You are palpating the image shown in a newborn

You are palpating the image shown in a newborn. Measurement reveals that there is significant enlargement of structure with the ??? (normal dimension is 2.1 cm) but this infant has dimensions of 3.9 cm. Before undertaking more complex investigations, what is the initial study you will order?

A. Lumbar puncture

B. Cytogenetic studies

C. TSH levels

D. Calcium and vitamin D levels

E. CT scan of the brain

  1. There are many causes of enlargement of the anterior fontanelle. Overall achondroplasia is the most common, followed by congenital hypothyroidism. Other causes of anterior fontanelle enlargement include rickets, Down syndrome and increased intracranial pressure.

  2. Infants with achondroplasia (an autosomal-dominant disorder) have problems with the epiphyseal plate cartilage that results in dwarfism. At birth, these infants usually have a very large head, prominent forehead, low nasal bridge, shortened extremities, and an enlarged fontanelle

  3. The first test to order should be TSH levels to screen for congenital hypothyroidism. This condition is also reversible with treatment.