Hypothyroidism is the most common thyroid disorder in children. It usually presents with nonspecific symptoms, that can be mild and occur slowly over time, compromising a timely diagnosis, with possible effects on pituitary gland, multiple organs and growth. In case of long-standing unrecognized hypothyroidism, myxedema or myxedema coma can occur, rare but severe conditions. This case report describes an adolescent presenting with extensive trunk and neck swelling. After excluding the main renal, gastrointestinal, and cardiac causes of edema, the ultrasound study showed a thickening of subcutaneous tissue and an enlarged thyroid, with ultrasound signs of thyroiditis. Blood exams showed extremely low FT4 concentrations (0.6 pg/ml), markedly increased TSH (>1000 IU/ml) and positive anti-thyroid peroxidase and anti-thyroglobulin antibodies. The condition was consistent with myxedema due to chronic autoimmune hypothyroidism. Other associated symptoms appeared mild, but significant neglected growth delay was present. Pituitary hyperplasia, hyperprolactinemia, increased serum creatinine and pericardial effusion were found. A prompt levothyroxine treatment allowed to reach an improvement of clinical status and edema regression in 2 weeks, a normalization of FT4 in 3 weeks and of TSH and creatinine in 2 months. Furthermore, Magnetic Resonance Imaging control at 6 months showed a complete regression of pituitary hyperplasia. Ongoing endocrinological follow-up will monitor growth, although current height and pubertal stage suggest a possibly compromised final height. The diagnostic delay could be linked to the apparent good health of the boy, not requiring pediatric evaluations, and to the underestimation of the growth delay, in presence of a family history of pubertal delay. This report suggests the importance of pediatric follow-up in adolescence, a critical period for identifying endocrine conditions which, if not diagnosed, can lead to severe clinical manifestations and even long-term sequelae.
15 Sep 2022 - 17 Sep 2022