Vocal Cord Paralysis: Symptoms, Types, Causes and Treatment

Vocal cord paralysis is a complex and potentially life-altering condition that affects the movement of one or both vocal cords. While it is not a disease in itself, it often signals an underlying medical issue that requires timely diagnosis and comprehensive management. This article will explore the symptoms, types, causes, and treatment options for vocal cord paralysis, drawing on the latest evidence and clinical studies to provide a clear and practical overview for patients, caregivers, and medical professionals.

Symptoms of Vocal Cord Paralysis

Vocal cord paralysis often presents with a range of symptoms that can vary in severity. Recognizing these symptoms early is key to seeking effective treatment and avoiding complications. Most commonly, people notice changes in their voice, but the condition can also affect breathing and swallowing.

Symptom	Description	Commonness	Sources
Hoarseness	Rough, weak, or breathy voice	Most common	1 2 3 5
Voice Change	Altered pitch, reduced volume, vocal fatigue	Very frequent	2 3 4
Stridor	High-pitched noisy breathing (esp. infants)	Common in BAVP	4 5
Aspiration	Coughing/choking while eating or drinking	Less common	3 5

Table 1: Key Symptoms

Hoarseness and Voice Changes

The predominant symptom of vocal cord paralysis, reported in up to 98% of cases, is a persistent hoarseness or a marked change in the quality, pitch, or strength of the voice. Many adults first notice that their voice becomes breathy, weak, or fatigues easily when speaking for extended periods. In infants and children, changes may manifest as a low-pitched or breathy cry 1 2 3 4.

Breathing Difficulties and Stridor

Bilateral vocal cord paralysis, especially in infants, can cause stridor—a high-pitched, whistling sound during inhalation—and may present with signs of airway obstruction or respiratory distress. This is especially critical in newborns, as it can be life-threatening and requires immediate medical attention 4 5.

Swallowing Difficulties and Aspiration

Some patients experience difficulty swallowing (dysphagia) and may cough or choke when eating or drinking. This is due to the inability of the vocal cords to close fully, increasing the risk of food or liquids entering the airway (aspiration), which can lead to recurrent respiratory infections 3 5.

Other Symptoms

• Shortness of breath
• Weak, ineffective cough
• Recurrent pneumonia (from aspiration)
• Loss of vocal pitch

Recognizing these symptoms early and seeking prompt evaluation can prevent complications and improve outcomes.

Types of Vocal Cord Paralysis

Vocal cord paralysis can be classified in several ways, depending on which cords are affected and the nature of their immobility. Understanding the different types is crucial for diagnosis, prognosis, and management.

Type	Description	Frequency	Sources
Unilateral	One vocal cord affected	Most common	1 2 3 9
Bilateral	Both vocal cords affected	Less common	2 3 4 13 15
Left-sided	Left cord more often involved	56–70% cases	1 2 3 9
Right-sided	Right cord affected	30–38% cases	1 2 3 9

Table 2: Types of Vocal Cord Paralysis

Unilateral Vocal Cord Paralysis

Unilateral paralysis, where only one vocal cord is affected, is by far the most common form, accounting for over 90% of cases in several studies 1 2 3 9. This type usually leads to hoarseness and mild swallowing difficulties but rarely causes severe breathing problems.

• Left-sided paralysis is more prevalent than right-sided, likely due to anatomical differences in the course of the recurrent laryngeal nerve. The left cord is involved in approximately 56–70% of cases, while the right cord is affected in 30–38% 1 2 3 9.

Bilateral Vocal Cord Paralysis

Bilateral paralysis is less frequent but potentially more serious. It often presents with significant breathing difficulties, stridor, and, in severe cases, respiratory distress requiring emergency intervention 2 4 13 15. Bilateral cases are more common in infants with certain congenital conditions or after surgical procedures such as thyroidectomy 4 13 15.

Additional Classifications

• Abductor vs. Adductor Paralysis: Refers to whether the muscles that open (abduct) or close (adduct) the vocal cords are affected. Abductor paralysis, especially when bilateral, is particularly dangerous for airway obstruction 4.
• Paresis vs. Paralysis: "Paresis" denotes partial loss of movement, while "paralysis" indicates complete immobility.

Clinical Implications

• Unilateral paralysis: Mainly a voice and swallowing issue; rarely life-threatening.
• Bilateral paralysis: Primarily a breathing concern; urgent management may be required.
• Laterality matters: Left-sided paralysis is more common, likely due to the anatomical path of the left recurrent laryngeal nerve 1 2 3 9.

Causes of Vocal Cord Paralysis

Vocal cord paralysis is not a disease but a sign of an underlying problem. Pinpointing the cause is essential for effective treatment and prognosis.

Cause	Typical Examples	Frequency/Significance	Sources
Surgical	Thyroidectomy, neck/chest surgery	Leading cause (up to 40%)	7 9 11 12 15
Neoplastic	Tumors (lung, thyroid, esophagus, etc.)	Major cause (up to 34%)	1 2 3 7 8 9 10
Idiopathic	Unknown origin	10–38% of cases	1 2 3 7 9 11
Traumatic	Blunt/penetrating neck trauma, intubation	8–23%	6 7 9 11
Central	Brainstem lesions, neuromuscular disorders	Less common	2 5 7
Inflammatory	Viral, other infections	Rare	6 7 9
Radiation	Head/neck cancer therapies	Uncommon	7
Vascular	Aortic aneurysm, vascular anomalies	Rare	4 8

Table 3: Main Causes of Vocal Cord Paralysis

Surgical Causes

Surgical injury is the most frequent cause of vocal cord paralysis in many modern series, particularly after thyroidectomy or other neck and chest procedures that may damage the recurrent laryngeal nerve. Thyroid surgery is especially high-risk, as the nerve runs close to the thyroid gland 7 11 12 15. Other surgeries, such as cardiac or esophageal operations, can also be implicated.

Neoplastic Causes

Tumors—especially of the lung, thyroid, esophagus, or mediastinum—can compress or invade the recurrent laryngeal nerve, leading to paralysis. In men, neoplasms are the most common cause 1 2 3 7 8 9 10. Imaging is critical to rule out malignancy before labeling a case as idiopathic.

Idiopathic Cases

In a significant minority (10–38%), no clear cause is identified even after thorough investigation. However, it is essential to exclude treatable or life-threatening causes, such as tumors, before designating a case as idiopathic 1 2 3 7 9 11.

Traumatic and Other Causes

Trauma, either from external injury, intubation, or prolonged pressure on the nerve, accounts for a notable share of cases 6 7 9 11. Less commonly, central nervous system disorders (e.g., brainstem lesions, neuromuscular diseases like Charcot–Marie–Tooth disease), infections, radiation, or vascular anomalies may be responsible 2 4 5 7 9.

Anatomical Considerations

The left recurrent laryngeal nerve has a longer and more complex course through the chest, making left-sided paralysis more common, especially with mediastinal disease or surgery 1 2 3 8 9 10.

Treatment of Vocal Cord Paralysis

Treatment aims to restore voice, prevent aspiration, and—most urgently—maintain a safe airway, especially in bilateral cases. The approach depends on the type, cause, and severity of paralysis, as well as the patient's overall health and needs.

Approach	Main Goal	Typical Use	Sources
Voice Therapy	Improve vocal function	Unilateral, early cases	12
Injection Medialization	Improve cord closure with fillers	Unilateral, early/temporary	12
Surgery (Unilateral)	Permanent correction (e.g., thyroplasty)	Persistent paralysis	11 12 14
Surgery (Bilateral)	Secure airway (e.g., laterofixation, cordectomy, arytenoidectomy)	Bilateral, airway compromise	4 12 13 15
Nerve Repair/Reinnervation	Restore nerve function (e.g., neurolysis, nerve grafts)	Select cases	12 14
Tracheostomy	Emergency airway	Severe bilateral cases	4 15

Table 4: Key Treatment Options

Conservative Management and Voice Therapy

For many cases of unilateral paralysis, especially those of recent onset or uncertain prognosis, initial management includes voice therapy with a speech-language pathologist. This can help compensate for the weak vocal cord and improve voice quality 12.

Injection Medialization

For immediate improvement of voice or prevention of aspiration, temporary fillers (such as absorbable gels) can be injected to "bulk up" the paralyzed cord and bring it closer to the midline. This is especially useful in the first year following nerve injury, as some cases will recover spontaneously 12.

Surgical Interventions

Unilateral Paralysis

• Medialization Thyroplasty (Type I thyroplasty): A permanent implant is placed to push the paralyzed cord toward the midline.
• Arytenoid adduction: Adjusts the cartilage to optimize vocal cord position.
• Reinnervation procedures: Attempt to restore nerve supply, especially in younger or selected patients 12 14.

Bilateral Paralysis

Bilateral paralysis poses a life-threatening risk due to airway obstruction. Surgical options focus on enlarging the airway while preserving voice and swallowing as much as possible:

• Laterofixation: Fixing one vocal cord in a lateral position to open the airway; shown to be effective and durable with minimal impact on voice or swallowing 13.
• Arytenoidectomy with posterior cordectomy: Widens the airway by removing part of the arytenoid cartilage and the posterior vocal cord; highly effective for decannulation (removal of tracheostomy) 15.
• Tracheostomy: May be required urgently in infants or adults with severe obstruction 4 15.

Advanced and Experimental Therapies

• Nerve guidance conduits with platelet-rich plasma: Novel techniques are being studied for nerve regeneration, showing promise in preclinical models 14.
• Laryngeal reinnervation: May be considered for unilateral paralysis not improving after 12 months 12.

Timing and Selection of Treatment

Early intervention (within 6–12 months) favors less invasive methods like voice therapy or injection laryngoplasty. Persistent cases after a year may require surgical correction or reinnervation 12.

Pediatric Considerations

Infants with bilateral paralysis—often associated with congenital anomalies—require specialized management, sometimes including neurosurgical intervention if a brainstem abnormality is present 4.

Conclusion

Vocal cord paralysis is a multifaceted condition with significant impact on voice, swallowing, and breathing. Understanding its varied symptoms, types, underlying causes, and evolving treatment options is crucial for optimal care.

Key takeaways:

• Hoarseness and voice changes are the most common symptoms, but breathing and swallowing can also be affected.
• Unilateral paralysis is far more common than bilateral, and left-sided involvement predominates.
• Surgical injury and tumors are the leading causes; always rule out malignancy before labeling a case as idiopathic.
• Treatment ranges from voice therapy and injections to advanced surgical procedures, tailored to the type and severity of paralysis.
• Early diagnosis and individualized management are essential for the best outcomes.

Prompt recognition, thorough evaluation, and a tailored, multidisciplinary approach offer the best chance for restoring function and quality of life in individuals with vocal cord paralysis.