Rhabdomyolysis Flashcards
What is rhabdomyolysis?
Rhabdomyolysis is a syndrome characterised by the breakdown of skeletal muscle cells, releasing intracellular contents into the bloodstream.
What are the common causes of rhabdomyolysis?
Causes include crush injuries, prolonged immobilisation, extreme exertion, surgery, statin use, infections, and inherited disorders like muscular dystrophy.
What is the pathophysiology of rhabdomyolysis?
Muscle cell necrosis releases creatine kinase, myoglobin, urate, and electrolytes into the blood. Myoglobin can cause tubular obstruction, leading to kidney injury.
What are the risk factors for developing rhabdomyolysis?
Risk factors include male sex, high BMI, chronic use of statins, and extreme physical exertion.
What are the typical clinical features of rhabdomyolysis?
Features include malaise, myalgias, muscle weakness, and tea-coloured urine due to myoglobinuria.
How is rhabdomyolysis diagnosed?
Diagnosis is based on elevated creatine kinase levels, myoglobinuria, and electrolyte disturbances, alongside clinical presentation.
What bedside investigations are useful in rhabdomyolysis?
Urinalysis, ECG for hyperkalaemia, and blood gas analysis for metabolic acidosis are useful.
What laboratory tests are important in rhabdomyolysis?
Important tests include creatine kinase, urea and electrolytes, liver function tests, and bone profile for phosphate and calcium levels.
What imaging studies might be considered in rhabdomyolysis?
Imaging may be used to assess complications like compartment syndrome or underlying causes, using ultrasound or MRI.
What is the primary treatment for rhabdomyolysis?
Intravenous fluid rehydration to prevent myoglobin precipitation and protect kidney function.
How are electrolyte disturbances managed in rhabdomyolysis?
Hyperkalaemia is treated with calcium gluconate, insulin-glucose infusions, and stopping potassium-raising medications.
When might renal replacement therapy be necessary in rhabdomyolysis?
RRT may be needed for severe AKI, persistent electrolyte imbalances, or fluid overload.
What complications can arise from rhabdomyolysis?
Complications include acute kidney injury, electrolyte imbalances, and disseminated intravascular coagulation.
How does rhabdomyolysis lead to acute kidney injury (AKI)?
Myoglobin released during muscle breakdown causes tubular obstruction and direct toxicity, resulting in AKI.
What is the significance of tea-coloured urine in rhabdomyolysis?
Tea-coloured urine indicates myoglobinuria, a hallmark of rhabdomyolysis from muscle breakdown.
Why is early fluid resuscitation important in rhabdomyolysis?
Early fluids dilute toxins and promote their excretion, reducing the risk of AKI.
How can statin use lead to rhabdomyolysis?
Statins can cause muscle toxicity, leading to breakdown and rhabdomyolysis, especially at high doses or with certain drug interactions.
What role does creatine kinase (CK) play in diagnosing rhabdomyolysis?
Elevated CK levels indicate muscle breakdown and are a key diagnostic marker, typically exceeding five times the upper limit of normal.
How is hyperkalaemia managed in the context of rhabdomyolysis?
Hyperkalaemia is managed with calcium gluconate, insulin-glucose infusions, and potassium restriction.
What is the role of bicarbonate therapy in rhabdomyolysis management?
Sodium bicarbonate can alkalinise the urine, reducing myoglobin toxicity and protecting the kidneys in severe cases.
What medications should be avoided in rhabdomyolysis?
Nephrotoxic drugs and potassium-sparing diuretics should be avoided to minimise complications.
What are the key goals of rhabdomyolysis management?
Goals include preventing AKI, correcting electrolyte imbalances, and treating underlying causes.
How is compartment syndrome associated with rhabdomyolysis managed?
Fasciotomy is performed to relieve pressure if compartment syndrome occurs.
What dietary advice is given to patients recovering from rhabdomyolysis?
Patients may be advised to avoid excessive protein intake and remain hydrated to reduce kidney strain.
How does prolonged immobilisation contribute to rhabdomyolysis?
Prolonged immobilisation causes ischaemia and compression of muscles, leading to cell necrosis and rhabdomyolysis.
