SSRI-induced reversal of levodopa benefit in two patients with dopa-responsive dystonia

Serotonergic perturbations in dystonia disorders-a systematic review

Dystonia is a hyperkinetic movement disorder characterized by sustained or intermittent muscle contractions. Emerging data describe high prevalences of non-motor symptoms, including psychiatric co-morbidity, as part of the phenotype of dystonia. Basal ganglia serotonin and serotonin-dopamine interactions gain attention, as imbalances are known to be involved in extrapyramidal movement and psychiatric disorders. We systematically reviewed the literature for human and animal studies relating to serotonin and its role in dystonia. An association between dystonia and the serotonergic system was reported with decreased levels of 5-hydroxyindolacetic acid, the main metabolite of serotonin. A relation between dystonia and drugs affecting the serotonergic system was described in 89 cases in 49 papers. Psychiatric co-morbidity was frequently described, but likely underestimated as it was not systematically examined. Currently, there are no good (pharmaco)therapeutic options for most forms of dystonia or associated non-motor symptoms. Further research using selective serotonergic drugs in appropriate models of dystonia is required to establish the role of the serotonergic system in dystonia and to guide us to new therapeutic strategies.

Nonmotor Symptoms in Dopa-Responsive Dystonia

Background

Dopa-responsive dystonia (DRD) is a rare inherited dystonia, caused by an autosomal dominantly inherited defect in the gene GCH1 that encodes guanosine triphosphate cyclohydrolase 1. It catalyzes the first and rate-limiting enzyme in the biosynthesis of tetrahydrobiopterin, which is the essential co-factor for aromatic amino acid hydroxylases. Mutation results in the typical scenario of a young-onset lower-limb dystonia with diurnal fluctuations, concurrent or subsequent development of parkinsonism and excellent response to levodopa. Given the myriad functions of tetrahydrobiopterin, it is reasonable that other systems, apart from motor, would also be impaired. So far, non-motor symptoms have been overlooked and very few and often contrasting data are currently available on the matter.

Methods

Here by searching the Medline database for publications between 1971 to March 2015, we render an in-depth analysis of all published data on non-motor symptoms in DRD.

Results

Depression and subtle sleep quality impairment have been reported among the different cohorts, while current data do not support any alterations of the cardiologic and autonomic systems. However, there is debate about the occurrence of sleep-related movement disorders and cognitive function. Non-motor symptoms are instead frequently reported among the clinical spectrum of other neurotransmitter disorders which may sometimes mimic DRD phenotype, ie, DRD plus diseases.

Conclusions

Further studies in larger and treatment-naïve cohorts are needed to better elucidate the extend of non-motor symptoms in DRD and also to consider treatment for these.

Extrapyramidal Reactions Associated with Serotonergic Antidepressants

OBJECTIVE

Extrapyramidal reactions (EPRs) associated with serotonergic antidepressant treatments have been reported since 1958. These reactions can be distressing for patients and complicate treatment. Our objective was to complete a follow-up review of published EPR cases reported for serotonergic antidepressants.

DATA SOURCES

Published cases between January 1998 and May 2015 were collected through a medical literature search. Citation reference lists were also searched manually.

STUDY SELECTION AND DATA EXTRACTION

Identified cases were reviewed for patient age, gender, psychiatric diagnosis, dosage, time to reaction onset, concurrent medications, and EPR description. Cases were excluded when there was not a clear description, if descriptions were not consistent with accepted definitions, or if the written English was poor. We included cases of akathisia, dystonia, dyskinesia, parkinsonism, or mixed EPRs. Authors scored each case using the Naranjo adverse drug reaction probability scale.

DATA SYNTHESIS

We identified 86 published reports involving 91 patients; selective serotonin reuptake inhibitors were implicated in 80.2% of cases. All EPR types were reported: 17 akathisia cases, 18 dyskinesia cases, 27 dystonia cases, 19 parkinsonism cases, and 10 mixed EPR cases. EPRs typically occurred within 30 days of either treatment initiation or dose increase. Age, gender, antidepressant dosing, or concurrent antipsychotic treatment did not appear to broadly contribute to EPR risk. Naranjo scores ranged from 2 to 8.

CONCLUSIONS

Case reports associating serotonergic antidepressants with EPRs continue to be published. Practitioners are advised that monitoring for such is important. Rigorous research efforts are needed to better understand the clinical risk factors for these adverse drug reactions.

Expanded motor and psychiatric phenotype in autosomal dominant Segawa syndrome due to GTP cyclohydrolase deficiency

BACKGROUND

Segawa syndrome due to GTP cyclohydrolase deficiency is an autosomal dominant disorder with variable expression, that is clinically characterised by l-dopa responsive, diurnally fluctuating dystonia and parkinsonian symptoms.

OBJECTIVE

To delineate the neurological and psychiatric phenotype in all affected individuals of three extended families.

METHODS

GTP cyclohydrolase deficiency was documented by biochemical analyses, enzymatic measurements in fibroblasts, and molecular investigations. All affected individuals were examined neurologically, and psychiatric data were systematically reviewed.

RESULTS

Eighteen affected patients from three families with proven GTP cyclohydrolase deficiency were identified. Eight patients presenting at less than 20 years of age had typical motor symptoms of dystonia with diurnal variation. Five family members had late-presenting mild dopa-responsive symptoms of rigidity, frequent falls, and tendonitis. Among mutation carriers older than 20 years of age, major depressive disorder, often recurrent, and obsessive-compulsive disorder were strikingly more frequent than observed in the general population. Patients responded well to medication increasing serotonergic neurotransmission and to l-dopa substitution. Sleep disorders including difficulty in sleep onset and maintenance, excessive sleepiness, and frequent disturbing nightmares were present in 55% of patients.

CONCLUSION

Physicians should be aware of this expanded phenotype in affected members of families with GTP cyclohydrolase deficiency.

[Drug-induced parkinson syndromes]

Parkinsonism is defined by the association of akinesia with one of the following symptoms: extrapyramidal rigidity, tremor at rest, or postural instability. A drug-induced aetiology must always be suspected when parkinsonian symptoms appear, or increase in a patient receiving drug treatment. Indeed drug-induced is the more frequent aetiology of secondary parkinsonism. The main treatments involved are antipsychotic and other neuroleptic drugs (accounting for up to two-thirds of drug-induced parkinsonism), and calcium-channel entry blockers. The risk associated with antipsychotics is often dose dependent and related to dopamine D2 striatal receptor occupancy induced by the antipsychotic drug. This risk is inferior for the second generation antipsychotics. The other treatments more rarely involved are antidepressants (tricyclic and selective serotonin reuptake inhibitors), lithium, valproic acid, and others. The main criterium for imputability is chronological, regression of symptoms being observed in 40-74% of cases, after a mean delay of 3 months from cessation of treatment. However, 15% of cases persist after drug withdrawal, leading to a diagnosis of underlying idiopathic Parkinson's disease.

Fluoxetine-induced tremor: clinical features in 21 patients

We report a cohort of 21 patients (12 females and nine males), with a mean age of 42.4 years, who developed tremor after receiving fluoxetine at a mean dose of 25.7 mg per day. The mean latency period for tremor appearance was 54.3 days. Severity was found to be mild. In all patients, tremor was postural, with P<0.0005, compared to patients with rest tremor and P<0.05 compared to action/intention-tremor patients. The frequency range was 6-12 Hz/s. After fluoxetine was discontinued, tremor disappeared in 10 patients after a mean latency period of 35.5 days. In the remaining 11 patients, tremor persisted up to the end of the observation period (a mean of 449 days). We believe that this tremor phenomenon is due to the involvement of the red nucleus and the inferior olivary nucleus through their projections to the thalamus and the spinal cord.