Approach to tremor: Clinical sciences

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Introduction 0:00–0:48

Tremor refers to an involuntary rhythmic oscillatory movement due to the actions of opposing muscles, which is most commonly observed in the upper extremities.
It could also be present in other parts of the body, including the lower extremities, head, jaw and trunk. The pathophysiology of tremor includes multiple neural pathways such as those involving the basal ganglia, premotor and motor cortices, thalami and cerebellum.
The most common causes of tremor include Parkinson disease, cerebellar dysfunction, essential tremor and enhanced physiologic tremor.
Now, if a patient presents with chief concerns, suggesting tremor, you should first obtain a focused history and physical examination.

Focused H&P 0:48–1:26

Patients typically report shaky hands which can often cause difficulty performing tasks such as eating or writing. Sometimes they might report shaking in other parts of the body as well as a family history of a tremor.
On examination. You might observe involuntary rhythmic oscillatory movements in the hands and possibly shaking of other parts of the body.
For example, the head with these findings, you can diagnose a tremor. Your next step is to find the cause.

Medication-induced tremor 1:26–2:20

So first assess for a medication induced tremor. If your patient is taking a medication with a known side effect of tremor such as lithium valproic acid, amiodarone, beta adrenergic agonists like albuterol or antipsychotics with antidopaminergic activity like haloperidol.
The likely diagnosis is a medication induced tremor. Here is your first clinical pearl.
Patients with a medication induced tremor can experience tremors at rest, known as a rest tremor or with action known as an action tremor.
Sometimes the tremors can be accompanied by a parkinsonism with rigidity and bradykinesia. Finally, when the offending drug is discontinued, the tremors will stop on the flip side.

Parkinson disease 2:20–4:29

If your patient does not report taking medications associated with tremor. The next step is to assess for a rest tremor.
All right, if the rest tremor is present, you should consider Parkinson disease. The patient will typically report the shakiness of their hands at rest with one hand worse than the other.
They will also report slowness of movement. And in some cases frequent falls on exam, you will observe a hand tremor at rest with movements that look like they are rolling a pill between their thumb and index finger known as a pill rolling tremor.
The tremor will improve with action, meaning when they move their arms or hands, there will also be bradykinesia which is slowness of movement and decrease in amplitude or speed with continued movement as well as rigidity.
Additionally, you might observe facial masking which refers to an impaired facial expression in response to emotion. Next, if you passively move a limb around a joint in a circular motion.
You might feel a series of sts or stalls which is called cog wheeling or cog wheel rigidity. Finally, you might notice a shorter stride length or stooped posture.
With these findings diagnose Parkinson disease time. For another clinical Pearl Parkinson plus syndromes are characterized by similar signs and symptoms as Parkinson disease including arrest tremor.
However, they include additional features such as early onset dementia psychosis and hallucinations and severe dysautonomia.
Additionally, you might notice gay's palsy and alien limb phenomenon in which your patient reports that their limb feels disconnected and controlled by someone else.
Parkinson plus syndromes include dementia with Lewy bodies, progressive supranuclear, palsy, multiple system, atrophy and corticobasal degeneration.
Now, let's discuss the scenario where the rest tremor is absent. In this case, your next step is to assess for cerebellar signs.

Cerebellar dysfunction 4:29–6:28

First, look for nonphysiologic nystagmus at resting or end gaze and impaired SADs when the patient rapidly shifts their gaze between two objects.
Next, you might find dysdiadokokinesia, which is the inability to perform rapid alternating movements such as during rapid alternating supination and pronation of the hands on finger, nose, finger and heel to shin testing.
You might find dysmetria which is the inability to perform smoothly coordinated and targeted movements. For example, on the finger, nose finger test, they might point past the finger as they're unable to judge the distance properly.
This is referred to as past pointing last but not least you might see gait ataxia which is characterized by a wide based unsteady gait with truncal instability and inconsistent stride length.
If these signs are present, diagnose cerebellar dysfunction as the cause of the tremor, which can occur as a result of traumatic brain injury, brain tumor, multiple sclerosis, stroke, or even genetic conditions like spinocerebellar ataxia.
Here's a clinical pearl to keep in mind, the tremor associated with cerebellar dysfunction usually has slow, large amplitude side to side oscillations occurs during movement known as a kinetic tremor and has an intentional component.
Meaning that it worsens as the limb approaches a target. Both kinetic and intention tremors fall under the broader category of action tremors, which can be detected on the finger, nose, finger exam maneuver.
Now let's go back and discuss patients with no cerebellar signs. In this case, consider essential or enhanced physiologic tremor.

Essential tremor 6:28–8:31

First, let's focus on essential tremor. These patients will report shakiness in their hands with arm movement for three or more years that improves with alcohol intake.
Additionally, they might have a family history of tremors on exam. You will observe bilateral slow co arm tremors during movement known as a kinetic tremor.
And when holding a posture, known as a postural tremor like kinetic tremor. A postural tremor is also a kind of action tremor.
You can observe the postural tremor while the patient is holding their arms in a wing position or if they outstretch their arms in front of them.
Also, you might notice a tremor in the neck, voice or jaw. With these findings diagnose essential tremor.
Here's a clinical pearl to keep in mind. Essential tremor is a progressive condition that can be inherited as an autosomal dominant condition.
However, patients may develop a resting tremor later on after several years, which can mimic Parkinson disease. This condition can significantly impair daily activities such as eating, writing, using the computer or getting dressed.
First line treatment options for essential tremors include a centrally acting beta blocker, primarily propranolol or a barbituate called primidone.
Most patients eventually require two medications for symptomatic control. Additional options include topiramate gabapentin, a benzodiazepine or botulinum toxin injection.
In severe cases, you should consider surgical therapy such as thalamotomy or deep brain stimulation, which involves the placement of an electrostimulator usually in the thalamus.
Finally, let's take a look at enhanced physiologic tremor. These individuals usually report episodes of tremor associated with the use of stimulants such as caffeine or during hyperadrenergic states such as stress, fright or anxiety.

Enhanced physiologic tremor 8:31–9:54

Additionally, there might be a history of a hyper metabolic condition such as hyperthyroidism or hypercortisolism. The physical exam might reveal bilateral, fast, symmetric, fine kinetic and postural tremors of the arms.
There might be a voice tremor but no neck tremor. In this case, you can diagnose enhanced physiologic tremor.
Here's one last clinical Pearl Wilson disease is a rare autosomal recessive condition characterized by excess copper accumulation, particularly in the liver, brain and cornea patients with this condition may have rest or action, tremors.
One important finding in these individuals is called wing beating tremor, which is noted when arms are abducted, elbows flexed and hands pointed towards each other with the palms facing down.
This tremor is also known as rubral tremor due to the involvement of the red nucleus in the midbrain. All right, as a quick recap, tremor refers to an involuntary rhythmic oscillatory movement due to the actions of opposing muscles.

Review 9:54–10:33

Once you diagnose tremor, you should first rule out medication induced tremor. Next.
Assess for rest tremor if present, consider Parkinson disease on the flip side. If there's no tremor at rest, assess for cerebellar signs.
If you identify cerebellar signs, diagnose cerebellar dysfunction. However, if there are no cerebellar signs, you should consider essential tremor or enhanced physiologic tremor.