Voice Disorders: Functional and Organic Dysphonia and Hoarseness

Definition and EtiologyTop

Dysphonia is the impaired ability to produce voice sounds as recognized by clinicians. Hoarseness is a symptom reported by patients that refers to alteration in the voice (vocal weakness, tremor, pitch alteration, or change in voice quality). This is distinct from dysarthria, which is the impaired movement of muscles to produce speech, including the lips, tongue, vocal cords, and diaphragm. Dysphonia is subdivided into categories based on the presence or absence of an identifiable etiology, namely, organic versus functional dysphonia.

The larynx is made up of several structures, which include a set of cartilages, extrinsic and intrinsic muscles, and the mucosal lining. The nerve supply to the larynx is mostly done by the branches of the vagus nerve (recurrentor superior laryngeal nerve). Hoarseness and/or dysphonia can be caused by damage, inflammation, or abnormal function of any of the structures that make up and innervate the larynx.

Dysphonia can be assessed and described by the GRBAS system, which is a voice-rating scale. GRBAS is an auditory-perceptual evaluation of voice, which grades the degree of hoarseness based on roughness, breathiness, asthenia, and strain using a 0 to 3 scoring system, with 0 being normal and 3 being a high degree of dysfunction.

Functional DysphoniaTop

Functional dysphonia is diagnosed when no anatomic or organic cause can explain voice dysfunction. Functional dysphonia may be classified as one of the following:

1) Psychogenic dysphonia: Impaired voice due to a psychogenic rather than a physical origin. It is generally associated with anxiety. Psychogenic dysphonia may be a result of excessive laryngeal muscle tension to provide glottis closure.

2) Vocal cord misuse: This is caused by vocal overuse.

3) Idiopathic vocal cord dysfunction: A paradoxical adduction of the vocal folds during inspiration, causing dyspnea.

Treatment

Depending on etiology, treatment involves a combination of speech therapy, psychotherapy therapy, behavioral therapy, and hypnosis.

Organic DysphoniaTop

Organic dysphonia includes several organic and anatomic pathologies. Given the vast differential diagnosis, organic dysphonia can be organized by system:

1) Vascular: Hemangiomas, arteriovenous malformation, lymphatic malformation.

2) Infectious: Laryngitis (viral, bacterial, and fungal), laryngopharyngitis, epiglottitis, laryngotracheitis, croup.

3) Trauma/toxin: Arytenoid dislocation, neck trauma, caustic inhalation injury, laryngopharyngeal reflux, gastroesophageal reflux disease (GERD), foreign body.

4) Autoimmune: Connective tissue disorder (cricoarytenoid arthritis in the setting of rheumatoid arthritis, systemic lupus erythematosus).

5) Malignancy: Laryngeal carcinoma (squamous cell carcinoma).

6) Iatrogenic: Postintubation neuropraxia; thyroid surgery; anterior cervical disc surgery; cardiothoracic, vascular, and neurologic procedures (eg, esophageal and aortic root surgery).

7) Neoplasm: Recurrent respiratory papillomatosis; benign laryngeal lesions (nodules, cysts, polyps); neoplasms of the skull base, mediastinum, esophagus, lung, and thyroid.

8) Neurologic: Stroke, including brainstem stroke (lateral medullary syndrome/Wallenberg syndrome), myasthenia gravis, Parkinson disease, amyotrophic lateral sclerosis, multiple sclerosis.

9) Endocrine: Hypothyroidism (laryngeal myxedema), diabetic neuropathy.

10) Congenital and other causes: Congenital webs, amyloidosis.

Diagnosis

Otolaryngology consultation is necessary. Diagnosis is based on nasolaryngoscopy for visualization or videostroboscopy (a special form of laryngoscopy that uses strobe lights, which allows for assessment of laryngeal vibration) for revealing mucosal wave abnormalities.

There is a role for laboratory evaluation if a specific medical etiology is expected on the basis of history and physical examination (eg, metastatic malignancy, amyloidosis, thyroid diseases, diabetes). If laryngoscopy shows evidence of a recurrent laryngeal nerve paralysis, a computed tomography (CT) scan of the neck and upper mediastinum should be performed. Follow-up investigations can include examination under anesthesia and esophagoscopy.

An ear, nose, and throat (ENT) assessment is necessary if hoarseness is not related to the common cold or influenza, has been present for >2 weeks in a patient with a history of smoking, or is accompanied by other alarming symptoms, such as dyspnea, hemoptysis, pain on speaking, dysphagia or odynophagia, neck masses, or serious problems with articulation persisting for more than several days. An ENT assessment should be considered if hoarseness persists longer (>4-8 weeks), even without the characteristics above. Neck and chest imaging should be considered as part of the workup in suspected malignancy cases. Rapid assessment is especially important in the presence of increasing cough, unilateral ear and/or throat pain, weight loss, or other significant risk factors for head and neck cancer.

Ancillary Tests

Acoustic analysis, speech aerodynamic study, laryngeal electromyography, CT/magnetic resonance imaging (MRI).

Treatment

Treat the underlying cause when discovered. Medical treatment rarely leads to resolution of symptoms; surgical treatment and voice therapy are generally more appropriate. Guidelines from the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) suggest the following:

1) Recommend against prescribing antireflux medications without signs of acid reflux.

2) As an option, you may prescribe antireflux medications for hoarseness with signs of chronic laryngitis.

3) Recommend against prescribing routine oral glucocorticoids.

4) Recommend against prescribing routine antibiotics.

5) Perform laryngoscopy before suggesting voice therapy and speech language pathology.

6) Recommend surgery for laryngeal malignancy, benign lesions, or glottis insufficiency.

7) Educate patients on control and preventative measures.