- Children with Duchenne muscular dystrophy are at risk for sleep-disordered breathing, including obstructive sleep apnea, central sleep apnea and hypoventilation.
- As children age and pulmonary function decreases, the risk of sleep-disordered breathing increases.
Isaiah's Story
Isaiah is a 14 year old boy with Duchenne muscular dystrophy here with his dad because he has started having frequent headaches. He reports his typical headache will begin when he wakes up in the morning and usually resolves after a few hours. He does not think that his headaches have ever woken him from sleep.
Expert Insights
BEARS Screening for Sleep Disordered Breathing
Due to the pediatrician’s concern for a possible sleep disorder, a BEARS assessment was done. Open the categories below to review some of the history that was obtained from Isaiah and his dad.
Bedtime Problems
Isaiah reports no problems falling asleep.
Expert Insights
Most children with sleep-disordered breathing do not have any problems at bedtime, and many will fall asleep quickly due to excessive sleepiness. Although in some cases, sleep-disordered breathing can cause insomnia.
Excessive Daytime Sleepiness
Isaiah reports that he usually wakes up feeling tired but has not fallen asleep in school.
Expert Insights
- Difficulty getting out of bed can be a sign of non-refreshing sleep and suggests an underlying sleep disorder.
Awakenings
Isaiah reports that he will sometimes wake at night feeling short of breath.
Expert Insights
- Frequent nocturnal awakenings can be seen in sleep-disordered breathing due to snore arousals or children waking up and feeling unable to breathe.
Regularity & Duration
Isaiah goes to bed at 10:00 every night and wakes at 7:30 in the morning. On weekends, he will sometimes sleep in an extra hour, but usually still goes to bed by 10:30.
Expert Insights
- Isaiah appears to have a consistent schedule and is getting an appropriate amount of sleep for his age.
Sleep-Disordered Breathing / Snoring
- Dad is unsure if Isaiah snores or stops breathing at night because he sleeps in his own room down the hall.
- Isaiah reports that he has begun sleeping on 3 pillows; he seems to sleep better like this.
Expert Insights
- For older children who sleep on their own, parents may not be aware about snoring or night time apneas. This may sometimes make the diagnosis more difficult to determine.
- There should be high suspicion for sleep-disordered breathing when patients report improved sleep with elevation of the head of the bed.
Isaiah's Evaluation & Diagnosis
What evaluation & diagnostic protocol should Dr. Matthews use to diagnose Isaiah’s morning headaches?
Check all that apply:
The evaluation protocol strategies we recommend for Isaiah's case are:
- Further determine child’s sleep history
- Perform a physical examination
- Order pulmonary function testing
- Order a sleep study
- Obtain an Epworth Sleepiness Score
Elements of Isaiah's Sleep History
| Sleep History | Case Specific Information | Chris's Evaluation Results |
|---|---|---|
Determine severity of sleep-disordered breathing symptoms |
How long have symptoms been going on? |
Isaiah has been waking up short of breath intermittently for the past 6 months. This was initially every few weeks, but it is now occurring almost nightly. |
How often does Isaiah have morning headaches? |
Isaiah reports his headaches have increased in frequency and are now occurring almost every day. |
|
Review medications that the patient is taking |
Some medicines such as opiates, sedatives or muscle relaxants may worsen sleep apnea. Some medicine such as nasal steroids or montelukast that may be prescribed for other conditions may help treat obstructive sleep apnea. |
Isaiah takes prednisone due to his muscular dystrophy and is not using any other medications currently. |
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Obtain a family history of sleep disorders |
Does anyone else in the family have sleep apnea? |
There is no known family history of sleep apnea. |
Perform a Physical Exam
| Information to obtain includes: | Case Evaluation Results |
|---|---|
A physical exam should be performed to assess for underlying factors that may contribute to sleep disordered breathing.
|
Isaiah’s BMI is at the 60th percentile. His ENT exam shows no 1+ tonsils, and his Mallampati score is 4. Cardiac examination reveals no murmurs with a normal S1 and S2. Chest examination reveals bilaterally clear lung fields with no increased work of breathing. Neuromuscular examination: Isaiah uses a power wheelchair, he has decreased muscle tone throughout. He also has mild kyphoscoliosis. |
Obtain pulmonary function testing
| Information to obtain includes: | Case Evaluation Results |
|---|---|
If not already done for the patient, pulmonary function testing may be useful to determine the patient’s current lung function. The presence of severe restrictive lung disease increases the likelihood of hypoventilation, and if severe enough, may suggest the need for daytime respiratory support. Additionally, a blood gas could be considered as well to assess for daytime hypoventilation if severe restrictive lung disease is present. |
Office spirometry was obtained. Isaiah’s FEV1 was 90% of predicted, his FVC was 60% of predicted, and his FEV1/FVC ratio was 110% of predicted, demonstrating moderate restrictive lung disease. |
Sleep Study
| Information to obtain includes: | Case Evaluation Results |
|---|---|
A diagnostic polysomnogram is the gold standard for diagnosing sleep-disordered breathing. During the study, respiratory flow, respiratory effort, end tidal CO2 and oxygen levels will be monitored (in addition to other parameters) to determine the presence of sleep-disordered breathing. The sleep study will report an Apnea-Hypopnea Index (AHI), the number of times per hour that the patient pauses breathing or breathes too shallowly while asleep, which is used to diagnose sleep-disordered breathing. In children, an obstructive AHI >1 event per hour is diagnostic of obstructive sleep apnea. Additionally, if the end tidal CO2 is greater than 50 mmHg for more than 25% of sleep time, this is also considered diagnostic of obstructive sleep apnea. Note that for older children (teenagers), adult scoring criteria may be considered, and an AHI of 5 events per hour may be used as the diagnostic threshold. If possible, the sleep study should be performed at a sleep center with experience managing pediatric patients. This is particularly important for children with neurodevelopmental disabilities, as experienced pediatric technicians will be better equipped to help children feel more comfortable with the procedure. |
Polysomnogram (PSG) was obtained and demonstrated an AHI of 4, with an obstructive AHI of 1.8 and a central AHI of 2.2. End tidal CO2 was greater than 50 for 80% of total sleep time. Additionally, he spent 75 minutes with an oxygen saturation less than 88%. His total sleep time was 375 minutes with a sleep efficiency of 88%. His cardiac and EEG tracings demonstrated no abnormalities. The periodic limb movement index was 0 (normal <5). |
Obtain an Epworth Sleepiness Score
| Information to obtain includes: | Case Evaluation Results | ||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
The Epworth Sleepiness Scale is a validated instrument to assess the level of sleepiness. The patient rates themselves from 0 (would never doze) to 3 (high chance of dozing) on their likelihood of falling asleep in eight different situations. A score greater than 10 suggests the presence of excessive sleepiness. |
Isaiah completed the Epworth Sleepiness Scale. The results are listed below:
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Options that are Not Recommended
Complete a sleep diary
A sleep diary can be considered to evaluate for other sleep disorders, but is not typically needed for suspected sleep-disordered breathing.
Refer to a specialist
Referral to a sleep medicine specialist should be considered, this may be before or after a polysomnogram is performed.
Red Flags
- Presence of daytime hypoventilation suggests the need for daytime respiratory support.
Expert Insights: Interpreting the Sleep Study
- The sleep study demonstrated a mildly elevated AHI and obstructive AHI (2), but showed severe hypoventilation, with both prolonged oxygen desaturation as well as elevated end tidal CO2.
- Additionally, his PFTs show the presence of significant restrictive lung disease.
Evaluation & Diagnosis
Which of the following results suggest the presence of hypoventilation?
Check all that apply:
The following results are suggestive of hypoventilation:
- End tidal CO2 >50 for 30% of the night during a polysomnogram.
- 3 hours of sleep time with an oxygen saturation <88% and an AHI of 0.5 in a 16 year old boy with Duchenne muscular dystrophy and known restrictive lung disease.
- pCO2 of 56 on a morning arterial blood gas.
Elevation of end tidal CO2 for >25% of the night on a polysomnogram is diagnostic of hypoventilation. Significant hypoxemia in the absence of sleep-disordered breathing is also common in hypoventilation and may be useful if end tidal CO2 monitoring was not performed during a sleep study. Similarly, elevated pCO2 on a blood gas, ideally done immediately after waking, is suggestive of the presence of hypoventilation.
Conversely, severe sleep apnea can result in a prolonged total period of hypoxemia, but this may be due to desaturation following apneas, and not due to hypoventilation. In this case, treatment of the sleep apnea will resolved the hypoxemia.
1 hour of sleep time with an oxygen saturation <88% and an AHI of 85 in a healthy 12 year old does not suggest the presence of hypoventilation.
Isaiah's Treatment & Referrals
Now it’s time to recommend treatment options for Isaiah.
Check all that apply:
The following treatment strategies are recommended for Isaiah:
- PAP therapy
- Refer to a sleep medicine physician
- Refer to pulmonology
Treatment Strategies for Hypoventilation
- PAP
- PAP therapy is the preferred treatment modality for hypoventilation.
- Although CPAP may sometimes be effective for hypoventilation, bilevel PAP therapy is more commonly used.
- In bilevel PAP therapy, a separate inspiratory and expiratory pressure are set. This results in increased ventilation of the patient.
- If needed, a backup breathing rate can also be used to provide breaths for the patient.
- Oxygen therapy
- Supplemental oxygen can be considered, but it is inferior to PAP therapy as a single treatment modality.
- In some cases, oxygen entrained into PAP is needed for patients with hypoventilation.
When to consult a sleep specialist or refer to another discipline:
- Patients with Duchenne muscular dystrophy and hypoventilation should be managed by a sleep and/or pulmonary physician.
Interdisciplinary Treatment Components
Isaiah's Results:
Isaiah underwent a PAP titration and was started on bilevel PAP therapy after being diagnosed with hypoventilation. At a follow up visit two months after starting therapy, he reports that his morning headaches have went away, and he is back to only sleeping on one pillow at night. He has also noticed that he feels more refreshed when he wakes in the morning.