Vocal Cord Paralysis

How vocal cord paralysis happens

The vocal cords sit in the larynx (voice box). They open to let you breathe and close to make sound and protect the airway when swallowing. Movement is controlled mainly by the recurrent laryngeal nerves, which take a long path: down into the chest (the left one loops around the aorta) and back up to the larynx. Damage anywhere along this route can paralyze the vocal cord on that side.

Causes

• surgery: thyroid and parathyroid surgery are the most common; also neck, spine (anterior cervical), chest, lung, esophageal and heart surgery
• breathing tubes (intubation)
• tumors: thyroid cancer, lung cancer, esophageal cancer, lymph node cancer, and skull base tumors pressing on the nerve
• viral infections: herpes viruses, flu and others can inflame the nerve
• neurological conditions: stroke, Parkinson's disease, multiple sclerosis, ALS, myasthenia gravis
• heart and vessel conditions: enlargement of the left atrium or aortic aneurysm (Ortner's syndrome)
• neck or chest injury
• idiopathic: no cause found in a significant share of cases, many of which recover

Symptoms

Unilateral (one side)

• breathy, hoarse or weak voice
• loss of vocal pitch and volume
• voice fatigue and needing to take breaths mid-sentence
• coughing or choking when drinking liquids (aspiration)
• weak, ineffective cough
• shortness of breath when talking

Bilateral (both sides)

• the cords often rest close together, narrowing the airway
• noisy breathing (stridor), especially with exertion or sleep
• shortness of breath, which can become an emergency
• the voice may be relatively normal

Diagnosis

• laryngoscopy: a thin flexible camera through the nose to see the cords move; the key test
• stroboscopy to view vibration
• laryngeal EMG: measures nerve function and helps predict recovery
• imaging: CT or MRI from the skull base to the chest to look for tumors or other causes along the nerve's path
• swallow study if aspiration is suspected
• blood tests if a neurological or systemic cause is suspected

Treatment

Waiting for recovery

Many nerve injuries, especially after viral infections or surgery where the nerve was stretched rather than cut, recover within 6 to 12 months. Voice therapy during this time helps.

Voice therapy

A speech-language pathologist teaches exercises to strengthen voice and breathing coordination, and safe swallowing techniques.

Procedures for unilateral paralysis

• injection medialization (injection laryngoplasty): filler is injected beside the paralyzed cord to move it toward the middle, improving voice and swallowing; temporary or longer-lasting materials
• medialization thyroplasty: a small implant placed through the neck permanently repositions the cord
• arytenoid adduction: repositions the cartilage that moves the cord
• reinnervation: connecting a nearby nerve to the paralyzed cord's nerve to restore muscle tone

Bilateral paralysis

The priority is a safe airway:

• tracheostomy in an emergency or severe cases
• cordotomy or arytenoidectomy: surgery to widen the airway, which may make the voice breathier
• reinnervation or newer pacing techniques in selected cases

Outlook

Many people recover spontaneously or achieve a good voice with treatment. Recovery is less likely if the nerve was cut or after 12 months without improvement. Finding and treating the underlying cause, especially tumors, is essential.

Frequently asked questions

What are the symptoms of vocal cord paralysis?

One-sided paralysis causes a breathy, weak or hoarse voice, voice fatigue, a weak cough and choking on liquids. Paralysis of both cords can cause noisy breathing and shortness of breath, sometimes with a relatively normal voice.

What causes vocal cord paralysis?

Common causes include damage during thyroid, neck, chest or heart surgery, tumors pressing on the nerve, viral infections, stroke and other neurological diseases. In many people, no cause is found.

Can vocal cord paralysis go away?

Yes. Many cases, especially after viral infections or surgical nerve stretching, recover within 6 to 12 months. If the nerve is cut or there is no improvement after a year, permanent treatment options can restore the voice.

How is vocal cord paralysis treated?

Treatment includes voice therapy, injections to move the paralyzed cord toward the middle, permanent implants (thyroplasty) and nerve reinnervation surgery. Bilateral paralysis may need airway procedures to improve breathing.

Is vocal cord paralysis dangerous?

One-sided paralysis is rarely dangerous, though food or liquid entering the lungs can cause pneumonia. Paralysis of both cords can block the airway and may be an emergency. Hoarseness from an unknown cause should be checked to exclude a tumor.