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Author: Geofrey Nochimson, MD, Consulting Staff, Department of Emergency Medicine, Sentara Careplex Hospital

Geofrey Nochimson is a member of the following medical societies: American College of Emergency Physicians

Editors: Samuel M Keim, MD, Associate Professor, Department of Emergency Medicine, University of Arizona College of Medicine; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Michael J Burns, MD, Instructor, Department of Emergency Medicine, Harvard University Medical School, Beth Israel Deaconess Medical Center; John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center; Asim Tarabar, MD, Assistant Professor, Department of Surgery, Section of Emergency Medicine, Yale University School of Medicine; Consulting Staff, Department of Emergency Medicine, Yale-New Haven Hospital

Author and Editor Disclosure

Synonyms and related keywords: neuroleptic drug therapy, drug treatment, neuroleptics, neuroleptic agents, dyskinesia, acute dystonic reaction, medication-induced dystonic reactions, dystonic reaction, neuroleptic drugs, involuntary muscle contractions

Background

Dystonic reactions are adverse extrapyramidal effects that often occur shortly after the initiation of neuroleptic drug therapy. These reactions may occur with a wide variety of medications. Dystonic reactions (ie, dyskinesias) are characterized by intermittent spasmodic or sustained involuntary contractions of muscles in the face, neck, trunk, pelvis, and extremities. Dystonic reactions are rarely life threatening, yet are very uncomfortable and often produce significant anxiety and distress for patients. Fortunately, treatment is extremely effective, and motor disturbances resolve within minutes.

Pathophysiology

Although dystonic reactions are occasionally dose related, these reactions are more often idiosyncratic and not predictable. They appear to result from drug-induced alteration of dopaminergic-cholinergic balance in the nigrostriatum (ie, basal ganglia). Most drugs produce dystonic reactions by nigrostriatal dopamine D2 receptor blockade, which leads to an excess of striatal cholinergic output. High-potency D2 receptor antagonists are most likely to produce an acute dystonic reaction. Agents that balance dopamine blockade with muscarinic M1 receptor blockade are less likely to produce a dystonic reaction. Paradoxically, an alternative cause of dystonic reactions may be increased nigrostriatal dopaminergic activity that occurs as a compensatory response to dopamine receptor blockade.

Frequency

United States

Incidence of acute dystonic reactions varies according to individual susceptibility, drug identity, dose, and duration of therapy. For patients on neuroleptics, the overall incidence of dystonic reactions is approximately 2%.

Mortality/Morbidity

  • In rare instances, airway management may be needed.
  • Dystonic reactions typically are not life threatening and result in no long-term effects.

Sex

Incidence of dystonic reactions is greater in males than in females.

Age

  • These reactions are most common in children, teens, and young adults (ie, 5-45 years).
  • The risk of reaction decreases as age increases.



History

Dystonic reactions most often occur shortly after initiation of drug treatment; 50% occur within 48 hours and 90% occur within 5 days of initiation of treatment. Risk factors include family history of dystonia, recent history of cocaine or alcohol use, or treatment with a potent dopamine D2 receptor antagonist (eg, fluphenazine, haloperidol).

  • Onset of symptoms is sudden, usually within minutes to days of initiating or increasing dose of causative agent.
  • Obtain history from others if patient is not able to speak.
  • Obtain medication history, including new medications and/or dosage increase.

Physical

  • Physical examination findings may include any of the following:
    • Oculogyric crisis, deviation of eyes in all directions
    • Buccolingual crisis
    • Protrusion of tongue
    • Trismus
    • Forced jaw opening
    • Difficulty in speaking
    • Facial grimacing
    • Torticollis, usually associated with oculogyric and buccolingual crisis
    • Opisthotonic crisis
    • Lordosis or scoliosis
    • Tortipelvic crisis - Typically involves hip, pelvis, and abdominal wall muscles, causes difficulty with ambulation
  • Mental status is unaffected.
  • Vital signs are usually normal.
  • Remaining physical examination findings are normal.

Causes

  • Drug-related adverse effects
    • Neuroleptics (antipsychotics), antiemetics, and antidepressants are the most common causes of drug-induced dystonic reactions.
    • Acute dystonic reactions have been described with every antipsychotic.
    • Alcohol and cocaine use increase risk.
  • Predisposing factors
    • Family history of dystonia
    • Viral infections



Conversion Disorder
Dislocations, Mandible
Hypocalcemia
Hypomagnesemia
Meningitis
Status Epilepticus
Stroke, Hemorrhagic
Stroke, Ischemic
Tetanus
Toxicity, Anticholinergic
Toxicity, Carbamazepine
Toxicity, Phenytoin
Toxicity, Valproate

Other Problems to be Considered

Metabolic or respiratory alkalosis
Toxicity, strychnine
Oropharyngeal infections



Emergency Department Care

  • Emergency interventions other than pharmacologic treatment rarely are required.
  • Securing the airway is necessary only rarely, when laryngeal and pharyngeal dystonic reactions place the patient at risk of imminent respiratory arrest.
  • Pharmacologic treatment resolves the reaction.



The goals of pharmacotherapy are to reduce morbidity and prevent complications.

Drug Category: Anticholinergic agents

Intravenous anticholinergic agents are the treatment of choice. IV is the route of choice, with signs and symptoms often resolving within 10 minutes. The medication can be delivered IM if an IV line cannot be established, but medications will take 30 min to be absorbed. More than 1 dose may be necessary for complete resolution of dystonia.

Drug NameBenztropine (Cogentin)
DescriptionBy blocking striatal cholinergic receptors, may help in balancing cholinergic and dopaminergic activity.
Adult Dose1-2 mg PO/IV/IM qd or bid; IV has most rapid onset
Pediatric Dose<3 years: Not established
>3 years: 0.02-0.05 mg/kg PO/IV/IM; not to exceed 2 mg/d
ContraindicationsDocumented hypersensitivity; angle-closure glaucoma; stenosing peptic ulcers; prostatic hypertrophy or bladder neck obstructions; myasthenia gravis; pyloric or duodenal obstruction; achalasia (megaesophagus); megacolon
InteractionsDecreases effects of levodopa; increases effects of narcotic analgesics, phenothiazines, quinidine, tricyclic antidepressants, and anticholinergics
PregnancyC - Safety for use during pregnancy has not been established.
PrecautionsMay exacerbate hypertension, tachycardia, cardiac arrhythmias, liver or kidney disorders, hypotension, prostatic hypertrophy, urinary retention, and obstructive disease of GI/GU tracts; may cause toxic psychosis in psychiatric patients with extrapyramidal reactions resulting from phenothiazine

Drug NameDiphenhydramine (Benadryl)
DescriptionAlthough an antihistamine, also possesses significant anticholinergic properties. Mechanism of action is identical to that of benztropine.
Adult Dose50-100 mg IV/IM repeat prn
Pediatric Dose1-2 mg/kg IV/IM repeat prn
ContraindicationsDocumented hypersensitivity; MAOIs; angle-closure glaucoma
InteractionsPotentiates effect of CNS depressants; alcohol content of syrup dosage form may cause disulfiramlike reaction in patients taking medications that can cause these reactions
PregnancyA - Safe in pregnancy
PrecautionsMay exacerbate angle-closure glaucoma, hyperthyroidism, peptic ulcer, and urinary tract obstruction

Drug Category: Benzodiazepines

Normal balance between dopamine and acetylcholine in the basal ganglia involves modulation from GABA-containing striatonigral neurons. GABA-ergic neurons are inhibitory and antagonize excitatory dopaminergic neurons. GABA agonists (eg, benzodiazepines) may be helpful for acute dystonic reactions.

Drug NameDiazepam (Valium)
DescriptionSome recommend using for patients with dystonic reactions refractory to anticholinergic therapy or when such therapy is contraindicated.
Adult Dose2.5-10 mg IV slow push
Pediatric Dose0.1 mg/kg IV slow push repeat prn
ContraindicationsDocumented hypersensitivity; narrow-angle glaucoma
InteractionsPhenothiazines, barbiturates, alcohols, and MAOIs may increase CNS toxicity
PregnancyX - Contraindicated in pregnancy
PrecautionsCaution with other CNS depressants, low albumin levels, or hepatic disease (may increase toxicity)



In/Out Patient Meds

  • Continue medication for 48-72 hours to prevent relapse.
    • Benztropine 1-2 mg PO bid
    • Diphenhydramine 25-50 mg PO qid
    • Trihexyphenidyl 2 mg PO bid



Medical/Legal Pitfalls

  • Failure to consider other diagnoses if symptoms have not abated after 2 IV doses of appropriate medication
  • Failure to continue treatment for 48-72 hours to prevent relapse

Special Concerns

  • Arrange psychiatric follow-up care if patient has a dystonic reaction while taking neuroleptic medication. When continued neuroleptic therapy is necessary, maintain patient on an anticholinergic agent or switch to a neuroleptic less likely to produce an acute dystonic reaction.



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Toxicity, Medication-Induced Dystonic Reactions excerpt

Article Last Updated: Feb 8, 2007