Rhabdomyolysis

Question 1

What is Rhabdomyolysis?

Answer 1

• Clinical syndorme associated c breakdown of skeletal muscle > release of muscle content into circulation

Question 2

What are the contents of muscle?

Answer 2

• Myoglobin
• K
• Phosphate
• CK

Question 3

What causes rhabdomyolysis?

Answer 3

• prolonged immobilty
• Extreme exercise
• Crush injuries
• Seizures
• Alcohol abuse
• Medications
• Hyper/hypo
• DKA

Question 4

What medications can cause rhabdomyolysis?

Answer 4

• Statins
• Erythromycin
• Cortocosteroids

Question 5

How does Rhabdomyolysis causes AKI?

Answer 5

1. Damaged myocytes > Ca influx > apoptosis
2. Muscle necrosis > release of contents into circulation
3. Myoglobin filtered by kidneys
4. Myoglobin toxic to kidneys > causes obstruction and inflammation > AKI
5. Tea-coloured urine produced & +haematuria

Question 6

How would AKI present?

Answer 6

• Myalgia
• Oedema
• Fatigue
• Confusion (particularly in elderly frail patients)
• Red-brown urine

Question 7

What Ix would you order for rhabdomyolysis?

Answer 7

• Bedside
  
  • Can be clinically diagnosed\
  • Urine dip
    
    • (+) blood macroscopically, (-) blood microscopically \
  • ECG - for hyperkalaemia
• Bloods
  
  • serum myoglobin
  • CK - 5x baseline or greater
  • U&E
    
    • high K, low ca, high phosphate

Question 8

How would you mx rhabdomyolysis?

Answer 8

1. Fluid - prevent percipitation of myoglobin
2. Tx high K - calcium gluconate + dextrose-insulin infusion
3. Consider IV bicarbonate - alkaline diuresis
4. Tx hypocalcaemia and hyperphosphataemia

Question 9

What are the cx of rhabdomyolysis?

Answer 9

• Hyperkalaemia
• Hypocalcaemia
• Metabolic acidosis
• AKI
• DIC
• Compartment syndrome