Advances in the Treatment of Hyperthyroidism: A Case Study on the Use of Radioactive Iodine Therapy

Abstract

Hyperthyroidism, characterized by excessive thyroid hormone production, can lead to severe systemic effects if left untreated. Radioactive iodine (RAI) therapy has been an effective treatment for hyperthyroidism, specifically for conditions like Grave’s disease. This case study discusses the clinical presentation, diagnosis, and management of a 35-year-old female patient with hyperthyroidism treated with RAI therapy. The patient’s response to treatment, follow-up, and overall outcomes are also evaluated, providing insights into the efficacy and safety of RAI in managing hyperthyroidism.

Introduction

Hyperthyroidism is a common endocrine disorder where the thyroid gland overproduces thyroid hormones, leading to symptoms such as weight loss, palpitations, heat intolerance, and tremors. Various treatment modalities are available, including antithyroid medications, surgery, and radioactive iodine therapy. RAI therapy is a widely used and effective treatment, particularly for patients with Grave's disease or toxic nodular goiter. This case study explores the use of RAI therapy in treating hyperthyroidism, emphasizing the patient’s clinical course, outcomes, and management.

Patient Information

A 35-year-old female patient presented with symptoms of hyperthyroidism, including unintentional weight loss, excessive sweating, palpitations, and tremors over the past three months. She also reported feeling anxious and experiencing frequent episodes of irritability. Her past medical history was unremarkable, and she had no family history of thyroid disorders.

Clinical Findings

Upon examination, the patient exhibited classic signs of hyperthyroidism: tachycardia with a heart rate of 110 beats per minute, hand tremors, warm and moist skin, and an enlarged thyroid gland (diffuse goiter) that was palpable. No eye symptoms, such as exophthalmos, were observed, ruling out severe Graves’ ophthalmopathy. Blood pressure was slightly elevated at 140/85 mmHg.

Laboratory investigations revealed the following findings:

Thyroid-stimulating hormone (TSH): 0.01 µIU/mL (Normal: 0.4–4.0 µIU/mL)

Free T4: 3.5 ng/dL (Normal: 0.9–2.3 ng/dL)

T3: 230 ng/dL (Normal: 80–180 ng/dL)

The elevated free T4 and suppressed TSH levels confirmed the diagnosis of hyperthyroidism.

Timeline

1. Day 0: Patient presents with symptoms of hyperthyroidism. Clinical evaluation and blood tests were performed.

2. Day 3: Diagnosis of hyperthyroidism confirmed. The patient was referred for a radioactive iodine uptake (RAIU) test.

3. Day 7: RAIU results show diffuse uptake, consistent with Graves’ disease.

4. Day 10: Decision made to proceed with RAI therapy.

5. Day 30: RAI therapy administered.

6. 1-month follow-up: Significant improvement in symptoms; free T4 levels begin to decline.

7. 6-month follow-up: Patient develops mild hypothyroidism; levothyroxine therapy initiated.

8. 12-month follow-up: Stable thyroid function achieved with ongoing levothyroxine therapy.

Diagnosis

The patient was diagnosed with Grave’s disease, the most common cause of hyperthyroidism. This diagnosis was supported by the clinical presentation, laboratory findings, and diffuse uptake on the radioactive iodine uptake scan.

Follow-Up and Outcome

The patient underwent radioactive iodine therapy (RAI) to ablate the overactive thyroid tissue. A dose of 15 mCi (millicurie) of radioactive iodine-131 was administered orally. RAI therapy is considered a definitive treatment for hyperthyroidism, particularly in patients with Graves’ disease who have failed or cannot tolerate antithyroid medications.

At the one-month follow-up, the patient reported significant relief from her hyperthyroid symptoms, including a reduction in palpitations, tremors, and anxiety. Blood tests showed a decrease in free T4 levels to 1.8 ng/dL, and TSH levels were still suppressed but rising gradually.

At the six-month follow-up, the patient's thyroid function shifted toward hypothyroidism, a common consequence of RAI therapy. Her TSH level was 6.5 µIU/mL, and free T4 was 0.6 ng/dL. The patient was started on levothyroxine therapy to replace the deficient thyroid hormone.

At the 12-month follow-up, the patient’s thyroid function tests had stabilized with a TSH of 1.5 µIU/mL and free T4 of 1.1 ng/dL. She remained asymptomatic and continued on a stable dose of levothyroxine. Her quality of life improved significantly, and she experienced no adverse effects from the RAI therapy.

Discussion

Radioactive iodine therapy is a well-established treatment for hyperthyroidism, particularly in patients with Graves' disease, toxic multinodular goiter, or toxic adenoma. RAI selectively destroys overactive thyroid tissue while sparing the surrounding healthy tissue. The therapeutic dose of radioactive iodine is calculated based on the thyroid gland's size and the degree of thyroid hormone overproduction.

The main advantage of RAI therapy is its high success rate in curing hyperthyroidism with a single treatment dose. However, a common outcome of RAI therapy is the development of hypothyroidism, as seen in this patient. Hypothyroidism typically occurs within the first six months following treatment and is managed effectively with levothyroxine replacement therapy.

The decision to use RAI therapy in this case was based on the patient’s preference for a definitive treatment, her intolerance to antithyroid medications, and the confirmed diagnosis of Graves’ disease. RAI therapy offers a safe and effective option, with minimal long-term side effects. However, it is contraindicated in pregnant women and should be used cautiously in patients with severe Graves' ophthalmopathy, as it may worsen eye symptoms.

Although hypothyroidism is a predictable outcome, it is generally well-tolerated and easily managed with lifelong hormone replacement therapy. For patients like the one in this case study, RAI offers a significant improvement in symptoms, quality of life, and overall disease management.

Patient's Perspective

The patient was initially concerned about the long-term implications of RAI therapy but was reassured by her endocrinologist regarding its safety and effectiveness. She opted for RAI therapy over other treatments due to the convenience of single-dose therapy and the potential for a permanent cure for her hyperthyroidism. After treatment, the patient expressed satisfaction with the outcome, especially after her thyroid hormone levels stabilized with levothyroxine supplementation. She appreciated the thorough follow-up care and felt well-informed throughout the treatment process.

Conclusion

Radioactive iodine therapy is an effective and safe treatment for hyperthyroidism, particularly in patients with Graves’ disease. This case study illustrates the successful use of RAI in a patient with hyperthyroidism who experienced a transition to hypothyroidism, a known side effect. Long-term management with levothyroxine replacement therapy was necessary to maintain normal thyroid function. Overall, RAI therapy provides a definitive solution for hyperthyroidism, improving the patient’s quality of life and reducing the risk of complications from untreated hyperthyroidism.

References

1. Cooper, D. S. (2003). Radioiodine for hyperthyroidism: Where do we stand after 50 years? Journal of Clinical Endocrinology & Metabolism, 88(6), 2401-2404.

2. Bahn, R. S., Burch, H. B., Cooper, D. S., et al. (2011). Hyperthyroidism and other causes of thyrotoxicosis: Management guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. Thyroid, 21(6), 593-646.

3. Ross, D. S. (2016). Radioiodine therapy for hyperthyroidism: An evidence-based approach. Thyroid, 26(4), 530-538.

4. Bonnema, S. J., & Hegedüs, L. (2012). Radioiodine therapy in benign thyroid diseases: Effects, side effects, and factors affecting therapeutic outcome. Endocrine Reviews, 33(6), 920-980.