Paroxysmal Neurology: a Guide to Diagnosing Transient Neurologic Dysfunction in Adults and Adolescents

To outline a practical and comprehensive approach to evaluating transient neurologic dysfunction (TND) in adults.

TNDs are a common reason for neurologic consultation. Diagnosis relies largely on history, as neurologic examination is usually normal in the post-ictal stage. The differential of TNDs is extensive, and testing should be targeted to the more likely etiologies and ones that may portend permanent loss of neurologic function. In addition to the more common causes - transient ischemic attack (TIA), seizures, migraine auras, drug-induced adverse events, hypoglycemia, blood pressure fluctuations, hyperventilation, panic attacks, and paroxysmal vestibular disorders, there are some distinctive TND presentations and special circumstances that may point to the less common etiologies. The article outlines the key features of the common presentations and presents a comprehensive differential diagnosis that includes many rare causes of TNDs in adults and adolescents. The proposed approach relies on carefully elucidating the nature, timeline, and circumstances of the symptoms, gathering examination clues, and seeking to determine whether the event is likely due to neuro-vascular, non-vascular neurologic (paroxysmal or chronic), non-neurologic, or rare neurologic etiologies. Specific diagnoses are listed for each of these categories.