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Guilherme Mazui

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What is the Difference Between Myositis and Rhabdomyolysis?

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Myositis and rhabdomyolysis are both related to muscle damage and dysfunction, but they differ in their underlying causes, symptoms, and consequences:

Myositis:

  • Inflammation of muscle tissue, usually caused by viral infections, autoimmune disorders, or medication side effects.
  • Common triggers include influenza A/B, enteroviruses, Epstein-Barr virus, and others.
  • Symptoms include muscle pain, weakness, and sometimes fever and fatigue.
  • Creatine kinase levels are only mildly elevated.
  • Influenza myositis usually resolves spontaneously within 6 weeks.

Rhabdomyolysis:

  • Rapid death of muscle tissue, resulting from injury, drug toxicity, disease, or other causes.
  • Causes include viral infections, trauma, myotoxic substances, autoimmune myositis, and medication side effects.
  • Symptoms include muscle pain (particularly in the shoulders, thighs, or lower back), muscle weakness, and dark red or brown urine (the color of tea) or decreased urine production.
  • Creatine kinase levels are markedly elevated, sometimes greater than 5,000 u/l.
  • Rhabdomyolysis can lead to acute kidney injury (AKI) and, in rare cases, death if not promptly treated.

In some cases, patients experiencing severe, acute-onset myositis may develop rhabdomyolysis as a complication. Early diagnosis and treatment of both conditions are crucial for successful outcomes.

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  • What is the Difference Between Myositis and Rhabdomyolysis?
  • Comparative Table: Myositis vs Rhabdomyolysis

    • Comparative Table: Myositis vs Rhabdomyolysis

    Here is a table comparing the differences between myositis and rhabdomyolysis:

    Feature Myositis Rhabdomyolysis
    Definition Myositis is a condition that causes inflammation of the muscle. Rhabdomyolysis is a condition that causes muscle breakdown and muscle death.
    Causes Myositis can be caused by various factors, including infections, autoimmune disorders, and certain medications. Rhabdomyolysis is often caused by drug or alcohol abuse, medicinal drug use, trauma, Neuroleptic Malignant Syndrome (NMS), and immobility.
    Symptoms Symptoms of myositis may include muscle pain, stiffness, and weakness. Symptoms of rhabdomyolysis include myalgia, weakness, and myoglobinuria, with an elevation in creatine kinase (CK) level being the most sensitive test for muscle injury-induced rhabdomyolysis.
    Diagnosis Diagnosis of myositis typically involves a thorough medical history, physical examination, and laboratory tests, such as blood tests and imaging studies. Diagnosis of rhabdomyolysis is based on the presence of muscle injury with an unexpected rise in serum CK levels, as well as clinical manifestations.
    Treatment Treatment for myositis depends on the underlying cause and may include rest, physical therapy, medications, and in some cases, surgery. Treatment for rhabdomyolysis involves addressing the underlying cause, managing complications, and supporting the affected patient, as well as preventing further muscle damage.
    Complications Untreated myositis can lead to muscle atrophy, contractures, and chronic pain. Untreated rhabdomyolysis can lead to acute kidney injury, hyperkalemia, and disseminated intravascular coagulation.

    Remember that both myositis and rhabdomyolysis can lead to life-threatening complications if not treated in a timely manner.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.