Week 227 - Acute Kidney Injury

Question 0

Give some potential causes of rhabdomyolysis

Answer 0

Traumatic accident (could include severe muscle strain)
Immobilisation
Surgery
Compartment syndrome
Alcohol or illicit drug use e.g. Cocaine, heroin, amphetamines
Medications e.g. Statins or antipsychotics

Question 1

What is rhabdomyolysis?

Answer 1

Skeletal muscle breakdown/necrosis secondary to injury
Releasing intracellular constituents into the circulation
MUST be treated early - can be life threatening due to kidney failure

Question 2

Name the 3 overarching causes/categories of Acute Renal Failure

Answer 2

Pre-renal
Renal (intrinsic)
Post-renal

Question 3

List causes of pre-renal AKI and describe briefly the main pathology involved

Answer 3

> due to disturbance in renal blood supply
Causes include:
- Reduced BP / volume
- heart failure
- cirrhosis
- renal artery stenosis or renal vein thrombosis

Question 4

List causes of renal/intrinsic AKI and describe briefly the main pathology involved

Answer 4

> Damage to parenchyma of the kidney
Common causes: 
- Glomerulonephritis 
- Acute Tubular Necrosis (ATN)
- Acute Interstitial Nephritis (AIN)

Question 5

List causes of post-renal AKI and describe briefly the main pathology involved

Answer 5

> Usually consequence of urinary tract obstruction
Common causes: 
- BPH
- Renal stones / Bladder stones
- Obstructed urinary catheter
- Malignancy

Question 6

What are the signs and symptoms of rhabdomyolysis?

Answer 6

Muscle pain
Muscle weakness
Abdo pain
Fever and tachycardia
Confusion / dehydration / reduced consciousness
Dark red or brown urine / reduced or no urine output

Question 7

What are the two main types of investigation you should perform with suspected rhabdomyolysis? Why?

Answer 7

• Blood tests for: creatinine kinase, potassium, phosphate, urea, calcium levels
• Urinalysis: colour, output, microscopy (for RBCs)

To assess for rhabdomyolysis induced AKI

Question 8

What results might you expect to see from blood tests and urinalysis in a pt with rhabdomyolysis induced AKI?

Answer 8

Bloods: Raised creatinine kinase, potassium, phosphate, urea
Reduced calcium (enters the muscle)
Urine: dark brown/red (myoglobin), blood on dipstick WITHOUT blood RBCs on microscopy

Question 9

What is the management for rhabdomyolysis?

Answer 9

IV fluids to improve urine output and prevent renal failure
Electrolyte correction (potassium, phosphate, calcium)

Rarely dialysis
Treat underlying cause

Question 10

What are urinary casts?

Answer 10

Cylindrical structures formed in the distal convoluted tubules and collecting ducts if the kidneys, which dislodge and pass into the urine in certain disease states

Question 11

Name the various types of cast you may see in urinalysis (microscopy)

Answer 11

Fatty; Granular; Hyaline; Red blood cell; Renal tubular epithelial cell; Waxy and White blood cell casts

Question 12

List a reason for the presence of the following:

• RBC casts
• WBC casts
• Fatty casts
• Hyaline casts

Answer 12

• RBC casts: bleeding into the kidney
• WBC casts: acute kidney infection
• Fatty casts: (ppl w/lipids in urine) complication of nephrotic syndrome
• Hyaline casts: dehydration, exercise or diuretic medications

Question 13

How can you prevent rhabdomyolysis induced AKI?

Answer 13

1. Forced alkaline diuresis (with sodium bicarbonate)

2. Mannitol “Forced Diuresis”

Question 14

What is the definition of diuresis?

Answer 14

Increasing production of urine

Question 15

What is the definition of dialysis?

Answer 15

The clinical purification of blood as a substitute for normal function of the kidney