CCHS, or Congenital
Central Hypoventilation Syndrome, is a disorder of the central
nervous system where, most dramatically, the automatic control
of breathing is absent or impaired. A CCHS child’s respiratory
response to low blood oxygen saturation (hypoxia) or to CO2 retention
(hypercapnia) is typically sluggish during awake hours and absent,
to varying
degrees, during sleep, serious illness, and/or stress.
In 2003 independent research efforts in France,
the United States and Italy confirmed the key role of a de novo
mutation of the phox2b gene in well over 90% (in the US study)
of CCHS cases. (See the CCHS Literature pages for further reading.)
These studies confirmed clinical observations that there is a
wide range of affectedness in CCHS and suggested that there may
be other candidate genes for explaining CCHS. These results mean,
for example, that each child of a CCHS parent (i.e., of a person
with the phox2b mutation) has a 50% chance of also having CCHS.
Testing for the phox2b mutation (or other factors in CCHS) is
now available. Similarly, testing for the presence of the mutation
in a fetus can also be done. Go to www.genetests.org for further information on accessing these blood tests for your
child or patient.
While most CCHS children breath adequately, though shallowly,
while awake, observation of their respiratory status is required
for optimal outcome, and, mechanical ventilation is required for
sleep (naps and nighttime), illness or any other period of low
blood oxygenation.
O2 and CO2 monitoring during sleep is optimal. Studies suggest
that between 10 and 17% of CCHS children require 24-hour ventilatory
support. These children benefit from phrenic nerve pacing during
the day and conventional home-vent support for nighttime sleep.
About 16% of CCHS patients suffer from Hirschsprungs
Disease and 18% report gastro-esophageal reflux. A range of ophthalmologic
and cardiac issues are reported in about 46% and 19% of CCHS patients
respectively. A study of 196 CCHS patients suggested that seizures
(42%), recurrent pneumonia (41%), developmental delays (45%), learning
disabilities (30%), fainting episodes (25%) and irregularities
of body temperature control (43%) occur in significant numbers
of CCHS patients, along with other medical issues. (See Vanderlaan,
et. al., Pediatric Pulmonology
37: 217-229, 2004.)
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Yet, while the health
issues initially appear daunting, with appropriate home care, family
support and careful medical supervision, these children can lead
fulfilling and productive, near-normal lives. The study cited above
found, for example, that over 60% of the children were making normal
progress in school, while another group required some or significant
special educational support. With advances in home health care
technology, such as portable ventilators, oximeters and ETCO2 monitors,
has come optimal health management and much-improved prognoses
for the infants diagnosed with CCHS. (On other topics such as schooling,
nursing support, annual testing and medical care, see this study.
Other readings are given on the literature page on this site.)
Reflecting the recency of the CCHS diagnosis, the oldest CCHS patients
today are in their thirties. CCHS young adults are in college,
in the workplace, and are having their own families.
Key to the CCHS patient’s longevity is informed
medical supervision by medical professionals who also work to support
the family in optimizing the home healthcare and school (or other)
settings. At minimum, this requires nighttime nursing support in
the home for the infant and young child, along with some respite
support for the parents and caregivers. Meanwhile, the study cited
above found that the majority of CCHS families’ medical costs
were covered by government and/or private insurance programs. That
support has meant that fewer than 1% of the affected children have
been placed in institutional settings on a long term basis. Support
for patients and their families has translated into good outcomes
for the great majority of CCHS families.
Educating families and medical professionals about
the nature and course of CCHS is the main purpose of the CCHS Family
Network. We work to share research findings, family observations
and “survival techniques,” and other news and information
to all those affected by congenital central hypoventilation syndrome.
One recent example of the kinds of issues we cover and educate
patients and their physicians on concerns the use or abuse of alcohol
and recreational drugs among a few CCHS young people. That the
use of alcohol or illicit drugs can very easily become deadly for
these patients with impaired respiratory drive is news that we
could very quickly send out with warnings to our families and their
caregivers.
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