Low iodine diet does not improve the efficacy of radioiodine for the treatment of Graves’ disease

Objective Consuming a low-iodine diet (LID) is a widely accepted practice before administering radioiodine (131I) to evaluate and to treat thyroid disease. Although this procedure is well established for the management of patients with differentiated thyroid cancer, its use in patients with benign disease is unclear. So, we aimed to evaluate the influence of a LID on the outcome in patients with Graves’ disease (GD) treated with131I. Subjects and methods We evaluated 67 patients with GD who were divided into 2 groups: one group (n = 31) consumed a LID for 1-2 weeks, and the second group (n = 36) was instructed to maintain a regular diet (RD). Results The LID group experienced a 23% decrease in urinary iodine after 1 week on the diet and a significant 42% decrease after 2 weeks on the diet. The majority (53%) of the patients in the LID group had urinary iodine levels that were consistent with deficient iodine intake. However, there was no difference in the rate of hyperthyroidism’s cure between the LID and the RD groups 6 months after 131I therapy. Furthermore, the therapeutic efficacy did not differ in patients with varying degrees of sufficient iodine intake (corresponding urinary iodine levels: < 10 μg/dL is deficient; 10-29.9 μg/dL is sufficient; and > 30 μg/dL is excessive). Conclusion In the present study, we demonstrated that although a LID decreased urinary iodine levels, those levels corresponding with sufficient or a mild excess in iodine intake did not compromise the therapeutic efficacy of131I for the treatment of GD.

Low iodine diet does not improve the efficacy of radioiodine for the treatment of Graves' disease.

OBJECTIVE: Consuming a low-iodine diet (LID) is a widely accepted practice before administering radioiodine (131I) to evaluate and to treat thyroid disease. Although this procedure is well established for the management of patients with differentiated thyroid cancer, its use in patients with benign disease is unclear. So, we aimed to evaluate the influence of a LID on the outcome in patients with Graves' disease (GD) treated with 131I. SUBJECTS AND METHODS: We evaluated 67 patients with GD who were divided into 2 groups: one group (n = 31) consumed a LID for 1-2 weeks, and the second group (n = 36) was instructed to maintain a regular diet (RD). RESULTS: The LID group experienced a 23% decrease in urinary iodine after 1 week on the diet and a significant 42% decrease after 2 weeks on the diet. The majority (53%) of the patients in the LID group had urinary iodine levels that were consistent with deficient iodine intake. However, there was no difference in the rate of hyperthyroidism's cure between the LID and the RD groups 6 months after 131I therapy. Furthermore, the therapeutic efficacy did not differ in patients with varying degrees of sufficient iodine intake (corresponding urinary iodine levels: < 10 µg/dL is deficient; 10-29.9 µg/dL is sufficient; and > 30 µg/dL is excessive). CONCLUSION: In the present study, we demonstrated that although a LID decreased urinary iodine levels, those levels corresponding with sufficient or a mild excess in iodine intake did not compromise the therapeutic efficacy of 131I for the treatment of GD.

Graves' disease, Celiac disease and liver function abnormalities in a patient--clinical manifestation and diagnostic difficulties.

Autoimmune diseases due to probable common pathogenesis tend to coexist in some patients. Complex clinical presentation with diverse timing of particular symptoms and sophisticated treatment with numerous side effects, may cause diagnostic difficulties, especially in children. The paper presents diagnostic difficulties and pitfalls in a child with Graves' disease, celiac disease and liver function abnormalities.

Incidence and clinical presentation of moderate to severe graves' orbitopathy in a Danish population before and after iodine fortification of salt.

CONTEXT: Population-based data on the incidence and clinical presentation of moderate to severe Graves' orbitopathy (GO) are scarce, and virtually nothing is known on the effect of an iodization program on the incidence and presentation of GO. OBJECTIVE: The objective of the study was to characterize incident moderate to severe GO in North Jutland County, Denmark, during the period 1992-2009, before and after the Danish salt iodization program. DESIGN AND PATIENTS: The design of the study was a prospective register of patients with incident moderate to severe GO in a population during 8.9 million persons × years of observation. SETTING: The study was conducted at a thyroid-eye clinic of university hospital. MAIN OUTCOME MEASURES: Clinical presentation and incidence before and after the year 2000 initiation of the mandatory Danish iodization of salt were measured. The incidence of GO was related to the incidence of Graves' hyperthyroidism (GH) in the same population. RESULTS: The incidence rate of moderate to severe GO was 16.1/million per year (women: 26.7; men: 5.4), with no change associated with iodization of salt. The moderate to severe GO incidence was 4.9% of the incidence of GH. The incidence rate ratio between women and men with GO (4.9) was not different from the ratio in GH. Compared with GH, only a few patients (<2%) suffered from moderate and severe GO below the age of 40 yr, whereas GO was relatively common in age groups 40-60 yr (∼8%). CONCLUSIONS: Approximately 5% of the patients with Graves' disease develop moderate to severe GO, with a similar risk in women and men with Graves' disease. The risk of GO is much higher in patients aged 40-60 yr than in young patients with Graves' disease. Salt iodization was not associated with a change in the incidence of GO.

Rhabdomyolysis associated with hyperthyroidism.

BACKGROUND: Nontraumatic rhabdomyolysis has been associated with alcohol and drug abuse, seizures, strenuous exercise, muscle hypoperfusion, hyperthermia, electrolyte disturbances, diabetic coma, and hypothyroidism. Hyperthyroidism can be associated with several neuromuscular manifestations, such as thyrotoxic myopathy and thyrotoxic periodic paralysis, both associated with weakness and normal creatine phosphokinase levels. There have been only three reported cases of rhabdomyolysis as a result of thyrotoxicosis. We are reporting the fourth case of such association. CASE REPORT: The patient is a 26-year-old black woman with history of hypertension. She presented to the clinic with blurred vision, headaches, palpitations, weight loss, weakness, and persistent high blood pressure. She was found to have exophthalmus, lid lag, and a symmetric, smooth, and diffuse goiter. Ptosis and diplopia were absent; neurologic examination findings was normal. The patient had positive TPO antibodies, elevated free T4 level, and low thyroid-stimulating hormone (TSH) level. Graves disease was diagnosed and propylthiouracil was prescribed. The patient then returned to the clinic 2 weeks later with weakness and myalgias. Her physical examination findings were unchanged except for mild muscle weakness. Laboratory evaluation showed normal electrolytes, normal renal function, and negative urine drug screening. Creatine phosphokinase was 1276 U/L. Her free T4 and T3 levels were elevated and TSH level was low. The patient was treated with aggressive oral fluid resuscitation. Propylthiouracil was continued and free T4 and T3 normalized along with creatine phosphokinase with resolution of symptoms. CONCLUSIONS: Hyperthyroidism may, theoretically, cause rhabdomyolysis by means of increasing energy consumption associated with depletion of muscle energy stores and substrates. Our patient constitutes the fourth reported case of rhabdomyolysis associated with hyperthyroidism.