Hoarseness due to bilateral vocal cord paralysis as an initial manifestation of familial amyotrophic lateral sclerosis

Multifaceted superoxide dismutase 1 expression in amyotrophic lateral sclerosis patients: a rare occurrence?

Amyotrophic lateral sclerosis (ALS) is a neuromuscular condition resulting from the progressive degeneration of motor neurons in the cortex, brainstem, and spinal cord. While the typical clinical phenotype of ALS involves both upper and lower motor neurons, human and animal studies over the years have highlighted the potential spread to other motor and non-motor regions, expanding the phenotype of ALS. Although superoxide dismutase 1 (SOD1) mutations represent a minority of ALS cases, the SOD1 gene remains a milestone in ALS research as it represents the first genetic target for personalized therapies. Despite numerous single case reports or case series exhibiting extramotor symptoms in patients with ALS mutations in SOD1 (SOD1-ALS), no studies have comprehensively explored the full spectrum of extramotor neurological manifestations in this subpopulation. In this narrative review, we analyze and discuss the available literature on extrapyramidal and non-motor features during SOD1-ALS. The multifaceted expression of SOD1 could deepen our understanding of the pathogenic mechanisms, pointing towards a multidisciplinary approach for affected patients in light of new therapeutic strategies for SOD1-ALS.

Vocal Fold Motion Impairment in Neurodegenerative Diseases

Vocal fold motion impairment (VFMI) is the inappropriate movement of the vocal folds during respiration, leading to vocal fold adduction and/or abduction problems and causing respiratory and vocal impairments. Neurodegenerative diseases (NDDs) are a wide range of disorders characterized by progressive loss of neurons and deposition of altered proteins in the brain and peripheral organs. VFMI may be unrecognized in patients with NDDs. VFMI in NDDs is caused by the following: laryngeal muscle weakness due to muscular atrophy, caused by brainstem and motor neuron degeneration in amyotrophic lateral sclerosis; hyperactivity of laryngeal adductors in Parkinson's disease; and varying degrees of laryngeal adductor hypertonia and abductor paralysis in multiple system atrophy. Management of VFMI depends on whether there is a presence of glottic insufficiency or insufficient glottic opening with/without severe dysphagia. VFMI treatment options for glottic insufficiency range from surgical interventions, including injection laryngoplasty and medialization thyroplasty, to behavioral therapies; for insufficient glottic opening, various options are available based on the severity and underlying cause of the condition, including continuous positive airway pressure therapy, botulinum toxin injection, tracheostomy, vocal fold surgery, or a combination of interventions. In this review, we outline the mechanisms, clinical features, and management of VFMI in NDDs and provide a guide for physicians who may encounter these clinical features in their patients. NDDs are always progressive; hence, timely evaluation, proper diagnosis, and appropriate management of the patient will greatly affect their vocal, respiratory, and swallowing functions as well as their quality of life.

Etiology and presenting features of vocal cord paralysis: changing trends over the last two decades

Background

The study was performed to evaluate the changing trends in etiology and presenting features of vocal cord paralysis (VCP) from March 1998 to March 2020.

Methods

Patient’s record collected from hospital database and divided into two groups, from March 1998 to March 2009 and from April 2009 to March 2020, to evaluate the changing trends in etiology and presenting features.

Results

Total of 711 VCP patients, 80.3% with unilateral (UVCP) and 19.7% with bilateral vocal cord paralysis (BVCP) included. The commonest etiology was non-surgical (57.1%) for UVCP and surgical (55.7%) for BVCP. The commonest surgical etiology was thyroid and parathyroid surgery for both UVCP (16.6%) and BVCP (38.5%). The commonest non-surgical etiology was idiopathic for UVCP (23.1%) and malignancies for BVCP (13.6%). There was increase in surgical etiology for both UVCP (39.3 to 45.3%) and BVCP (51.2 to 57.7%), and decrease in non-surgical etiology for both UVCP (60.7 to 54.6%) and BVCP (48.8 to 42.3%). The change in voice was most common presenting features for both UVCP (69.2%) and BVCP (92.8%). The frequency of the presenting features was comparable, with decrease in the duration of symptom onset over the time period.

Conclusion

The most common etiology for UVCP was idiopathic, and for BVCP was thyroid and parathyroid surgery. For both, UVCP and BVCP there was increasing trend for surgical and decreasing trend for non-surgical etiology. The change in voice was the most common presenting complain, with decrease in duration of symptom onset over time period.

Unilateral vocal cord adductor weakness: an atypical manifestation of motor neurone disease

Background

Bulbar involvement is a recognised feature of motor neuron disease/amyotrophic lateral sclerosis (MND/ALS), both as a presenting complaint and as a consequence of advancing disease. Hoarseness and dysphonia have been associated with vocal cord abductor weakness. This is usually bilateral and has also been reported as the presenting clinical feature in a handful of patients with superoxide dismutase 1 (SOD1) gene mutations. Presentation with an isolated, unilateral vocal cord adductor weakness, however, is atypical and rare.

Case

In this report, we detail the case of a 38-year-old woman with dysphonia and a family history of an SOD1 mutation. Neurological features remained confined to the territory of the left vagus nerve for the next 12 months, before a more rapid rate of disease dissemination and progression.

Conclusions

This case highlights the importance of recognition of vocal cord palsy as an early manifestation of MND/ALS and the critical need for monitoring to recognise potential disease progression.

Case Report: Laryngospasm as Initial Manifestation of Amyotrophic Lateral Sclerosis in a Long-Survival Patient With Heterozygous p.D90A - SOD1 Mutation

Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease affecting motor neurons. Although its etiology is still unknown, many genes have been found to be implicated in ALS pathogenesis. The Cu/Zn superoxide dismutase (SOD1) gene was the first to be identified. Currently, more than 230 mutations in the SOD1 gene have been reported. p.D90A (p. Asp90Ala) is the most common SOD1 mutation worldwide. It shows both autosomal and recessive inheritance in different populations. To date, five Italian patients with the heterozygous p.D90A mutation have been reported. None of them complained of laryngological symptoms as the initial manifestation of ALS, although they had atypical clinical features. We describe a long-survival patient carrying heterozygous p.D90A mutation who presented with severe laryngospasm due to bilateral vocal cord paralysis. We suggest that genetic analysis may help to diagnose ALS with insidious onset like hoarseness, laryngospasm, and other type of voice disturbances.

Stridor: a rare presentation of motor neuron disease

A 74-year-old farmer presented to the emergency department with a subacute history of progressive dyspnoea, wheeze and dysphonia. He was treated for an exacerbation of asthma with poor response to pharmacological therapy. Investigation of dysphonia via laryngoscopy identified a bilateral vocal cord palsy. Subsequently, the patient developed an episode of life-threatening stridor and hypercapnic respiratory failure requiring an emergency tracheostomy. Neurology input identified evidence of widespread muscle fasciculations on clinical examination. MRI of the brain and cervical spine were unremarkable. Electromyogram testing identified changes of acute denervation in several limbs consistent with a diagnosis of motor neuron disease (MND). Bilateral vocal cord palsy has been rarely reported in the literature as the heralding symptom resulting in the diagnosis of MND. In patients with a subacute onset of dysphonia, dyspnoea and stridor, MND should be a differential diagnosis.

Laryngeal electromyography in amyotrophic lateral sclerosis

BACKGROUND

Bulbar involvement is a hallmark of amyotrophic lateral sclerosis (ALS), but surprisingly very few studies have addressed the frequency, pattern and clinical relevance of laryngeal involvement in the disease.

METHODS

Twenty-six patients with spinal-onset ALS underwent nasofibroscopy (NF), followed by laryngeal electromyography (LEMG). We also studied resting activity and motor unit potentials of the genioglossus and masseter muscles.

RESULTS

Twenty-four patients presented neurogenic changes in at least one laryngeal muscle. There were fibrillation and/or fasciculation potentials associated with chronic neurogenic changes in the same muscle in 16 patients; of these, 9 had no alteration in the genioglossus. We found no patient with tongue neurogenic changes and normal LEMG. NF was abnormal in 14 patients; in the remaining 12, LEMG identified neurogenic changes in 11 of them.

CONCLUSION

LEMG is able to identify laryngeal denervation in patients with ALS, sometimes before clinical manifestations are noticed. This technique may be a useful diagnostic tool for selected patients with suspicion of ALS.

Familial congenital bilateral vocal fold paralysis: a novel gene translocation

OBJECTIVES

True vocal fold (TVF) paralysis is a common cause of neonatal stridor and airway obstruction, though bilateral TVF paralysis is seen less frequently. Rare cases of familial congenital TVF paralysis have been described with implied genetic origin, but few genetic abnormalities have been discovered to date. The purpose of this study is to describe a novel chromosomal translocation responsible for congenital bilateral TVF immobility.

METHODS

The charts of three patients were retrospectively reviewed: a 35 year-old woman and her two children. The mother had bilateral TVF paralysis at birth requiring tracheotomy. Her oldest child had a similar presentation at birth and also required tracheotomy, while the younger child had laryngomalacia without TVF paralysis. Standard karyotype analysis was done using samples from all three patients and the parents of the mother, to assess whether a chromosomal abnormality was responsible.

RESULTS

Karyotype analysis revealed the same balanced translocation between chromosomes 5 and 14, t(5;14) (p15.3, q11.2) in the mother and her two daughters. No other genetic abnormalities were identified. Neither maternal grandparent had the translocation, which appeared to be a spontaneous mutation in the mother with autosomal dominant inheritance and variable penetrance.

CONCLUSIONS

A novel chromosomal translocation was identified that appears to be responsible for familial congenital bilateral TVF paralysis. While there are other reports of genetic abnormalities responsible for this condition, we believe this is the first describing this particular translocation.

[A case of amyotrophic lateral sclerosis with bilateral vocal cord paralysis necessitating tracheotomy]

Vocal cord movement disorders are increasingly recognized in patients with amyotrophic lateral sclerosis (ALS). We describe a patient with limb-onset ALS who developed vocal cord paralysis. A 74-year-old Japanese male consulted our clinic with a 6-month history of weakness in both arms. His family history was unremarkable. There were fasciculations and mild atrophy of the tongue and both arms. In the legs, muscle strength was almost normal but widespread fasciculations were present. All tendon reflexes were hypoactive and pathological reflexes were absent. Thereafter, he developed weakness of the legs and showed increased eating time. Babinski sign was positive bilaterally at this stage. The forced vital capacity dropped from 90% at the initial evaluation to 62% of the predicted value 14 months later. Two years after disease onset, the patient developed aspiration pneumonia with hoarseness and had difficulty clearing his throat of phlegm. Laryngoscopy demonstrated severe vocal cord paresis on both sides, particularly in the abductor muscles possibly leading to obstruction. Tracheotomy was performed because of the risk that the patient could choke to death. A review of the literature suggests that severe impairment of vocal cord abduction could be a prelude to sudden death in ALS. Follow up by laryngoscopic examination is necessary.

Postcricoid pharyngeal carcinoma mimicking bulbar amyotrophic lateral sclerosis

Bulbar weakness, including dysarthria, dysphagia, or progressive respiratory weakness, occurs as the presenting feature in approximately 25% of patients with amyotrophic lateral sclerosis (ALS). Misdiagnosis of ALS in patients with progressive bulbar symptoms is uncommon. This report describes a 73-year-old man who had a 10-month history of progressive hoarseness, dysphagia, and respiratory failure. The initial diagnosis was bulbar ALS. Computed tomography of his neck identified a postcricoid squamous cell carcinoma, which was causing bilateral vocal cord paralysis. To the author's knowledge, postcricoid carcinoma has not been previously described as mimicking ALS but should be considered in the differential diagnosis of bulbar ALS.

Amyotrophic lateral sclerosis associated with mutations in the CuZn superoxide dismutase gene

This review highlights recent epidemiologic, clinical-genetic, and neurochemical advances in our understanding of sporadic amyotrophic lateral sclerosis (ALS) and their relationships to familial ALS caused by superoxide dismutase (SOD1) gene mutations. It is of fundamental importance to recognize that ALS is a biologically heterogeneous syndrome in which genetics, environment, and aging are inter-related. The discovery of mutations in the SOD1 gene is the greatest breakthrough in ALS research since Charcot's description of the disorder, but the putative toxic gain of function of mutant SOD1 remains elusive despite intense research. Currently, two dominant theories for the pathogenesis of SOD1 mutations exist: specific protein cytotoxicity and protein aggregation. Mutant SOD1 interacts specifically with neurofilament-light chain mRNA and the dynein/dynactin complex, suggesting that cytoskeletal defects and axonal transport are key players. In addition, mutant SOD1 protein has increased propensity to form aggregate-prone monomers, and the degree of instability correlates inversely with length of survival; therefore, increased propensity to aggregate may be the unifying common denominator for the 119 diverse SOD1 mutations.