripheral resistance, and reduced cardiac output.