Diagnosis and Radioablation Treatment of Toxic Multinodular Goiter in a Hemodialysis Patient Trudy M. Demko, MD, Mark Tulchinsky, MD, Kenneth L. Miller, MS, Joseph Y. Cheung, MD, PhD, and James A. Groff, DO ● Toxic multinodular goiter is rare in hemodialysis patients. In addition, establishing the diagnosis of hyperthyroid- ism in the elderly patient with renal failure is difficult because abnormal thyroid function tests can erroneously be attributed to euthyroid sick syndrome. Treatment of hyperthyroidism in dialysis patients by radioiodine ablation involves careful calculation of 131 I dose, determination of interval between 131 I administration and its removal by hemodialysis, and minimization of radiation hazards during dialytic removal of 131 I. We described the clinical presentation of an elderly dialysis patient with toxic multinodular goiter and discussed our diagnostic and therapeutic approaches. The patient’s recovery after 131 I ablation was complete and uneventful.  1998 by the National Kidney Foundation, Inc. INDEX WORDS: Hyperthyroidism; end-stage renal disease; euthyroid sick syndrome; radioactive iodine. T OXIC MULTINODULAR goiter (TMNG) is typically a disease of the elderly, yet thyro- toxicosis remains a relatively uncommon entity; as the prevalence of thyrotoxicosis is 1% to 2% in those older than 60 years of age. 1 Even more unusual is the presentation of TMNG in patients with end-stage renal disease requiring dialysis. There have been rare case reports of clinical hyperthyroidism in the dialysis population, 2-4 with some postulating that uremia is protective against the development of thyrotoxicosis. 2 The differen- tiation of clinical hyperthyroidism from abnor- mal thyroid function tests in a euthyroid patient has been a challenge in the dialysis population. 2-4 Radioiodine ( 131 I) is a common treatment ap- proach to hyperthyroidism in elderly patients with TMNG. There are only a few reports in the literature on 131 I ablation therapy of thyroid car- cinoma in dialysis patients. 5-7 The cases that address the treatment of hyperthyroidism in the dialysis patient do not adequately discuss dosim- etry or the safety issues involved with radioio- dine ablation therapy. 2,4 Problems encountered in iodine therapy in dialysis patients include the correct calculation of the 131 I dose to adequately treat the thyroid goiter, the safe administration of radioactive therapy in the dialysis setting, and the disposal of radioactive waste during hemodi- alysis. The following case addresses these diffi- culties. CASE REPORT A 76-year-old white woman with end-stage renal disease secondary to diabetes mellitus and hypertension was stable on hemodialysis for approximately 1 year. She developed new-onset atrial fibrillation with a rapid ventricular response before her presentation of increasing fatigue, shortness of breath, and accelerated hypertension. Physical examination was remarkable for blood pressure of 200/85-100 mm Hg. Heart rate was irregularly irregular, ranging from 85 to 120 beats/min. She had mild proptosis but no lid lag. There was mild enlargement of the thyroid gland but no tenderness or nodules. Cardiac examination showed a II/VI systolic ejec- tion murmur located at the apex. There were decreased breath sounds and dullness to percussion bilaterally in the lung bases. Extremities showed 2+ pitting edema to the knees bilaterally. Her deep tendon reflexes were 2+ and symmetrical. Her motor strength was 4/5 bilaterally in the extremities. Cardiovascular evaluation included a dipyridamole thal- lium stress test, which showed mild ischemia. Echocardiog- raphy showed hyperdynamic systolic function with an en- larged left atrium of 4.6 cm. Free T 4 was 1.4 ng/dL (0.7 to 1.8), free T 3 was 303 pg/dL (230 to 420), and thyroid- stimulating hormone (TSH) was less than 0.05 μIU/mL. These results were initially interpreted as the patient having euthyroid sick syndrome. Medications included metoprolol 150 mg twice daily, enalapril 10 mg twice daily, transdermal nitroglycerin, vita- min D, erythropoietin, calcium carbonate, and oral iron sulfate. Long-term anticoagulation was not instituted for this frail, elderly lady who lived alone. Over the course of the next 2 months, the patient devel- oped increasing anxiety, insomnia, tremors, and the inability From the Departments of Nephrology, Radiology, Medi- cine, and Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, The Milton S. Hershey Medical Center, Hershey, PA. Received March 5, 1997; accepted in revised form Septem- ber 26, 1997. Address reprint requests to Joseph Y. Cheung, MD, PhD, Chief, Division of Nephrology, Department of Medicine, Pennsylvania State University College of Medicine, Her- shey, PA 17033. E-mail: jcheung@med.hmc.psghs.edu  1998 by the National Kidney Foundation, Inc. 0272-6386/98/3104-0019$3.00/0 698 American Journal of Kidney Diseases, Vol 31, No 4 (April), 1998: pp 698-700