Drug-induced tremor, clinical features, diagnostic approach and management

As the injectable drug has a short half-life it is followed by a short course of oral anticholinergic drugs.4,5,7 Benzodiazepines have also been used. It is important to avoid the offending drug in the future due to the risk of a recurrent dystonic reaction. To decrease fall risk, medicines such as opioids and antidepressants may need to be slowly decreased and eventually stopped. However, stopping medicines could create a greater risk of health issues. For some people, the benefits of taking certain medicines outweigh the risks.

What Are the Symptoms?

Drinking caffeinated beverages, like coffee and certain teas or sodas, can make your tremors worse. Tremors aren’t life-threatening, but they may be embarrassing for you if they happen in public. You might want to go to a support group while you wait for your symptoms to subside. A tremor that occurs when the muscles are relaxed or that affects the legs or coordination may be a sign of another condition, such as Parkinson disease. The speed of the tremor can be an important way to determine its cause. Your health care provider can make the diagnosis by performing a physical exam and asking about your medical and personal history.

Patient

Although no tremor was described in the original report that identified the p.E706K mutation (Martinsson et al. 2000), a 2004 study by Tajsharghi and colleagues noted that two patients in the family exhibited hand tremor in addition to muscle weakness and contractures (Tajsharghi et al. 2004). While MyHC mutations may exert dominant negative effects on muscle function by altered myosin-actin interactions, defects in myosin ATPase activity, or interference with filament assembly and sarcomeric structure, the exact effect of the p.E706K mutation has yet to be elucidated (Martinsson et al. 2000). Examination of serum creatine kinase (CK) levels, an indicator of muscle damage, revealed great variability among patients, as some maintained normal levels while others showed an 8-fold increase above the normal upper limit (Lamont et al. 2006). In some samples, intermediate fibers could be also seen, suggesting progressive fiber type switching (Lamont et al. 2006).

Drug-induced tremor

Interestingly, all three mutations are located in the coiled coil region of the light meromyosin tail domain of the myosin heavy chain β isoform, similar to the Campus mutations described above. Tremor is the shaky movements of your hands, limbs, head or voice that you can’t control. Sometimes tremor is a normal reaction to a situation such as fear, fatigue or anger. It also can be a side effect of too much caffeine, a medication, or withdrawal from a drug or medicine. When tremor occurs during activities and there is no anatomic, emotional or chemical cause, it can be a sign of a neurological disease called essential tremor. Several intriguing findings argue against the striatonigral dopaminergic deficit directly causing PD tremor.

Table 1. Common Medication-induced Tremors and Typical Tremor Phenomenology.

Orr and Ahlskog25 found that only 2.8% of patients treated with amiodarone in the recent Mayo Clinic experience developed a neurotoxic side effect and they related this lower incidence of tremor and other side effects to lower doses (now 200 mg per day) of amiodarone in practice over time compared to the past. Exposure to toxic levels of certain drugs (e.g., ethanol, lithium, etc.) for longer periods of time can lead to permanent tremors, especially if they affect the cerebellum. Levodopa-induced dyskinesia is a common cause of dyskinesia in individuals with Parkinson’s disease. It occurs due to the relationship between dopaminergic loss and the resultant response to levodopa, rather than being due to excess levodopa ingestion only. Risk factors for developing dyskinesia include young age at onset of Parkinson’s disease, higher levodopa dose, low body weight, and more severe disease.10 A careful history is vital in establishing a pattern to the timing and duration of dyskinesias, which can then assist in altering the levodopa dose.

• Enhanced physiologic tremor, intention tremor, and dystonic tremor are discussed.
• They may lead to a lower quality of life, a loss of independence, an increased risk of admission to a nursing home and death.
• Talk to your doctor if any of these medications could be worsening your tremor.
• But there is one other common condition that induces the symptoms of PD, including a rest tremor, which must be considered every time PD is being considered as a diagnosis, and that is drug-induced parkinsonism.
• Essential tremor is most noticeable when your body is in action, such as when you are writing, typing or pouring a beverage.
• Eye movement abnormalities may suggest cerebellar disease, and Kayser-Fleischer rings are specific for impaired copper homeostasis, although their absence does not exclude Wilson’s disease.

There are also special medicines that can help with the symptoms of TD. Sometimes with the early symptoms of TD, you may not even know that you are having symptoms. In the meantime, make sure to keep taking all your medicines as your doctor has prescribed. If you have any of these risk factors, it’s important to talk with your doctor about your chances of getting TD. Linkage mapping pinpointed a six-base pair insertion c.4320_4321insCCCGCC located in exon 30 of the MYH7 gene, which segregated perfectly with the Campus syndrome phenotype in all pigs heterozygous for the mutant allele (Murgiano et al. 2012) (Fig. 1 and Table 1). The mutation causes an in-frame insertion of two amino acids, proline and alanine, in a highly conserved region of the protein.

From a physiologic standpoint, this can be considered a tremor at rest, as the body part has been held motionless in this position for a period of time. Thus, tremor that reemerges after a short period should not be classified as true postural tremor. Medication-induced tremor (MIT) is common in clinical practice and there are many medications/drugs that can cause or exacerbate tremors.

• Table 3 summarizes the most common medications and toxins that cause tremor.
• Anticonvulsant drugs are among the most common causes of drug-induced tremors.
• Bronchodilators, which are commonly used in the treatment of conditions such as asthma, can also cause tremors.
• In 2015, Marra et al. reported a case of NM with tremor in a non-Amish patient also caused by a mutation in the TNNT1 gene (Marra et al. 2015).
• By two and a half years, the patient was referred to a hospital due to hypotonia and developmental delay.
• There is rigidity in neuroleptic malignant syndrome whereas myoclonus, hyperreflexia with clonus, and mydriasis are more common in serotonin syndrome.
• Nobody likes to feel out of control of their body, so developing tremor can be concerning.

Similar to the identified human patients with the MYBPC1 mutations, the functional effects of the amino acid change were predicted to be intolerable and damaging for normal muscle structure/function by in silico predictors (Wiedemar et al. 2015, Shashi et al 2019). In vitro biochemical studies showed significantly increased binding of both mutant proteins to heavy meromyosin (Stavusis et al. 2019). However, it is noteworthy that the charge of the histidine sidechains can be greatly affected by even small changes in pH, therefore making it more difficult to predict the exact effect of the p.Y247H mutation in vitro (Li and Hong 2011). The purported increase in electrostatic binding between mutant sMyBP-C proteins and myosin may result in the formation of abnormal and deregulated cross-bridges, which in addition to causing a deficit in force production underlying muscle weakness, may act as the primary pacemaker of the observed tremor. A variety of treatment options for essential tremor are what medications cause tremors available today which makes it possible, but also necessary, to select the most appropriate solution for the individual patient. The patient’s subjective experience of the tremor’s severity and the degree of impairment and disability that it causes in the patient’s life are more important than the objective assessment during the patient’s clinic visit.

The clinical and electrophysiological features of valproic acid-induced tremor appear typical of EPT given treated patients had a reduction in their tremor frequency by 3 Hz or more by weight loading.15,45 This is typical of an alteration in the frequency of the mechanical component of physiological tremor. Taken together, we propose to establish this form of myopathy accompanied by tremor, of likely myogenic origin, as a new disease entity with the ultimate goal to improve diagnosis and develop more appropriate and effective therapies. It is our hope that in the immediate future, an emphasis will be given by the muscle scientific community in dissecting the complexity and intricacies of this new form of sarcomeric myopathy with tremor. Furthermore, tremor may diminish in later stages of the disease, when bradykinesia becomes more prominent.46 The typical and rather complex movements of parkinsonian rest tremor (Fig. 2) indicate PD with high specificity. They include agonist and antagonist activation alternating in a precisely tuned manner, often leading to a stereotypical series of movements, such as the typical pill-rolling tremor. Sometimes, a person without a diagnosis of PD is prescribed a medication which leads to a side effect of drug-induced parkinsonism.