Dystonic reaction

Background

• adverse extrapyramidal effect (intermittent spasmodic or sustained involuntary contractions of muscles) that occurs shortly after initiation of new drugs
• rarely life threatening but patient is in distress from pain and discomfort
• men are affected more frequently than women

Predisposing Factors

1. young age
2. family history of dystonic reaction
3. history of EtOH or drug use
4. associated with administration of antiemetics or antipsychotic medications
5. 25% of patients treated with Haldol have been known to develop this reaction
6. reaction usually occurs within 48 hrs of drug treatment but can occur up to 5 days after starting therapy
7. severity and onset of reaction depends on an individual, no association with dose, drug type, potency of drug, or duration of treatment

Diagnosis

• History of recent drug exposure or increase in drug dosage
• Thorough drug history (prescription, over the counter, herbals, illegal)

1. Physical exam is usually normal except for dystonia of any striated muscle group. Some common presentations include:
   1. torticollar reaction
   2. buccolingual reaction
   3. oculogyric crisis
   4. oromandibular dystonia
   5. lingual dystonia
   6. kyphosis/lordosis/scoliosis
   7. trismus
   8. facial grimacing
   9. tortipelvic crisis

Medications Associated with Dystonic Reaction

• Amitriptyline
• Amoxaine
• Azatadine
• Buproprion
• Chlorpromazine
• Chlorprothixene
• Cimetiddine
• Cisapride
• Cocaine
• Clomipramine
• Clozapine
• Cyclizine
• Dexgtromethorphan
• Diazepam
• Diphenhydramine
• Doxepin
• Etomidate
• Fluoxetine
• Fluphenazine
• Fluvoxamine
• Haloperidol
• Imipramine
• Ketamine
• Lozapine
• Mesoridazine
• Methohexital
• Metoclopraminde
• Olanzpine
• Paroxetine
• Perphenazine
• Phenelzine
• Pheyntoin
• Pimozide
• Prochlorperazine
• Promazine
• Promethazine
• Propofol
• Quietiapine
• ranitidine
• Risperidone
• Sertraline
• Thiethylperazine
• Thiopental
• Thioridazine
• Thiothixene
• Tigabine
• tranylcypromine
• Trifluoperazine
• Triflupromazine

Work-Up

• consider Utox if no offending agent given by history

DDx

1. tetanus
2. hysterical conversion disorder
3. dislocation of mandible
4. electrolyte abnormality (Calcium, magnesium)
5. meningitis
6. seizure disorder
7. strychnine poisoning
8. akathisia
9. stroke
10. drug toxicity (anticholinergic, phenytoin, valproate, carbamazepine)

Treatment

1. Anticholinergic medication:
   1. Diphenhydramine: 50-100mg over 2 minutes
   2. Benztropine: 1-2 mg in adults over 2 minutes
   3. Biperiden
   4. Trihexyphenidyl 2mg PO BID
   5. IV > IM > PO
   6. symptoms will typically begin resolving in 2-15 minutes but may take up to 90 minutes to completely abate (depends on route in which medication was given)
   7. patients may require more than one dose of IV medication before symptoms resolve completely
2. Benzodiazepines
3. Airway Management
   1. rare, but may be indicated in patients with severe respiratory distress from laryngeal or pharyngeal dystoni

Disposition

1. stop the offending agent (if antipsychotic, speak with patients psychiatrist before just stopping the medication)
2. continue to treat with PO anticholinergic to prevent relapse of symptoms
   1. Diphenhydramine: 12.5-50mg PO TID-QID
   2. Benztropine: 1-2mg PO BID

Source

Adapted from Harwood-Nuss

emedicine