Critical care considerations in rhabdomyolysis-associated acute kidney injury and kidney replacement therapy

Table 1 Causes of rhabdomyolysis[16,20,73,105,106]

Acquired
Trauma	Crush injuries; compression; electrical injury
Exertion	Strenuous activities; seizures; alcohol withdrawal syndrome
Prolonged immobilisation	Surgery (vascular, orthopaedic)
Body temperature changes	Malignant hyperthermia; neuroleptic malignant syndrome; exposure to extreme heat; hypothermia
Infections	Influenza A and B; coxsackie virus; Epstein-Barr virus; primary human immunodeficiency virus; Legionella species; Streptococcus pyogenes; Staphylococcus aureus; enterobacteria
Drugs and toxins	Lipid-lowering drugs (statins, fibrates, ezetimibe); antibiotics (macrolides, protein synthesis inhibitors, quinolones); antivirals; antiparasitics; anaesthetics (succinylcholine, propofol); heroin, cocaine, lysergic acid diethylamide, amphetamine
Electrolyte imbalances	Hypokalaemia; hypophosphatemia; hypocalcaemia; diabetic ketoacidosis
Inflammatory myopathy	Dermatomyositis; polymyositis; overlap myositis
Genetic
Disorders of lipid metabolism	Carnitine palmitoyltransferase deficiency
Disorders of carbohydrate metabolism	McArdle’s disease; Tarui’s disease
Mitochondrial myopathy	Succinate dehydrogenase deficiency

Table 2 Differential diagnoses of rhabdomyolysis[1,20,21,24]

	Urine dipstick (blood)	Urine microscopy	Creatine kinase level	Liver function test	Electrocardiogram changes
Rhabdomyolysis	Positive	No/minimal RBCs	High (often > 1000 IU/L)	AST raised; AST > ALT; normal GGT/ALP	Absent
Hematuria	Positive	Raised RBCs	Normal	Normal	Absent
Hemoglobulinuria	Positive	No RBCs	Normal	Raised indirect bilirubin	Absent
Myocardial infarction	Negative	No RBCs	Mild-moderately increased	Normal (may have mildly raised AST)	Present (ST elevations)
Liver disease	Negative	No RBCs	Normal	Raised AST, ALT, GGT/ALP, bilirubin; AST ≥ ALT	Absent

RBC: Red blood cell; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; GGT: Gamma-glutamyl transpeptidase; ALP: Alkaline phosphatase.

Table 3 Summary of management strategies of rhabdomyolysis-associated acute kidney injury

Management therapy	Recommendation
Fluid resuscitation	Early initiation; use crystalloids (lactated Ringer’s or normal saline); volume of 6 L/day or more
Bicarbonate, mannitol and antioxidant use	Based on clinician’s judgement; limited evidence with little difference in outcomes
Monitoring	Electrolyte imbalances: Hyperkalemia, hyperphosphatemia, hypocalcemia, hypomagnesemia; hemodynamic monitoring: Mean arterial pressure, renal perfusion pressure
Diuretics	Not necessary, except in fluid overload

Table 4 Indications of kidney replacement therapy in rhabdomyolysis-associated acute kidney injury[78,107,108]

	Indications for kidney replacement therapy
Absolute indications	Refractory hyperkalemia (K+ > 6.5 mmol/L, rapidly increasing or associated with cardiac arrhythmias)
	Refractory pulmonary edema (diuretic resistant)
	Refractory metabolic acidosis (pH < 7.2)
	Blood urea nitrogen concentration of > 40.0 mmol/L
	Uremia with signs and symptoms (e.g., pericarditis, encephalopathy, bleeding)
	Refractory fluid overload with organ dysfunction
	Concomitant drug/toxin intoxication that is dialysable
Relative indications	Severe non-renal organ dysfunction from AKI/fluid overload
	Progressive/persistent AKI (serum creatinine > 3 times baseline and/or profound oliguria)
	Worsening trajectory of critical illness

AKI: Acute kidney injury.