By: Jana Andersson
Gastroschisis (gas-troh-skee-sis) may not be a term you are familiar
with until you or someone you know has been given this terrifying diagnosis.
While the better news is that in most cases with access to modern care this
otherwise lethal condition is highly treatable. But the alarm call to all is
that the prevalence of gastroschisis is on the rise. The cause of the disease
remains unknown as does the reason for its increase. The following provides an
overview of this congenital birth defect and also serves to increase public
awareness and concern.
What is
gastroschisis?
Gastroschisis belongs in the category
of “ventral wall defects” (ventral
meaning “front of abdomen”) and is the most common disease in this class. Due
to a malformation of the abdominal wall just to the right of the umbilical
insertion the fetal intestines extrudes into the amniotic
fluid. The event is generally isolated with rare instances of accompanying
birth defects and few instances of genetic or chromosomal abnormalities.
However, the number of new cases of has been markedly increasing. Gastroschisis
is fatal without access to modern treatment. With treatment the survival rate
is 95%.
Image Courtesy of the Centers for Disease Control and
Prevention, National Center on Birth Defects and Developmental Disabilities
How is gastroschisis diagnosed?
Gastroschisis may be diagnosed by pregnancy screenings in
the 2nd trimester. Due to the abdominal wall defect Alpha-fetoprotein
(AFP) from the fetus is released into the amniotic fluid and crosses the
placenta. The elevated levels in maternal blood will register on a blood test
in 77-100 % of cases. A follow up ultrasound may identify gastroschisis. Additionally,
a routine 2nd trimester ultrasound may independently diagnose the
condition if no blood-work was performed or if previous levels were
undetectable. There are no other maternal signs or symptoms.
Fetal signs in utero
·
AFP released into amnion from fetal
tissues.
·
Sections of bowel float free in the
amniotic sac and may include other organs.
·
In early pregnancy the bowel is of
normal size but later the diameter may increase leading to obstruction,
perforation, and lack of blood-flow.
·
Due to exposure the bowel may become
irritated causing it to shorten, twist, or swell.
·
Primary nutrient loss is from membrane and
muscular dysfunction.
·
Growth restriction occurs in 38-77%
of cases
·
48% of fetuses/births are small size
·
Shortened gestation period of 35-37
weeks (40 is normal)
Treatment begins immediately after birth
Actions include:
·
Placement of IV for antibiotics, pain
relief, and nutrition
·
Access to ventilator
·
Insertion of nasogastric tube to
decompress/draw out bowel contents which could otherwise be taken up into the
lungs.
·
Maintaining a temperature controlled
environment
·
Maintaining sterile conditions
If the the amount of exposed bowel is small the organ can
be put back in and the hole sutured within a day of birth.
If the amount of exposed bowel is large it may be repaired
in stages. In such cases the intestines are put into a sterile plastic
cylindrical bag called a silo. Utilizing spring tension the base of the bag
seats tightly around the abdominal opening and the top of the bag mounts to a
hook and is suspended over the infant much like an IV drip. The intestinal feed
works by gravity and every 48 hours physical pressure is applied to the bag
with a twist from the top. Over the course of 7-10 days a once large and
swollen herniation will eventually fit back inside the cavity. The surgeon will
then remove the silo and close up the wound.
The next challenge is recovery. The intestines may delay
in working. Furthermore infants may experience disinterest in feeding, reflux,
serious infections, and areas of intestinal death. Ultimately babies go home
when they are feeding entirely by mouth, gaining weight and intestinal function
has returned. The best case scenario for hospitalization is about a month but
this can extend up to four.
Many afflicted infants go on to lead normal lives but 40%
will need additional treatment at some point. Gastroschisis is the leading
cause of intestinal transplantation.
What causes gastroschisis and why is there a hole in the
abdominal wall to the right of the cord insertion?
The cause for gastroschisis is unknown. In normal early
development the primitive gut evolves from the yolk sac and becomes the midgut
– basically a long narrow tube. Thereafter this tube elongates faster than the embryonic body which
forces an embryonic loop into the amnion. Later, this loop recedes back into
abdomen. Earlier but in a different area of development the right umbilical
vein regresses and dissolves in order to make way for an improved vascular
system required for expanding growth. In gastroschisis the vascular disruption theory suggests a premature withdrawal of this right side umbilical
vein before 28-32 conceptual days may lead to ischemia (cell death due to lack
of blood flow) thereby adversely affecting the early evolving tissues that
ultimately give rise to the abdominal defect specific to that region. Similarly
it is also thought that ischemic injury to the mesenteric artery gives rise to the high rates of intestinal artresia (intestinal death)
associated with gastroschisis.
What is the risk of having a baby with this birth defect?
According to the CDC
Cases per Births: 1 in 2,229
Estimated Annual Cases: 1871
·
Since the 1980s, the number of babies
born with gastroschisis has increased, especially among young mothers aged
younger than 20 years.
·
Between 1995-2005 cases of
gastroschisis nearly doubled.
·
The prevalence of gastroschisis
increased from 1995 to 2012 among mothers in every age group and for each
racial/ethnic group that was studied (non-Hispanic whites, non-Hispanic blacks,
and Hispanics).
FIGURE. Trends in gastroschisis prevalence, by maternal age group — 14 states,* 1995–2012
Graph image: CDC, Morbidity Mortality
Weekly Report Weekly / January 22, 2016 / 65(2);23–26
Can gastroschisis
be prevented?
Because the cause is unknown
prevention is difficult to identify. Risk lessens after maternal age 25.
Furthermore use of vasoconstrictors such as aspirin, ibuprofen, nasal decongestants,
alcohol, and cigarettes during the first trimester of pregnancy can be related
to the vascular pathology of the disease. More research is needed to explore genetic and environmental
influences.
References
Chabra, Shilpi, Gleeson, Christine A.. 2006. Gastroschisis: Embryology, Pathogenesis, Epidemiology. NeoReviews Vol 6 No 11. Retrieved from: http://pedsurg.com.pe/Gastroquisis%20embriologia %20patogenesis%20y%20epidemiologia.pdf
Debich-Spicer, Diane E., Gilbert-Barness, Enid. Embryo and Fetal Pathology. 2004 May 31. Retrieved from: https://books.google.com/books?id=os_NQOiTu_4C&pg=PA510&lpg=PA510&dq=embryo+involution+veins+arteries&source=bl&ots=BX5Mji-ayl&sig=U3tknYr_vRr-hDyHdYqXAi5P8fg&hl=en&sa=X&ved=0ahUKEwif-suajuzKAhVU72MKHbsjCPMQ6AEIKjAD#v=onepage&q=embryo%20involution%20veins%20arteries&f=false
Facts about gastroschisis 2015 Nov 12. Retrieved from: http://www.cdc.gov/ncbddd/birthdefects/gastroschisis.html
Feldkamp, M. L., Carey, J. C. and Sadler, T. W. (2007), Development of gastroschisis: Review of hypotheses, a novel hypothesis, and implications for research. Am. J. Med. Genet., 143A: 639– 652. doi: 10.1002/ajmg.a.31578 Retreived from: http://onlinelibrary.wiley.com/doi/10.1002/ajmg.a.31578/abstract
Glasser, James G.. 2015 April 28. Pediatric Omphalocele and Gastroschisis. Retrieved from: http://emedicine.medscape.com/article/975583-overview
Ionescu, S., Mocanu, M., Andrei, B., Bunea, B., Carstoveanu, C., Gurita, A., ... & Selleh, M. (2014). General Report. Chirurgia, 109, 7-14. http://www.revistachirurgia.ro/pdfs/2014-1-7.pdf
Jones AM, Isenburg J, Salemi JL, et al. Increasing Prevalence of Gastroschisis — 14 States, 1995–2012. MMWR Morb Mortal Wkly Rep 2016;65:23–26. DOI: http://dx.doi.org/10.15585/mmwr.mm6502a2.
Key findings: gastroschisis – a serious birth defect - continues to increase. 2016 Jan 21. Retrieved from: http://www.cdc.gov/ncbddd/birthdefects/features/keyfindings-gastroschisis-increase.html
Key Findings: Updated National Birth Prevalence Estimates for Selected Birth Defects in the United States, 2004-2006. Reviewed 2016 Jan 21. Retrieved from: http://www.cdc.gov/ncbddd/birthdefects/features/birthdefects-keyfindings.html
National Library of Medicine (US). Genetics Home Reference [Internet]. Bethesda (MD): The Library; 2016 Feb 08. Abdominal Wall Defect; [reviewed 2012 Aug]. Available from: http://ghr.nlm.nih.gov/condition/abdominal-wall-defect
The Children's Hospital of Philadelphia (Producer). (2011, July 01) Inside out: understanding abdominal wall defects (AWD) [Video transcript] http://www.chop.edu/video/inside-out-understanding-abdominal-wall-defects-awd#.Vr9tD-YYFKm
Thomas, Kayle. Gastroschisis. Retrieved from http://averysangels.org/gastroschisis/