Hypothyroxinemia and effectiveness of thyroxin supplementation in very low birth weight infants with abdominal distension and poor weight gain.
BACKGROUND
Very low birth weight (VLBW) infants sometimes develop abdominal distension and poor weight gain. The influence of thyroid function on these symptoms in VLBW infants has not been reported.


METHODS
In a retrospective study, 18 VLBW infants whose abdominal distension and poor weight gain did not improve with standard treatment were enrolled as subjects. Serum levels of free thyroxin (fT(4)) and thyroid stimulating hormone (TSH) were measured. Subjects with serum fT(4) levels less than 1.3 ng/dl received thyroxin supplementation. Another 18 VLBW infants were recruited as age- and weight-matched controls. We compared degree of intestinal dilation on X-ray, weight gain, and quantity of milk tolerated before and after starting thyroxin supplementation in the subjects and the controls.


RESULTS
All subjects had serum fT(4) levels less than 1.3 ng/dl (mean, 0.72 ng/dl). TSH values varied widely and were less than 8 microU/ml in 12 subjects. Therefore, all subjects received thyroxin supplementation; after starting this, mean serum fT(4) level increased significantly to 1.31 ng/dl. In parallel with fT(4) increase, intestinal dilation improved in 16 of 18 subjects (mean grade of dilation decreased from 2.8 to 1.6). Weight gain and quantity of tolerated milk were significantly increased with thyroxin supplementation in all and 17 of the 18 subjects, respectively.


CONCLUSIONS
Thyroxin supplementation was effective in improving abdominal symptoms in VLBW infants whose serum fT(4) level was less than 1.3 ng/dl.
Komiyama
Mami
M
Department of Pediatrics, Jichi Medical University School of Medicine, 3311-1, Yakushiji, Shimotsuke, Tochigi 329-0498, Japan.
Takahashi
Naoto
N
Yada
Yukari
Y
Koike
Yasunori
Y
Honma
Yoko
Y
Aihara
Toshinori
T
Momoi
Mariko
M
D000005:Abdomen / Q000473:pathology*; D005183:Failure to Thrive; D006801:Humans; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight; D012189:Retrospective Studies; D013961:Thyroid Gland / Q000503:physiopathology; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000008:administration & dosage* / Q000097:blood*; D015430:Weight Gain
D013972:Thyrotropin; D013974:Thyroxine