Oedema of the neck after ablation of the thyroid with radioactive iodine.

Six out of 30 patients who underwent thyroid ablation with 131I during the period 1975-85 developed acute oedema of the neck within 48 h of the therapeutic dose. The condition was painless and responded well to treatment with corticosteroids. The early onset and absence of pain distinguish this complication from radiation thyroiditis. Dosage calculations and thermoluminescent-dosimeter measurements of the dose at various points on the anterior surface of the neck of a patient with a toxic adenoma of the thyroid treated with 131I were in fairly good agreement with one another and confirmed that the oedema of the neck could not be a direct effect of irradiation on the extrathyroidal tissues. It is suggested that this phenomenon may be a hypersensitivity reaction associated with massive destruction of thyroid tissue.