Laryngeal dystonia in a case of severe motor and intellectual disabilities due to Japanese encephalitis sequelae

Clinical spectrum and management of dystonia in patients with Japanese encephalitis: A systematic review

BACKGROUND

Japanese encephalitis (JE) is a potentially fatal viral infection with a wide range of manifestations and can also present with a variety of movement disorders (MD) including dystonia. Dystonic features in JE are uncommon. Here, we have tried to summarize the clinical features and management of dystonia among JE patients with a comprehensive literature search.

METHODS

Various databases, including PubMed, Embase, and Google Scholar, were searched against the predefined criteria using suitable keywords combination and boolean operations. Relevant information from observational and case studies was extracted according to the author, dystonic features, radiological changes in the brain scans, treatment options, and outcome wherever provided.

RESULT

We identified 19 studies with a total of 1547 JE patients, the diagnosis of which was confirmed by IgM detection in serum and/or cerebrospinal fluid in the majority of the patients (88.62%). 234 (15.13%) of JE patients had dystonia with several types of focal dystonia being present in 131 (55.98%) either alone or in combination. Neuroimaging showed predominant involvement of thalami, basal ganglia, and brainstem. Oral medications including anticholinergics, GABA agonists, and benzodiazepines followed by botulinum toxin were the most common treatment modalities.

CONCLUSION

Dystonia can be a disabling consequence of JE, and various available medical therapies can significantly improve the quality of life. Owing to insufficient studies on the assessment of dystonia associated with JE, longitudinal studies with a larger number of patients are warranted to further clarify the clinical course, treatment, and outcome of dystonia.

Low-dose levodopa is effective for laryngeal dystonia in xeroderma pigmentosum group A

Xeroderma pigmentosum (XP), a genetic disorder in DNA nucleotide excision repair, is characterized by skin hypersensitivity to sunlight and progressive neurological impairment. Laryngeal dystonia and vocal cord paralysis are complications that can arise in older XP group A (XPA) patients. We report three patients with XPA being administered low-dose levodopa (0.3-1.5 mg/kg/day) for laryngeal dystonia. Patients were aged from 13 to 18 years, exhibited paroxysmal choking and inspiratory stridor, and were diagnosed with laryngeal dystonia. Two XPA patients responded to low-dose levodopa, and paroxysmal choking and involuntary movements resolved, although one of the two patients showed incomplete resolution due to suspected vocal cord paralysis. The other patient was unable to tolerate the medication because of a transient decrease of muscle tone in the extremities. We previously reported a decreased immunostaining of dopaminergic (DA) terminals in the basal ganglia of XPA patients, which may be involved in laryngeal dystonia. Low-dose levodopa has been reported to alleviate DA receptor supersensitivity in tic patients, while laryngeal dystonia occurs in patients with tardive dyskinesia caused by DA receptor supersensitivity. Thus, low-dose levodopa may improve laryngeal dystonia by alleviating DA receptor supersensitivity in XPA patients. We recommend that low-dose levodopa be used for treatment of paroxysmal respiratory disturbances and/or involuntary movements in XPA patients.

Oxidative stress as a biomarker of respiratory disturbance in patients with severe motor and intellectual disabilities

Oxidative stress plays an important role in aging and various diseases such as cancer, cardiovascular diseases, diabetes mellitus and bronchial asthma. However, little is known about a potential role of oxidative stress in the pathogenesis of severe motor and intellectual disabilities (SMID) in terms of respiratory disturbance, which is the most common complication. In the present study, we examined the urinary levels of oxidative stress markers, 8-hydroxy-2'-deoxyguanosine (8-OHdG), hexanoyl-lysine adduct (HEL) and acrolein-lysine adduct (ACR) in patients with SMID. The mean level of urinary 8-OHdG in SMID patients was significantly higher than that in normal controls (18.8 +/- 9.0 ng/mg Cre and 10.5 +/- 2.9 ng/mg Cre, respectively) (p < 0.01). There was no significant difference of the mean level of urinary HEL between patients with SMID and normal controls (81.9 +/- 40.3 pmol/mg Cre and 69.2 + /-37.7 pmol/mg Cre, respectively), while the mean level of ACR in patients with SMID was higher than that of normal controls (220.5 +/- 118.6 nmol/mg Cre and 144.9 +/- 62.0 nmol/mg Cre, respectively) (p < 0.05). In addition, the level of 8-OHdG was strongly correlated with the severity of respiratory disturbance evaluated as the respiratory disturbance score (RDS) (Spearman r = 0.73, n = 14, p < 0.01). In contrast, there was no correlation between the levels of these oxidative stress markers and age or medication of antiepileptic drugs. These results suggest that urinary 8-OHdG is a potentially useful biomarker for evaluating the severity of respiratory failure in patients with SMID.

Laryngeal dystonia in xeroderma pigmentosum

We report on three patients with xeroderma pigmentosum group A (XPA) who showed laryngeal stridor in their 20s. The stridor appeared on feeding and emotional excitation, was exaggerated during respiratory infection and was life-threatening on some occasions. Adduction of the vocal cords during inspiration, observed by laryngoscopy, confirmed laryngeal dystonia in all cases. This type of focal dystonia may be characteristic in XPA and requires special attention during the management of these patients to avoid serious complications.