Background Children with severe hypothyroidism are known to present with significant growth restriction. Institution of treatment with thyroxine results in catch-up growth. However, treatment commenced in pubertal period may result in loss of adult height in cases with longstanding severe untreated hypothyroidism.

Objective The objective of our study is to evaluate the presentation, investigations and catch-up growth after initiation of treatment with Thyroxine.

Methods We describe a retrospective case series of three peripubertal girls who presented with severe growth restriction as a result of primary autoimmune hypothyroidism between September 2014 and April 2015.

Results Case : A 15 year old girl presented with 1 year history of constipation and short stature. Her pubertal staging was B3P3A2M1. Her height SDS was –4.99 and weight SDS was –3.22. Her TSH was > 100 mU/l, Free T4 was undetectable and TPO antibodies were positive. Her bone age was delayed by 5 years. Three months after starting treatment with thyroxine, her height SDS improved to –4.63.

Case 2: A 13 year old girl presented with one year history of cold intolerance, poor growth, low mood and constipation. Her pubertal staging was B3P3A2M1. Her height SDS was

-3.23 and weight SDS was –0.61. Her TSH was > 100 mU/l and FT4 was undetecTable. Her bone age was delayed by 15 months.

Case 3: A 14 year old girl presented with dizziness and collapse at school. She also had 2 year history of cold intolerance, dry skin and dry hair. Her pubertal staging was B2P2A1M0. Her height SDS was –4.35 and weight SDS was –1.93. Her TSH was > 100 mU/l and free T4 was undetecTable. Thyroid ultrasound was suggestive of Thyroiditis with no nodules. Her bone age was delayed by 3 years. 6 months after starting treatment with Thyroxine, her height SDS improved to –3.43.

All girls had normal response to growth hormone and gonadotropin stimulation tests, which confirmed that short stature was entirely secondary to severe hypothyroidism.

Conclusions Prompt recognition of hypothyroidism in childhood is essential to initiate treatment early, so that adult height is not compromised.