- neuroleptic-induced dystonia usually begins 12 - 36 hours after a new neuroleptic drug is started, or the dose of an existing drug is increased Black widow spider bite 
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 - neuroleptic-induced dystonia usually begins 12 - 36 hours after a new neuroleptic drug is started, or the dose of an existing drug is increased Black widow spider bite

EM guidemap - Drug-induced dystonia

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Clinical presentation

Differential diagnosis

neuroleptic malignant syndrome
black widow spider bite
other diagnostic entities

{*filter*} associated with acute dystonia
Introduction and general principles

- this guidemap is mainly focused on providing problem-solving information about acute
drug-induced dystonic reactions, and it does not discuss chronic dystonia

Dystonia is defined as a movement disorder characterized by sustained muscle contractions,
frequently causing twisting and repetitive movements, or abnormal postures

- there is clinical overlap with athetosis, a term used to describe abnormal movements
that are slow, writhing and sinuous in nature

- dystonic movements often involve large muscle groups, and the exaggerated muscle
contraction may result in distorted postures, which are often painful

- dystonic movements may be sustained or intermittent, and they may be jerky, rhythmic or

- dystonic movements are often aggravated by purposeful actions and emotional stress, and
they may sometimes be task specific eg. writing, speaking or chewing; occuring during
walking but not during dancing

- the tendency for dystonic movements to vary according to task and stress, may
incorrectly suggest psychogenic dystonia

- drug-induced dystonia may occur within minutes-hours of exposure to an inciting drug,
and the reaction can be idiosyncratic or dose-related

- there are a number of different patterns of drug-induced dystonia

laryngeal dystonia (forced spasm of pharyngeal and laryngeal muscles => dysphagia and
oculogyric crisis (forced spasm of extra-ocular muscles causing forced conjugate gaze
blepharospasm (forced spasm of the eyelid muscles causing forced eyelid closure)
buccolingual crisis (forced spasm of the face, jaw, tongue and pharnyx muscles)
opisthotonus (forced spasm of the paravertebral muscles, forcing the trunk and neck into
retrocollis (forced spasm of the neck muscles forcing the neck into hyperextension)
torticollis (forced spasm of the neck muscles forcing the neck to the side)
anterocollis (forced spasm of the anterior neck muscles forcing the neck forward)
tortipelvic crisis (forced spasm of the trunk and pelvic muscles casusing bizarre body
- the most common {*filter*} causing dystonia include:-
neuroleptic {*filter*}
phenothiazine anti-emetics
{*filter*}, "street" valium (haloperidol) or other street {*filter*} (eg. LSD)
cyclic antidepressants
Clinical presentation

- neuroleptic-induced dystonia usually begins 12 - 36 hours after a new neuroleptic drug
is started, or the dose of an existing drug is increased

- 50% of cases occur within 24 hours, 90% of cases occur within 5 days, and all cases
occur within two weeks => a delayed onset may cause a patient and/or clinician to miss the
causal-association between the inciting drug and the acute dystonia

- risk factors include young age, male sex, and known use of neuroleptic or {*filter*} street

- the most common muscle groups affected are the eyes, jaw, tongue, and neck +/- pharynx
and larynx

Some common types of acute drug-induced dystonic reactions

Oculogyric crisis

- characterized by involuntary tonic deviation of the eyes

- the eyes are usually conjugatedly deviated upwards, although they may be deviated
laterally, or obliquely

- the crisis may be heralded by rapid eyelid blinking or eyelid spasm and/or compulsive

- during the crisis, the patient may still be able to overcome the conjugate eye deviation
by voluntary eye blinking, and rapid voluntary eye movements from one point of fixation to
another (darting eyes); however, the patient may be unable to look downwards

- the crisis may be accompanied by fear, restlessness or compulsive thoughts, which start
and stop synchronously with the oculogyric crisis

- oculogyric crisis may be associated with torticollis and buccolingual crisis eg. forced
jaw opening

Buccolingual crisis

- involves the face, or jaw or tongue

- characterized by protrusion or twisting movements of the tongue, forced jaw opening or
closing (trismus), lip distortion or {*filter*} grimacing

- difficulty speaking (dysarthria), apparent mutism or dysphagia may occur

- rarely causes laryngeal involvement (dysphonia), and vocal cord adduction may threaten
the airway

- may be associated with other forms of dystonia - oculogyric crisis, and torticollis


- usually combined with oculogyric or buccolingual crisis

- characterized by spasm of the neck muscles causing lateral neck deviation (lateral
torticollis), anterior neck deviation (anterior torticollis) or hyperextension of the neck

- may be associated with shoulder elevation or arm dystonia; the shoulder is usually
elevated on the side towards which the chin is pointing

Opisthotonic crisis

- involvement of the paravertebral muscles of the back causing back hyperextension => the
body appears to be arched forwards

- usually associated with tortipelvic crisis

Tortipelvic crisis

- involvement of muscles of the abdominal wall, pelvis and hip causing abdominal wall
spasm, truncal torsion and inability to stand erect

- may be associated with limb dystonia causing adduction and hyperpronation of the limbs
+/- athetoid movements

- children are more likely to manifest generalized truncal and limb involvement
  Differential diagnosis


- presents with jaw-locking (75% of cases) and/or risus sardonicus (sustained orbicularis
oris muscle contraction causing a sneering grin that exposes the teeth)

- also presents with muscle stiffness, neck rigidity, dysphagia, dysarthria and reflex

- muscle rigidity and reflex spasms are the most common manifestation

- reflex spasms may be triggered my minimal external stimuli such as light, noise or touch

- generalized tetanic seizures may produce opisthotonus, flexion and {*filter*} of the
arms, and extension of the lower limbs

- autonomic instability is a later phenomenon

- an important clinical clue is a recent wound or animal bite, and no/incomplete tetanus

Neuroleptic malignant syndrome

- may present with diffuse muscular rigidity and hyperreflexia; or bradykinesia,
cogwheeling, wazy flexibility and involuntary movements suggestive of Parkinson's disease

- may also present with opisthotonus, retrocollis, trismus, oculogyric crises and seizures

- associated with hyperpyrexia, altered LOC and autonomic instability

- an important clinical clue is known exposure to long-term neuroleptic drug therapy +/-
recent increase in drug dose

(* see the fever + rigidity + altered LOC guidemap for further details)


- prodromal symptoms include pain or paresthesia around a recent animal bite site, and
malaise, anorexia, fever, headache, chills, anxiety, agitation, insomnia and pharyngitis

- early neurologic signs may include subtle cognitive and personality changes

- overt neurologic symptoms include dysphagia, aphasia, incoordination, muscle paralysis,
myoclonus, altered mental status (bizarre behaviour - inordinate agitation, hyperactivity,
thrashing, biting, hallucinations), seizure and coma

- may be associated with increased lacrimation and hypersalivation

- aerophobia (blowing air on the face) and hydrophobia (drinking liquids) are very
suggestive of rabies, and the provoking stimulus may incite severe pharyngeal, laryngeal
or diaphragmatic spasms

- an important clinical clue is a recent rabid animal bite, or rabid bat exposure +/-
hydrophobia + personality changes

Black widow spider bite

- associated with diffuse muscle cramping, most noticeable around the bite site

- diffuse large muscle spasms involving the chest, abdomen and limbs may ensue

- pain around the bite site is usually trivial and may not be noticed

- associated autonomic symptoms are common

- an important clue is known/possible exposure to a black widow spider bite


- symptoms include muscle cramping or carpopedal spasms, distal extremity paresthesia,
positive Chvostek's and Troussaeau's sign

- smooth muscle contraction can cause laryngeal stridor, dysphagia and bronchospasm

- altered mental status or seizures may occur

- important clinical clues include recent neck surgery (thyroidectomy), or
hypoparathyroidism, or acute pancreatitis, or rhabdomyolysis syndrome (sepsis or toxic


- may present with muscle cramps, muscle weakness, marked neuromuscular irritability,
hyperreflexia, positive Chovsteks and Troussaeau signs, seizures, coarse or flapping
tremors, athetoid movements, ataxia, nystagmus and altered mental status (irritability,
combativeness, acute, psychosis)

- important clinical clues include underlying disorders causing magnesium loss (renal and
gastrointestinal) and/or malnutrition

Other diagnostic entities that one should consider

peri-tonsillar abscess (trismus)
odontogenic or deep space infection of the oropharynx (trismus)
encephalitis or meningitis (herpes simplex)
CVA (dysphagia, slurred speech, and neck stiffness)
scorpion envenomation (roving or rotatory eye movements, tongue fasiculation, loss of
control over pharyngeal movements, hypersalivation, restlessness, involuntary muscle
jerking, seizures, autonomic instability)
strychnine poisoning (history of occupational exposure, initial apprehension and
heightened sense of awareness, reflex spasms in response to auditory stimuli, opisthotonic
seizures with clear consciousness during and after seizures, chest and diaphragmatic
muscle spasms and respiratory arrest, trismus, muscle rigidity, hyperreflexia)
lethal catatonia syndrome (rigidity, akinesia, cera flexibilitas, and mutism)
malignant hyperthermia syndrome (rigidity, trismus, fever, inciting drug exposure, family
history of MH)
LSD or phencylidine intoxication (acute psychosis with combativeness, hallucinations,
mutism, muscle rigidity, hyperreflexia, dystonia, catatonia, nystagmus, ataxia)
epilepsia continua partialis

- emergency management is focused on discontinuation of the offending drug + the
administration of an anticholinergic drug

- either one-of-two anticholinergic {*filter*} are recommended for use in the ED - benztropine
or diphenhydramine

- the IV route is recommended for severe reactions; IM or po adminstration should be
reserved for milder reactions

- symptoms should resolve within 15 - 30 minutes following IV administration


- dose is 1 - 2mg IV over 2 min (peds. dose = 0.01 - 0.02 mg/kg)

- the dose may be repeated after 15 - 30 minutes if symptoms persist

- the same dose should be used po bid for 2 - 5 days after resolution of the symptoms, in
order to prevent a relapse


- 50 - 100mg IV over 2 min (peds. dose = 1 - 2 mg/kg)

- the dose may be repeated after 15 - 30 minutes if symptoms persist

- the same dose should be used po tid for 2 - 5 days after resolution of the symptoms, in
order to prevent a relapse

- admission to ICU is advisable if there is any evidence of airway involvement (dysphagia,
dyspnea, dysphonia or stridor), even if there is a satisfactory initial response to
anticholinergic drug therapy in the ED

- benzodiazepines can be used prn if anxiolytic therapy is required

Failure to respond to repeated doses of an anticholinergic drug suggests non-drug-induced
dystonia, or a disease mimicing an acute dystonic reaction

{*filter*} associated with acute dystonia

erythromicin ethylsuccinate

Disclaimer: My EM guidemaps reflect my personal approach to problem-solving/managing
clinical cases in an ED setting and they should not be regarded as the standard of care.
They merely represent the personal opinions of the author and they should only be used in
clinical practice if the reader-user has substantial reason to believe that the clinical
advice contained in the guidemaps is valid and accurate. The guidemaps are not meant to be
"authoritative" and the reader-user should consult standard medical textbooks and expert
opinion articles/guidelines for more authoritative advice. The reader-user should
particularly confirm all drug doses, their indications and contra-indications, prior to
their use.

I'm not a humanitarian, I'm a hell-raiser."
                     -Mother Jones

Sat, 23 Apr 2005 16:59:36 GMT
 [ 1 post ] 

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