Endocrine Abstracts

Introduction: Hashimoto’s thyroiditis is the most common cause of acquired hypothyroidism in children and adolescents affecting ten time more females than males. Diagnosis is based on clinical features and antibodies against thyroid peroxidase (TPO) or thyroglobulin (TG). Addison’s is an autoimmune disease resulting in primary adrenal insufficiency. It is extremely rare in children and easily misdiagnosed. Levothyroxine may precipitate adrenal crisis in individuals with undiagnosed adrenal insufficiency.

Case Report: A 14 year old girl was referred to Adult Endocrinology with acutely tender diffuse goitre and tiredness. Laboratory results indicated hypothyroidism alongside strongly positive TPO antibodies resulting in the diagnosis of Hashimoto’s thyroiditis. No further blood tests were undertaken, and levothyroxine was commenced. 14 weeks later she presented to the Emergency Department with severe lethargy, abdominal pain, anorexia and nausea and vomiting and was referred to the tertiary referral centre (TRC) as a surgical abdomen. On assessment in TRC, she was noted to have metabolic acidosis (pH 7.23), hyponatremia (Na+ 121 mmol/l), hypoglycaemia (3.0 mmol/mol) alongside tachycardia (125 bpm) and hypotension (95/57 mmHg) requiring fluid resuscitation (3x10 ml/kg 0.9%NaCl) and dextrose bolus (2x2 ml/kg 10% Dextrose). Blood pressure remained labile despite fluid resuscitation and there was a noted reluctance to continue in light of hyponatremia. On further assessment, significant hyperpigmentation was noted and confirmed not to be fake tan and a diagnosis of adrenal crisis made. Two doses of Intravenous hydrocortisone was administered followed by an intravenous infusion due to limited response. She was referred to the Paediatric Intensive Care Unit (PICU) for inotropic support and ongoing care. Further Endocrine assessment was carried out but all bloods were normal except for very high levels of anti-adrenal antibodies which lead to a diagnosis of Addison’s disease. She was discharged home five days later.

Conclusion: Levothyroxine can precipitate adrenal crisis in individuals with undiagnosed adrenal insufficiency due to increased metabolism in the liver. The potential coexistence of adrenal insufficiency should be suspected in patients with diagnosed autoimmune thyroid disease and an early morning cortisol checked prior commencement of levothyroxine.