Updated: Jan 4, 2010
Myoglobinuria is usually the result of rhabdomyolysis or muscle destruction. Any process that interferes with the storage or use of energy by muscle cells can lead to myoglobinuria. The release of myoglobin from muscle cells is often associated with an increase in levels of creatine kinase (CK), aldolase, lactate dehydrogenase (LDH), serum glutamic-pyruvic transaminase (SGPT), and other enzymes. When excreted into the urine, myoglobin, a monomer containing a heme molecule similar to hemoglobin, can precipitate, causing tubular obstruction and acute kidney injury.
A clinician caring for a patient with crush injuries or other causes of muscle destruction must recognize the presence and severity of myoglobinuria and initiate aggressive hydration to prevent acute kidney injury.
The most common causes of myoglobinuria in adults are trauma, alcohol and drug abuse, usually in relation to muscle necrosis from prolonged immobilization and pressure by the body weight. Prolonged ethanol consumption and seizure activity, similar to excessive physical activity, can produce an imbalance between muscle energy consumption and production, resulting in muscle destruction. In children and adolescents, the most common causes of rhabdomyolysis and myoglobinuria are viral myositis, trauma, exertion, drug overdose,[1 ]seizures, metabolic disorders, and connective tissue disease.
Myoglobin is released from muscle tissue by cell destruction and alterations in the permeability of the skeletal muscle cell membrane.[2,3,4 ]Under normal conditions, the sodium potassium ATPase pump maintains a very low intracellular sodium content. A separate sodium-calcium channel then serves to pump additional sodium into the cell in exchange for calcium extrusion from the cell. In addition, most intracellular calcium is normally sequestered within organelles. Damage to muscle cells interferes with both mechanisms, leading to an increase in free ionized calcium in the cytoplasm. The high intracellular calcium activates numerous calcium-dependent enzymes that further break down the cell membrane, leading to the release of intracellular contents such as myoglobin and creatine kinase into the circulation. A model of the helical domains of myoglobin is shown in the image below.
The frequency of myoglobinuria varies with the incidence of natural disasters and environmental trauma. Epidemics of viral myositis may temporarily increase the incidence in local areas. In urban areas with a high incidence of drug and alcohol abuse, many patients with myoglobinuria may present to emergency departments. Hot weather increases the incidence of stress induced rhabdomyolysis, especially in young athletes.
Acute kidney injury due to rhabdomyolysis was first described by Bywaters and Beall during World War II; they noted the hypovolemic shock, dark urine, and kidney failure that developed in survivors from the rubbles of the London bombings. Crush injuries related to earthquakes and other natural disasters are the major cause of cases reported internationally. Any person dug from the rubble of such disasters should be considered to have rhabdomyolysis, myoglobinuria, and potential acute renal failure and, therefore, should be given rapid fluid resuscitation.
Myoglobinuria causes little or no morbidity or mortality unless it is associated with the secondary complications of rhabdomyolysis, including hyperkalemia, hypocalcemia, and acute kidney injury.{{ Ref2} However, when it is associated with severe rhabdomyolysis, myoglobinuria-induced acute renal failure is a potentially lethal complication.
In adults, rhabdomyolysis can be complicated by acute kidney injury in approximately 30% of patients,[5 ] with about 5% of those requiring hemodialytic support. In the pediatric age group, although previous small case series reported acute renal failure rates of 40-50%, a large retrospective review indicates that only about 5% of subjects with rhabdomyolysis develop acute kidney injury (defined as a serum creatinine level >97.5 percentile for age and gender).[6 ] Rhabdomyolysis accounts for or contributes to about 7% of all causes of acute kidney injury in the United States.[7 ] In both adults and children, the overall mortality rate of acute severe rhabdomyolysis is reported to be 7-8% and is primarily related to acute renal failure and multiorgan failure.
Race is a factor only when natural disasters and economic shortfalls increase the rates of drug and alcohol abuse and the mortality rate among certain racial groups.
Myoglobinuria tends to affect males more than females because of the former group's predisposition to trauma and participation in strenuous physical exercise. Persons who exercise and have increased muscle mass have an increased intracellular myoglobin content.
In a recent large retrospective review, the median age was 11 years.[6 ] The leading cause of rhabdomyolysis in the 0-9 year age range was viral myositis, whereas the leading diagnosis in the 9-18 year age range was trauma.
The classical triad of symptoms of rhabdomyolysis includes myalgia, muscle weakness, and dark urine. The typical history may include drug use, coma, trauma, or strenuous exercise. Patients who use diuretics and develop severe potassium deficiency may be predisposed to rhabdomyolysis.
| Acidosis, Metabolic | Hypokalemia |
| Asthma | Hyponatremia |
| Bacteremia | Mixed Connective Tissue Disease |
| Birth Trauma | Parainfluenza Virus Infections |
| Child Abuse & Neglect: Physical
Abuse | Rhabdomyolysis |
| Dehydration | Status Epilepticus |
| Down Syndrome | Tumor Lysis Syndrome |
| Head Trauma | Viral Hemorrhagic Fevers |
| Hypercalcemia | |
| Hyperthyroidism | |
| Hypocalcemia |
Metabolic myopathies
Sepsis
All patients with suspected myoglobinuria or rhabdomyolysis should be admitted for intravenous (IV) hydration and management of complications. A creatine kinase (CK) level of more than 5000 U/L is considered to be an absolute indication for hospitalization and vigorous IV hydration. Initial treatment focuses on preventing myoglobin precipitation in the urine by inducing and maintaining a brisk diuresis. Immediately administer saline to patients with suspected myoglobinuria or rhabdomyolysis because early hydration is the key to ameliorate acute kidney injury. Isotonic saline boluses of 20 mL/kg should be initially administered, with repeat boluses depending on the hydration status of the patient. This should be followed by continued hydration with IV fluids given at a rate of 2-3 times maintenance.[4 ]
Achievement of a urine output goal of 2-3 mL/kg/h is recommended. IV hydration should be continued until the CK level is consistently less than 1000 U/L, the urine clears, and the patient is able to maintain adequate oral hydration.
Follow-up with mannitol to induce diuresis, supported by adequate IV fluids, has been advocated. Mannitol causes diuresis, which minimizes intratubular myoglobin deposition, acts as a free radical scavenger and reduces tubule cell damage, and may act as a direct renal vasodilator. However, the clinical benefit of this therapy remains unproven. In retrospective studies, volume expansion with saline alone prevented acute renal failure, and mannitol had no additional benefit.[12 ]
Raising the pH of the urine to 6.5 or more can be facilitated by adding sodium bicarbonate to the fluids. Alkalinization of the urine has been postulated to minimize the breakdown of myoglobin into its nephrotoxic metabolites and to reduce crystallization of uric acid, thereby decreasing damage to tubule cells. However, this modality of therapy remains somewhat controversial because large volumes of crystalloid alone may be sufficient to alkalinize the urine and because bicarbonate therapy can aggravate the hypocalcemia. No large randomized trials have demonstrated that alkalinization of urine is superior to early aggressive hydration with crystalloid in the management of rhabdomyolysis.
Surgical debridement may be needed if muscle damage or necrosis is extensive. Fasciotomy may be required to manage compartment compression syndrome.
Nephrologists may facilitate the safe initiation of diuresis to avoid dialysis. If dialysis is needed, consultation with a nephrologist is necessary.
Activity is restricted by the extent of muscle damage. Persons who have had exertional myoglobinuria must limit their future activity and maintain adequate hydration.
In patients with myoglobinuria, administer a sodium chloride solution for volume depletion as 0.9% NaCl solution, lactated Ringers solution, or a solution of 0.45% NaCl and sodium bicarbonate 50 mEq/L. Mannitol may be administered to facilitate osmotic diuresis. Diuretics such as furosemide are less desirable because they may accentuate intravascular volume depletion.
These agents raise the osmolality of plasma and renal tubular fluid, which creates an osmotic inhibition of water transport in the proximal tubule. This effect subsequently decreases the gradient for passive sodium absorption in the ascending limb of the loop of Henle. The increased urinary flow is achieved by means of nonelectrolyte solute diuresis. Increased glomerular filtration rate may also be observed.
Osmotic diuretic. Inhibits tubular reabsorption of electrolytes by increasing osmotic pressure of glomerular filtrate. Increases urinary output.
0.25-0.5 g/kg/dose IV; limit to bid for no more than 2 d to avoid resistance
Administer as in adults
May decrease serum lithium levels
Documented hypersensitivity; anuria; severe pulmonary congestion; progressive renal damage; severe dehydration; active intracranial bleeding; progressive heart failure
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Carefully evaluate cardiovascular status before rapid administration because a sudden increase in extracellular fluid may lead to fulminating CHF; avoid pseudoagglutination, when blood is administered simultaneously, add at least 20 mEq NaCl to each liter of mannitol solution; do not administer electrolyte-free mannitol solutions with blood
Sodium bicarbonate is used as a gastric, systemic, and urinary alkalinizer. Sodium bicarbonate is administered IV to alkalinize the urine in patients with rhabdomyolysis because it may prevent the toxicity that can result from the presence of myoglobin in acidic urine and prevent the crystallization of uric acid.
Useful in alkalizing urine to prevent acute myoglobinuric renal failure. Titrate dose to increase pH >7, usually available as 1 mEq/mL. Add to 0.45% NaCl to deliver 1-2 mEq/kg/d.
1-2 mEq/kg/d IV; adjust dose according to serum and urinary pH
Administer as in adults
Urinary alkalinization induced by increased sodium bicarbonate concentrations may cause decreased levels of lithium, tetracyclines, chlorpropamide, methotrexate, and salicylates; increases levels of amphetamines, pseudoephedrine, flecainide, anorexiants, mecamylamine, ephedrine, quinidine, or quinine
Alkalosis; hypernatremia; hypocalcemia; severe pulmonary edema; unknown abdominal pain
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
May cause alkalosis, decreased plasma potassium, hypocalcemia, or hypernatremia; caution in electrolyte imbalances (eg, CHF, cirrhosis, edema, corticosteroid use, renal failure); use extravasation precautions to avoid tissue necrosis
[Guideline] Clarke W, Frost SJ, Kraus E, et al. Renal function testing. Laboratory medicine practice guidelines: evidence-based practice for point-of-care testing. National Academy of Clinical Biochemistry (NACB). 2006;[Full Text].
Chatzizisis YS, Misirli G, Hatzitolios AI, Giannoglou GD. The syndrome of rhabdomyolysis: complications and treatment. Eur J Intern Med. Dec 2008;19(8):568-74. [Medline].
Bosch X, Poch E, Grau JM. Rhabdomyolysis and acute kidney injury. N Engl J Med. Jul 2 2009;361(1):62-72. [Medline].
Luck RP, Verbin S. Rhabdomyolysis: a review of clinical presentation, etiology, diagnosis, and management. Pediatr Emerg Care. Apr 2008;24(4):262-8. [Medline].
Lima RS, da Silva Junior GB, Liborio AB, Daher Ede F. Acute kidney injury due to rhabdomyolysis. Saudi J Kidney Dis Transpl. Sep 2008;19(5):721-9. [Medline].
Mannix R, Tan ML, Wright R, Baskin M. Acute pediatric rhabdomyolysis: causes and rates of renal failure. Pediatrics. Nov 2006;118(5):2119-25. [Medline].
Elsayed EF, Reilly RF. Rhabdomyolysis: a review, with emphasis on the pediatric population. Pediatr Nephrol. Jun 16 2009;[Medline].
Fujii K, Minami N, Hayashi Y, et al. Homozygous female Becker muscular dystrophy. Am J Med Genet A. May 2009;149A(5):1052-5. [Medline].
Mannix R, Tan ML, Wright R, Baskin M. Acute pediatric rhabdomyolysis: causes and rates of renal failure. Pediatrics. Nov 2006;118(5):2119-25. [Medline].
Coco TJ, Klasner AE. Drug-induced rhabdomyolysis. Curr Opin Pediatr. Apr 2004;16(2):206-10. [Medline].
Huerta-Alardin AL, Varon J, Marik PE. Bench-to-bedside review: Rhabdomyolysis -- an overview for clinicians. Crit Care. Apr 2005;9(2):158-69. [Medline].
Brown CV, Rhee P, Chan L, et al. Preventing renal failure in patients with rhabdomyolysis: do bicarbonate and mannitol make a difference?. J Trauma. Jun 2004;56(6):1191-6. [Medline].
Dalakas MC. Toxic and drug-induced myopathies. J Neurol Neurosurg Psychiatry. Aug 2009;80(8):832-8. [Medline].
David WS. Myoglobinuria. Neurol Clin. Feb 2000;18(1):215-43. [Medline].
Fernandez WG, Hung O, Bruno GR, Galea S, Chiang WK. Factors predictive of acute renal failure and need for hemodialysis among ED patients with rhabdomyolysis. Am J Emerg Med. Jan 2005;23(1):1-7. [Medline].
Giannoglou GD, Chatzizisis YS, Misirli G. The syndrome of rhabdomyolysis: Pathophysiology and diagnosis. Eur J Intern Med. Mar 2007;18(2):90-100. [Medline].
Kilfoyle D, Hutchinson D, Potter H, George P. Recurrent myoglobinuria due to carnitine palmitoyltransferase II deficiency: clinical, biochemical, and genetic features of adult-onset cases. N Z Med J. Feb 25 2005;118(1210):U1320. [Medline].
Lin AC, Lin CM, Wang TL, Leu JG. Rhabdomyolysis in 119 students after repetitive exercise. Br J Sports Med. Jan 2005;39(1):e3. [Medline].
Malinoski DJ, Slater MS, Mullins RJ. Crush injury and rhabdomyolysis. Crit Care Clin. Jan 2004;20(1):171-92. [Medline].
Melli G, Chaudhry V, Cornblath DR. Rhabdomyolysis: an evaluation of 475 hospitalized patients. Medicine (Baltimore). Nov 2005;84(6):377-85. [Medline].
Ocana J, Echarri R, Liano F. Rhabdomyolysis. Am J Kidney Dis. Jan 2006;47(1):A32, e1-2. [Medline].
Sharp LS, Rozycki GS, Feliciano DV. Rhabdomyolysis and secondary renal failure in critically ill surgical patients. Am J Surg. Dec 2004;188(6):801-6. [Medline].
rhabdomyolysis, acute renal failure, acute kidney injury, hyperkalemia, hypocalcemia, myoglobinuria, tubular obstruction, acute renal insufficiency, crush injury, viral myositis, connective tissue disease, hyperkalemia, hypocalcemia
Prasad Devarajan, MD, Louise M Williams Endowed Chair in Pediatrics, Professor of Pediatrics and Developmental Biology, Director of Nephrology and Hypertension, Director of Clinical Nephrology Laboratories, Chief Executive Officer of Dialysis Unit, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine
Prasad Devarajan, MD is a member of the following medical societies: American Heart Association, American Society of Nephrology, American Society of Pediatric Nephrology, National Kidney Foundation, and Society for Pediatric Research
Disclosure: Nothing to disclose.
Watson C Arnold, MD, Director, Department of Pediatric Nephrology, Cook Children's Medical Center
Watson C Arnold, MD is a member of the following medical societies: American College of Medical Quality, American Federation for Medical Research, American Society for Nutritional Sciences, American Society of Nephrology, American Society of Pediatric Nephrology, International Society of Nephrology, Sigma Xi, Southern Society for Pediatric Research, Texas Medical Association, and Texas Pediatric Society
Disclosure: Nothing to disclose.
Laurence Finberg, MD, Clinical Professor, Department of Pediatrics, University of California at San Francisco and Stanford University
Laurence Finberg, MD is a member of the following medical societies: American Medical Association
Disclosure: Nothing to disclose.
Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine
Disclosure: Nothing to disclose.
Frederick J Kaskel, MD, PhD, Director of the Division and Training Program in Pediatric Nephrology, Vice Chair, Department of Pediatrics, Montefiore Medical Center and Albert Einstein School of Medicine
Frederick J Kaskel, MD, PhD is a member of the following medical societies: American Academy of Pediatrics, American Association for the Advancement of Science, American Pediatric Society, American Physiological Society, American Society of Nephrology, American Society of Pediatric Nephrology, American Society of Transplantation, Eastern Society for Pediatric Research, Federation of American Societies for Experimental Biology, International Society of Nephrology, National Kidney Foundation, New York Academy of Sciences, Renal Physicians Association, Sigma Xi, and Society for Pediatric Research
Disclosure: Nothing to disclose.
Howard Trachtman, MD, Program Director, Pediatrics Research, Schneider Children's Hospital, Department of Pediatrics, Division of Nephrology, Professor, Albert Einstein College of Medicine
Howard Trachtman, MD is a member of the following medical societies: American Society of Hypertension, American Society of Nephrology, American Society of Pediatric Nephrology, and Society for Pediatric Research
Disclosure: Nothing to disclose.
Craig B Langman, MD, The Isaac A Abt, MD, Professor of Kidney Diseases, Feinberg School of Medicine, Northwestern University; Division Head of Kidney Diseases, Children's Memorial Hospital, Chicago
Craig B Langman, MD is a member of the following medical societies: American Academy of Pediatrics, American Society of Nephrology, and International Society of Nephrology
Disclosure: Amgen Grant/research funds None; Altus Pharmaceuticals Grant/research funds None; Genzyme Grant/research funds None; Merck Grant/research funds None; NIH Grant/research funds None
© 1994-
by Medscape.
All Rights Reserved
(http://www.medscape.com/public/copyright)