Red Flag Symptoms Associated with Essential Tremor
When evaluating a patient with suspected essential tremor, red flags that suggest an alternative diagnosis include: duration of attacks greater than 1 minute, age of onset over 20 years, abnormalities on brain CT/MRI scanning, unilateral tremor, gait disturbance, rigidity, bradykinesia, rest tremor, and rapid onset of symptoms. 1, 2
Key Red Flags Indicating Alternative Diagnoses
Temporal and Demographic Red Flags
- Attack duration exceeding 1 minute suggests a paroxysmal movement disorder rather than essential tremor 1
- Age of onset after 20 years should raise suspicion for secondary causes or alternative tremor disorders 1
- Rapid onset of symptoms is atypical for essential tremor, which typically has a gradual, progressive course 2
Neurological Examination Red Flags
- Unilateral tremor is inconsistent with classic essential tremor, which is characteristically bilateral 2
- Gait disturbance beyond what would be expected from tremor alone suggests cerebellar pathology or parkinsonism 2
- Rigidity and bradykinesia indicate Parkinson's disease rather than essential tremor 2
- Rest tremor as a predominant feature points toward Parkinson's disease, though subtle rest tremor can occur as a "soft sign" in ET-plus 2, 3
Neuroimaging Red Flags
- Abnormalities on brain CT/MRI scanning, including cerebrovascular disease, demyelinating disease, focal lesions of the basal ganglia, or cerebral atrophy, exclude the diagnosis of essential tremor 1
Red Flags for Functional/Psychogenic Tremor
When considering whether tremor may be functional rather than organic essential tremor, specific warning signs include:
- Adult age of onset (functional movement disorders typically begin in adulthood) 4
- Altered level of responsiveness during attacks (consciousness remains intact in true essential tremor) 4, 1
- Distractibility and variability of clinical presentations between different episodes 4
- Suggestibility of symptoms 4
- Additional psychogenic physical signs or medically unexplained somatic symptoms 4
- Atypical response to medications (essential tremor typically responds to propranolol or primidone in up to 70% of cases) 4, 5
Distinguishing Essential Tremor from Other Tremor Disorders
Parkinson's Disease
The presence of rest tremor as the predominant feature, along with rigidity, bradykinesia, and asymmetric onset, strongly suggests Parkinson's disease rather than essential tremor 2. While subtle parkinsonian signs (rest tremor and bradykinesia) can occur in ET-plus, these are typically asymmetric and not concordant on the same side 3.
Dystonic Tremor
Isolated focal, position-specific, and task-specific tremors are probably not essential tremor in most patients and often indicate subtle dystonia 2. Essential tremor characteristically presents as bilateral action tremor without such task specificity 1, 2.
Cerebellar/Intention Tremor
Intention tremor with a "wing-beating" appearance, accompanied by dysarthria and ataxic gait, indicates cerebellar pathology rather than essential tremor 6.
Clinical Pitfalls to Avoid
- Do not diagnose essential tremor if the patient has isolated head or voice tremor without limb involvement for the first 3 years of symptoms 1
- Be cautious about diagnosing essential tremor in patients with task- or position-dependent tremor, as this more commonly represents dystonic tremor 1
- Remember that numerous drugs can aggravate tremor, so a thorough medication review is essential to exclude drug-induced tremor 7
- Essential tremor requires bilateral action tremor present for at least 3 years for definitive diagnosis 1