Describe vocal cord palsy.

Vocal Cord Palsy

• Vocal cord palsy is paralysis of the intrinsic laryngeal muscles from a lesion of the vagus or recurrent laryngeal nerve.
• It is a sign with a cause that must be found, not a diagnosis in itself.
• The first question IS whether IT IS unilateral or bilateral.
• Unilateral palsy gives a voice problem with a safe airway — a breathy, weak voice, vocal fatigue, an ineffective (bovine) cough, and aspiration, particularly of liquids, from incomplete closure
• Bilateral abductor palsy gives an airway problem with a good voice — the cords lie near the midline.
• Bilateral adductor palsy gives aphonia with a patent airway and a high risk of aspiration
• The causes, in the order worth reciting:
• Surgical and iatrogenic, which is the commonest group — thyroid and parathyroid surgery, which is much the commonest cause of bilateral palsy; oesophageal, cardiac, aortic, cervical spine and carotid surgery; and prolonged intubation
• Malignant — bronchial carcinoma.
• Other — aortic aneurysm; left atrial enlargement (ORTNER syndrome); tuberculosis and mediastinal disease; neurological disease — stroke, motor neurone disease, multiple sclerosis, Guillain-Barré; trauma; viral neuritis; and idiopathic.
• The cardinal investigative rule: a left cord palsy demands imaging of the entire course of the nerve, from the skull base to the mediastinum.
• Investigation — flexible nasendoscopy to confirm the palsy and the position of the cord; CT from skull base to the diaphragm; chest radiograph.
• Laryngeal electromyography distinguishes paralysis from mechanical fixation of the cricoarytenoid joint, and gives prognostic information about reinnervation
• Management of unilateral palsy — treat the cause; and wait, since spontaneous recovery or compensation by the opposite cord occurs in many over 6 to 12 months
• Speech therapy in the interim, teaching compensatory closure and safe swallowing
• Where symptoms persist beyond 9 to 12 months, or where aspiration is significant earlier — medialisation: injection laryngoplasty (fat, hyaluronic acid or calcium hydroxyapatite).
• Management of bilateral abductor palsy — secure the airway first, frequently by tracheostomy.
• Later, if a permanent airway is wanted — cordotomy, arytenoidectomy or lateralisation (cordopexy), endoscopic and by laser
• The unavoidable trade-off must be explained before any such procedure: widening the glottis to improve the airway worsens the voice and increases aspiration, and there is no way around it — the patient chooses which they value
• Wait at least 9 to 12 months before a permanent destructive procedure, in case of recovery
• Bilateral abductor palsy is dangerous precisely because the voice sounds normal and reassures everyone