Thyrotoxic crisis as an acute clinical presentation in a child

A previously well, 4-year-old girl presented with a 4-6 weeks' history of increased appetite, weight loss, tiredness, sleep difficulty, excessive sweating, swelling in the neck and new-onset 'prominent, protruding eyes.' Family history revealed paternal grandmother receiving treatment for hyperthyroidism. Clinical assessment demonstrated features of thyrotoxicosis (tachycardia, warm peripheries, small smooth goitre with no nodules, exophthalmos). TFT (Free T4=101 pmol/L, thyroid-stimulating hormone <0.05 mIU/L) with raised thyroid peroxidase antibody levels (TPO=541 IU/mL) confirmed autoimmune hyperthyroidism. Observation on the ward showed features of thyrotoxic crisis with persistent severe tachycardia on ECG (sinus tachycardia with left ventricular hypertrophy (LVH)) and hypertension. Ultrasound thyroid showed diffuse thyroiditis with no focal lesion. Echocardiogram confirmed the above findings. A diagnosis of Graves' disease with thyrotoxic crisis was made. Antithyroid treatment (carbimazole) and beta-blocker (propranolol) was commenced. Thyrotoxic crisis resolved over 2 weeks and the child has continued to respond to carbimazole treatment at 1-year follow-up.