Infant with failure to thrive and hypotonia
A 4-month-old girl arrives at the clinic for a well-child visit. Her mother voices concerns about the infant’s poor weight gain, slow feeding habits, and physical delays such as head lag, poor grasp reflex, and rolling over. The mother is in the military and getting ready to be deployed; the father had abandoned her when he learned of the pregnancy. The maternal grandmother plans to care for the infant until the mother returns from her tour of duty.
The infant was born to a 30-year-old primigravida mother at 39 weeks via spontaneous vaginal delivery. Although the pregnancy was unplanned, the mother had regular prenatal care and was negative for gonorrhea, chlamydia, and human immunodeficiency virus (HIV) infection. Birth weight was appropriate for gestational age (2.78 kg), and the infant’s Apgar scores were 9 and 9 at 1 and 5 minutes, respectively. There was no hypotonia noted during her nursery stay, and there were no concerns for inadequate suck or for jaundice. At discharge from the nursery, she weighed 2.49 kg, a 10% weight loss from her birth weight.
At the 2-week visit, the patient had not regained her birth weight; the mother reported that the infant took only 2 ounces of formula every 3 hours. At the 4-month visit, the patient was taking about 4 to 5 ounces of formula every 3 hours and had not started juice or other solid foods. However, the mother mentioned that the infant took about an hour to finish each bottle with some increased effort and grunting, but no distress or hypoxia. There was no history of coughing with feeding, vomiting, diarrhea, or gastroesophageal reflux.
Developmentally, the patient smiled responsively, regarded her hands, followed past midline, cooed and looked to voice, but did not laugh or turn to voice. Also, she was not yet lifting her head to 45 degrees, bearing weight on her legs, or rolling over.