Rhabdomyolysis

Question 1

Most common cause of rhabdomyolysis

Answer 1

trauma

Question 2

Drug reaction causes of rhabdomyolysis

Answer 2

statins, fibrates, alcohol, ecstasy, heroin, carbon monoxide, neuroleptic malignant syndrome

Question 3

genetic disorder causes of rhabdomyolysis

Answer 3

McArdle’s disease, Duchenne’s muscular dystrophy

Question 4

other causes of rhabdomyolysis

Answer 4

prolonged immobilisation, post ischaemia, burns, excessive exercise, uncontrolled seizures, metabolic disorders, myositis, malignant hyperpyrexia

Question 5

infection causes of rhabdomyolysis

Answer 5

coxsackie, EBV, influenza

Question 6

physical damage to muscle cells occurs via

Answer 6

damage of muscle cells directly or interfere with blood supply

Question 7

non physical damage occurs via

Answer 7

interference with muscle cell metabolism

Question 8

initial reaction to damaged muscle tissue

Answer 8

Swelling itself can destroy muscle
rise in intracellular calcium ions; the accumulation of calcium outside the sarcoplasmic reticulum leads to continuous muscle contraction and depletion of ATP, the main carrier of energy in the cell. ATP depletion can itself lead to uncontrolled calcium influx. Persistent contraction leads to breakdown of intracellular proteins and disintegration of the cell

Question 9

what type of inflammatory cell is released

Answer 9

neutrophil granulocytes

Question 10

what muscle breakdown products are released into the blood

Answer 10

Myoglobin
Potassium
Creatinine kinase (CK)
Phopsphate urate

Question 11

release of potassium leads to

Answer 11

hyperkalaemia

Question 12

release of phosphate urate

Answer 12

binds to calcium in circulation leading to low calcium in the blood

Question 13

how does rhabdomyolysis lead to kidney failure

Answer 13

myoglobin > haptoglobin
myoglobin interacts with tamm-horsfall protein forming casts
casts obstruct fluid
iron released causes reactive oxygen
further kidney damage via constriction blood vessels and uric acid forming crystals

Question 14

clinical features of rhabdomyolysis

Answer 14

Often associated with the cause
Muscle aches
Oedema
Red-brown urine
Non-specific: nausea, vomiting, confusion, coma, abnormal heart rate/rhythm

Question 15

diagnostic features of blood tests

Answer 15

↑CK > 1000iU/L

U+E’s – hyperkalaemia

Question 16

diagnostic features of urine dipstick

Answer 16

+ve for haemoglobin, but absence of red cells on microscopy – due to myoglobin

Question 17

complications of rhabdomyolysis

Answer 17

hyperkalaemia
acute renal failure
increased coagulability - disseminated intravascular coagulation
compartment syndrome

Question 18

management of rhabdomyolysis

Answer 18

treatment of hyperkalaemia
IV fluids
IV sodium bicarbonate

Question 19

management of hyperkalaemia

Answer 19

IV calcium gluconate
Insulin + glucose
Nebulised salbutamol
Polystyrene sulfonate Resin
Dialysis