75severe hypothyroidism should be initiated with low doses of L-thyroxine, and the
dose should be increased gradually. The reasons for initiating low doses in such
scenario include potential risk of adrenal crisis (lazy adrenal syndrome), seizures
(water and electrolyte imbalance), and hyperkinetic manifestations (upregulation
of thyroid hormone receptors). Hydrocortisone should be added along with
L-thyroxine in patients suspected to have adrenal insuffi ciency either primary (due
to polyglandular endocrinopathy) or secondary (due to pituitary pathology) or in
patients with long-standing hypothyroidism (lazy adrenal syndrome). Our patient
was initiated on hydrocortisone and low dose of L-thyroxine and later L-thyroxine
dose was gradually increased to 125 μg/day. She had polyuria after initiation of
therapy which occurs as a result of passage of glycosaminoglycans through urine.
Others symptoms of hypothyroidism progressively abate within 4–8 weeks except
hoarse voice and skin changes which take longer time to resolve. Children usually
experience “catch-up” growth after initiation of treatment with L-thyroxine; how-
ever, they may not be able to attain the target adult height particularly in those who
have been diagnosed late (as growth is a cumulative phenomenon) and in those
who are in peripubertal age. This occurs because skeletal maturation is much
faster than statural growth after initiation of L-thyroxine therapy. Adolescents in
peripubertal age may soon enter into puberty after initiation of L-thyroxine ther-
apy, which may further compromise their fi nal adult height. Other untoward con-
sequences of long-standing hypothyroidism like multicystic ovaries and
thyro-lactotrope hyperplasia resolve by 6–12 months with optimum L-thyroxine
replacement and do not require surgical intervention.
3.3 Clinical Rounds
- What is congenital hypothyroidism?
Congenital hypothyroidism (CH) is a disorder characterized by thyroid hormone
defi ciency at birth. Congenital hypothyroidism can be sporadic or endemic.
Sporadic CH is usually due to thyroid dysplasia or dyshormonogenesis and
neonates with sporadic CH have less severe manifestations of hypothyroidism
due to transplacental transfer of maternal thyroxine to the fetus. Timely initia-
tion of L-thyroxine therapy is associated with almost near-normal neurocogni-
tive outcome. Endemic CH is due to severe maternal and fetal iodine defi ciency
with consequent severe thyroid hormone insuffi ciency resulting in neurocogni-
tive dysfunction at birth. Even timely initiation of L-thyroxine therapy does not
improve the neurocognitive outcome but only improves myxoedematous mani-
festations. Infants with neurological cretinism should not be considered to have
congenital hypothyroidism as their thyroid functions are normal at birth.3 Thyroid Disorders in Children