A 5-day-old girl is brought to the emergency department due to fussiness. The patient was born at home to a 36-year-old woman, gravida 5 para 5, via spontaneous vaginal delivery. The mother received no prenatal care. The newborn has been breastfeeding exclusively and has had nonbloody, nonbilious vomiting after feeds for the past day. Head circumference and length are at the 50th percentile. Weight is at the 20th percentile. Temperature is 37.2 C (99 F) and pulse is 180/min. The newborn has poor tone and is jaundiced. The anterior fontanelle is sunken with overriding sutures. Eye examination shows bilateral cataracts. Ears are in the normal position, and the palate is intact with a normal tongue. Cardiopulmonary examination is normal. The liver is palpable 4 cm below the costal margin. Which of the following is the most likely cause of this newborn's presentation?

Question

A 5-day-old girl is brought to the emergency department due to fussiness.  The patient was born at home to a 36-year-old woman, gravida 5 para 5, via spontaneous vaginal delivery.  The mother received no prenatal care.  The newborn has been breastfeeding exclusively and has had nonbloody, nonbilious vomiting after feeds for the past day.  Head circumference and length are at the 50th percentile.  Weight is at the 20th percentile.  Temperature is 37.2 C (99 F) and pulse is 180/min.  The newborn has poor tone and is jaundiced.  The anterior fontanelle is sunken with overriding sutures.  Eye examination shows bilateral cataracts.  Ears are in the normal position, and the palate is intact with a normal tongue.  Cardiopulmonary examination is normal.  The liver is palpable 4 cm below the costal margin.  Which of the following is the most likely cause of this newborn's presentation?

Quizplus · Accepted Answer

11ec25c8_d65d_5323_bc81_a116413ea58f_MD0003_00 This patient most likely has galactosemia, an inborn error of metabolism caused by a deficiency of the enzyme galactose 1-phosphate uridylyltransferase (GALT). GALT is responsible for the metabolization of galactose, found in breast milk and cow's milk-based formula, into glucose. Therefore, newborns with galactosemia develop hypoglycemia and accumulation of galactose. galactose 1-phosphate uridylyltransferase (GALT) Presentation typically occurs in the first week of life with vomiting, jaundice, and hepatomegaly. Poor feeding can lead to lethargy, hypotonia, and dehydration (eg, sunken fontanelle). Newborns with galactosemia often fail to gain weight and are at risk for Escherichia coli sepsis. Severe hypoglycemia may also cause seizures in the neonatal period. Cataracts are a characteristic feature that occur in about one-third of patients with galactosemia. They may be present at birth but more commonly develop during the first few weeks of life as accumulated galactitol (a galactose by-product) deposits in the lens. With prompt initiation of a galactose-free diet (eg, soy-based formula), symptoms (including cataracts) typically resolve. (Choice A) Advanced maternal age is a risk factor for Down syndrome, which can cause hypotonia, poor feeding, and cataracts. However, jaundice and hepatomegaly are not associated with Down syndrome, and individuals with this condition have characteristic dysmorphic features not seen in this patient. characteristic dysmorphic features (Choice B) Fetal alcohol syndrome is characterized by facial anomalies (eg, smooth philtrum, thin vermillion border, small palpebral fissures) that are not present in this patient. Fetal alcohol syndrome (Choice C) Lack of maternal rubella vaccination puts the fetus at risk for congenital rubella syndrome if the infection is contracted during the first trimester. Newborns may have jaundice, hepatomegaly, and cataracts but typically also have microcephaly and a heart defect (eg, patent ductus arteriosus). This patient has a normal head circumference and cardiac examination. (Choice E) Congenital myotonic dystrophy, an autosomal dominant condition, may present with hypotonia and poor feeding. However, cataracts do not develop until adulthood in these patients. Educational objective: Galactosemia is an inborn error of metabolism that presents in the first week of life with vomiting, jaundice, hypotonia, and hepatomegaly. Progressive deposition of galactitol, a by-product of galactose, leads to cataracts. Management is a galactose-free diet (eg, soy-based formula). References: Literature review and outcome of classic galactosemia diagnosed in the neonatal period. (http://www.ncbi.nlm.nih.gov/pubmed/24273939) Sweet and sour: an update on classic galactosemia. (http://www.ncbi.nlm.nih.gov/pubmed/28281081)

A 5-Day-Old Girl Is Brought to the Emergency Department Due