Distinguishing between isthmic thyroglossal duct cyst and goitre on nuclear thyroid scan: A case report

Thyroglossal duct cysts, which are the most frequently encountered congenital cervical anomalies in children, occur due to embryologic remnants of the thyroglossal duct. Although diagnosis may be challenging, clinicians can be aided by imaging and fine-needle aspiration biopsies. We describe the clinical management of a two-year-old boy with a thyroglossal duct cyst mimicking a goitre on a pertechnetate thyroid scan.

Low-Dose Prednisone Therapy is Efficacious in Treating Painful Subacute Thyroiditis

Subacute thyroiditis (SAT) usually presents with neck pain, radiating to ears and is often associated with hyperthyroidism. Currently the available treatment involves administration of NSAID or in more symptomatic patients prednisone 40mg daily tapered over 6 weeks or longer. We report successful treatment of 3 patients (Pts) with SAT with low-dose prednisone therapy (20mg/day) (LDP20) initially and tapered over 4 weeks. Patient 1: A 32-year-old female presented with severe neck pain radiating to both ears and low- grade fever of 2-weeks duration. Two weeks prior, patient had cold-like symptoms lasting for 3 days. Physical examination: HR 110bpm, tremors of fingers noted, tenderness of the anterior neck present, thyroid 30-gms in size. Labs: ESR 92 mm/hr, CRP 3.2 mg/dL, TSH <0.005 uIU/mL, free T4 2.71 ng/dL, total T3 168 ng/mL. Thyroid scan and uptake showed a 24-hrs uptake <1%, thyroid gland not visualized, consistent with SAT. Patient was treated with atenolol and LDP20 tapered over 4 weeks. Pain significantly improved after 2 days of treatment. Six weeks later TSH was 0.9 uIU/mL with a free T4 1.4 ng/dL and ESR 8 mm/hr. Patient 2: A 19-year-old female presented with left-ear pain, anterior neck pain, fever, and extreme fatigue. PE: HR 111bpm, heat shield present, tender-to-palpation thyroid, brisk DTR. Lab: CBC normal, ESR 98 mm/hr, CRP 9.9 mg/dL, TSH <0.01 uIU/mL, free T4 3.8 ng/dL, total T3 210 ng/mL. Thyroid scan and uptake: uptake <1%, no thyroid gland visualized and SAT was diagnosed. Patient was started on LDP20 and atenolol. Four days following prednisone therapy her symptoms completely resolved and prednisone was tapered off over 4 weeks. Thyroid functions were normal by the seventh week. Patient 3: A 38-year-old male presented with fever, fatigue, severe neck pain, palpitation and a weight loss of 8 pounds. PE: HR 120 bpm, thyroid severely tender on palpation, brisk DTR. Lab: normal CBC, ESR 128 mm/hr, CRP 11.9 mg/dL, TSH <0.001 uIU/mL, free T4 4.2 ng/dL, total T3 201 ng/mL. Thyroid scan: thyroid gland not visualized and uptake was < 1%. SAT was diagnosed and patient was treated with propranolol and LDP20. After 5 days the dose of prednisone was reduced to 15mg/day and the prednisone was tapered over five weeks. Patient had resolution of symptoms in 70 hours and remained asymptomatic for the next 12 months of follow-up. Thyroid function normalized by the eighth week. Conclusion: SAT is a painful disabling thyroid disorder apparently caused by a viral infection; and NSAID or high-dose steroid treatment remains the standard of care. We have treated 3 Pts with relatively lower doses of prednisone than previously recommended and attained remission successfully. Thus side effects can be avoided with lower prednisone dose.

Treatment of Graves’ Disease With a Combination of Low Iodine Diet and Potassium Iodide Plus Radioactive Iodine Treatment

Introduction: Graves’ disease (GD) is usually treated with radioactive iodine I131 (RAI), thionamide or surgery. Of these, RAI remains the safest and most efficacious treatment. We report 3 patients with GD who were treated with low iodine diet (LID), followed by RAI and subsequent potassium iodide (SSKI) administration.Case series:Patient 1 - A 50-year-old male presented with weight loss, heat intolerance and palpitations. Physical examination: HR 120 bpm, BP 110/80mmHg, no evidence of thyroid orbitopathy. Thyroid: 50 grams diffusely enlarged and brisk DTR. Lab findings: TSH 0.001, FT4 4.2, total T3 410, TSI 172. A thyroid scan revealed diffuse uptake 72% at 4-hours. He was diagnosed with GD and treated with methimazole. Three weeks later a CBC showed an absolute neutrophil count 820. After discontinuing methimazole, he was placed on prednisone 40mg daily and LID. Two weeks later (24-hours urine iodine <50 mcg), he received 15mCi I131. 72 hours later he was administered SSKI one drop BID for 3 days. Four weeks after RAI, TFT was normal. Two months later, he required levothyroxine treatment for hypothyroidism. Patient 2 - A 23-year-old female presented with weight loss and nervousness. Physical examination revealed HR 110 bpm, BP 100/70 mmHg, no thyroid orbitopathy, a diffusely enlarged thyroid. Serum TSH <0.005, FT4 3.9, total T3 398, TSI 149. Thyroid uptake showed 70% at 24-hours. Patient was started on methimazole and atenolol. Four weeks later she developed severe generalized erythematous rash. After treating with prednisone for one week she was placed on LID and treated with 15 mCi I131. Six weeks later TSH was 0.4 with a free T4 of 1.8 and four months later she required levothyroxine therapy for hypothyroidism. Patient 3 - A 40-year-old male presented with atrial fibrillation and hyperthyroidism. Patient received treatment for atrial fibrillation and physical examination confirmed heart rate 78 (on treatment), no evidence of thyroid orbitopathy, and diffusely enlarged thyroid. Serum TSH <0.005, FT4 3.1, total T3 298, TSI 231. Thyroid scan was consistent with GD with a 24-hr uptake of 62%. He refused to take methimazole due to fear of adverse side effects. After placing him on prednisone along with LID for 2weeks, he was treated with I131 15 mCi. 72 hours later he received SSKI one drop BID for 3 days. Prednisone was discontinued 2 weeks later. Six weeks following treatment, TSH was 1.1 with FT4 1.32. Patient remained euthyroid for the next 12 months of follow up. Discussion: LID given before RAI therapy has a potential of depleting total iodine pool which can increase the I131 uptake in the thyroid gland and facilitate β-radiation to the thyroid gland. SSKI following RAI can improve retention of I131 in the thyroid gland and reduce the recycling of radioactivity between the thyroid and the blood. In summary, a LID prior to RAI and SSKI following RAI treatment be beneficial in certain patients with GD.

Developing anterior mediastinum mass after orthotopic thyroidectomy: a case report

Background Ectopic thyroid tissue is a rare embryological aberration described by the occurrence of thyroid tissue at a site other than in its normal pretracheal location. Depending on the time of the disruption during embryogenesis, ectopic thyroid may occur at several positions from the base of the tongue to the thyroglossal duct. Ectopic mediastinal thyroid tissue is normally asymptomatic, but particularly after orthotopic thyroidectomy, it might turn out to be symptomatic. Symptoms are normally due to compression of adjacent structures. Case presentation We present a case of a 66-year-old male submitted to a total thyroidectomy 3 years ago, due to multinodular goiter (pathological results revealed nodular hyperplasia and no evidence of malignancy), under thyroid replacement therapy. Over the last year, he developed hoarseness, choking sensation in the chest, and shortness of breath. Thyroid markers were unremarkable. He was submitted to neck and thoracic computed tomography, magnetic resonance imaging, and radionuclide thyroid scan. Imaging results identified an anterior mediastinum solid lesion. A radionuclide thyroid scan confirmed the diagnosis of ectopic thyroid tissue. The patient refused surgery. Conclusions Ectopic thyroid tissue can occur either as the only detectable thyroid gland tissue or in addition to a normotopic thyroid gland. After a total thyroidectomy, thyroid-stimulating hormone can promote a compensatory volume growth of previously asymptomatic ectopic tissue. This can be particularly diagnosis challenging since ectopic tissue can arise as an ambiguous space-occupying lesion.

EFFECT OF POST-SURGICAL RAI THERAPY ON PARATHYROID FUNCTION IN PATIENTS WITH DIFFERENTIATED THYROID CANCER

Objective: Radiotherapy with radioactive iodine (RAI) has become a common treatment for postsurgical differentiated thyroid carcinoma (DTC). The objective of this study was to determine the effect of RAI therapy following surgery on the function of the parathyroid glands in DTC patients. Methods: A total of 81 DTC patients who received RAI therapy after surgery were enrolled in the study. The size of the residual thyroid was detected by technetium-99m (99mTc)-pertechnetate thyroid scan (99mTc thyroid scan) before RAI therapy. The iodine uptake ability of residual thyroid was evaluated by iodine-131 (131I) whole-body scan (WBS). All patients were treated with an activity of 3.7 GBq (100 mCi) 131I. Parathyroid hormone (PTH), serum calcium, phosphorus, and magnesium were evaluated at 1 day before treatment, and at 1 month and 3 months after treatment. Results: The results show that there was no statistically significant difference in blood PTH level observed ( P>.05) between 3 time points (pre-treatment, 1 month post-treatment and 3 months post-treatment). The serum calcium and phosphorus did not change significantly ( P>.05), but serum magnesium level was elevated after treatment ( P<.05). There were no significant differences between PTH changes and sex, age, scores of 99mTc thyroid scan, scores of 131I WBS, Tumor (T) stage, and Node (N) stage. Conclusion: RAI therapy following surgery did not significantly affect parathyroid function in DTC patients. Abbreviations: ATA = American Thyroid Association; DTC = differentiated thyroid carcinoma; FT3 = free triiodothyronine; FT4 = free thyroxine; 131I = iodine-131; PTH = parathyroid hormone; RAI = radioiodine; 99mTc = Technetium-99m; TG = thyroglobulin; TNM = Tumor Node Metastasis; TSH = thyroid-stimulating hormone; WBS = whole-body scan

Assessment of Agreement Between Peak Systolic Velocity of Inferior Thyroid Artery And Thyroid Scan In Differentiating Diffuse Toxic Goiter And Subacute Thyroiditis.

Objective:To analyze agreement between Peak Systolic Velocity (PSV) of inferior thyroid artery (ITA) and Tc99m Thyroid Scan for evaluation of thyrotoxicosis(diffuse toxic goiter and sub-acute thyroiditis) Patients and Methods: This prospective cross sectional study was conducted in National Institute of Nuclear medicine and Allied sciences (NINMAS)From July 2016 to June 2017.Total sixty four patients with thyrotoxicosis were included in the study. History, clinical examination and thyroid function tests were done for all patients. The thyroid glands of all patients wereevaluated by gray scale ultrasonography for size, shapeand echotexture. Color-flow Doppler ultrasonographyof the thyroid tissue was performed and spectral flowanalysis of both inferior thyroid arteries were assessed. Tc99m Thyroid scan was done for all patients. The patients were divided into two groups. Group A- Diffuse toxic goiter(DTG) and Group B- Subacute thyroiditis(SAT).The diagnosis of diffuse toxic goiter and subacute thyroiditis was supported by the clinical picture, RAIU uptake and Thyroid Scan. Results:All patients had suppressed thyrotropin.Thyroid blood flow, measured by PSV of ITA (CFDS) was highthan normal in DTG patients, while low PSV ofITA than normal was found in SAT.According to Thyroid Scan,Radiotracer concentration (RTC)was diffusely increased with low BKG (background) and almost absent RTC with high BKG was noted in DTG and SAT respectively.In our study Tc99m Thyroid Scan shows agreement with Peak Systolic Velocity of ITA.Here Kappa value was 0.818 and 0.871 in DTG and SAT respectively with P value <0.05 which was statistically significant with almost perfect agreement. Conclusion:An Almost perfect agreement between the two modality (PSV of ITA and Tc99m Thyroid Scan) establishes that they are useful alternativein the differential diagnosis of thyrotoxicosis (Diffuse toxic goiter and Subacute thyroiditis) Bangladesh J. Nuclear Med. 21(2): 97-101, July 2018