Rhabdomyolysis

Labs:

    • CBC with diff, CMP, serum albumin, uric acid, CPK (usually >10,000 IU/L or 5 x upper limit of normal), CK-MB (<5% of total CPK), CPK peaks at 24 – 72 h, then declines after 72 h; if it doesn’t think about ongoing injury or some other cause.

    • LDH, aldolase, UA, urine myoglobin (cleared within 1 – 6 h after injury), troponin, CBC with diff, TSH, BMP, UDS, blood alcohol, BC x 2, LFTs, PT/INR, aPTT, plasma fibrinogen, factors V, VIII, FDP, Fibrin monomers, D-dimer

    • Influenza A & B. ABGs

    • Urine dipstick test that dips positive for Hb without the presence of RBC on microscopic urine exam indicates the possible presence of myoglobin.

    • Hyperkalmeia, hyperphosphatemia initially and then hypophosphatemia if the condition progresses, hyperuricemia, hypocalcemia, metabolic acidosis

    • ECG

Consult: Nephrology, toxicology

    • Nursing: I/O, Foley (target UO: 200 – 300 mL/h)

    • Avoid IVP, metformin.

Management:

    • Check for ECFV status, CVP, and UO.

    • Measure Sr. CK levels. Measurement of other muscle enzymes (myoglobin, aldolase, lactate dehydrogenase, ALT, AST) adds little information relevant to the Dx or management.

    • Measure plasma and urine Cr, potassium, sodium, BUN, total and ionized calcium, Mg, phosphorus, and uric acid and albumin. Evaluated acid-base status, blood cell count, and coagulation.

    • Perform a urine dipstick test and examine the urine sediment.

    • Initiate volume repletion with NS promptly at a rate of approximately 400 mL/hr (200 - 1000 mL/hr) depending on the setting and severity), with monitoring of the clinical picture or of CNS.

    • Target urine output of approximately 3 mL/kg of body wt. per hour (200 mL/hr)

    • Check serum potassium frequently.

    • Correct hypocalcemia only if symptomatic (e.g., tetany or seizures) or if severe hyperkalemia occurs.

    • Investigate the cause of rhabdomyolysis.

    • Check urine pH, if it is less than 6.5, alternate each liter of NS with 1 liter of D5W or 1/2 NS + 100 mmol bicarbonate. Avoid potassium and lactate-containing solutions.

    • Consider treatment with mannitol (up to 200 g per day and cumulative dose up to 800 g). Check for plasma osmolality and plasma osmolal gap. Discontinue if diuresis (>20 ml/hr) is not established.

    • Maintain volume repletion until myoglobinuria is cleared (as evidenced by clear urine or a urine dipstick testing result that is negative for blood).

    • Consider renal-replacement therapy if there is resistant hyperkalemia of more than 6.5 mmol per liter that is symptomatic (as assessed by ECG), rapidly rising serum potassium, oliguria (<0.5 mL of urine per kg per hr x 12 hr), anuria, volume overload, or resistant metabolic acidosis (pH <7.1)

    • Treat underlying cause

    • Aggressive IVF hydration (10 L a day)

    • Give NaHCO3, 2 - 3 amp in D5W 1L. Or NS - IVF

    • Mannitol 20%, 1 kg IV x 30 minutes, or furosemide 40 – 200 mg IV. Bicarbonate 44 – 100 mEq/L in 0.45% NS to promote diuresis and urine alkalinization.

    • Keep pH >6

    • If compartment synd, check compartment pressures and fasciotomy should be considered.

    • HD

    • Hyperkalemia and hypocalcemia treated with calcium gluconate. Kayexlate.

    • Hyperphosphatemia treated with phosphate binders if Sr. Phos >7 mg/dL. Replace if Sr. Phos <1 mg/dL.

    • If sodium bicarbonate is used, urine pH and Sr. HCO3, Ca, and K levels should be monitored q4hr and if the urine pH does not rise after 4 - 6 hours of treatment or if symptomatic hypocalcemia develops, alkalinization should be discontinued and hydration continued with normal saline.

    • Anticipate hypercalcemia in late rhabdomyolysis. Do not mix with bicarbonate solutions.

Etiology:

    • Direct muscle injury: Trauma or muscle compression, electrical injury, lighting injury.

    • Drugs of abuse: Amphetamines, caffeine, cocaine, ETOH, gasoline, heroin, LSD, marijuana, mescaline, methamphetamines, opiates, PCP, polyweed, toluene.

    • Excessive muscular activity: acute dystonia, DTs, isometric exercise, lethal catatonia, psychosis, seizurs, status asthmaticus.

    • Genetic: Involving -CHO and lipid metabolism

    • Immunologic: DM, PM

    • Infection: Gas gangrene, GABH strep, Legionnaires’ disease, Salmoneall, septic shock, shigella, S. aureus, S. pneumoniae, trichinosis, RMSF, Coxsackievirus, CMV, echovirus, EBV, Hepatitis, HSV, HIV, influenza A and B, rotavirus.

    • Ischemic injury: compartment synd, compression, sickle cell disease, embolism, thrombosis, vasculitis.

    • Medications: amphotericin-B, antihistamines, azathioprines, barbiturates, benzos, butyrophenones, chlorpromazine, cimetidine, clofibrate, codeine, cohlchicine, corticosteroids, TMP/SMX, epsilion aminocaproic acid, IH anesthetics, INH, lindane, lithium, statin, MAOI, narcotics, neuroleptics, organic solvents, pentamidine, phenothiazines, phenylpropanolamine, phenytoin, procainamide, quinine, salicylates, sertonergic agents, succinylcholine, theophylline, TCA, vasopressin

    • Metabolic d/o: DKA, hyperaldosteronism, hypernatremia, hyponatremia, hypokalemia, hypophosphatemia, hypothyroidism, HHNKS, thyroid storm, sympathetic storm.

    • Temperature related: heatstroke, hyperthermia, hypothermia, malignant hyperthermia. NMS

    • Toxins: brown spider bite, CO, centipede bite, cyanide, ethylene glycol, Haff disease, hymenoptera sting, isopropyl alcohol, mercuric chloride, methanol, snake venom, tetanus toxin, typhoid toxin, water hemlock.

Alkalinization of urine:

    • Tamm-Horsfall protein-myoglobin complex is increased in acidic urine.

    • Alkalinization inhibits reduction-oxidation (redox) cycling of myoglobin and lipid peroxidation in rhabdomyolysis, thus ameliorating tubule injury.

    • Metmyoglobin induces vasoconstriction only in acidic medium in the isolated perfused kidney.

Disadvantage of alkalinization is the reduction in ionized calcium which can exacerbate the symptom of initial hypocalcemic phase of rhabdomyolysis.