Rhabdomyolysis, Muscular injury 4.64/5 (14)

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Definition

Rhabdomyolysis is serious damage to muscle tissue (muscle cells). Proteins (among others myoglobin) from the muscle cells is released into the bloodstream, which can damage the kidneys (reference: Knochel JP, 1993). The muscle enzyme Creatine kinase (CK) is very high in the blood. Rhabdomyolysis is not one systemic connective tissue disease, but some disease features can be similar and can sometimes be seen as a complication. The condition is usually treated in a department of internal medicine.

Disease Cause

Rhabdomyolysis may occur during exercise. City www.localfitness.com.au - Own work, CC BY-SA 3.0

Several possible conditions can cause rhabdomyolysis. The most common causes of illness are muscular overload (hard exercise), alcohol abuse, drugs (cholesterol-lowering statins, SSRIs for depression, colchicine, ciclosporin, erythromycin, zidovudine (Retrovir), acetylsalicylic acid, amphotericin B, isoniazid, trimethoprim-sulfa, benzodiazepines, ketamine, propofol) and illegal drugs such as cocaine, ecstasy (MDMA), LSD, heroin. Below is an alphabetical list of some causes of rhabdomyolysis:

Symptoms

Rhabdomyolysis. Muscle damage causes the CK enzyme to be released in large quantities and via the bloodstream damage the kidneys. The urine turns "cola" brown. By AquapatMedia / creativecommons.org /Wikimedia Commons. CC BY SA 3.0
  • Mild forms (moderately elevated CK) may have few symptoms
  • Muscle Pain
  • Muscle weakness
  • Brown-colored urine: "Coca-Cola urine"
  • Muscle swelling
  • Other

Examinations

Disease history should include possible predisposing causes such as drug abuse, insect bites, overheating, recent surgery, recently increased drug doses, antibiotics and dietary supplements, anabolic agents, as well as unfamiliar exercise, injuries and other physical stresses.

Clinical examination A general examination can reveal thickened (hypertrophic) muscles or thin (atrophic) muscles with reduced strength, particularly in the thighs and upper arms. Swelling (oedema) can develop and cause pressure on nerves and blood vessels in the form of compartment syndrome in the legs or arms. At the same time, signs of experienced, triggering muscle damage are assessed. Signs of systemic manifestations include personality change with agitation, decreased urinary output, brown-colored urine (“tea/cola urine”), vomiting, fever, nausea and fatigue.

Blood tests. Routine tests include CRP, SR, Hgb, leukocytes with differential counts, liver, kidney and thyroid function tests, albumin, creatine kinase (CK), electrolytes and urine dipstick. Slightly increased CRP, SR and leukocytosis are common findings. Creatine kinase (CK) increases to at least 5 times (usually over 40 x ) the upper normal value. The increase starts 2-12 hours after the triggering event, reaches its maximum after 1-3 days and decreases after 3-5 days. CK is halved every 24-36 hours (half-life) when the triggering cause has been removed. In the differential diagnosis Myositis (inflammatory connective tissue disease) CK more than 15.000 U/L is rarely seen, but in rhabdomyolysis CK 30.000 to 100.000 U/L is not unusual. About 30% with rhabdolysis develop kidney failure with increasing creatinine and low eGFR in the blood. Initially low calcium, then high values ​​may occur. Bleeding disorders in the form of disseminated intravascular coagulation (DIC) are a feared complication associated with increased thrombin time, activated thromboplastin time, INR, D-dimer and reduced platelets and fibrinogen in the blood.

Urine. Myoglobin from muscle cells is excreted in the urine and causes a rash of "blood" on a urine sample, but without erythrocytes on microscopy.

Imaging. MRI shows swelling (edema) in the affected muscles, but is not specific for rhabdomyolysis. MRI can locate a suitable place for a tissue sample (muscle biopsy). X-ray or CT of the lungs and X-ray of any skeletal injuries. CT can also reveal signs of compartment syndrome.

ECG with hyperkalemia, may show signs of rhythm disturbances and electrolyte disturbances with elevated T waves, prolonged PR interval, wide QRS with or without conduction block, ventricular arrhythmia or tachycardia.

Tissue sample (biopsy). Muscle biopsy shows cell death (necrosis), but without inflammation unlike myositis.

Similar conditions / differential diagnoses

  • Myositis. Not so high CK values, ANA test most often fails, slower disease onset. Dermatomyositis with eczema.
  • Muscular Dystrophy and other non-inflammatory muscle diseases.
  • Guillain-Barre syndrome. Not high CK. Rapidly increasing numbness and paralysis
  • Children: Infections (viruses, bacteria), injuries (including abuse), congenital enzyme defects.

Treatment

The treatment takes place in a hospital, most often in a department of internal medicine. The purpose is primarily to prevent kidney damage/kidney failure while the condition normalizes spontaneously over days-weeks. One must remove the triggering cause (drug, other chemical substance), counteract shock and preserve renal function Intravenous fluid (0,9% NaCl), correction of electrolyte disturbances (which often occur) and, if necessary, alkalinization of the urine to PH 7-8 . Dialysis in severe renal failure. Hospitals often have their own procedures.

Prognosis

Life prospects depend on the underlying cause, and whether salts in the blood (electrolytes) and the kidneys are seriously affected. CK value alone is not a good parameter for the prognosis, but everyone with a CK of more than 10.000 U/L initially has a risk of kidney damage and other complications (see above). Most people with exercise-induced rhabdomyolysis regain normal kidney and muscle function.

Literature


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