Rhabdomyolysis

Question 1

A 42 year old male recommenced weight training after a hiatus of 10 years. He presents 48 hours after his first session, which included 2 hours of heavy weightlifting, complaining of severe pain and tenderness in his back, shoulders and biceps muscles. He describes “blood” in his urine for the last 24 hours and his urinalysis shows +++blood and +++protein. His serum Creatinine is 169 mcrmol/L (NR < 120 mcrmol/L). How would you investigate and manage him?

Imp/DDx/Goasl

Answer 1

Impression
In context of recent gym activity and triad of rhabdomyolysis (muscle pain, weakness and likely myoglobinuria) plus the mildly elevated CK, this is likely a case of rhabdomyolysis with subsequent AKI.

DDx

• haematuria (UTI, stone, malignancy)
• nephritic syndrome
• rheumatological (polymyocitis, dermatomyocitis)
• other causes of rhabdo: compartment syndrome, long-lie, poison (snake bite, etc).
• mitochondrial disorders (enzymre)

Goals

• take targeted H/E/I to identify underlying aetiology of presentation
• treat to prevent further complication and kidney injury

Question 2

Rhabdomyolysis - History

Answer 2

History

• sx: myalgia, muscle weakness, darkened urine.
• REDF: pain greater than expected (compartment syndrome), snake/spider bite

Question 3

Rhabdomyolysis - Examination

Answer 3

Examination

• General observation + vital signs
• Fluid balance: in particular urine output
• abdominal examination: loin to groin pain, masses

Question 4

Rhabdomyolysis - Investigations

Answer 4

Investigations:
- key/diagnostic: urine dipstick (myoglobins), serum CK, UEC (eGFR, potassium, creatinine)

• Bedside: urine dipstick,
• Bloods: UEC, CMP, serum CK (serial) - peaks at 1-3 days post-rhabdo, ESR/CRP
• imaging: renal tract US/ CT KUB if suspicious of nephrolithiasis
• other: muscle biopsy, ENA/ANA (if rheumatological cause considered)

Question 5

Rhabdomyolysis - Management

Answer 5

Management:
Fluid therapy is mainstay

Supportive:

• fluids: IV NS infusion to maintain urine output
• manage and maintain normal electrolyte balance
• analgesia
• regular obs, fluid balance monitoring
• regular rolling/moving to prevent further pressure sores

Definitive

• consider dialysis if kidney function worsening/severe rhabdo
• renal consult for ongoing mx