Taleah English, 3, of Orem, Utah, has SMA type 1. She's "suctioning" her bunny, who shares her BiPAP noninvasive ventilation device. Preface Muscular Dystrophy Affects Breathing Respiratory Therapy: Treatments, Techniques, Equipment For More Information Pulmonary Monitoring and Treatment Plan

MUSCULAR DYSTROPHY AFFECTS BREATHING

When to Start Lung Evaluations
Pulmonary Function Testing
Healthy Lifestyle Key to Prevention of Respiratory Problems
Preventing More Serious Lung Complications
Clues to Respiratory Problems
Scoliosis Needs Watching

Breathing is accomplished by respiratory muscles — mostly a dome-shaped muscle called the "diaphragm" and the muscles between the ribs — that pull air into the lungs (inspiration or inhalation), followed by a passive relaxation of these muscles when air leaves the lungs (expiration or exhalation). When a person forcefully inhales or exhales, extra, or "accessory," muscles of breathing are used. Accessory respiratory muscles include abdominal, chest wall and neck muscles. Over time, neuromuscular disorders can weaken all these muscles.

Of the 40-plus neuromuscular diseases in MDA's program, nine are muscular dystrophies. These are inherited, progressive disorders that gradually weaken the respiratory muscles as they do the muscles that move the limbs and trunk. The spinal muscular atrophies and many other neuromuscular disorders can also lead to breathing problems and lung complications.

Research is being directed toward finding treatments and possible cures for the genetic defects of MD and related disorders, but, in the meantime, attention continues to be focused on finding effective physical and medical treatments for these conditions.

In the case of Duchenne MD, standing and walking can now be prolonged by one to five years by orthopedic surgery and rehabilitation. Continued physical therapy, either formally by a licensed therapist, by a home program or both, can prevent contractures of the joints. Contractures can become painful (yes, even more painful than the physical therapy itself), and physical therapy is recommended even though walking can't be restored. Scoliosis, or curvature of the spine (see Scoliosis Needs Watching), also needs to be closely watched and often requires surgical correction.

Periodic evaluations of your child's respiratory status can assist the pulmonary doctor in determining when to begin a particular treatment for the lungs. Following a careful review of the physical examination and lung function tests, an individual respiratory care plan will be fashioned to meet the specific needs of your child.

The first evaluation of breathing (respiratory) muscle function should be done at the time of diagnosis of MD or spinal muscular atrophy. This will allow a "baseline" to be formed, against which future tests can be compared.

Most likely, your child's lung function will be normal for his/her weight, height and age. (Doctors usually refer to these "normal" test scores as "predicted" scores, since they reflect what would be predicted for a child's weight, height and age.) A thorough lung history and physical examination, along with pulmonary function tests, will give the pulmonary doctor a description of your child's breathing status before the respiratory muscles are affected by weakness.

An objective assessment of your child's lung function should be done one to six times a year. Frequency will be based on the type of MD your child has, his/her age, and a history and physical examination. Prior to the clinic visit, doctors will determine if pulmonary function tests will be obtained at that visit, so your child may have the testing before even seeing the doctor. The results can then be discussed at the clinic visit.

If any acute lung problems occur, pulmonary function tests will be required. You'll probably take these tests after having been referred to a pulmonary specialist or respiratory therapist. The information from the tests will assist the doctors in providing specific respiratory care for your child.

Children with neuromuscular disorders whose exercise capability is limited rarely show signs of what most of us would call "difficulty breathing." Instead, they may have trouble sleeping or concentrating, have headaches and other problems (see Symptoms of Chronic Hypoventilation). If your child starts to show these problems, bring them to the attention of your MDA clinic physician immediately.

PULMONARY FUNCTION TESTING

Tests to evaluate the function of the lungs are generally noninvasive — that is, no needles or penetration of the body. These kinds of tests require your child to breathe into a computerized machine through a mouthpiece while a clip blocks the nose. The child must be mature enough to follow verbal instructions and cooperate with the respiratory therapist. Sometimes the therapist will use a computer, sometimes a simple hand-held measuring device. The function of the lungs is plotted over time, and when the numbers and physical exam show a decline, it's time to initiate some form of ventilatory assistance to move more air into and out of the lungs. If the rate of decline in breathing muscle function is well understood, decisions about the best form of assistance can be carefully considered before a breathing crisis develops.

Computerized testing

Pulmonary function tests include:

lung flow rates, capacities and volumes
A frequently used test is the "FVC," or "forced vital capacity," which measures how much air a person can expel as fast as possible after taking a deep breath. Information from a vital capacity maneuver can assist the physician in structuring a respiratory care plan for the specific needs of your child.
breathing pattern analysis, which measures rib cage and abdomen coordination
oximetry, which measures the amount of oxygen carried by the red blood cells
capnography, which measures the amount of carbon dioxide in a breath
(under some circumstances) capillary or arterial blood gases, which measure oxygen, carbon dioxide and bicarbonate levels in the blood
A finger prick is needed to get a tiny amount of blood for capillary blood gas tests.

HEALTHY LIFESTYLE KEY TO PREVENTION OF RESPIRATORY PROBLEMS

Early and effective pulmonary rehabilitation is essential if hospitalizations for lung infection or acute respiratory failure are to be avoided in children with MD. Obesity should be avoided because extra body weight further restricts breathing. Heavy, large meals can add to this problem. Parents may benefit from dietary counseling to explain and plan nutritious eating habits.

Extremes of temperature and humidity as well as crowded areas should be avoided. These can reduce your child's exposure to germs that cause respiratory tract infections. Deep breathing and coughing should be encouraged because these are the body's natural mechanisms for clearing the lungs of mucus accumulation. Cough suppressants and sedatives should be avoided, especially at bedtime. These, too, interfere with the lungs’ ability to clear mucus.

Early attention should be given to upper respiratory tract infection (URI, or cold). A URI begins with nasal stuffiness and drainage. An inability to breathe through the nose due to swelling and secretions frequently occurs. A low-grade fever (body temperature of 100 degrees or less) may develop along with muscle aches and tiredness. Sometimes appetite is diminished.

Parents can treat a cold by encouraging the child to drink lots of fluids. Fluids help keep mucus thin for easy clearance. Thick, sticky mucus can clog the airways and lead to serious lung complications. Body temperature should be monitored regularly. Anti-fever drugs can be given every four to six hours for fever control. Decongestants can be given to reduce nasal stuffiness and secretions.

A lower respiratory tract infection occasionally develops after five to seven days. Symptoms of a lower respiratory tract infection (in the lung) include hoarseness and cough with higher, spiking fevers.

A majority of colds are viral, not bacterial, and therefore antibiotics aren't helpful. If a high fever (101 degrees or higher) develops, it may be a sign of a secondary bacterial infection in the throat or ear. High fever always requires an assessment by your primary care doctor, who will make recommendations specifically for the needs of your child.

Immunizations should be up to date. Appropriate flu vaccinations are encouraged annually. Excessive muscular fatigue should be avoided, but as much activity as tolerated without pain or fatigue is encouraged. A healthy lifestyle can prolong stable lungs for your child.

In the presence of any muscle weakness, both bacterial and viral infections of the lung can cause more severe illness, such as pneumonia. Because of the decreased activity level and a weakened cough effort, children with MD can accumulate more mucus in the lungs than do other children. The mucus becomes thick due to the infection and can obstruct (plug off) airways.

Obstructed airways can cause areas of the lung to collapse. The medical term for lung collapse is "atelectasis." A chest film (X-ray) is required for accurate determination of the presence of pneumonia or atelectasis. These kinds of serious lung complications may require communication between your neurologist or primary care doctor and the pulmonary doctor treating your child.

Watchful parents and medical team members can prevent most episodes of pneumonia and atelectasis with early and aggressive treatment of respiratory illness and monitoring with pulmonary function testing.

Routine pulmonary assessments over time can help the medical team determine changes in your child's breathing and the risk of complications. Before severe complications arise, the pulmonary doctor can initiate respiratory therapy measures in a step-by-step approach that will diminish the need for hospitalization and maintain breathing stability.

For many children with MD, the beginnings of ventilatory failure (failure to move enough air in and out of the lungs) come on slowly and may be mistaken for other problems. Shortness of breath — the best-known symptom of too little oxygen — may not occur in these children, especially when weakness prevents them from exercising.

SYMPTOMS OF CHRONIC HYPOVENTILATION fatigue sleep disturbances nightmares, night terrors morning headaches confusion, disorientation, anxiety poor appetite, weight loss weakened or softened voice unproductive cough

Instead, the most common symptoms are fatigue, poor sleep, nightmares or night terrors, and headaches, especially right after waking. In fact, underventilation at night is often the first problem, both because the natural urge to breathe is lower during sleep, and because the abdomen pushes up against the diaphragm when a person lies down.

Anxiety, confusion, loss of appetite and weight loss are also possible signs of underventilation (also called "hypoventilation"). Weakening of the voice and weak coughing that doesn't move mucus up toward the mouth indicate that respiratory muscles are losing their power.

It's very important to tell your doctor about any of these symptoms. Addressing these issues early and effectively often results in improvement in energy and well-being.

SCOLIOSIS NEEDS WATCHING

Scoliosis — curvature of the spine — is a common complication in MD and other neuromuscular disorders. Scoliosis prevents full expansion of the chest and can lead to loss of breathing capacity.

Scoliosis in these diseases occurs because of weakening of the muscles that normally support the spine. At clinic visits, your child's spine will be physically examined for curvature, and the degree of the curve may
be measured by X-ray. Following the degree of scoliosis is important for a growing child, whose curve may progress surprisingly quickly.

Significant scoliosis develops in 90 percent of children with Duchenne MD and more than 90 percent of children with the severe, early-onset spinal muscular atrophies. Maintaining a straight spine not only permits children to sit comfortably and helps them avoid being confined to bed, but it also slows the progression of breathing difficulties.

The timing of possible surgical intervention is important. It should be completed when the child is in good pulmonary health and at the lowest risk for complications. Scoliosis surgery is a major surgery planned by the family in consultation with the rehabilitation, pulmonary and orthopedic doctors.

Straightening the spine when curvature is present can slow the rate of decline of the lungs' vital capacity. The vital capacity can decline as much as 20 percent annually without surgery but may decline as little as 5 percent annually following surgery.