The mother of a 2-week-old infant reports that since birth, her infant sleeps most of the day; she has to awaken her every 4 hours to feed, and she will take only an ounce of formula at a time. She also is concerned that the infant has persistently hard, pellet-like stools. On your examination you find an infant with normal weight and length, but with an enlarged head. The heart rate is 75 beats per minute and the temperature is 35degC (95degF). The child is still jaundiced. You note large anterior and posterior fontanelles, a distended abdomen, and an umbilical hernia. This clinical presentation is likely a result of which of the following?

The clinical findings of congenital hypothyroidism are subtle, and may not be present at all at birth; this is thought to be a result of passage of some maternal T4 transplacentally. Infants with examination findings will usually have an umbilical hernia and a distended abdomen. The head may be large, and the fontanelles will be large as well. The child may be hypothermic and have feeding difficulties; constipation and jaundice may be persistent. Skin may be cold and mottled, and edema may be found in the genitals and extremities. The heart rate may be slow, and anemia may develop. As these findings may be subtle or nonexistent, neonatal screening programs are extremely important for early diagnosis of these infants.Sepsis can cause hypothermia and poor feeding, but the 2-week course makes this choice unlikely. Hirschsprung disease may cause chronic constipation and abdominal distension, but not the other findings. Botulism can cause a flaccid paralysis and poor feeding, but the large fontanelles and umbilical hernia are not caused by this infection.