Recommendations for Evaluation of Breathing Abnormalities
Associated with Sleep in Prader-Willi Syndrome
PWSA (USA) Clinical Advisory Board Consensus
Statement - 12/2003
Problems with sleep and
sleep disordered breathing have been long known to affect individuals with
Prader-Willi Syndrome (PWS). The problems have been frequently diagnosed as
sleep apnea (obstructive [OSA], central or mixed) or hypoventilation with
hypoxia. Disturbances in sleep architecture (delayed sleep onset, frequent
arousals and increased time of wakefulness after sleep onset) are also
frequently common. Although prior studies have shown that many patients with
PWS have relatively mild abnormalities in ventilation during sleep, it has been
known for some time that certain individuals may experience severe obstructive
events that may be unpredictable.
Factors that seem to
increase the risk of sleep disordered breathing include young age, severe
hypotonia, narrow airway, morbid obesity and prior respiratory problems
requiring intervention such as respiratory failure, reactive airway disease and
hypoventilation with hypoxia. Due
to a few recent fatalities reported in individuals with PWS who were on growth
hormone therapy (GH) some physicians have also added this as an additional risk
factor. One possibility (that is currently unproven) is that GH
could increase the growth of lymphoid tissue in the airway thus worsening
already existing hypoventilation or OSA. Nonetheless, it must be emphasized
that there are currently no definitive data demonstrating GH causes or worsens
sleep disordered breathing. However, to address this new concern, as well as
the historically well documented increased risk of sleep-related breathing
abnormalities in PWS, the Clinical Advisory Board of the PWSA (USA) makes
the following recommendations:
A sleep study or a
polysomnogram that includes
measurement of oxygen saturation and carbon dioxide for evaluation of
hypoventilation, upper airway obstruction, obstructive sleep apnea and central
apnea should be contemplated for all individuals with Prader-Willi syndrome.
These studies should include sleep staging and be evaluated by experts with
sufficient expertise for the age of the patient being studied.
Risk factors that should be
considered to expedite the scheduling of a sleep study should include:
Severe obesity - weight over 200% of
ideal body weight (IBW).
History of chronic respiratory
infections or reactive airway disease (asthma).
History of snoring, sleep apnea or
frequent awakenings from sleep.
History of excessive daytime
sleepiness, especially if this is getting worse.
Before major surgery including
tonsillectomy and adenoidectomy.
Prior to sedation for procedures,
imaging scans and dental work.
Prior to starting growth hormone or
if currently receiving growth hormone therapy.
Additional sleep studies
should be considered if patients have the onset of one of these risk factors,
especially a sudden increase in weight or change in exercise tolerance. If a
patient is being treated with growth hormone, it is not necessary to stop the
growth hormone before obtaining a sleep study unless there has been a new onset
of significant respiratory problems.
Any abnormalities in sleep
studies should be discussed with the ordering physician and a pulmonary
specialist knowledgeable about treating sleep disturbances to ensure that a
detailed plan for treatment and management is made. Referral to a pediatric or
adult pulmonologist with experience in treating sleep apnea is strongly
encouraged for management of the respiratory care.
In addition to a
calorically restricted diet to ensure weight loss or maintenance of an
appropriate weight, a management plan may include modalities such as:
Continuous positive airway pressure (CPAP)
Oxygen should be used with care as some
individuals may have hypoxemia as their only ventilatory drive and oxygen
therapy may actually worsen their breathing at night.
Behavior training is sometimes needed to
gain acceptance of CPAP or BiPAP.
Medications to treat behavior may be
required to ensure adherence to the treatment plan.
If sleep studies are
abnormal in the morbidly obese child or adult (IBW > 200%) the primary problem
of weight should be addressed with an intensive intervention – specifically, an
increase in exercise and dietary restriction. Both are far preferable to
surgical interventions of all kinds. Techniques for achieving this are
available from clinics and centers that provide care for PWS and from the
national parent support organization (PWSA-USA). Behavioral problems
interfering with diet and exercise may need to be addressed simultaneously by
persons experienced with PWS.
If airway related
surgery is considered, the treating surgeon and anesthesiologist should be
knowledgeable about the unique pre- and postoperative problems found in
individuals affected by Prader-Willi syndrome
(see “Medical News” article regarding “Anesthesia and PWS” written
by Drs. Loker and Rosenfeld in the Gathered View, vol. 26, Nov. – Dec.,
2001 or visit www.pwsausa.org). Tracheostomy surgery and
management presents unique problems for people with PWS and should be avoided in
all but the most extreme cases. Tracheostomy is typically not warranted in
the compromised, morbidly obese individual because the fundamental defect
is virtually always hypoventilation, not obstruction. Self endangerment and
injury to the site are common in individuals with PWS who have tracheostomies
At this time there is no
direct evidence of a causative link between growth hormone and the respiratory
problems seen in PWS. Growth hormone has been shown to have many beneficial
effects in most individuals with PWS including improvement in the respiratory
system. Decisions in the management of abnormal sleep studies should include a
risk/benefit ratio of growth hormone therapy. It may be reassuring for the
family and the treating physician to obtain a sleep study prior to the
initiation of growth hormone therapy and after 6-8 weeks of therapy to assess
the difference that growth hormone therapy may make. A follow up study
after one year of treatment with growth hormone may also be indicated.
Members of the Clinical
Advisory Board are available for consultation with physicians and families
through the Prader-Willi Syndrome Association (USA).
Prader-Willi Syndrome Association (USA)
8588 Potter Park Drive, Suite 500
Sarasota, Florida 34238
Telephone: (800) 926-4797
or (941) 312-0400
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