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.