Approach to involuntary movements: Clinical sciences

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Introduction0:00–0:42

Involuntary movements are unintentional body movements that can occur due to various conditions, including metabolic derangements, medication effects, and neurodegenerative conditions.
There are several distinct types of involuntary movements, such as tremors, dystonia, myoclonus, and chorea, and the underlying pathology is different for each condition.
Important conditions associated with involuntary movements include those secondary to anti-dopaminergic medications, and neurologic conditions, such as Parkinson disease, Creutzfeldt-Jakob disease, Tourette syndrome, and Huntington disease.

Focused H&P0:42–1:36

Now, if a patient presents with involuntary movements, first obtain a focused history and physical examination, and order a complete metabolic panel.
History reveals body movements that the patient cannot control. The physical exam shows abnormal movements that persist even if you distract the patient, while the complete metabolic panel is normal.
These findings are suggestive of movement disorder. Here’s a clinical pearl!
Metabolic derangements can cause different abnormal movements. For example, hypocalcemia can increase membrane excitability of peripheral nerves and cause muscle fasciculations and tetany.
Less commonly, hypomagnesemia and hypokalemia can also cause fasciculations and tetany. Lastly, renal or hepatic failure might lead to asterixis, which is flapping of the hands when the arms are outstretched.
Your next step is to assess the use of anti-dopaminergic medications, including antipsychotics, especially first-generation antipsychotics, and anti-emetics, such as metoclopramide.

Medication-induced movement disorder1:36–1:57

If your patient is taking an anti-dopaminergic medication, diagnose medication-induced movement disorder and determine the type of medication reaction the patient is having.

Medication-induced Dystonia1:57–2:33

Let’s start with medication-induced dystonia. These patients report sustained muscle tightening, twisting of the body that typically involves the face and neck, and recent use of an anti-dopaminergic agent within the last few hours to days.
On the physical exam, you’ll find sustained muscle contractions, such as torticollis; twisting of the tongue; trismus, which is contraction of the muscles of mastication resulting in lockjaw; or opisthotonus, which refers to an extreme arching of the neck and back.
With these findings, diagnose medication-induced dystonia. Okay, let’s discuss medication-induced Parkinsonism.

Medication-induced Parkinsonism2:33–3:14

In this case, patients report slowness, stiffness of movement, and possibly shaky hands at rest and frequent falls. Additionally, they have used an anti-dopaminergic agent in the last few weeks to months.
On the physical exam, you’ll observe bradykinesia, rigidity, and, sometimes, rest tremor. In this case, diagnose medication-induced parkinsonism.
Remember, patients with medication-induced parkinsonism are less likely to have a tremor than patients with idiopathic Parkinson disease, and the symptoms are more likely to be symmetric.

Tardive Dyskinesia3:14–4:08

Finally, let’s look at tardive dyskinesia. Here, history reveals frequent grimacing, lip-smacking, eye blinking, or tongue protrusion and twisting.
Patients might also report abnormal twisting or posturing of the limbs or body. This type of involuntary movement occurs when anti-dopaminergic medications have been used for months to years.
Next, the physical exam reveals repetitive stereotyped movements of the perioral region, extremities, and/or trunk. In this situation, you can diagnose tardive dyskinesia.
Here’s a clinical pearl! Treatment for medication-induced movement disorders involves cessation of the offending agent and benzodiazepine.
Keep in mind that unlike medication-induced dystonia and Parkinsonism, tardive dyskinesia may not resolve after stopping the medication.
Alright, let’s switch gears and discuss situations in which an anti-dopaminergic agent was not used. In this case, your next step is to assess if the main involuntary movement is a tremor.

Parkinson Disease4:08–5:43

If it is, detailed history and physical exam will give you clues about the underlying cause, which most commonly includes Parkinson disease and essential tremor.
Patients with Parkinson disease report shaky hands at rest, slowness of movement, sometimes in combination with frequent falls, and a loss of smell.
The physical exam reveals bradykinesia, which is slowness of movement and a decrease in amplitude or speed with continued movement.
Additionally, you’ll notice a pill-rolling tremor at rest and rigidity. Moreover, if you passively move the patient’s limb, you might feel a series of stops or stalls, which is known as cogwheeling or cog-wheel rigidity.
Some patients could also present with facial masking, which refers to an impaired facial expression in response to emotion, shorter stride length, and a stooped posture.
At this point, consider Parkinson disease, and start a trial of dopaminergic therapy with levodopa and carbidopa. Next, assess the supportive criteria for Parkinson disease, which include adequate response to dopaminergic therapy, levodopa-induced dyskinesia, the presence of a rest tremor of a limb, and olfactory loss or cardiac sympathetic denervation.
If you find at least two of the four supportive criteria, diagnose Parkinson disease. Next, let’s focus on essential tremor.

Essential Tremor5:43–6:29

These individuals typically report shakiness in their hands when moving and using their arms, which improves with alcohol use.
They might also have a family history of tremors. On exam, you’ll find bilateral slow, coarse arm tremors during movement, known as a kinetic tremor, and when holding a posture, known as a postural 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.
Finally, you might notice a neck, voice, or jaw tremor. With these findings, diagnose essential tremor.
Treatment involves primidone or propranolol. Alright, time to move on to conditions in which the tremor is not the predominant involuntary movement.

Tic Disorder6:29–7:47

These include tic disorder, Creutzfeldt-Jakob disease, and Huntington disease. Tic disorder is associated with repeated, sudden, quick movements after an urge to move, like nonrhythmic eye blinking or shoulder shrugging.
In addition, the patient might repeatedly have urges to suddenly vocalize or make sounds, such as barking, grunting, or clearing their throat.
In some cases, they might even have an urge to yell out words, such as repeating others’ words or yelling out profanity.
On exam, you’ll observe repetitive motor tics and, in some individuals, vocal tics. In this case, diagnose a tic disorder.
Patients might be able to suppress their tics, especially with behavioral therapy, but it can be extremely uncomfortable to do so, and they might even have a cluster of increased frequency of tics after a period of suppression.
Time for a high-yield fact! Tics are much more prevalent in the pediatric population.
Tourette syndrome is the presence of motor and vocal tics for at least a year, with an onset before 18 years of age, and no evidence of another medical condition or substance use that could cause tics.
Next, let’s discuss Creutzfeldt-Jakob disease, or CJD, which is associated with abnormal accumulation of prion proteins in brain cells and subsequent misfolding of normal prions, leading to neurodegeneration.

Creutzfeldt-Jakob disease7:47–10:00

In this case, your patient or loved one reports involuntary fast muscle or limb jerking and rapidly worsening cognition.
They might also report a decrease in spontaneous movement and speech, a loss of emotion or interest in things, and personality changes.
The patient may also have vision loss or loss of coordination. The physical exam will reveal cognitive impairment and myoclonus, which are sudden, brief muscle contractions.
You might observe akinetic mutism, which is the loss of spontaneous speech and movement despite the patient maintaining a normal level of consciousness.
Other findings might include cortical visual loss, which is the loss of vision due to cortex injury, with a normal pupillary and eye exam, and ataxia of the limb or trunk.
In this case, consider CJD and analyze the CSF for the presence of 14-3-3 protein, which is a nonspecific protein released by damaged cells.
Additionally, you should perform a real-time quaking-induced conversion assay, also called the RT-QuIC assay, to detect misfolded prions.
Finally, don’t forget to obtain a brain MRI and EEG. Now, if you identify 14-3-3 protein; the RT-QuIC assay is positive; the brain MRI shows either abnormal signal in the caudate and putamen or different cortical regions, which is also known as cortical ribboning; or EEG shows generalized periodic discharge complexes, diagnose CJD, more specifically sporadic Creutzfeldt-Jakob disease.
In this case, the cause is usually unknown. However, keep in mind that there are also familial cases of CJD; iatrogenic cases, such as surgical contamination and blood transfusions; and transmission of CJD from bovine to humans.

Huntington Disease10:00–12:13

Finally, let’s discuss Huntington disease. These patients report fidgety movements, usually of the face, arm, or leg; trouble walking; and worsening cognition.
Additionally, they have family members who had similar symptoms present at an older age compared to the patient, due to the phenomenon of anticipation, where following generations present with earlier and more severe symptoms.
Remember that Huntington disease is an autosomal dominant disorder. History might also reveal depression, aggressive behavior, or psychosis.
On physical exam, you’ll find cognitive impairment; chorea, which are involuntary, irregular movements that can affect the face, limbs, or trunk; as well as athetosis.
Athetosis is similar to chorea but smaller in amplitude and more continuous, usually causing writhing movements of distal limbs.
When athetosis is present in the hand and fingers, it can look like the patient is playing the piano. There is also often motor impersistence, which is the inability to sustain a motor task, such as protruding the tongue or maintaining a hand grasp.
With these findings, think Huntington disease, and order genetic testing of the huntingtin gene. If genetic testing shows a CAG trinucleotide repeat expansion in the huntingtin gene, you can diagnose Huntington disease.
Here’s a couple of clinical pearls about Huntington disease! When it comes to treatment, chorea related to Huntington disease is treated with tetrabenazine or haloperidol.
And here’s one more clinical pearl, why not! If a pediatric patient presents with chorea, assess for a history of group A streptococcal infection and rheumatic fever.
If present, the patient likely has Sydenham chorea, which can develop several weeks to several months after exposure to Group A strep, is often accompanied by behavioral changes, and is thought to be due to autoimmunity.
Sydenham chorea particularly affects the head, tongue and arms, and usually resolves within a few weeks. A significant number of these patients also have carditis, so make sure to obtain an echocardiogram.

Review12:13–12:42

Alright, as a quick recap... If the patient is presenting with a movement disorder, first, you should assess if they are taking anti-dopaminergic medications.
If yes, diagnose a medication-induced movement disorder, such as dystonia, parkinsonism, and tardive dyskinesia. On the flip side, if you rule out medication-induced conditions, consider conditions such as Parkinson disease, essential tremor, tic disorder, Creutzfeldt-Jakob disease,