Differential Diagnosis for Epilepsy

The following differential diagnosis is based on the provided patient scenarios:

• Single most likely diagnosis:
  • 17-year-old male adolescent who had one tonic-clonic seizure of unknown origin without evidence of a structural lesion on MRI. This patient is most likely to be diagnosed with epilepsy, as a single unprovoked seizure increases the risk of developing epilepsy, especially in the absence of a clear underlying cause.
• Other Likely diagnoses:
  • 65-year-old man who had an ischemic stroke secondary to atherosclerotic cerebrovascular disease and had a focal to bilateral tonic-clonic seizure 1 month later. This patient is at risk of developing post-stroke epilepsy, which is a recognized complication of cerebrovascular disease.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
  • 31-year-old woman who has a history of diabetes and had one focal seizure in the setting of hypoglycemia. Although hypoglycemia is a clear precipitating factor, recurrent or severe hypoglycemic episodes could indicate an underlying issue with diabetes management or an insulinoma, which would need prompt attention.
  • 85-year-old woman who has a history of focal myoclonic seizures in the setting of fevers associated with recurrent UTIs. Infections, especially in the elderly, can sometimes be a sign of an underlying, more serious condition (e.g., sepsis, meningitis, or encephalitis), which would require immediate medical intervention.
• Rare diagnoses:
  • The scenarios provided do not strongly suggest rare diagnoses such as autoimmune encephalitis, paraneoplastic syndromes, or specific genetic disorders without additional information (e.g., family history, specific seizure types, or associated symptoms). However, these conditions should be considered if initial evaluations do not yield a clear diagnosis or if the clinical presentation is atypical.