What is vocal cord paralysis?
The vocal cords are two muscular flaps located at the top of the trachea (windpipe). With the passage of air, these cords vibrate producing sounds, which allow us to speak. If the cords stop vibrating, we can speak of paresis or paralysis of the vocal cords. Paralysis can affect one or both cords: usually, since the recurrent nerve connecting the brainstem to the larynx is longer, the left cord is more prone to paralysis than the right. In case of paralysis of both vocal cords, swallowing and breathing problems may occur.
Methods for treating vocal cord paralysis vary depending on the type of paralysis.
Symptoms of vocal cord paralysis
The most common symptoms in case of vocal cord paralysis are:
- Hoarseness
- Labored and/or noisy breathing
- Reduced voice pitch
- Dysphagia (choking or coughing when swallowing food, liquids, or saliva)
- Need to take deep breaths while speaking
- Difficulty speaking out loud
- Need to clear throat frequently
Diagnosis of vocal cord paralysis
Diagnosis is based on the medical history and objective testing by a specialist using laryngoscopy, as well as some tests performed to identify the cause of the paralysis. In some cases, it may be necessary to perform further extensive tests such as, for example:
- CT scan with contrast dye
- MRI scan of the neck, head and chest
- Thyroid scan
- Bronchoscopy or barium swallow
- Esophagoscopy
What are the causes of vocal cord paralysis?
The paralysis, as mentioned in the first paragraph, can be unilateral or bilateral. Unilateral paralysis is the most common and is usually due to lesions that may affect the recurrent laryngeal nerves, the nucleus ambiguus, its supranuclear features and the main trunk of the vagus nerve. It is estimated that one third of monolateral palsies are caused by cancerous lesions, another third are due to trauma and the remaining third are idiopathic. The nucleus ambiguus is particularly affected by vascular or demyelinating pathologies and endocranial tumors, while neoplasms of the cranial base and cervical trauma mainly affect the vagus nerve. Finally, the recurrent nerve of the larynx can be damaged by diseases affecting the neck and thorax (e.g. mitral stenosis, aortic aneurysm, etc.), thyroidectomies or surgery, infections due to exposure to neurotoxins (lead, arsenic, mercury), viral diseases and Lyme disease. Bilateral paralysis, on the other hand, is usually caused by cervical or thyroid interventions, tracheal intubation, neuromuscular or neurodegenerative diseases and trauma.
Treatments for vocal cord paralysis
Methods of treating vocal cord paralysis vary depending on the type of paralysis and the patient. Treatments may include voice treatment, fat or collagen infiltrations or surgery (vocal cord repositioning, nerve replacement, tracheotomy, implants, etc.).
Which specialist to contact?
In case of vocal cord paralysis, you should consult an otolaryngologist or a phoniatrist.