Hoarseness (Dysphonia)

Definition, Etiology, PathogenesisTop

Hoarseness is a symptom reported by patients that refers to alteration in the voice. This alteration can be vocal weakness, tremor, pitch alteration, or change in voice quality. Dysphonia refers to impaired voice generation as recognized by clinicians.

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 (recurrent laryngeal nerve or superior laryngeal nerve).

Hoarseness can be caused by damage, inflammation, or abnormal function of any of the structures that make up and innervate the larynx.

Causes:

1) Primary disorders of the larynx:

a) Acute: Laryngopharyngitis, epiglottitis, laryngotracheitis, croup.

b) Chronic: Occupational voice overuse, exposure to tobacco smoke, pharyngeal or laryngeal cancer, gastroesophageal reflux disease (GERD), foreign body, endotracheal intubation–related trauma.

2) Secondary disorders of the larynx:

a) Weakness or paralysis of the extrinsic or intrinsic muscles: Bulbar palsies (polio, amyotrophic lateral sclerosis), demyelinating diseases, brainstem strokes (lateral medullary syndrome/Wallenberg syndrome), hypothyroidism, myasthenia gravis, long-term inhaled glucocorticoid treatment. Other neurologic disorders, including Parkinson disease and motor neuron diseases, are also associated with dysphonia.

b) Cricoarytenoid arthritis: Rheumatoid arthritis, systemic lupus erythematosus, gout.

c) Recurrent laryngeal nerve damage: Iatrogenic (most commonly following thyroid surgery, although damage during esophageal and aortic root surgery is also extremely common), cancer (esophageal cancer, lung cancer, mediastinal tumors, metastatic spread to the mediastinal lymph nodes), neuropathy (diabetic neuropathy), marked enlargement of the left atrium, or dilation of the main pulmonary artery (Ortner syndrome).

d) Other: Laryngeal amyloidosis, which may be isolated or associated with systemic amyloidosis.

3) Functional disorders: No organic cause.

DiagnosisTop

The most important tests for detection of the underlying etiology are laryngeal evaluation with laryngoscopy or videostroboscopy (a special form of laryngoscopy that uses strobe lights, which allows for assessment of laryngeal vibration). There is role for laboratory evaluation if a specific 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 (over 4-8 weeks), even without the above characteristics. 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.