Rhabdomyolysis

Question 1

What is rhabdomyolysis?

Answer 1

Breakdown of skeletal muscle and release of breakdown products into blood i.e. apoptosis of myocytes

Question 2

What breakdown products are released?

What are the possible complications of the release of these products?

Answer 2

Myoglobin

Potassium

Phosphate

Creatine kinase

Consequences:

• rise in potassium might induce lethal cardiac arrhythmias
• myoglobin= nephrotoxic-> AKI -> leads to exacerbation of accumulation of breakdown products in blood due to reduced kidney function being unable to filter blood as affectively

Question 3

What causes rhambdomyolisis?

Answer 3

Prolonged immobility I.e. frail patients who fall and spend long time lying (LONG LIE FALLS)

Extremely rigorous exercise i.e. beyond person level of fitness

Crush injury

Seizures

Question 4

How might someone with rhabdomyelitis present?

Answer 4

Muscle aches and pains

Oedema

Fatigue

Confusion -> elderly

Red-brown urine i.e. myoglobinurea

Question 5

What investigations should be done if rhabdomyolisis is suspected?

Answer 5

Creatine kinase

• 1000 -100,000 units
• rise for 12 hrs then remains elevated for 1-3 days before gradually falling

Urine dip
-positive for blood due to myoglobin in urine

U+Es

• AKI
• hyperkalamaemia

ECG
-look for arrythmias and signs of hyperkalaemia

Question 6

How is rhambdomyelitis managed?

Answer 6

IV fluids
-rehydration and filtration of breakdown products

IV sodium bicarb (consider it)
-makes urine more alkaline which reduces the toxicity of myoglobin in kidneys

IV mannitol
-increases GFR + reduce oedema Due to inducing diuresis by increasing conc of filtrates in kidneys and block H20 reabsorption

Treat hyperkalaemia
-calcium gluconate