Author:
Kenneth C.Jackimczyk
Description
- Normal pattern of CNS neurotransmission maintained by balance between dopaminergic and cholinergic receptors:
- Certain drugs antagonize dopamine receptors in the basal ganglia resulting in an imbalance of dopaminergic and cholinergic stimulation
- This imbalance leads to acute involuntary muscle spasms of the face or neck (the trunk, pelvis, or extremities can also be affected)
- Although the spasms are uncomfortable and frightening, they are not life threatening except in very rare cases when laryngeal muscles are involved
- Usually occurs within hours of ingestion:
- Almost always within first week after exposure to offending drug
- Risk factors:
- Children and young adults are at higher risk
- Rarely occurs in patients >45 yr of age
- Males more often affected
- Prior episodes of dystonia significantly increase risk
- Recent cocaine use increases risk
Etiology
- Usually occurs after patient has taken antipsychotic, antiemetic, or antidepressant drug
- Incidence of dystonic reactions varies widely (2-25%) depending on the potency of the agent
- Higher with more potent drugs (haloperidol, fluphenazine)
- Lower with less potent drugs (chlorpromazine, thioridazine)
- Lowest with atypical antipsychotics (quetiapine, olanzapine, risperidone)
- Antiemetic agents:
- Other agents:
- Cyclic antidepressants
- H2 blockers
- Some antimalarial agents
- Antihistamines
- Some anticonvulsants
- Doxepin
- Lithium
- Phencyclidine
- Cocaine
Pediatric Considerations |
| Children are particularly vulnerable to dystonic reactions when dehydrated or febrile |
Signs and Symptoms
History
- Ingestion of neuroleptic, antiemetic, or other drug within a week of symptom onset:
- May occur in patients on neuroleptic agents who increase their dose of neuroleptics or reduce medications (anticholinergic agents) used to treat extrapyramidal symptoms
- Difficulty with vocalization
- Completely alert and able to answer questions, although facial muscle involvement may make speech difficult
- Involuntary muscle contractions or spasms usually involving the face or neck (see “Physical Exam”):
- Muscles of the trunk, pelvis, or extremities can also be involved
Physical Exam
- Characteristic involuntary muscle spasms occur
- Oculogyric crisis:
- Involves eye and periorbital muscles
- Evolves into painful upward or lateral deviation of the eyes
- Blepharospasm:
- Involuntary eyelid closure
- Buccolingual crisis:
- Involves facial muscles and the tongue
- May have difficulty speaking
- Facial grimacing
- Trismus
- Tongue protrusion
- Dysphagia
- Spasmodic torticollis:
- Torticopelvic crisis:
- Abdominal wall muscle spasm
- Opisthotonos:
- Involves muscles of trunk and back
- Twisting and arching of spine
- Laryngeal dystonia:
- Very rare but potentially life threatening
- May develop airway obstruction due to laryngospasm
- Presents as dysphonia or stridor
Essential Workup
- Clinical diagnosis is based on characteristic signs and symptoms with history of possible drug exposure
- Diagnosis is confirmed by response to treatment:
- Lack of response to treatment should lead one to consider alternative diagnosis
Diagnostic Tests & Interpretation
Lab
- Lab testing not routinely indicated
- If no response to treatment, hypocalcemia should be considered and calcium level obtained
Imaging
No imaging studies needed
Differential Diagnosis
- Tardive dyskinesia:
- Complication of chronic antipsychotic therapy
- Usually choreiform movements
- Does not rapidly improve with administration of anticholinergic drug
- Akathisia:
- Seizure:
- History of prior seizures
- Not responsive to verbal stimuli
- Tonic-clonic-type motor movements rather than spasm
- Hysteria or pseudoseizure:
- History of precipitating emotional event
- Tonic-clonic motor activity rather than sustained spasm
- Tetanus
- Strychnine poisoning
- Chronic dystonias:
- Cerebral palsy, familial choreas
- Usually history of dystonia is associated with chronic neurologic process
- Scorpion envenomation:
- Oculogyric crisis and opisthotonos are common manifestations of scorpion envenomation
- Patient lacks history of drug exposure
- Meningitis and encephalitis may present with atypical seizures that mimic dystonic reaction
- Mand ible dislocation
- Hypocalcemia
Prehospital
- Rarely life threatening
- Direct attention toward spasm of larynx and tongue to be sure dystonic reaction is not causing respiratory compromise
- Ask family and friends about ingestions of antipsychotic medications, antiemetics, and recreational drugs
- Transport pill bottles
Initial Stabilization/Therapy
Stabilize airway to prevent spasm of larynx or tongue from causing respiratory compromise
ED Treatment/Procedures
- Administer diphenhydramine (Benadryl) or benztropine mesylate (Cogentin):
- Rapid resolution of muscular spasm by restoring cholinergic-dopaminergic balance in CNS
- IV administration is preferred route of treatment
- Onset of relief in 2-5 min
- Complete resolution of symptoms in 30 min
- IM administration is alternate route of treatment
- Begins to work in 15-30 min
- Continue oral administration for 3 d to prevent redevelopment of symptoms
- Diazepam (Valium):
- Administer in cases of dystonia unresponsive to adequate doses of anticholinergic medications
- Failure to respond to stand ard treatment should lead physician to consider other diagnoses
Medication
- Benztropine mesylate (Cogentin): 1-2 mg either IV (over 2 min) or IM followed by 1-2 mg PO b.i.d for 2-3 d:
- Not to be used in children <3 yr old
- For children >3 yr old: 0.02 mg/kg IV (over 2 min) or IM followed by 0.02 mg/kg PO b.i.d for 2-3 d
- Diphenhydramine (Benadryl): 1-2 mg/kg up to 100 mg either IV (over 2 min) or IM followed by 25-50 mg (peds: 1-2 mg/kg) PO q6-8h for 2-3 d, or
- Diazepam: 5-10 mg IV followed by 5 mg PO q4-6h as necessary for 2-3 d
First Line
Diphenhydramine (Benadryl)
Second Line
Benztropine mesylate (Cogentin):
- Not to be used in children <3 yr old
- Diazepam
Disposition
Admission Criteria
- Patients are not admitted unless symptoms do not resolve with treatment, there are concerns about maintaining the airway, or the diagnosis is not certain
- If the dystonic reaction causes laryngospasm patient should be observed for 12-24 hr after symptoms resolve
Discharge Criteria
- Discharge after resolution of symptoms
- The offending agent should be discontinued
- Patient should not drive or perform tasks that require full alertness while taking sedating medications
Follow-up Recommendations
Patients should follow-up with the prescribing physician of the causative agent
ICD9
333.72 Acute dystonia due to drugs
ICD10
G24.01 Drug induced subacute dyskinesia
G24.02 Drug induced acute dystonia
G24.09 Other drug induced dystonia
G24.0 Drug induced dystonia
SNOMED