Lab Case 10 – Interpretation

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35 year old man with altered mental state:

Elevated CK with renal failure (high urea and creatinine). Life threatening hyperkalaemia requiring immediate correction.

Rhabdomyolysis in this patient is likely due to Compartment syndrome in his left arm.

Other biochemical abnormalities expected in this patient may include:

1.severe acidosis (lactic acidosis)

2. hypocalcaemia

3. hyperphosphataemia

4. DIC (release of thromboplastins)

5. hyperuricaemia

Immediate priorities in treatment:

1. Correct hyperkalaemia (continuous cardiac monitoring)

2. Fluid rehydration – 0.9% Saline (aim for urine output of 2-3ml/kg/hr), may require up to 500ml/hr and up to 12 litres may be lost due to third spacing.

3. Facilitate myoglobin excretion by urinary alkalinization (NaHCO3 infusion) – also helps correct severe acidosis as temporizing. Aim for urine pH of >6.5

4. Identify the cause of his altered mental state

5. Wound care – analgesia, antibiotics, ADT, debridement, reduce fractures, fasciotomy (orthopaedics, surgeons)

6. Monitor Coagulation profile

7. ICU consult for supportive care and possible dialysis.

Other adjunct – Mannitol if fluid status is optimised but urine output is poor. Frusemide diuresis is controversial as it acidifies the urine and may precipitate myoglobin deposition in the renal tubules.

Causes of Rhabdomyolysis include:

  • Alcohol use and resultant unresponsiveness
  • Illicit drug use, medications (SSRI, antipsychotics, statins, steroids)
  • Heatstroke
  • Infection
  • Trauma
  • Metabolic disorders
  • Inflammatory myopathies

CK levels of 15000-20000 are usually associated with a significant risk of renal failure.

Mortality rates are up to 5% in Rhabdomyolysis

Further history from friends (after a long delay) suggested that this patient may have been unconscious/ asleep from the afternoon before. He did indeed have compartment syndrome of his left arm and required a fasciotomy. The best explanation we could come up with was that he had passed out and collapsed onto his left arm (and probably been lying on it for up to 20 hours).