Severe hypothyroidism due to atrophic thyroiditis from second year of life influenced developmental outcome

Thyroid function and dysfunction in preterm infants-Challenges in evaluation, diagnosis and therapy

Thyroid hormone levels have a crucial role for optimal brain development from gestation through the first 2 postnatal years. However, thyroid hormones vary with gestational age, and their levels vary between term and preterm infants. Preterm newborns are prone to thyroid dysfunction which is now more frequently observed with the advances of neonatal care and improved survival of extremely premature infants. Thus, hypothyroxinaemia of prematurity associated with delayed TSH elevation is very common in low birth weight premature infants most likely due to the immaturity of the hypothalamic-pituitary thyroid axis. Furthermore, postnatal illness, medications and iodine status may contribute to the thyroid dysfunction or affect the interpretation of the thyroid function tests. Despite available guidelines, timing of screening and optimal treatment of thyroid dysfunction in premature infants remains controversial. Furthermore, it is unknown whether untreated thyroid dysfunction in premature babies affects neurodevelopmental outcome. In the vast majority of preterm infants, hypothyroxinaemia is transient; however, permanent hypothyroidism due to thyroid dysgenesis or enzyme defects might also occur. Therefore, careful monitoring of thyroid function and long-term follow-up is needed to assess an appropriate therapeutic approach. This article reviews thyroid physiology in preterm infants, the influences of gestation and other neonatal conditions on thyroid function tests, optimal timing of screening and possible predictors to differentiate transient hypothyroxinaemia from permanent hypothyroidism.

Very early onset of autoimmune thyroiditis in a toddler with severe hypothyroidism presentation: a case report

BACKGROUND

In infants under 3 years of age acquired primary hypothyroidism caused by autoimmune thyroiditis is very rare. Hypothyroidism can manifest with different signs and symptoms and has a wide range of presentations from subclinical hypothyroidism to overt form. We describe a child with acquired autoimmune thyroiditis during a very early period of life and with a severe hypothyroidism presentation.

CASE PRESENTATION

A 22-month-old white male patient with normal neonatal screening presented with a six-month history of asthenia and cutaneous pallor. At general clinical and biochemical exams he showed weight gain, statural growth deceleration, poor movements, sleepy expression, instability while walking, myxoedema, bradycardia, open anterior fontanelle, changes in the face habitus, macrocytic anaemia, ascites, and high CPK, creatinine and cholesterol levels. Acquired autoimmune thyroiditis was the final diagnosis. The thyroxine replacement therapy normalized all the clinical and biochemical abnormalities but at the age of 30 months his mental age showed a delay of 6 months.

CONCLUSIONS

Our case could give useful learning points: i) although the screening for congenital hypothyroidism is routinely performed, a severe hypothyroidism (for example due to autoimmune thyroiditis) can anyway occur early in life and the clinicians should consider this possibility; ii) hypothyroidism can have a misleading and multi-face clinical presentation; iii) anemia, rhabdomyolysis and high creatinine levels should always include the hypothyroidism in the differential diagnosis; iv) thyroxine replacement therapy is able to revert all the clinical manifestations related to the hypothyroidism; v) evaluating the patient's previous pictures could play an important role in resolving a diagnostic conundrum.