Onabotulinum toxin A for the treatment of sialorrhea in familial dysautonomia

Management of paediatric sialorrhea

PURPOSE OF REVIEW

To summarize current understanding of and recent literature on the management of sialorrhea in children.

RECENT FINDINGS

Sialorrhea is a symptom of oropharyngeal dysphagia and reduced clearance. Sialorrhea can be anterior, with forward overflow of saliva, causing skin rash, social embarrassment and spillage on communication devices; or posterior, where there is pharyngeal pooling of saliva, which may cause aspiration.Assessment of sialorrhea involves a clinical evaluation, focusing on the individual's age, development, underlying medical condition and whether the sialorrhea is anterior, posterior or both. Craniomaxillofacial structure, posture, airway patency, neuromotor control, level of social awareness, motivation and caregiver concerns are assessed. To manage sialorrhea, integration of multiple strategies is usually needed. There is good evidence for behavioral intervention, oral appliances, anticholinergic medications, botulinum toxin injection and surgery. The role of various options of surgery in providing a longer lasting effect is supported. Adjunctive airway and craniomaxillofacial surgery may be indicated.

SUMMARY

Sialorrhea is a modifiable condition with multifactorial causes requiring multimodal therapy by an inter-disciplinary team. There is increasing evidence on the role of saliva surgery in improving the quality of life for the person with sialorrhea and their caregivers.

Familial dysautonomia

Familial dysautonomia (FD) is an autosomal recessive hereditary sensory and autonomic neuropathy (HSAN, type 3) expressed at birth with profound sensory loss and early death. The FD founder mutation in the ELP1 gene arose within the Ashkenazi Jews in the sixteenth century and is present in 1:30 Jews of European ancestry. The mutation yield a tissue-specific skipping of exon 20 and a loss of function of the elongator-1 protein (ELP1), which is essential for the development and survival of neurons. Patients with FD produce variable amounts of ELP1 in different tissues, with the brain producing mostly mutant transcripts. Patients have excessive blood pressure variability due to the failure of the IXth and Xth cranial nerves to carry baroreceptor signals. Neurogenic dysphagia causes frequent aspiration leading to chronic pulmonary disease. Characteristic hyperadrenergic "autonomic crises" consisting of brisk episodes of severe hypertension, tachycardia, skin blotching, retching, and vomiting occur in all patients. Progressive features of the disease include retinal nerve fiber loss and blindness, and proprioceptive ataxia with severe gait impairment. Chemoreflex failure may explain the high frequency of sudden death in sleep. Although 99.5% of patients are homozygous for the founder mutation, phenotypic severity varies, suggesting that modifier genes impact expression. Medical management is currently symptomatic and preventive. Disease-modifying therapies are close to clinical testing. Endpoints to measure efficacy have been developed, and the ELP1 levels are a good surrogate endpoint for target engagement. Early intervention may be critical for treatment to be successful.

Comparative Efficacy of Botulinum Toxin in Salivary Glands vs. Oromotor Therapy in the Management of Sialorrhea in Cerebral Palsy Impact on Sleep Quality

Aims

The aim of this study was to compare the effects of intraglandular abobotuliniumtoxinA application and oromotor therapy in the management of sialorrhea in patients with cerebral palsy and its effect on sleep quality.

Methods

A comparative study (n = 134), mean age 7.1 years (± 3.9 years) was performed in pediatric patients, between the efficacy of abobotuliniumtoxinA in salivary glands and oromotor therapy (JT), with a control group receiving exclusive oromotor therapy (EOMT). Demographic variables, as well as Gross Motor Function Classification System (GMFCS), Drooling Severity and Frequency Scale (DSFS), Sleep Disturbance Scale for Children (SDSC) and Eating and Drinking Ability Classification System (EDACS) were analyzed in 134 patients considering two measurements 6 months apart. Statistical analysis was developed between both groups.

Results

The greatest improvement in safety and efficacy of swallowing were those in the JT group with initial levels of EDACS IV and V. Both therapies result in favorable changes of all subscales means of SDSC, with joint therapy showing the greater benefit (p = 0.003) over EOMT (p = 0.06), especially for Sleep Breathing Disorders and Disorders of initiating and maintaining sleep (p < 0.01 vs. p = 0.07). No major adverse effects were found, only those expected from the application of the toxin, such as pain, mild, and transient local inflammation.

Interpretation

A correlation between frequency and intensity of sialorrhea, with the frequency of sleep disorders and dysphagia was found. Conventional EOMT proved to be useful, improving the safety and efficacy of swallowing, sialorrhea and sleep disorder, however it can be enhanced with the application of abobotuliniumtoxinA.

Respiratory care in familial dysautonomia: Systematic review and expert consensus recommendations

BACKGROUND

Familial dysautonomia (Riley-Day syndrome, hereditary sensory autonomic neuropathy type-III) is a rare genetic disease caused by impaired development of sensory and afferent autonomic nerves. As a consequence, patients develop neurogenic dysphagia with frequent aspiration, chronic lung disease, and chemoreflex failure leading to severe sleep disordered breathing. The purpose of these guidelines is to provide recommendations for the diagnosis and treatment of respiratory disorders in familial dysautonomia.

METHODS

We performed a systematic review to summarize the evidence related to our questions. When evidence was not sufficient, we used data from the New York University Familial Dysautonomia Patient Registry, a database containing ongoing prospective comprehensive clinical data from 670 cases. The evidence was summarized and discussed by a multidisciplinary panel of experts. Evidence-based and expert recommendations were then formulated, written, and graded using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Recommendations were formulated for or against specific diagnostic tests and clinical interventions. Diagnostic tests reviewed included radiological evaluation, dysphagia evaluation, gastroesophageal evaluation, bronchoscopy and bronchoalveolar lavage, pulmonary function tests, laryngoscopy and polysomnography. Clinical interventions and therapies reviewed included prevention and management of aspiration, airway mucus clearance and chest physical therapy, viral respiratory infections, precautions during high altitude or air-flight travel, non-invasive ventilation during sleep, antibiotic therapy, steroid therapy, oxygen therapy, gastrostomy tube placement, Nissen fundoplication surgery, scoliosis surgery, tracheostomy and lung lobectomy.

CONCLUSIONS

Expert recommendations for the diagnosis and management of respiratory disease in patients with familial dysautonomia are provided. Frequent reassessment and updating will be needed.

Histopathologic Effects of Onabotulinum Toxin A Treatment in Pediatric Submandibular Glands

Onabotulinum toxin A (OBTXA) is an effective treatment for drooling. Our objective was to determine if there are histologic changes in the submandibular glands (SMGs) after repetitive OBTXA injections. The study included blinded histologic analysis and comparison of SMGs with ≥4 OBTXA injections versus controls who never received OBTXA. The number of acinar cells were counted, and the morphology of the cells was evaluated within each histologic sample of the SMGs. Thirty-one glands were analyzed (14 control, 17 cases). No physical differences were observed between the 2 acinar cell groups. There was no significant difference in the number acinar cells per surface area in the control group as compared with the OBTXA group (1.29 ± 0.13 vs 1.17 ± 0.11 cells/μm², respectively). To conclude, no significant histologic findings were established in this first human study on SMGs post-OBTXA treatment.

Association of onabotulinum toxin A treatment with salivary pH and dental caries of neurologically impaired children with sialorrhea

BACKGROUND

Sialorrhea is a common manifestation of several neurological disorders. The use of intraglandular onabotulinum toxin A (OBTXA) injection has been recognized to effectively treat sialorrhea. As OBTXA injection reduces salivary flow rate and alters salivary quality, its use may have a detrimental effect on oral health.

AIM

To examine the effect of OBTXA injection on caries experience and salivary pH of neurologically impaired children with sialorrhea.

DESIGN

Twenty-five children receiving OBTXA treatment and 25 control children were enrolled in the study. Whole saliva was collected to determine salivary pH. All participants underwent an interview on their dietary habits. Dental clinical examinations were carried out to evaluate caries experience and oral hygiene level.

RESULTS

Overall, mean salivary pH value was significantly lower in the OBTXA group (6.92 ± 0.77) compared with the control group (7.36 ± 0.70). Caries activity was significantly higher in the OBTXA group (P = 0.01). The regression analyses showed a significant association between OBTXA treatment and salivary pH value (P = 0.03). Results from the logistic regression show that dental caries was significantly associated with OBTXA treatment (OR = 1.73, CI = 1.14-27.3).

CONCLUSIONS

The study showed an intricate relationship between OBTXA treatment and oral findings. Hence, special dental care should be given to children receiving OBTXA treatment.

Current treatments in familial dysautonomia

INTRODUCTION

Familial dysautonomia (FD) is a rare hereditary sensory and autonomic neuropathy (type III). The disease is caused by a point mutation in the IKBKAP gene that affects the splicing of the elongator-1 protein (ELP-1) (also known as IKAP). Patients have dramatic blood pressure instability due to baroreflex failure, chronic kidney disease, and impaired swallowing leading to recurrent aspiration pneumonia, which results in chronic lung disease. Diminished pain and temperature perception result in neuropathic joints and thermal injuries. Impaired proprioception leads to gait ataxia. Optic neuropathy and corneal opacities lead to progressive visual loss.

AREAS COVERED

This article reviews current therapeutic strategies for the symptomatic treatment of FD, as well as the potential of new gene-modifying agents.

EXPERT OPINION

Therapeutic focus on FD is centered on reducing the catecholamine surges caused by baroreflex failure. Managing neurogenic dysphagia with effective protection of the airway passages and prompt treatment of aspiration pneumonias is necessary to prevent respiratory failure. Sedative medications should be used cautiously due to the risk of respiratory depression. Non-invasive ventilation during sleep effectively manages apneas and prevents hypercapnia. Clinical trials of compounds that increase levels of IKAP (ELP-1) are underway and will determine whether they can reverse or slow disease progression.