Differential Diagnosis for Encephalopathy plus Elevated CPK
Single Most Likely Diagnosis
- Viral Encephalitis with Muscle Injury: This could be due to various viral infections that affect both the brain and muscles, leading to elevated CPK (creatine phosphokinase) levels due to muscle damage and encephalopathy due to brain inflammation.
Other Likely Diagnoses
- Autoimmune Encephalitis with Myositis: Conditions like NMDA receptor encephalitis or other forms of autoimmune encephalitis can present with encephalopathy and, if accompanied by myositis, could explain elevated CPK levels.
- Toxic or Metabolic Encephalopathy with Rhabdomyolysis: Certain toxins or metabolic disorders can cause both encephalopathy and muscle breakdown (rhabdomyolysis), leading to elevated CPK levels.
- Infectious Myositis with Secondary Encephalopathy: Bacterial or viral myositis can lead to significant muscle damage and elevated CPK, with secondary encephalopathy due to systemic infection or toxin effects.
Do Not Miss Diagnoses
- Malignant Hyperthermia: A life-threatening medical emergency triggered by certain drugs used for general anesthesia, characterized by muscle rigidity, high fever, and can lead to encephalopathy and elevated CPK.
- Neuroleptic Malignant Syndrome (NMS): A rare but life-threatening side effect of neuroleptic or antipsychotic drugs, presenting with fever, muscle rigidity, altered mental status (encephalopathy), and can have elevated CPK.
- Status Epilepticus with Rhabdomyolysis: Prolonged seizures can lead to muscle damage and elevated CPK, along with encephalopathy due to the seizures themselves or post-ictal states.
Rare Diagnoses
- Mitochondrial Myopathies with Encephalopathy: Rare genetic disorders affecting mitochondria can lead to both muscle and brain involvement, presenting with encephalopathy and elevated CPK due to muscle disease.
- Glycogen Storage Diseases: Certain types can lead to muscle damage and elevated CPK, especially during episodes of metabolic crisis, and may also present with encephalopathy due to hypoglycemia or other metabolic derangements.
- Inflammatory Myopathies with CNS Involvement: Conditions like dermatomyositis or polymyositis can rarely have central nervous system involvement, presenting with encephalopathy, and would have elevated CPK due to muscle inflammation.