Neuromuscular disorders

Laryngeal innervation and the functional disorders associated with lower motor neuron paralyses are reviewed. Causes of diffuse denervation, such as drug toxicities and demyelinating disease, are also discussed. Symptoms and treatment of myasthenia gravis, amyotrophic lateral sclerosis, and botulism are discussed as examples of neuromuscular blockade at various levels.     

Management of neurologic disorders of the larynx

OBJECTIVES: I review the literature on management of neurologic disorders of the larynx. METHODS: I reviewed the literature on laryngeal physiology, clinical evaluation of laryngeal function, and the clinical presentation and treatment of neurologic disorders that frequently affect the larynx. RESULTS: Laryngeal function is complex, as this organ is important in breathing, speech, and swallowing. Coordination of these roles is very susceptible to disruption by neurologic disorders. Diagnosis of neurologic disease is primarily based on history and physical examination; however, the diagnosis of laryngeal dysfunction is frequently overlooked, because the larynx is not easily accessible to examination by non-otolaryngologists. Evaluation of laryngeal function includes listening to the voice, systematic observation of the larynx during speech and nonspeech tasks, and, sometimes, ancillary tests. Neurologic disorders that affect laryngeal function include Parkinson's disease, essential tremor, stroke, amyotrophic lateral sclerosis, multiple sclerosis, and dystonia. The otolaryngologist can sometimes provide treatment to specifically improve symptoms of laryngeal involvement. CONCLUSIONS: Otolaryngology consultation is important in the diagnosis and treatment of neurologic disorders that affect laryngeal function. The otolaryngologist should be able to perform a systematic evaluation of laryngeal and pharyngeal function, and should be aware of the clinical presentation of neurologic disorders that affect the larynx.     

Differentiation of organic and functional voice disorders in slight adduction disorders of the larynx

Patients with organic or functional voice disorders show a considerable agreement between the individual aerodynamic phonatory pattern and the appearances on indirect laryngoscopy during phonation. Both groups were characterized by incomplete dorsal glottic closure. The aerodynamic data (subglottal pressure and transglottal flow) and the laryngeal efficiency support a pathophysiological explanation of abnormal and breathy voicing. Division of the transglottal flow into modulated and unmodulated parts explains how a better voice will be obtained with equal or lower flow values by relaxation of the musculature. The decreased tension of the muscles also produces phonation with a lower subglottal pressure. The onset of fatigue is therefore delayed. It is concluded that mild adduction disorders are neither organic nor functional disorders. Rather there is a continuum of organic alterations with different laryngeal functional disturbances.     

A radiologic advance in the diagnosis of disorders of the larynx

The cervical spine greatly reduces the usefulness of anteroposterior soft tissue radiologic examination of the larynx. Fractures of the laryngeal and cricoid cartilages are difficult to diagnose by soft tissue technique, and time-consuming laminagraphy is often required. A new technique for single exposure anteroposterior soft tissue radiography of the cartilages and airway is described. An esophageal cassette containing ultraspeed dental film placed in a retrolaryngeal position is shown to yield detailed radiographs of high contrast. The feasibility of this technique is illustrated by the presentation of radiographs from patients with laryngeal disorders. The new technique is compared with existing examinations available to the clinician and its application in other disorders of laryngeal cartilages and soft tissue is discussed.     

Neuromuscular disorders presenting as congenital bilateral vocal cord paralysis

Congenital bilateral vocal cord paralysis (BVCP) can be associated with an underlying neuromuscular disorder, and may present before other features of the neuromuscular disorder become apparent. All infants less than 12 months of age presenting with BVCP between July 1987 and July 1999 at the Royal Children's Hospital, Melbourne, in whom a neuromuscular disorder was subsequently diagnosed were followed. Three children in whom BVCP was diagnosed soon after birth and before recognition of an underlying neuromuscular disorder were identified. All presented with upper airway obstructive symptoms at birth, had a diagnosis of bilateral abductor vocal cord paralysis made at awake flexible laryngoscopy, and had no underlying structural laryngeal abnormality on microlaryngoscopy and bronchoscopy. Two children required a tracheostomy, and 1 child was weaned from nasopharyngeal continuous positive airway pressure after 3 weeks. Subsequent neuromuscular symptoms were recognized between 4 months and 7 years later, leading to diagnoses of facioscapulohumeral myopathy, spinal muscular atrophy, and congenital myasthenia gravis. In each case, the prognosis for recovery from symptoms related to BVCP reflected that of the underlying neuromuscular disorder. This experience suggests that congenital BVCP may be a feature of an unrecognized neuromuscular condition. This possibility should be considered particularly in the presence of associated neurodevelopmental or neuromuscular dysfunction, or in cases in which BVCP is progressive.     

Adenocarcinoma of the larynx.

Adenocarcinomas make up less than one per cent of laryngeal malignancies. Nonspecific adenocarcinomas and adenoid cystic carcinomas comprise most of the glandular neoplasms. Adenoid cystic carcinoma has a slight preponderance in females, and often follows a long course similar to this tumor when it occurs in salivary glands. The nonspecific adenocarcinomas occur predominately in males and have a low survival with most patients dying within two years. Less common adenocarcinomas include oncocytoid carcinoma, mucoepidermoid carcinoma, and metastatic adenocarcinoma.     

Rhabdomyosarcoma of the larynx.

A case of rhabdomyosarcoma of the larynx in a 54-year-old man is reported. Patient presented dramatically with a large tumour mass obstructing his laryngeal inlet. The patient remains alive and well sixteen months after a total laryngectomy. Only seven previous reports of a rhabdomyosarcoma of the larynx could be found in the literature and these are compared with the case reported. It would seem that a rhabdomyosarcoma of the larynx has a better prognosis than elsewhere in the body, probably because of its earlier recognition and accessibility to radical surgery.     

Chemodectoma of the larynx.

The ninettenth reported case of chemodectoma of the larynx is presented and its management discussed. Some reflections on the laryngeal paraganglia are made and the past literature is reviewed.     

Cryptococcosis of the larynx.

An unusual case of cryptococcosis of the larynx initially developed as an acute upper airway obstruction that necessitated tracheostomy. Concomitant findings were tracheobronchial ulcerations and edema with severe mainstem bronchial constriction on the left side. Budding "yeast-like organisms" that were consistent with Cryptococcus neoformans appeared in tissue specimens. Epithelial changes that were consistent with pseudoepitheliomatous hyperplasia occurred in areas in the immediate vicinity of the organisms. Sputum and bronchial washing cultures grew nonmycelial, mucinous, encapsulated forms that were positive to staining with mucicarmine and Alcian blue. Treatment with amphotericin B resulted in resolution of the laryngeal obstruction, permitting decannulation. Follow-up direct laryngoscopy and biopsy three months after completion of therapy revealed only mild edema of the false vocal folds. No organisms were found in the tissue, and the pseudoepitheliomatous hyperplastic mucosal changes had resolved.     

Tuberculosis of the larynx.

Tuberculosis of the larynx, once a common disease, has become quite rare with the advent of anti-tuberculous chemotherapy. In the pre-antibiotic era two modes of laryngeal infection were recognized; bronchogenic and hematogenous. The literature is briefly reviewed. Thirteen patients in the past 15 years in whom tuberculous laryngitis was diagnosed upon indirect laryngoscopy by members of the University of Michigan Department of Otorhinolaryngology are presented. Bronchogenic infection was present in 11, and in two patients the disease was consistent with hematogenous spread. Tissue biopsy from a case of bronchogenic contamination demonstrated epithelioid tubercles, while numerous subepithelial acid-fast bacilli without typical tuberculous histological change were present in a case of hematogenous laryngeal infection. A case of cicatricial laryngeal stenosis was successfully treated surgically by laryngofissure, excision of fibrosis with arytenoidectomy, and free mucous membrane grafting. Finally, the initial subtle presentation of many of our patients emphasizes the importance of a consideration of tuberculosis in the differential diagnosis of chronic laryngitis.