Clinical scenario: Neonatal period admission | E-coli sepsis | Cataract
A 5-month-old girl is brought to the pediatric clinic because her parents have noticed that she does not fix and follow objects well and appears to have poor vision. She was born at term and was admitted during the neonatal period with poor feeding, jaundice, hypoglycemic seizures, and Escherichia coli sepsis, from which she recovered after intensive care treatment. She has remained on standard infant formula since discharge.
On examination, she has bilateral central lens opacities (cataracts) and mild hepatomegaly. Growth is below the 10th percentile.
Which of the following is the most likely diagnosis?
A. Hereditary fructose intolerance
B. Galactosemia
C. Maple syrup urine disease
D. Tyrosinemia type I
E. Zellweger syndrome
Correct answer & Explanation:
Correct Answer: B. Galactosemia
Explanation
Classic galactosemia is an autosomal recessive disorder caused by galactose-1-phosphate uridyltransferase (GALT) deficiency.
The neonatal presentation typically includes:
- Poor feeding
- Persistent jaundice
- Vomiting
- Hypoglycemia
- Hepatic dysfunction
- Escherichia coli sepsis (highly characteristic)
- Seizures secondary to metabolic derangement
Continued exposure to lactose/galactose leads to accumulation of galactitol within the lens, causing early bilateral cataracts, often presenting during the first few months of life.
The combination of neonatal E. coli sepsis followed by infantile cataracts is a classic examination clue.
Why the Other Options Are Incorrect
A. Hereditary fructose intolerance
- Symptoms begin after introduction of fruits or sucrose, not during exclusive milk feeding.
- Cataracts are not a feature.
C. Maple syrup urine disease
- Causes neonatal encephalopathy and characteristic sweet-smelling urine but does not cause cataracts or liver disease.
D. Tyrosinemia type I
- Causes liver failure, renal tubular dysfunction, and rickets but not cataracts.
E. Zellweger syndrome
- May present with cataracts and liver disease, but is characterized by profound hypotonia, dysmorphic facies, neuronal migration defects, and does not typically present with neonatal E. coli sepsis.
High-Yield Pearls
- Enzyme deficiency: Galactose-1-phosphate uridyltransferase (GALT)
- Inheritance: Autosomal recessive
- Classic neonatal clue: E. coli sepsis
- Ocular manifestation: Bilateral oil-droplet cataracts due to galactitol accumulation
- Diagnosis:
- Reduced GALT enzyme activity in red blood cells
- Elevated erythrocyte galactose-1-phosphate
- Treatment: Immediate lifelong elimination of lactose and galactose from the diet.
Exam Pearl
A young infant with:
- Neonatal jaundice and hypoglycemic seizures
- E. coli sepsis
- Later development of bilateral cataracts
→ Think classic galactosemia (GALT deficiency).
