Differential Diagnosis for Elevated CK

The differential diagnosis for elevated creatine kinase (CK) levels can be organized into the following categories:

• Single Most Likely Diagnosis
  • Muscle strain or injury: This is the most common cause of elevated CK levels, as muscle damage leads to the release of CK into the bloodstream. Activities such as intense exercise, trauma, or even minor strains can cause this elevation.
• Other Likely Diagnoses
  • Myopathies (e.g., muscular dystrophy): These are diseases that affect the muscles, leading to muscle damage and elevated CK levels.
  • Statin-induced myopathy: Certain cholesterol-lowering medications, known as statins, can cause muscle damage as a side effect, leading to elevated CK levels.
  • Hypothyroidism: This condition, where the thyroid gland does not produce enough thyroid hormones, can lead to muscle damage and elevated CK levels.
• Do Not Miss Diagnoses
  • Rhabdomyolysis: A serious condition where muscle tissue breaks down, releasing CK and other substances into the bloodstream. This can lead to kidney damage and other complications if not promptly treated.
  • Acute myocardial infarction (heart attack): Elevated CK levels, particularly the CK-MB isoform, can indicate heart muscle damage.
  • Neuroleptic malignant syndrome: A life-threatening neurological disorder caused by certain medications, which can lead to muscle damage and elevated CK levels.
• Rare Diagnoses
  • McArdle's disease: A rare genetic disorder that affects the muscles, leading to elevated CK levels.
  • Dermatomyositis: A rare inflammatory disease that affects the muscles and skin, causing elevated CK levels.
  • Polymyositis: A rare inflammatory disease that affects the muscles, leading to elevated CK levels.

Each of these diagnoses has a unique set of clinical features and laboratory findings that can help guide the diagnosis. It is essential to consider the patient's medical history, physical examination, and other laboratory results when evaluating elevated CK levels.