Acutely unwell / ITU

Question 1

Rhabdomyolysis; 5 key points (BJAed 2013)

Answer 1

1. Rhabdomyolysis is characterized by breakdown of skeletal muscle with the release of myoglobin and other intercellular proteins and electrolytes into the circulation.
2. Creatine kinase concentration is the most useful indicator of muscle damage.
3. Hyperkalaemia can be life-threatening and needs prompt management.
4. Acute kidney injury is common.
5. Fluid resuscitation is the mainstay of management.

Question 2

Traumatic causes of rhabdomyolysis (3 subheadings, 6 points)

Answer 2

1. Crush injury and trauma (collapsed buildings, road traffic collisions)
2. Compartment syndrome (alcohol-associated immobility, prolonged collapse, perioperative positioning, prolonged tourniquet use)
3. Electrocution

Question 3

Non-traumatic causes of rhabdomyolysis (7 subheadings, 15 points)

Answer 3

1. Exertional (strenuous exercise, seizures)
2. Body temperature changes (MH, neuroleptic malignant syndrome, hypothermia)
3. Genetic defects (disorders of glycolysis or GNG, disorders of the mitochondria)
4. Drugs or toxins (statins, alcohol, heroin, cocaine)
5. Infections (influenza A and B, EBV, HIV, Strept pyogenes, Staph aureus)
6. Metabolic and electrolyte disorders (non-ketotic hyperosmotic state, DKA)
7. Idiopathic

Question 4

Diagnostic criteria for Rhabdomolysis

Answer 4

Typically diagnosed when the CK is >5000 units litre−1.

This value represents five times its normal upper limit.

Question 5

Investigations in rhabdomyolysis (11)

Answer 5

1. Creatine kinase >5000 units litre−1
2. Serum and urine myoglobin - Present
3. Urinary dipstick+pH Positive for blood
4. Urea and creatinine - Raised
5. Potassium - Raised
6. Calcium - Low
7. Phosphate, uric acid - Raised
8. Coagulation studies -
   Prolonged in severe cases
9. Blood gas - Lactic acidosis
10. Anion gap - Raised
11. ECG - Changes of hyperkalaemia

Question 6

Management of rhabdo

Answer 6

1. Early fluid resuscitation (prevention of AKI)
2. Bladder catheterization (to monitor urine output)
3. invasive monitoring (arterial & CVP; to guide fluid resuscitation)
4. urine outputs of 3 ml kg−1 h−1 or >300 ml h−1

Question 7

Which fluid to use in Rx of rhabdo?

Answer 7

1. Hartmann’s - may aid in urinary alkalinization but should probably be avoided as it contains potassium.
2. Normal saline is devoid of potassium and is more appropriate, but it may contribute to hyperchloraemic acidosis.

Question 8

How would you alkalinize urine in Rhabdo?

What is the evidence for doing so?

Answer 8

1. Sodium bicarbonate may be administered as boluses of 50–100 mmol or as 1.26% to aid in volume resuscitation.
2. A target urinary pH of >6.5 should be achieved.
3. Evidence for the use of sodium bicarbonate as a therapy to prevent AKI in rhabdomyolysis is lacking.

Question 9

How would you treat hyperkalaemia in rhabdomyolysis?

Answer 9

1. Hyperkalaemic ECG changes should be treated with calcium gluconate 10 ml of 10%.
2. Patients with hyperkalaemia >6.5 mmol−1 should be given insulin 10 IU in 50 ml of 50% dextrose over 15 min & nebulized salbutamol 10 mg
3. Renal replacement therapy should be reserved for the management of hyperkalaemia, acidosis, or volume overload.

Question 10

How should suspected compartment syndrome be treated? (10 points)

Answer 10

1. Prompt diagnosis and relief of compartmental pressures.
2. External pressure from dressings, casts, or rubble at trauma scenes must be removed.
3. Oxygen should be administered
4. Analgesia offered as pain often appears out of proportion to the injury sustained.
5. Hypotension should be avoided as it further reduces limb perfusion.
6. Urgent fasciotomy is commonly the definitive therapy and should be performed early.
7. Delays in performing fasciotomy increase morbidity, including the need for amputation.
8. After fasciotomy, patients should be closely monitored with serial CK levels and hourly urine output to detect impending rhabdomyolysis and AKI.
9. High-risk patients with multiple injuries should be cared for in a critical care environment.
10. Medical and surgical management of patients with established rhabdomyolysis should occur simultaneously.