Summary about Disease
Extrapyramidal symptoms (EPS), also known as drug-induced movement disorders, are a group of side effects caused by certain medications, primarily antipsychotics. These medications affect the extrapyramidal system, a neural network responsible for motor control, coordination, and posture. EPS manifest as a range of involuntary movements, muscle stiffness, and other motor disturbances. The severity and type of EPS vary depending on the medication, dosage, and individual susceptibility.
Symptoms
EPS encompass several distinct conditions:
Acute Dystonia: Sudden, sustained muscle contractions, often affecting the neck, tongue, jaw, or eyes.
Parkinsonism: Symptoms resembling Parkinson's disease, including tremor, rigidity, slow movements (bradykinesia), and postural instability.
Akathisia: A subjective feeling of inner restlessness and an irresistible urge to move, often involving pacing or fidgeting.
Tardive Dyskinesia (TD): Repetitive, involuntary movements, usually affecting the face, mouth, tongue, and sometimes the limbs. TD can be persistent and, in some cases, irreversible.
Neuroleptic Malignant Syndrome (NMS): A rare but life-threatening reaction characterized by fever, muscle rigidity, altered mental status, and autonomic dysfunction.
Causes
The primary cause of EPS is the use of medications that block dopamine receptors in the brain, particularly dopamine D2 receptors in the nigrostriatal pathway of the extrapyramidal system. This pathway is critical for motor control. Antipsychotics, used to treat schizophrenia and other psychiatric disorders, are the most common offenders. Other medications, such as some antiemetics and antidepressants, can also cause EPS in rare cases. Individual susceptibility, age, and underlying neurological conditions can increase the risk.
Medicine Used
Treatment of EPS depends on the specific symptoms and their severity:
Acute Dystonia: Anticholinergic medications (e.g., benztropine, diphenhydramine) are often used to provide rapid relief.
Parkinsonism: Anticholinergics, amantadine, or dopamine agonists may be used.
Akathisia: Beta-blockers (e.g., propranolol), benzodiazepines, or anticholinergics may be helpful.
Tardive Dyskinesia: Valbenazine and deutetrabenazine are VMAT2 inhibitors specifically approved for treating TD. Other options include switching to an atypical antipsychotic with a lower risk of EPS or using medications to manage the symptoms.
Neuroleptic Malignant Syndrome: Immediate discontinuation of the offending medication, supportive care (e.g., cooling, hydration), and medications such as dantrolene or bromocriptine are necessary.
Is Communicable
EPS is not a communicable disease. It is a side effect of medication, not an infectious illness.
Precautions
Careful medication management: Prescribers should carefully consider the risk of EPS when prescribing medications known to cause these side effects. The lowest effective dose should be used.
Monitoring: Patients on these medications should be regularly monitored for signs and symptoms of EPS.
Early intervention: Early detection and treatment of EPS can help prevent more severe or persistent problems.
Awareness: Patients and caregivers should be educated about the risk of EPS and what symptoms to watch for.
Alternative medications: When possible, consider using medications with a lower risk of EPS.
How long does an outbreak last?
EPS is not an outbreak. EPS duration varies:
Acute Dystonia: Resolves relatively quickly (within hours or days) with treatment.
Parkinsonism/Akathisia: Can resolve within weeks or months of reducing or discontinuing the offending medication, or may persist if untreated.
Tardive Dyskinesia: Can be persistent, even after the medication is stopped. It may be long-lasting or permanent.
Neuroleptic Malignant Syndrome: Requires immediate treatment; recovery can take days to weeks.
How is it diagnosed?
Diagnosis of EPS is primarily clinical, based on observation of symptoms and a history of medication use.
Physical Examination: A thorough neurological examination to assess motor function, muscle tone, and the presence of involuntary movements.
Medication History: A detailed review of the patient's medication list, including dosages and duration of use.
Rating Scales: Standardized rating scales (e.g., Abnormal Involuntary Movement Scale - AIMS) may be used to quantify the severity of EPS symptoms.
Differential Diagnosis: Ruling out other neurological conditions that may cause similar symptoms (e.g., Parkinson's disease, Huntington's disease).
Timeline of Symptoms
The onset of EPS varies:
Acute Dystonia: Develops rapidly, often within hours or days of starting or increasing the dose of an offending medication.
Parkinsonism/Akathisia: May develop within days to weeks of starting or increasing the dose of an offending medication.
Tardive Dyskinesia: Typically develops after months or years of chronic exposure to dopamine-blocking medications, but can occur earlier in some individuals.
Neuroleptic Malignant Syndrome: Can develop rapidly, often within days of starting or increasing the dose of an offending medication.
Important Considerations
Patient Education: Educating patients about the potential risks and benefits of medications that can cause EPS is crucial.
Adherence: Patients need to adhere to their prescribed medication regimen and attend regular follow-up appointments.
Individual Variability: Individuals respond differently to medications. Some people are more susceptible to EPS than others.
Early Detection: Early detection and management of EPS are important to minimize the impact on the patient's quality of life.
Discontinuation Syndrome: Abruptly stopping certain medications can sometimes trigger withdrawal symptoms or a rebound of the underlying psychiatric condition. Medication changes should be made gradually and under medical supervision.