[lemontea88]

Need your help guys, with this question.

Newborn has high TSH, low Tyroxine levels. He also has an anterior cervical mass high in neck. Thyroid gland is not palpable. What is the cause of this findings?

A) Anti-TSH antibodies
B) Lingual thyroid
C) Negative iodine balance
D) Sodium/iodine symporter gene mutation
E) Thyroid carcinoma

 

[Sabio]

Am not sure
but here's how I think of it

Choice A: Anti-TSH antibodies should cause a secondary hypothyroidism with low TSH, this condition is seen temporarily in newborns of thyrotoxic mothers and there's nothing in the question pointing to that.
Choice C: Iodine deficiency is certainly one of the common causes of hypothyroidism in children but it usually presents with goiter and is seen in older children as the newborn did not have much time to develop Iodine deficiency.
Choice E: Certainly this option is wrong as newborns do not develop thyroid carcinoma.

So we are left with Lingual thyroid (B) and a genetic defect in thyroid hormone genesis that may include a defective Sodium/Iodine symporter as it's needed for Iodine trapping into the thyroid gland (D).

Of these I choose B, because the question is specifically mentioning a mass up in the neck.
Underdeveloped and un-migrated thyroid gland with only a trace of tissue up near the tongue's foramen cecum is one of the most common causes of congenital hypothyroidism.

 

[lemontea88]

Wow, thanks sabio!