Endocrine Abstracts

A 9-year-old boy presented to his local hospital having had a respiratory arrest at home. He had a background of a chromosomal microdeletion, and there had been several days of cough and coryza. CPR was underway and upon arrival in A&E he was resuscitated and retrieved to PICU. The working diagnosis was lower respiratory tract infection.

On day 4 of his PICU stay, with progressive signs on his chest X-ray, an ultrasound scan was performed. This confirmed bilateral moderate pleural effusions and, surprisingly, a large pericardial effusion. A percutaneous pericardial drain was inserted and 750 mls of serous fluid was drained over 24 h with smaller volumes thereafter. Following drainage, the patient’s ventilation became easier and he made slow but steady progress towards extubation and PICU discharge.

The aetiology of the pericardial effusion was unclear. The fluid was acellular with a high protein concentration. Extensive microbiology and virology testing was negative; his heart was structurally and functionally normal; immunology testing for inflammatory conditions was negative and there was no known association with his particular genetic condition. Thyroid function tests however revealed gross hypothyroidism with a TSH >100; mU/l and free T4 <5 pmol/l. Furthermore, his anti-thyroid peroxidise antibodies were >1000 U/ml, in keeping with severe autoimmune hypothyroidism. Thyroxine replacement was commenced and he was discharged home after a total of 4 weeks in hospital.

This case highlights the difficulty in recognising symptoms of hypothyroidism in a child with neurodisability, both for caregivers and medical professionals. In hindsight, symptoms such as dry skin, cool peripheries and worsening of his usual constipation were forthcoming and the medical team recognised a relative bradycardia and hypothermia during his early stay.

Small asymptomatic pericardial effusions occur often in association with hypothyroidism but large clinically significant effusions are very rare. The fluid builds up slowly due to increased capillary leak of albumin and large volumes can be accommodated over time by stretching of the pericardium, protecting the system from tamponade. Hypothyroidism should be considered in the differential diagnosis of any child presenting with an otherwise unexplained pericardial effusion.