The Causal Relationship Between Over Incidence of Necrotizing Enterocolitis (NEC) and Hypothyroidism

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The Causal Relationship Between Over Incidence of
Necrotizing Enterocolitis (NEC) and
Hypothyroidism

• Elena NUEL MD, Erez NADIR MD, Shmuel YURMAN MD,
  Michael FELDMAN MD
• Department of Neonatology
• Hillel Yaffe Medical Center
• Hadera, Israel

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Background

• NEC of large and small intestines, is an
  emergency situation in the newborn's digestive
  systems.
• Currently the etiology is unknown, and treatment
  is far from effective.
• Former research confirmed that thyroid gland
  hormones are essential for normal nervous
  system's development in fetus and infant.

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Infant with Necrotizing Enterocolitis (NEC)
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Background, continued

• Hypothyroidism causing a decrease in electrical
  and mechanical activity in the digestive system
  may in turn cause a decrease of peristalsis
  ileus meteorism of the stomach and the lessening
  of blood to the intestinal lining.
• Immediately after birth, thyroxin and
  thyrotropin
• levels change significantly. 80 of
  premature infants during their first 3-8 weeks
  are in state of Transient Hypothyroxinemia (TH).
  The lower the week of birth, the increase in TSH
  is smaller as are the levels of T4 and T3

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Infant with congenital hypothyroidism
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Gross pathology of neonatal necrotizing
enterocolitis.Close up of intestine of infant
showing necrosis and pneumatosis intestinalis.
Autopsy

• Close up of intestine of infant showing necrosis
  and pneumatosis intestinalis. Autopsy

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Methods

• Retrospective study including
• Hospitalized newborn patient files from Hillel
  Yaffe between 1995 2005
• Patient files from 2 additional hospitals
  (Liniado, Netanya and Bnai Tsion, Haifa) between
  2001-2005

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Methods, continued

• Inclusion criteria
• Newborns defined by Bell's Classification as NEC
  levels 2-3
• 71 infants with diagnosis at discharge of NEC
  from 3 neonatal units
• 28 were excluded due to
• 16 NEC grade I
• 10 missing thyroid functioning test
• 2 died d/t NEC before blood sampling

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The 43 cases included

• Gestational age between 24-42 weeks

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Breakdown of the birth weight of cases in our
study

• Birth weight between 730-3825 grams.

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Methods, continued

• The results of TSH levels and FT4 taken from the
  National Newborn Survey
• Normal levels of FT4 gt5 ng/dl
• Normal level of TSH lt 20 mU/L
• Historical control
• Hypothyroidism incidence 13500 at birth
• Transient hypothyroxinemia in premature infants
  between 58-84

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Results

• 18 (41.8) had poorly functioning thyroid glands
  
• 15 (34.9) had TH
• 3 (6.9) had true congenital hypothyroidism

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Results
True congenital hypothyroidism
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Conclusions

• In our study group, TH incidence was lower than
  previously reported.
• However, we found the incidence of congenital
  Hypothyroidism, statistically significantly
  higher than historical control.

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Conclusion, continued

• This study raises the possibility that thyroid
  gland dysfunction may be greater among infants
  suffering of NEC grades II-III
• A multi-center study may resolve this enigma