The key difference between tardive dyskinesia and dystonia is that the tardive dyskinesia is always secondary to the long-term use of neuroleptics, but dystonia may be due to various other causes. Further, dystonia is the abnormal muscle tone resulting in muscle spasms or abnormal postures. Whereas, tardive dyskinesia refers to uncontrollable mouthing and lip-smacking grimaces that develop following the long-term use of neuroleptics.
Both of these conditions are abnormal movement disorders; dystonias include a variety of movement disorders that occur due to various reasons while tardive dyskinesia is only a subgroup of primary dystonias.
CONTENTS
1. Overview and Key Difference
2. What is Tardive Dyskinesia
3. What is Dystonia
4. Side by Side Comparison – Tardive Dyskinesia vs Dystonia in Tabular Form
5. Summary
What is Tardive Dyskinesia?
Tardive dyskinesia refers to uncontrollable mouthing and lip-smacking grimaces that develop following the long-term use of neuroleptics. These drugs are usually prescribed to treat psychiatric conditions such as schizophrenia. There is a worsening of these movements when the drug is abruptly stopped, or the dose is reduced. Stopping the use of the drug cannot guarantee the complete disappearance of tardive dyskinesia. The use of atypical neuroleptics is associated with a lesser incidence of these abnormal movements.
Drugs that Cause Tardive Dyskinesia
- Haloperidol
- Chlorpromazine
- Fluphenazine
- Thioridazine
- Trifluoperazine
- Antiemetics such as metoclopramide
Any condition that impairs the hepatic enzyme activity and menopausal changes increase the risk of getting these adverse drug effects. Drugs such as valbenazine can treat tardive dyskinesia.
What is Dystonia?
Dystonia is abnormal muscle tone resulting in muscle spasms or abnormal postures.
There are few broad categories of dystonia as
- Primary dystonia – Dystonia is the sole manifestation or the symptom. The usual cause is genetic abnormalities
- Secondary dystonia – due to other causes such as cerebral injuries
- Heredo-degenerative dystonia – dystonia is a part of some other neurodegenerative disorders
- Paroxysmal dystonia – involuntary movements that include both chorea and dystonia
Primary Dystonias
Primary dystonias can appear in age group but are commoner among elderly people.
- Torticollis – dystonic spasms of the neck causing the neck to be drawn back or sideways.
- Writer’s cramp or task-specific dystonias – the inability to perform a previously highly developed skill is the characteristic feature of this.
- Oromandibular dystonia – spasms of forced blinking
- Dopa-responsive dystonias – these can be terminated by giving a small dose of levodopa
- Movement disorders associated with neuroleptics
- Akathisia – restless and irresistible urge to move
- Parkinsonism
- Acute dystonic reactions- spasmodic torticollis and other manifestations develop after a single dose of neuroleptics in an unpredictable manner.
- Tardive dyskinesia
What is the Difference Between Tardive Dyskinesia and Dystonia?
Tardive dyskinesia refers to uncontrollable mouthing and lip-smacking grimaces that develop following the long-term use of neuroleptics. Dystonia refers to abnormal muscle tone resulting in muscle spasms or abnormal postures.
Tardive dyskinesia is always caused by the long-term use of neuroleptics. However, various factors such as different drugs, neurodegenerative diseases and traumatic damages to central nervous system can cause dystonia. Moreover, dystonias include a variety of movement disorders that occur due to various reasons while tardive dyskinesia is only a subgroup of primary dystonias.
Summary – Tardive Dyskinesia vs Dystonia
The basic difference between tardive dyskinesia and dystonia stems from their cause; the former is always a result of long-term use of neuroleptics while the latter has various causes such as different drugs, neurodegenerative diseases and traumatic damages to CNS. Tardive dyskinesia is a subgroup of primary dystonias.
Reference:
1. Kumar, Parveen J., and Michael L. Clark. Kumar & Clark clinical medicine. Edinburgh: W.B. Saunders, 2009.
Image Courtesy:
1. “1885550” (CC0) via Pixabay