Rhabdomyolysis

Question 1

What is rhabdomyolysis?

Answer 1

Rhabdomyolysis is a syndrome characterised by the breakdown of skeletal muscle cells, releasing intracellular contents into the bloodstream.

Question 2

What are the common causes of rhabdomyolysis?

Answer 2

Causes include crush injuries, prolonged immobilisation, extreme exertion, surgery, statin use, infections, and inherited disorders like muscular dystrophy.

Question 3

What is the pathophysiology of rhabdomyolysis?

Answer 3

Muscle cell necrosis releases creatine kinase, myoglobin, urate, and electrolytes into the blood. Myoglobin can cause tubular obstruction, leading to kidney injury.

Question 4

What are the risk factors for developing rhabdomyolysis?

Answer 4

Risk factors include male sex, high BMI, chronic use of statins, and extreme physical exertion.

Question 5

What are the typical clinical features of rhabdomyolysis?

Answer 5

Features include malaise, myalgias, muscle weakness, and tea-coloured urine due to myoglobinuria.

Question 6

How is rhabdomyolysis diagnosed?

Answer 6

Diagnosis is based on elevated creatine kinase levels, myoglobinuria, and electrolyte disturbances, alongside clinical presentation.

Question 7

What bedside investigations are useful in rhabdomyolysis?

Answer 7

Urinalysis, ECG for hyperkalaemia, and blood gas analysis for metabolic acidosis are useful.

Question 8

What laboratory tests are important in rhabdomyolysis?

Answer 8

Important tests include creatine kinase, urea and electrolytes, liver function tests, and bone profile for phosphate and calcium levels.

Question 9

What imaging studies might be considered in rhabdomyolysis?

Answer 9

Imaging may be used to assess complications like compartment syndrome or underlying causes, using ultrasound or MRI.

Question 10

What is the primary treatment for rhabdomyolysis?

Answer 10

Intravenous fluid rehydration to prevent myoglobin precipitation and protect kidney function.

Question 11

How are electrolyte disturbances managed in rhabdomyolysis?

Answer 11

Hyperkalaemia is treated with calcium gluconate, insulin-glucose infusions, and stopping potassium-raising medications.

Question 12

When might renal replacement therapy be necessary in rhabdomyolysis?

Answer 12

RRT may be needed for severe AKI, persistent electrolyte imbalances, or fluid overload.

Question 13

What complications can arise from rhabdomyolysis?

Answer 13

Complications include acute kidney injury, electrolyte imbalances, and disseminated intravascular coagulation.

Question 14

How does rhabdomyolysis lead to acute kidney injury (AKI)?

Answer 14

Myoglobin released during muscle breakdown causes tubular obstruction and direct toxicity, resulting in AKI.

Question 15

What is the significance of tea-coloured urine in rhabdomyolysis?

Answer 15

Tea-coloured urine indicates myoglobinuria, a hallmark of rhabdomyolysis from muscle breakdown.

Question 16

Why is early fluid resuscitation important in rhabdomyolysis?

Answer 16

Early fluids dilute toxins and promote their excretion, reducing the risk of AKI.

Question 17

How can statin use lead to rhabdomyolysis?

Answer 17

Statins can cause muscle toxicity, leading to breakdown and rhabdomyolysis, especially at high doses or with certain drug interactions.

Question 18

What role does creatine kinase (CK) play in diagnosing rhabdomyolysis?

Answer 18

Elevated CK levels indicate muscle breakdown and are a key diagnostic marker, typically exceeding five times the upper limit of normal.

Question 19

How is hyperkalaemia managed in the context of rhabdomyolysis?

Answer 19

Hyperkalaemia is managed with calcium gluconate, insulin-glucose infusions, and potassium restriction.

Question 20

What is the role of bicarbonate therapy in rhabdomyolysis management?

Answer 20

Sodium bicarbonate can alkalinise the urine, reducing myoglobin toxicity and protecting the kidneys in severe cases.

Question 21

What medications should be avoided in rhabdomyolysis?

Answer 21

Nephrotoxic drugs and potassium-sparing diuretics should be avoided to minimise complications.

Question 22

What are the key goals of rhabdomyolysis management?

Answer 22

Goals include preventing AKI, correcting electrolyte imbalances, and treating underlying causes.

Question 23

How is compartment syndrome associated with rhabdomyolysis managed?

Answer 23

Fasciotomy is performed to relieve pressure if compartment syndrome occurs.

Question 24

What dietary advice is given to patients recovering from rhabdomyolysis?

Answer 24

Patients may be advised to avoid excessive protein intake and remain hydrated to reduce kidney strain.

Question 25

How does prolonged immobilisation contribute to rhabdomyolysis?

Answer 25

Prolonged immobilisation causes ischaemia and compression of muscles, leading to cell necrosis and rhabdomyolysis.