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OJHAS: Vol. 4, Issue
4: (2005 Oct-Dec) |
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Drug Induced
Parkinsonism Presenting As Isolated
Jaw Tremors |
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Ravi Gupta
Senior Resident
Manjeet Singh Bhatia,
Professor & Head
Department of Psychiatry,
University College of Medical
Sciences & GTB Hospital,
Dilshad Garden, Shahdara,
Delhi-110095
(India) |
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Address For Correspondence |
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Ravi Gupta
1061, Kissan Marg,
Barkat Nagar, Jaipur-302015
(India)
E-mail:
guptaravi_2003@yahoo.co.in |
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Gupta R, Bhatia MS. Drug Induced
Parkinsonism Presenting as isolated
Jaw Tremors.
Online J Health Allied Scs.2005;4:3 |
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Submitted: Dec 29,
2005; Revised: Mar 01, 2006; Accepted: Mar 07, 2006; Published:
Mar 31, 2006 |
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| Abstract: |
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We
describe a case of drug induced parkinsonism (DIP) that
presented with isolated mandibular tremors despite prophylactic
anticholinergic therapy. Varied presentations of DIP may
be explained by anatomical & functional neuro-circuitry
of striatum.
Key Words:
Drug Induced Parkinsonism, Tremors, Antipsychotics |
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Drug induced
Parkinsonism has been described after use of conventional as well as
atypical antipsychotics. This usually appears after 2-4 weeks of therapy.(1)
We present a case that developed tremors of the jaw one week after starting atypical antipsychotic drug
along with prophylactic Trihexyphenidyl.
A 55 year
old man with the diagnosis of Manic
Depressive Psychosis for 20 years developed acute manic episode. He
was put on the Risperidone 4 mg/day & Trihexyphenidyl 4 mg/day in
divided doses. After 8 days he developed abnormal movements of the jaw
consisting of repeated opening & closing. The frequency was 3-4
Hz. Since we did not have the facility for electromyogram, a frequency
assessment was done by capturing the video of the patient for one minute
and then counting average number of movements
for one second with the help of Windows Movie Maker.
Movements were aggravated during stress and relieved while speaking,
chewing and sleep. His physical & neurological examination was normal.
Subject had contolled hypertension on cardioselective beta blockers..
He was advised MRI Head to rule out the possibility of lacunar infarct
& it appeared normal. Diagnosis of Drug Induced Parkinsonism was
made based on these findings. Risperidone was reduced to 3 mg/day
& Valproate in the doses of 1200 mg/ day in divided doses p.o. started.
Jaw tremors disappeared in 10 days. His Risperidone & Trihexyphenidyl
was withdrawn gradually over three weeks.
Occurrence
of mandibular tremors in a patient receiving antipsychotic and a
prophylactic anticholinergic drug is uncommon. The jaw tremors that
this patient had, needed to be differentiated from 'Rabbit Syndrome',
which presents as fine tremors of peri-oral muscles rather than
the jaw movements.
Induction of Drug-Induced-Parkinsonism is related to the
relative balance of muscarinic blockade & D2 blockade rather than the absolute number of D2 blockade
as explained by Kapur et al (3) and Daskalakis et al.(4) This is further evident by the
fact that antipsychotics with higher anticholinrgic activity have lesser
propensity to induce drug-induced-parkinsonism (5) and similarly this
patient improved only with the reduction of risperidone dose. However,
this imbalance theory has been challenged & the major role of GABA
controlled Substantia nigra pars reticulata has been demonstrated.(6)
Drug-induced-parkinsonism commonly
affects the upper limbs and only sometimes involves face, jaw,
neck and other body parts.(1,6) It is still not clear why drug-induced-parkinsonism
shows preference for some body parts.(6) One probable reason may be the neuro-circuitry of Cortico-Striato-thalamo-cortical loops.
Since the striatum has topographical reciprocal connections with the
cortex through thalamus(7), it is possible that a particular group
of neurons gets blocked in each individual, affecting different body
parts in drug-induced-parkinsonism.(6) Though we could not find any
report of drug-induced-parkinsonism presenting as isolated jaw tremors
in humans, jaw tremors as a sign of drug-induced-parkinsonism has been
described in rats.(6)
In conclusion, although jaw tremors are a rare presentation, all clinicians dealing with drug induced
movement disorders must recognize them at the earliest for appropriate
management. Examination of such cases may help in understanding the pathophysiology of Parkinson’s disease
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Kapur S, Zipursky R, Jones C, Remington
G, Houle S. Relationship between dopamine D2 occupancy, clinical
response, and side effects: a double-blind PET study of first-episode
schizophrenia. Am J Psychiatry 2000;157:514–520
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Daskalakis
Z, Christensen B, Zipursky R, Zhang-Wong J, Beiser M. Relationship between
D2 occupancy and prolactin levels in first episode psychosis.
Biol Psychiatry 1998; 43:113S
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Barnes
TRE, Spence SA. Movement Disorders associated with antipsychotic drugs:
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The Psychopharmacology of Schizophrenia. Bangalore: Panther Publishers
Private Limited; 2000: 178-210
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Finn M, Mayorga
AJ, Conlan A, et al. Involvement of pallidal and nigral GABA mechanisms
in the generation of tremulous jaw movements in rats. Neuroscience 1997;80(2):535-544
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Young AB, Penney
JB. Biochemical & functional organization of the basal ganglia.
In: Jankovic JJ, Tolosa E, eds. Parkinson’s Disease & Movement
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2002:1-10
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