What is the differential diagnosis for a young male with significantly elevated creatine kinase (CK) levels one week after a weightlifting session, without excessive weight or medication use?

Differential Diagnosis for Elevated CK in a Young Guy

Single most likely diagnosis

• Exertional Rhabdomyolysis: This condition is caused by intense physical activity, such as weight lifting, leading to muscle damage and release of creatine kinase (CK) into the bloodstream. The fact that the patient's CK level is elevated 1 week after weight lifting, even with not too much weight, supports this diagnosis. The patient's age and lack of medication use also make this a likely cause.

Other Likely diagnoses

• Muscle Strain or Injury: Weight lifting can cause muscle strain or injury, leading to elevated CK levels. Although the patient reported not lifting too much weight, any injury to the muscle can cause CK elevation.
• Viral Myositis: Viral infections, such as influenza or coxsackievirus, can cause muscle inflammation and elevated CK levels. The patient's age and lack of medication use make this a possible diagnosis.

Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)

• Duchenne Muscular Dystrophy: Although rare, this genetic disorder can cause progressive muscle weakness and elevated CK levels. It is essential to consider this diagnosis, especially if the patient has a family history or other symptoms such as muscle weakness or wasting.
• McArdle Disease: This rare genetic disorder affects the muscle's ability to break down glycogen, leading to elevated CK levels and muscle cramps after exercise. Although unlikely, it is crucial to consider this diagnosis to avoid missing a potentially treatable condition.
• Statins or other medication-induced myopathy: Although the patient reported not being on medication, it is essential to consider the possibility of medication-induced myopathy, especially if the patient is taking statins or other medications that can cause muscle damage.

Rare diagnoses

• Polymyositis: This autoimmune disorder causes muscle inflammation and weakness, leading to elevated CK levels. Although rare, it is essential to consider this diagnosis, especially if the patient has other symptoms such as muscle weakness, fever, or rash.
• Dermatomyositis: This autoimmune disorder causes skin and muscle inflammation, leading to elevated CK levels. Although rare, it is crucial to consider this diagnosis, especially if the patient has other symptoms such as skin rash, fever, or muscle weakness.