Charcot-Marie-Tooth disease (CMT) is named after the three doctors who first described the disease in 1886: Jean-Martin Charcot (shar-coh), Pierre Marie, and Howard Henry Tooth. Today, CMT refers to any peripheral neuropathy with a genetic cause, whether or not the specific genetic mutation is known.
While most people living with CMT will never experience breathing difficulties, CMT can affect breathing for some. Early awareness, monitoring, and specialized care can make a meaningful difference in managing respiratory health and maintaining quality of life.
Does CMT Cause Breathing Problems?
Yes, CMT can cause breathing problems for some. However, most with CMT will not develop breathing issues. When breathing is affected, it is due to a specific type of impairment called CMT-induced neuromuscular respiratory muscle weakness. This condition weakens the muscles used for breathing but does not affect the lungs or airways themselves.
How Does CMT Affect Breathing?
CMT can weaken the muscles involved in breathing by affecting the nerves that control them. Just as CMT can weaken muscles in the lower legs, hands, or arms, it can also weaken the diaphragm and other muscles used for breathing.
The phrenic nerve, which controls the diaphragm, is often discussed because the diaphragm is the primary muscle used for breathing. However, many muscles and nerves are involved in breathing, including the external intercostal muscles, respiratory accessory muscles (such as those in the neck, chest, and abdomen), and the intercostal and cervical spinal nerves.
Symptoms of CMT-Related Breathing Problems
- Shortness of breath (dyspnea)
- Shallow breathing
- Difficulty breathing when lying flat (orthopnea)
- Increased shortness of breath during physical exertion
- Weak cough
- Obstructive sleep apnea (OSA)
- Central sleep apnea (CSA)
- Nocturnal hypopnea
- Elevated carbon dioxide levels
Early signs often include gradual difficulty getting a full breath, shallow breathing, and difficulty breathing when lying down. Sleep-disordered breathing may also develop, including obstructive and central sleep apnea or nocturnal hypopnea.
Can CMT-Related Breathing Problems Affect Carbon Dioxide or Oxygen Levels?
CMT-related breathing problems can cause elevated carbon dioxide levels (hypercapnia) because weakened muscles may limit carbon dioxide removal. Symptoms of hypercapnia include headaches, confusion, excessive sleepiness, and worsening breathing difficulties.
Oxygen levels typically remain normal because lung tissue is unharmed. However, oxygen levels may drop temporarily during sleep-disordered breathing events.
How Are CMT-Related Breathing Problems Diagnosed?
Pulmonary function tests (PFTs) measure how well the respiratory system works. CMT-related respiratory impairment shows a restrictive pattern on PFT due to hypoinflation. However, it is not a restrictive lung disease.
What About Scoliosis and Breathing Problems?
CMT can cause scoliosis, which in severe cases can reduce chest cavity size and restrict lung inflation. Scoliosis can lead to restrictive lung disease if it becomes severe enough to impact breathing. Corrective spine surgery may be recommended when needed.
How Are CMT-Related Breathing Problems Treated?
Breathing problems in CMT are highly manageable. Treatment depends on the underlying cause.
When breathing problems are related to obstructive sleep apnea (OSA) without respiratory muscle weakness, airway support therapies such as CPAP (Continuous Positive Airway Pressure), BiPAP (Bi-level Positive Airway Pressure), or VPAP (Variable Positive Airway Pressure) are commonly used and are very successful.
Treatment must address pressure and volume support when respiratory muscle weakness is present. In these cases, therapies such as AVAPS (Average Volume Assured Pressure Support) or iVAPS (Intelligent Volume Assured Pressure Support) are preferred.
- AVAPS delivers a consistent tidal volume with each breath to assist weakened breathing muscles.
- iVAPS targets alveolar volume, automatically adjusting to lung needs throughout the use cycle.
Volume support helps fully inflate the lungs with each breath, reduces the workload on weakened muscles, and supports healthy carbon dioxide removal.
Which Treatment Is Right for You?
Treatment depends on whether respiratory muscle weakness is present. If breathing muscles are unaffected and obstructive sleep apnea is the primary issue, CPAP, BiPAP, or VPAP may be appropriate. If respiratory muscle weakness is present, volume support using AVAPS or iVAPS is typically recommended by CMT respiratory specialists.
Finding the Right Specialist
A pulmonologist diagnoses and treats respiratory impairment. Ideally, individuals with CMT-related breathing problems should be seen by a pulmonologist with experience in neuromuscular respiratory care. Several CMTA Centers of Excellence offer pulmonology services, including Cedars-Sinai in Los Angeles, Rush University in Chicago, and the University of Florida in Gainesville. These clinics provide access to specialized respiratory care for people living with CMT.
Managing Breathing Health with CMT
CMT-related breathing problems are manageable with appropriate care. Early diagnosis, proactive management, and the right support can greatly improve quality of life. If you experience any breathing symptoms, talk with your healthcare provider and follow their guidance.
Breathing Resources
- CMT Related Breathing Impairment Webinar: Watch Here
Find a CMTA Center of Excellence
CMTA Centers of Excellence offer expert care for people with CMT, including access to specialists familiar with breathing-related challenges. Visit the CMTA Center of Excellence directory to find a provider near you.
