4
Differential Diagnosis
Medications and Other Causes of Tremor
• The medication list should be reviewed carefully since medications such as
stimulants, antidepressants, antipsychotics and many immunosuppressants
can cause tremor.
• While most medications trigger tremor in a predictable dose-related
fashion, there are some, like valproic acid and amiodarone, that can trigger
tremor even after long-standing low-dosage exposure.
• When diagnosing ET, consider ruling out thyroid issues (e.g.
hyperthyroidism) and metabolic disorders (e.g. B-12 deficiency).
• Also consider ruling out dystonic tremor, especially if tremor is present in
or isolated to the head. Dystonia and ET are two movement disorders that
may occur independently or coexist.
ET Plus
• There are several soft signs that can be seen with ET that can be termed
"ET Plus."
▶ For instance, many people with very long-standing ET may develop gait ataxia and
rest tremor.
▶ Dystonic features (subtle posturing of the hands or head) can be seen in some
people with ET.
▶ At this time, it is not known whether these are distinct neurological disorders
different from classical ET but it seems likely that many, if not most, patients may
evolve ET Plus features over time.
