Causes and Diagnoses

Causes and Diagnoses of Vocal Cord Paralysis

Vocal cord paralysis is caused by the disruption of nerve impulses to the muscles of the larynx. In about half of all cases, physicians cannot detect why this occurs. The nerves controlling the vocal cords are long and may be vulnerable to injury in parts of the body not usually associated with the vocal cords.

Possible causes include:

  • Surgery to the head, neck or chest
  • Injury to the head, neck or chest
  • Tumors of the skull base, neck and chest
  • Lung or thyroid cancer
  • Intubation (breathing tube) injury
  • Viral infections, including:
    • Epstein-Barr or other herpes virus
    • Lyme disease
  • Stroke
  • Parkinson’s disease
  • Multiple sclerosis

Diagnosing vocal cord paralysis

  • Blood tests: Lab tests can identify if other conditions, such as Lyme disease or herpes viruses are involved
  • Laryngeal electromyogram (EMG): This test can confirm nerve involvement and measure the severity of the damage to the nerves serving the larynx.
  • Laryngoscope: An endoscope (a thin, flexible tube with a light and camera on the end) is inserted into your throat to view the movement of your vocal cords.
  • Computed tomography (CT) scan: This test combines X-ray and computer technology to produce detailed cross-sectional images.
  • Magnetic resonance imaging (MRI) scan: This test creates detailed images using a large magnet, a computer and radiofrequencies. Unlike computed tomography (CT or CAT) scans or X-rays, MRI does not use radiation.