Respiratory Problems in Prader-Willi Syndrome
James Loker, M.D. Pediatric
PWSA (USA) Clinical Advisory Board Member
Several recent articles continue to show that individuals with Prader-Willi
syndrome are at risk for respiratory problems. In particular problems of central
hypoventilation/apnea, and obstructive apnea in Prader-Willi syndrome have
recently been investigated.
Central hypoventilation is a disorder of decreased breathing rate or depth
particularly during sleep. This usually causes problems with daytime sleepiness
and if significant can cause problems with elevated blood pressure in the lungs.
Individuals with Prader-Willi syndrome may be at increased risk for this due to
decreased muscle tone and mass, excessive obesity, and possibly decreased neural
drive for breathing. Studies have shown some individuals with Prader-Willi
syndrome have decreased depth and rate of breathing.
Central apnea means the complete cessation of breathing during sleep. There
are several studies that show an alteration in the response of some individuals
with Prader-Willi syndrome to chemicals that would normally increase breathing.
Both receptors in the body and the area of the brain that is involved with
breathing are being investigated. The clinical significance of central apnea is
still under investigation.
Obstructive sleep apnea is well known to occur in Prader-Willi syndrome as
well as in other syndromes with hypotonia (poor muscle tone) such as Down
syndrome. It is seen in 2% of the normal pediatric population as well. This
results when the individual is trying to breath while asleep, but due to
obstruction in the airway, no air enters the lungs. The obstruction can occur
anywhere from the nose to the small airway passages in the lungs. These
individuals usually have loud breathing and snoring associated with periods of
quiet where no air movement is noted. Untreated obstructive apnea can have
serious complications including death.
Other problems that can cause respiratory difficulties in the young can be
chronic stomach reflux and aspiration. Although the lack of vomiting is felt to
be prominent in Prader-Willi syndrome, reflux has been documented and should be
investigated in young children with chronic respiratory problems. Individuals
with obstructive apnea are at more risk for reflux as well.
The American Academy of Pediatrics has recently set forth guidelines for
diagnosis and management of obstructive sleep apnea. The guidelines suggest that
all children be screened with history of snoring or other evidence of airway
obstruction. Your physician may wish to obtain a sleep study if there is
excessive sleepiness, significant obesity or before surgery. In those
individuals with a positive history, a sleep study is performed where breathing
patterns, heart rate, oxygen levels and air movement are recorded. If the test
is positive, further evaluation may need to be performed to individualize the
treatment. The primary treatment as suggested by the guidelines would include
tonsillectomy and/or adenoidectomy or CPAP (Continuous Positive Airway
Pressure), where the individual wears a mask at night to keep the airway open.
Frequently obstructive and central apnea may occur in the same patient. This
is probably true in the majority of individuals with Prader-Willi syndrome with
respiratory problems. Both obstructive and central apnea can be evaluated by a
In summary, individuals with Prader-Willi syndrome are at risk for
respiratory problems, most commonly obstructive apnea. If any child has symptoms
of obstructive apnea, a sleep study should be obtained. The role of central
apnea in Prader-Willi syndrome is under investigation.
A special thank you for their contribution to this article goes to:
· Dan J. Driscoll, Ph.D., M.D. PWSA (USA) Clinical Advisory Board Chair
· Merlin G. Butler, M.D., Ph.D. PWSA (USA) Scientific Advisory Board Chair
· David M. Agarwal, M.D. PWSA (USA) Research Advisory Committee Member
Permission is granted to reproduce this article in its entirety, but it may
not be reused without the following credit line: Reprinted from The Gathered
View (ISSN 1077-9965), which is published bimonthly by the Prader-Willi Syndrome
Prader-Willi Syndrome Association (USA)
8588 Potter Park Drive, Suite 500
Sarasota, Florida 34238
Telephone: (800) 926-4797 or (941) 312-0400