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Causes of Acute Kidney InjuryAmy Livesey

+Overview

Why Acute Kidney Injury?

Definition

Recap of types of AKI

Causes of Acute Kidney Injury

How to recognise AKI clinically

Summary

+Why Acute Kidney Injury?

8.10 Acute renal failure

By the end of phase II students should be able to:

Recognise acute renal failure, distinguish is from chronic renal failure and relate the changes to the underlying pathophysiology

Act to prevent the condition as far as possible

Initiate investigation and management for the patient

Discuss the prognosis of acute renal failure

+Why Acute Kidney Injury?

8.10 Acute renal failure Kidney Injury

By the end of phase II students should be able to:

Recognise acute renal failure, distinguish is from chronic renal failure and relate the changes to the underlying pathophysiology

Act to prevent the condition as far as possible

Initiate investigation and management for the patient

Discuss the prognosis of acute renal failure

+Definition

Can anybody think of a succinct definition?

+Definition

Acute Kidney Injury is defined as:

A significant deterioration in renal function, which is potentially reversible, over a period of hours or days.

+DefinitionRenal Association criteria:

Serum creatinine rises by ≥ 26µmol/L within 48 hours or

Serum creatinine rises ≥ 1.5 fold from the reference value, which is known or

presumed to have occurred within one week or

urine output is < 0.5ml/kg/hr for >6 consecutive hours (oliguria)

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Acute Kidney Injury(acute renal failure)

Hours - weeks

Chronic Kidney Disease

recovery

End stage renal disease (failure)

Months - years

Kidney Disease and Renal Failure

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Causes ofAcute Kidney Injury

+Causes of AKI

Normal urine output requires:

1. Adequate blood supply to the kidneys

2. Functioning kidneys

3. Unobstructed flow of urine from kidneys, down the ureters, into the bladder and out via the urethra.

+Causes of AKI

1. Pre-renal

2. Intrinsic/ renal

3. Post-renal

+1. Pre-renalI.e. Inadequate blood supply to the kidneys

Inadequate cardiac function

Hypovolaemia

Obstruction of arterial supply Drugs altering renal

haemodynamics NSAIDs ACEi

+2. Intrinsic/ RenalI.e. Damage resulting in impaired kidney function

1. Tubular Acute Tubular Necrosis (‘Muddy brown casts’ in urinalysis)

2. Glomerular Glomerulonephritis

3. Interstitial Interstitial nephritis (usually drug induced e.g NSAIDs, ABX)

4. Vascular Vasculitis, emboli, Malignant HTN, DIC...

5. Infectious Malaria, Legionnaires’ disease, Leptospirosis

6. Complex mechanism (!) Multiple Myeloma

+3. Post-renali.e. obstruction to urinary flow

1. Ureters (e.g Abdominal/pelvic mass compressing ureters, bilateral calculi, retroperitoneal fibrosis).

2. Bladder (e.g Neuropathic bladder, bladder tumour of calculi)

3. Uretha (e.g BPH, blocked catheter, prostate cancer, urethral stricture, trauma, infection)

+How to recognise AKI clinically

General pattern of acute kidney injury:

Increase in K+

Increase in urea

Increased creatinine

Reduced pH

• Low BP• Tachycardia• Reduced urine output• Weight loss• Drugs:

• NSAIDs• ACEI/ ARB• Radio contrast

• Fever

+Hopefully you can now all….

Have an idea of how to define AKD

Know how to tackle answering a question about causes of AKI Pre-renal Renal Post-renal

Be able to recognise AKI clinically