Endocrine Abstracts

Graves' disease is known to occur with increased frequency in patients with Type 1 diabetes mellitus (T1DM) especially women. Undiagnosed thyrotoxicosis can aggravate glucose intolerance and precipitate diabetic ketosis and ketoacidosis. Among the various presenting symptoms of hyperthyroidism, vomiting is a recognized but uncommon symptom.

We present the case history of a 30 year old woman with T1DM of 10 years duration presenting with a short history of persistent vomiting precipitated by thyrotoxicosis. She had diabetic retinopathy and peripheral neuropathy. Her glycaemic control was suboptimal for a few months prior to admission. She did not have diarrhoea, abdominal pain or dysuria .There was no weight loss and her appetite was normal. She had a tachycardia of 110 per minute, blood pressure was normal, was not febrile or clinically dehydrated on admission. There was no obvious septic focus. Capillary glucose at presentation was 18 millimols per deciliter. She was not acidotic but ketones were present in urine. Urea, electrolytes, full blood count, C - reactive protein, blood cultures, liver function tests, urine culture, D-dimers, chest x- ray and echocardiogram were normal. She was treated with anti-emetics, IV fluids and subcutaneous insulin. Despite treatment with IV fluids she continued to have a tachycardia at rest. Further clinical examination revealed a uniform goitre .She did not have a tremor or eye signs. Thyroid function tests revealed a free thyroxine of 86.4 picomols per litre (NR 9-25) and thyroid stimulating hormone less than 0.05 microunits per litre (NR 0.3 - 4.7) .Thyroid uptake scan was consistent with Graves' disease. She was treated with carbimazole and propranolol and her symptoms subsided and her glycaemic control gradually improved.

This case emphasizes the need to screen for hyperthyroidism in patients with T1DM with poor glycaemic control and in diabetic ketosis / ketoacidosis without an obvious triggering factor. This case also highlights the need to exclude hyperthyroidism in unexplained vomiting especially among patients with diabetes.