MANUAL MINORS
Dystonic reactions are involuntary, sustained muscle contractions that result in abnormal postures or spasms. These reactions are commonly drug-induced, particularly by medications that block dopamine receptors, such as antipsychotics and certain antiemetics (e.g., metoclopramide).
Dystonias can affect any muscle group, but frequently involve the neck (torticollis), jaw (trismus), eyes (oculogyric crisis), and limbs.
Diagnosis
Diagnosis is clinical and based on the sudden onset of involuntary muscle movements, abnormal postures, or spasms following the administration of a known dystonia-inducing medication. Symptoms can appear hours or days after starting treatment.
The physical examination reveals sustained muscle contractions or painful spasms, and it is important to rule out structural or neurological causes. A history of recent use of antipsychotics, metoclopramide, or other dopamine-interfering drugs helps confirm the diagnosis.
Differential Diagnosis
Pathology | Characteristics |
|---|---|
Neuroleptic malignant syndrome | Muscle rigidity, hyperthermia, altered mental status, linked to antipsychotic use |
Seizure | Rhythmic muscle movements, loss of consciousness |
Tetanus | Generalised muscle spasms, history of contaminated wounds |
Hemifacial spasm | Involuntary facial muscle movements, unrelated to medications |
Basilar migraine | Headache with oculogyric crisis, not drug-related |
Emergency Management
Emergency treatment involves administering an anticholinergic, such as biperiden or benztropine, which usually reverses symptoms rapidly. Diazepam or lorazepam can also be useful for relieving muscle spasms in some cases.
It is essential to discontinue the causative medication. Patients should be monitored to ensure complete resolution of symptoms and to prevent recurrence.
Definitive Treatment
Definitive management includes stopping or adjusting the medication responsible for the dystonic reaction. For patients requiring continued use of antipsychotic drugs, dose adjustment or switching to lower-risk medications may be necessary.
In some cases, prophylactic use of anticholinergics or benzodiazepines may be recommended if discontinuing the triggering medication is not possible. Educating the patient on early symptom identification is crucial to prevent future episodes.
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