Primary Autoimmune Hypothyroidism Research Articles

Mucoepidermoid Carcinoma of the Thyroglossal Duct: Two Rare Entities in a Unique Case Report.

Mucoepidermoid Carcinoma (MEC) of the thyroid represents less than 0.5% of all thyroid neoplasms. Thyroglossal duct cyst carcinoma is a rare condition with only approximately 300 cases reported. A 34-year-old pregnant woman at 37 weeks gestation presented to an endocrinological center for primary autoimmune hypothyroidism. The thyroid ultrasound revealed a pseudonodular pattern. The patient was followed up after two years. She reported a full-term delivery without complications. A new thyroid ultrasound was performed, showing a cystic lesion in the median suprathyroid area, measuring 6 x 9 x 10 mm, not previously reported. After 4 months, the suprathyroid cystic lesion was confirmed by thyroid ultrasound, measuring 6 x 11 x 12 mm. The patient was referred for fine-needle aspiration cytology. Cytological examination showed lymphocytes, red blood cells, and some epithelial aggregates with large cytoplasm and nuclear polymetrism with oxyphilic aspects. The patient underwent the Sistrunk procedure for the suprathyroid lesion. The histological examination revealed lymphocytic thyroiditis in heterotopic thyroid tissue with solid cell nest, epidermoid epithelium, and mucus-secreting cells suggestive of low-grade mucoepidermoid carcinoma. The immunohistochemistry study was positive, exhibiting thyroid transcription factor 1 and cytokeratin-19. No positivity was observed for thyroglobulin, calcitonin, galectin-3, and Hector Battifora mesothelial antigen 1. The recent follow-up examination, 13 months after the surgery, has been found negative for disease recurrence. This is the first case of an MEC occurring within a thyroglossal duct. Considering the age of the patient, the histological diagnosis, and the absence of thyroid nodules and metastasis, we decided on the Sistrunk procedure without total thyroidectomy.

Cardiac tamponade - a rare cause of sudden death in autoimmune polyglandular syndrome.

A 27-year-old male died suddenly due to cardiac tamponade arising from pericarditis complicating autoimmune polyglandular syndrome (APS) type 2. He had a history of primary Addison disease and autoimmune hypothyroidism which were corroborated at autopsy. In addition a florid fibrinous pericarditis was associated with 287g of turbid fluid in the pericardial sac. Although pericarditis with tamponade is a potential complication of APS, it has rarely if ever, been reported as a cause of sudden death. Lethal mechanisms may involve both compressive and restrictive effects.

Growth impairment in children with atrophic autoimmune thyroiditis and pituitary hyperplasia.

Atrophic autoimmune thyroiditis (AAT) is a rare phenotype of autoimmune thyroiditis (AT) in pediatric age. AAT occurs without thyroid enlargement leading to a delay in its diagnosis. Growth impairment is infrequent in autoimmune thyroiditis, if timely diagnosed. Prolonged severe hypothyroidism is a rare cause of pituitary hyperplasia (PH) in childhood. Loss of thyroxine negative feedback causes a TRH-dependent hyperplasia of pituitary thyrotroph cells resulting in adenohypophysis enlargement. A transdifferentiation of pituitary somatotroph cells into thyrotroph cells could explain growth failure in those patients. Twelve patients were retrospectively evaluated at five Italian and Polish Centres of Pediatric Endocrinology for height growth impairment. In all Centres, patients underwent routine clinical, biochemical and radiological evaluations. At the time of first assessment, the 75% of patients presented height growth arrest, while the remaining ones showed growth impairment. The study of thyroid function documented a condition of hypothyroidism, due to AT, in the entire cohort, although all patients had no thyroid enlargement. Thyroid ultrasound showed frankly atrophic or normal gland without goiter. Cerebral MRI documented symmetrical enlargement of the adenohypophysis in all patients and a homogeneous enhancement of the gland after the administration of Gadolinium-DPTA. Replacement therapy with levothyroxine was started and patients underwent close follow-up every 3 months. During the 12 months of follow-up, an improvement in terms of height growth has been observed in 88% of patients who continued the follow-up. Laboratory findings showed normalization of thyroid function and the control brain MRI documented complete regression of PH to a volume within the normal range for age and sex. This is the largest pediatric cohort with severe autoimmune primary hypothyroidism without goiter, but with pituitary hyperplasia in which significant growth impairment was the most evident presenting sign. AAT phenotype might be correlated with this specific clinical presentation. In youths with growth impairment, hypothyroidism should always be excluded even in the absence of clear clinical signs of dysthyroidism.

FRI271 A Case Of Autoimmune Polyglandular Syndrome Type 2 Presenting With Cardiac Symptoms

Abstract Disclosure: J. Lin: None. C. Lee: None. A.R. Crawford: None. C. Taub: None. Autoimmune polyglandular syndrome type 2 (APS 2) is characterized by the combination of autoimmune adrenal insufficiency with autoimmune primary hypothyroidism, and/or type 1 diabetes mellitus, as well as other autoimmune conditions. The estimated prevalence is reported to be 1.4-4.5 cases per 100,000 persons. Presenting symptoms are often nonspecific, leading to delayed diagnosis; however, manifestations can sometimes become rapidly life-threatening. Cardiac symptoms, rare but clinically significant, can be the first presentation for APS 2. 34 year old male with history of asthma presents with nausea and chest pain, found to have pericarditis that was complicated by pericardial tamponade and cardiogenic shock requiring emergent pericardiocentesis and mechanical support with veno-arterial extracorporeal membrane oxygenation. Stress dose steroids were given due to concern for fulminant myocarditis. His condition improved with glucocorticoid treatment, but the etiology of his acute decompensation was unclear. He completed the prednisone taper before discharge and was started on amiodarone for atrial flutter. He presented with recurrent symptoms a week later. Cardiac MRI showed pericarditis without myocarditis. PET scan showed pericardial inflammation without evidence of malignancy or vasculitis. Broad infectious workup including viral studies was negative. An extensive biochemical workup showed low serum aldosterone and high renin activity while on prednisone. Autoimmune workup was positive for 21-hydroxylase antibody, thyroid peroxidase antibody, and homozygous for celiac HLA DQ8, suggestive of APS 2. Patient was started on levothyroxine for subclinical hypothyroidism with TSH >20. Interleukin blockade with anakinra was initiated, and patient was discharged with 25mg of daily prednisone pending insurance authorization for anakinra. A month later, patient re-presented with pericarditis. Patient received stress dose steroids, and was started on fludrocortisone. Levothyroxine was stopped because of amiodarone induced thyrotoxicosis. Patient was discharged on a prednisone taper regimen, and anakinra was approved a month later. Few case reports have described the association between APS 2 with pericardial tamponade. In healthy patients presenting with unexplained pericarditis, autoimmunity should be considered as a differential diagnosis as it can rapidly become life-threatening requiring urgent intervention. It is important to recognize for these patients, they are at risk for recurrent pericarditis and cardiac tamponade. Presentation: Friday, June 16, 2023

Hemorrhagic Cerebrovascular Disease

Introduction: Stroke is a major cause of morbidity and mortality worldwide, with hemorrhagic stroke being the deadliest form of acute stroke. Therefore, the cause of the event should be determined to direct the associated therapy and take preventive measures. Hyperhomocysteinemia has been described as a rare etiology of stroke. Although hyperhomocysteinemia has been associated with venous thrombotic events, altered endothelial function, and procoagulant states, its clinical role in stroke remains controversial. Case description: We present a case of a 60-year-old male patient with primary autoimmune hypothyroidism who presented with dysarthria, facial paresis, and left upper-limb monoparesis after sexual intercourse. A simple skull computed tomography scan showed hyperintensity in the right basal ganglion, indicating an acute hemorrhagic event. Etiological studies were performed, including ambulatory blood pressure monitoring, cerebral angiography, and transthoracic echocardiogram, which ruled out underlying vascular pathology. During follow-up, vitamin B12 deficiency and hyperhomocysteinemia were detected, without other blood biochemical profile alterations. Supplementation was initiated, and homocysteine levels gradually decreased, without new neurological deficits observed during follow-up. Conclusion: Quantification of homocysteine should be considered in patients with a cerebrovascular disease without apparent cause, as documenting hyperhomocysteinemia and correcting its underlying etiology are essential not only for providing appropriate management but also for preventing future events.

Fatal bleeding and thrombosis in a patient with autoimmune primary hypothyroidism

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

“White knight,” “giraffe hide,” and “Swiss cheese” appearance

Sir, Recently, four women, being treated with levothyroxine sodium tablet for primary autoimmune hypothyroidism, were referred to us for further evaluation of “suspicious” features, detected on thyroid ultrasonography (USG). The first woman had one small hyperechoic space-occupying lesion (SOL) [Figure 1a], while the second woman had a larger SOL with similar appearance [Figure 1b and c]. Multiple echogenic nodules were noticed in the third patient [Figure 1d and e], while the fourth patient demonstrated multiple hypoechoic areas scattered throughout the gland [Figure 1f and g]. Thyroid glands were enlarged in all of them with lobular surfaces, and USG-guided fine-needle aspiration cytology (FNAC) was suggestive of chronic lymphocytic thyroiditis (CLT).Figure 1: USG appearances of the patients. (a) (Patient 1): Sagittal view showing hypoechoic gland with a small “white knight” nodule (black arrow). Note the heterogeneous appearance of the gland and the linear hyperechoic lines (represents fibrous bands). (b) (Patient 2): Sagittal view showing large “white knight” nodule (white arrow). (c) (Patient 2): Transverse view showing the same “white knight” nodule (white arrow) in the left lobe. Note the isoechoic nodule in the right lobe (notched white arrow) in the background of hypoechoic gland. (d and e) (Patient 3): Transverse and sagittal views showing focal hypoechoic area (notched white arrow in d) and “giraffe hide” pattern (e). (f and g) (Patient 4): Sagittal view showing the “Swiss cheese” pattern. USG: UltrasonographyCLT, also termed as chronic Hashimoto’s thyroiditis, is the most common etiology of primary hypothyroidism worldwide. The pathological hallmark of CLT is lymphocytic (B-cells and cytotoxic T-cells) infiltration of the thyroid gland; the degree of glandular involvement depends on the stage of the disease. The thyroid gland in CLT typically is diffusely enlarged without any palpable nodule. However, heterogeneous and patchy involvement produces regional parenchymal distortion resulting in a lobular or nodular appearance leading to ultrasonographic evaluation of the thyroid gland. USG in such glands often detects one or more “pseudonodule(s).” Normal thyroid parenchyma appears homogeneously hyperechoic compared to the surrounding strap muscles of the neck. Areas of lymphocytic infiltration appear hypoechoic compared to normal thyroid parenchyma. The thyroid gland in CLT usually has heterogeneous echotexture on USG; regions of lymphocytic infiltration appear hypoechoic, unaffected islands of thyroid parenchyma demonstrate normal echogenicity, and early fibrosis appears as linear echogenic bands. However, the sonological appearance in CLT varies, and the characteristic pattern recognition obviates unnecessary FNAC. A solitary, well-circumscribed, homogenous, markedly hyperechoic nodule of varying size, without internal vascularity, cystic degeneration, or calcifications termed “white knight” nodule [Figure 1a-c], may occasionally be encountered in such patients. Present on a background of a hypoechoic gland, these nodules seem to be regenerative nodules of CLT. Despite its remarkable appearance, such a nodule is considered benign and does not merit further evaluation.[1,2] When multiple echogenic nodules (represents uninvolved areas with normal follicular structure) dispersed across the gland are separated from one another by bands of hypoechogenicity, the ultrasound appearance is called “giraffe hide” (1E), reminiscent of giraffe’s skin. This distinctive pattern is always benign and characteristic of CLT.[1,2] Although the reverse pattern, i.e., multiple hypoechoic areas (represents aggregates of lymphocytes) with ill-defined margins surrounded by echogenic areas of thyroid parenchyma or fibrosis, more closely resembles giraffe skin, which consists of dark areas surrounded by bright lines, the term “giraffe hide” pattern was originally described for the former one. The later pattern, however, is also a characteristic of CLT. More discrete aggregates of lymphocytes appear as discrete focal hypoechoic regions on the background of an echoic gland. Numerous such well-defined hypoechoic areas give the gland a “Swiss cheese” appearance [Figure 1f and g], similar to the holes in Swiss cheese. Once these small hypoechoic areas become almost confluent and there is marked fibrosis with very little parenchyma separating the hypoechoic tissue, the appearance is called “honeycomb” variant. The vascular pattern distinguishes these hypoechoic “pseudonodules” from thyroid nodules. These hypoechoic areas do not demonstrate vascular flow, whereas vascular flow is seen over the isoechoic normal thyroid parenchyma, especially along the areas of fibrosis. The decision for FNAC from a thyroid nodule depends on the size of the nodule and the American College of Radiology (ACR) Thyroid Imaging, Reporting and Data System (TI-RADS) staging.[3] However, the ACR TI-RADS classification does not consider these patterns. Recognition of such characteristic morphologic patterns substantially decreases the number of unnecessary invasive interventions. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

A massive ovarian cyst masquerading as malignancy in unrecognised primary hypothyroidism

We report here probably a huge ovarian cyst of size 7.9x16.4x23 cms which regressed on thyroxine therapy with severe autoimmune primary hypothyroidism in a young woman. It is necessary to consider hypothyroidism and other endocrine disorders in the differential diagnosis of adult patients with ovarian multiple cyst formation in order to prevent inadvertent ovarian surgery.

A case with primary autoimmune hypothyroidism causing pituitary enlargement mimicking pituitary macroadenoma and secondary adrenal insufficiency

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Abstract #1176320: Graves orbitopathy in a patient with primary autoimmune hypothyroidism

Graves’ disease is characterized by hyperthyroidism, ophthalmopathy and dermopathy. Orbitopathy is rarely seen with primary hypothyroidism or an euthyroid state. We present a patient with bilateral exophthalmos in the presence of primary autoimmune hypothyroidism.

Association between thyroid autoimmunity and ovarian reserve in women with hypothyroidism

BackgroundThe ovarian function and therefore the ovarian reserve may be compromised by the pathogenesis of autoimmune diseases of which, Hashimoto’s thyroiditis (HT) is the most common in women of reproductive age. Furthermore, a prolonged reduction in thyroid hormone concentration results in a broad spectrum of reproductive alteration. Previous reports in the literature have been controversial regarding the impact of hypothyroidism and alterations in the ovarian reserve. Thus, this prospective and comparative study aimed to evaluate the association of hypothyroidism with low ovarian reserve.Materials and MethodsA subset of 27 patients with primary autoimmune hypothyroidism were compared to healthy women. The ovarian reserve was assessed through the anti-Mullerian hormone (AMH) and the antral follicle count (AFC).ResultsOverall, the two groups did not display significant differences in length of their menstrual cycles neither in the AMH serum levels nor the AFC.ConclusionsNo significant alteration was found in the ovarian reserve of women with HT.

Thyrotropin Secreting Adenoma in a Patient with Autoimmune Hypothyroidism: Case Report of a Challenging Diagnosis

Clinical presentation: We describe a case of a 47-year-old woman with a longtime primary autoimmune hypothyroidism with a progressive rising of TSH levels despite increasing of LT4 therapy. LT4 dose was increased up to 2.9 mcg/kg/day causing an excess of circulating fT4 a minor increase of fT3 concentrations without, however, achieving TSH normalization. The patients was asymptomatic and during the long observation period she had two term pregnancies. A withdrawal of thyroid hormone replacement therapy appropriately induced a further increase of TSH levels and a decrease of fT3 and fT4 below the normal range. LT4 therapy was then resumed and, because TSH levels failed to normalize, central hyperthyroidism or thyroid hormone resistance were suspected. Thyroid levels of first grade relatives were normal, and TSH response to TRH was positive, leaving the diagnosis unclear. The magnetic resonance imaging (MRI) of sellar region revealed a pituitary macroadenoma. The remaining pituitary function was normal. The patient underwent transphenoidal surgery (TNS) and histological examination showed positive immunostaining for TSH, and a mild positivity for GH. After surgery, TSH levels quickly fall down and her replacement therapy could finally be optimized.

SUN-290 Pituitary Hyperplasia Due to Uncontrolled Primary Hypothyroidism: Case Series and Literature Review

Background: Pituitary hyperplasia secondary to primary hypothyroidism results from the loss of thyroxine feedback inhibition and the subsequent overproduction of TSH. Case 1: A 18-year-old female presented with a chronic history of spontaneous galactorrhea, headache and malaise. Autoimmune primary hypothyroidism was diagnosed, with elevated TSH of 490 mIU/L (0.3-5) and low fT4 of 0.33 ng/dL (0.63-1.34). Pituitary MRI showed an enlarged pituitary with compression of the optic chiasm. Hormonal replacement with levothyroxine 75 mcg qd was started. Five months later she was asymptomatic, and normal TSH (1.64 mIU/L) and fT4 (0.9 ng/dL) levels. A new MRI revealed normal size of pituitary gland, with no compression of the optic chiasm and an intact infundibulum. Case 2: A 24-year-old female with type 1 diabetes and autoimmune primary hypothyroidism, presented with a five-year history of galactorrhea and oligomenorrhea. She was treated with insulin glargine 20U qd, and levothyroxine 200 mcg/day. However, patient’s adherence was bad. She consulted a primary health physician who suspected a prolactinoma after high prolactin levels (77.65, normal 2.64-13.13 ng/mL). Cabergoline was started without any clinical improvement. She then was referred to our service for follow-up. TSH results showed 500 mIU/L, with low fT4 (0.08 ng/dL). Prolactin levels was normal. Pituitary MRI revealed diffuse enlargement of the gland, with compression of infundibulum and optic chiasm. Treatment was modified to levothyroxine/liothyronine 100/20mcg 1 ½ tablet qd. After 7 months, we confirmed normal TSH (0.76 mIU/L) and fT4 (1.23 ng/dL), and the patient was asymptomatic. After 17 months, new MRI showed normal pituitary gland without any compression. Case 3: A 23-year-old female with a history of Addison′s disease and hypothyroidism diagnosed at age 17 presented with a 6-month history of somnolence, fatigue, headache and amenorrhea. She was previously treated with hydrocortisone 25mg/day, fludrocortisone 0.1mg/day, and levothyroxine 200mcg/day. Patient’s adherence was bad, and multiple hospitalizations because of adrenal crises were reported. Her initial hormonal evaluation revealed high TSH of 460 mIU/L and low fT4 of 0.25 ng/dL, mild hyperprolactinemia (32.16 ng/mL), and very high ACTH levels (2,700 pg/mL, normal 10-100). Pituitary MRI revealed an enlarged pituitary with mild compression of the optic chiasm. Hormonal replacement was modified to fasting levothyroxine alternating 200mcg and 300mcg qd. Her last follow-up showed normal TSH (0.53 mIU/L) and fT4 (1.18 ng/dL) levels. New MRI showed normal pituitary size Conclusion: We presented three young women, with autoimmune hypothyroidism, who developed pituitary hyperplasia and responded to proper hormonal replacement normalizing pituitary size. Reference: Endocrinol Diabetes Metab Case Rep. 2015; 2015: 150056.

Perspective Summary of Brief Report on Thyroid Disease of Post Glaciations Quaternary Is Endocrinology of Ecology System in Centre Marc Sankale Setting in Dakar

Reflexions about immunoradiometric Tsh and Trh test during on Optimal thyroid hormonal therapy (Optimal dosages and overdosages) as Pionnary Auto-immune Primary Hypothyroidism in Dakar [Senegal] gives us A Propose of Whitaker Syndrome Case Report and THYROID GLAND AND ITS PEPTIDES OR ACTUALITYOF GENERAL ENDOCRINOLOGY. Many peptides by their cell molecular metabolism in the thyroid gland are involved: mutations of TSH receptor is linked to hormone resistance with congenital hypothyroidism; a new oroxigenic peptide, Ghrelin is widespread in endocrine tissues; tachykinine is another novel peptide with endocrine paracrine effect. PTTG and FGF-2 are prognostic markers of differentiated cancers; CRIF1 is a novel protein of nucleus interacting with Gadd45 and could negatively regulate cycle cell progression and cell growth; mutations of RET protooncogene is now the best CMT biomarker in the place of calcitonin in addition with CGRP, CGRPβ and Amylin; regulating proteins of CAMP, protein G, Gi alpha 1, MAL proteolipid are identified near immunologic antigens involved in Grave’s disease, autoimmune polyendocrinopathies. These peptides by their diversity of function support the concept of general endocrinology equivalent of medical sciences. Bastenie P. A. classification is a bio-clinical semeiology that could be reviewed by doing the integration of obesity as the incipient stage of epigenetic thyroid turnover of deiodinase realizing an inactive TSH. Thus primary hypothyroidism in an historical-technically point of view can recognize since Bastenie: -1 Atrophic thyroid myxedema with: low T4 and low T3 and High TSH and TRH positive. -2 Mild hypothyroidism where only TSH is High and TRH Test positive. -3 Infra-clinic hypothyroidism where only TRH Test is positive. -4 Compensated thyroiditis where only auto-antibodies are positive. -5 Common obesity where deiodinase turnover is only disturbed. Iodine regulates nutritional metabolism probably via the microbiome. Thyro-diabetes has concerned clinicians. Endocrine disruptors have come to recall us if necessary that thyroid gland is a gate keeper of the environment which in our approach is the testimony of primordial role of mineral iodine in the majority of living beings. Here are the perspectives of General Practitioner of Endocrine Diseases and Clinical Medicine Department.

Physician Perception and Patient Input Are Important Influences in the Treatment of Hypothyroidism

Physician Perception and Patient Input Are Important Influences in the Treatment of Hypothyroidism

SUN-551 Massive Pericardial Effusion Complicating Systemic Lupus Erythematosus and Autoimmune Hypothyroidism: A Case Report

Background: The presence of autoantibodies is a mutual ground for Systemic Lupus Erythematosus (SLE) and Autoimmune Hypothyroidism (AH). Pericardial effusion (PEEF) is a common manifestation for each disease condition however massive PEEF especially with tamponade is a rare occurrence. The coexistence of SLE and AH causing massive PEEF is even rarer and only few cases have been reported. This presents as a diagnostic dilemma whether the massive PEEF is primarily driven by SLE, AH or is it a synergistic effect of both. Clinical Case: A case of a 54-year-old female, hypertensive, non-diabetic diagnosed previously with primary hypothyroidism came in with progressive dyspnea. She has been non-compliant to levothyroxine therapy for 1 year. Upon presentation at the Emergency Department, she was noted to be overtly hypothyroid. Thyroid panel was consistent with primary AH: elevated TSH = 95.66 uIU/mL (NV=0.35-4.94), low FT3 = <1 pg/mL (NV=1.71-3.71), low FT4 = <0.4 ng/dL (NV=0.7-1.48) and elevated anti-TPO = 770.9 IU/mL (NV=<9.0). Ultrasound of the thyroid showed non-uniform echopattern. Pertinent physical findings were an elevated JVP and muffled heart sounds but with stable blood pressure. A 2-dimensional echocardiogram (2D-Echo) confirmed the presence of massive PEEF with doppler evidence of beginning tamponade. Other laboratory findings were anemia, leukopenia, albuminuria and high creatinine level. With this unusual clinical presentation, SLE as a secondary cause of PEEF was entertained. ANA at 1:320 with speckled pattern as well as anti-dsDNA at 516.25 IU/ml (NV=<0-200) were both positive with low complement factor 3 level (C3) = 0.89 g/L (NV=0.9-1.8) fulfilling the Systemic Lupus International Collaborating Clinics (SLICC) criteria for SLE. The patient was given levothyroxine and prednisone for primary hypothyroidism and SLE, respectively. There was then gradual improvement of symptoms with a decrease in the PEEF on repeat 2D-Echo. She was noted to be clinically stable on subsequent follow-ups with further resolution of the massive PEEF. Conclusion: This was a rare case of SLE and AH causing massive PEEF with beginning tamponade which was successfully managed medically. This gave us valuable insight that massive PEEF occurring in hypothyroidism may be secondarily caused by other co-existing disease entities. Although it remained to be a diagnostic dilemma whether the massive PEEF was primarily because of SLE or AH or an effect of both, this case offered another opportunity to further explore the relationship of AH and connective tissue diseases such as SLE.

SAT-085 Severe Dyslipidemia Secondary to Autoimmune Hypothyroidism: A Case Report

Background: Up to 28% of patients have an underlying potential secondary cause for dyslipidemia. Frequently, the treatment of the underlying cause can lead to normalization of lipid profile. Case report: A 34-year-old male presented with a 12-months history of asthenia, facial swelling, cold intolerance, sleepiness, poor concentration, but stable weight. Physical examination highlighted bilateral palpebral edema. His past medical history was significant for mixed dyslipidemia at least for 2 years (total cholesterol [TC] 326 mg/dL, high-density lipoprotein cholesterol [HDL-C] 84 mg/dL, low-density lipoprotein cholesterol [LDL-C] 199 mg/dL and triglycerides [TG] 211 mg/dL), but no secondary causes of dyslipidemia were excluded, namely hypothyroidism, neither treatment was instituted. He also had overweight (body mass index [BMI] of 29 kg/m2) and hepatic steatosis. There was no familial history of dyslipidemia. Laboratory assessment revealed TC 426 mg/dL, HDL-C 89 mg/dL, LDL-C 293.6 mg/dL, TG 217 mg/dL, thyroid-stimulating hormone (TSH) > 100 μUI/mL (reference: 0.550-4.780), free thyroxine (FT4) < 0.3 ng/dL (reference: 0.70-1.58), free triiodothyronine (FT3) < 0.195 pg/mL (reference: 1.71-3.71), positive thyroglobulin antibody and negative peroxidase antibody. Thyroid ultrasonography showed a normal size gland, with heterogeneous texture and pseudonodular areas, without nodular lesions, suggesting thyroiditis. Given the diagnosis of primary autoimmune overt hypothyroidism and mixed dyslipidemia, the patient was given oral levothyroxine up to 137 μg/day and atorvastatin 10 mg/day. After normalization of thyroid function by treatment with levothyroxine, there was an important improvement in overall well-being and in the lipid profile (TC 184 mg/dL, HDL-C 46 mg/dL, LDL-C 115 mg/dL, TG 113 mg/dL), leading to statin withdrawal. Conclusion: This case highlighted a severe dyslipidemia secondary to overt autoimmune hypothyroidism in a young male. The delayed diagnosis of hypothyroidism could have been avoided if a secondary cause for dyslipidemia was initially suspected. Secondary causes of dyslipidemia, namely hypothyroidism, should be considered and excluded in any young patient with no or few risk factors.

SUN-547 Primary Autoimmune Hypothyroidism Presenting with Sleep Apnea and Recurrent Episodes of Rhabdomyolysis in a Pediatric Patient: A Case Report

Background: Hypothyroid myopathy has different presentations including rhabdomyolysis, Hoffman’s syndrome, acute compartment syndrome and Kocher-Debre-Semelaigne syndrome, with most cases being reported in adults. Rarity of this condition in pediatric population, leads to delay in diagnosis of underlying hypothyroidism in children with myopathy. Pathophysiology is not fully understood but is known to occur due to deposition of glycosaminoglycans, poor contractility of actin-myosin units, low myosin ATPase activity, and low ATP turnover in skeletal muscle [1].Treatment with thyroxine replacement results in resolution of myopathy. Clinical Case: A 13-year-old female presented to the emergency department with 4 weeks of intermittent abdominal pain. She reported history of strenuous exercise but denied any exposure to medications. Workup revealed elevated creatine kinase of 2411 units/L ( 21-232 units/L) and creatinine 1.2 mg/dL (0.3-1.0 mg/dL). Creatinine kinase level came down to 1891 units/L after two days of IV hydration and she was discharged with diagnosis of viral or exercise induced rhabdomyolysis. Four weeks later patient returned due to worsening edema and six pound weight gain. Workup revealed elevated creatine kinase 7936 units/L. Thyroid function studies obtained showed an elevated TSH 318 microIU/mL (0.40-5.34 microIU/mL), low Free T4 level 0.13 ng/dL (0.65-2.30 ng/dL), low total T4 0.5 mcg/dL (5.6-14.4 mcg/dL), positive titers of thyroid peroxidase antibody 642 IU/ml (0.0-9.0 IU/mL) and thyroglobulin antibody 2.3 IU/mL (0.0-1.0 IU/mL). Further history revealed fatigue, academic decline and polysomnograpy confirmed obstructive sleep apnea a couple of months prior to presentation. Levothyroxine replacement therapy was initiated at 25 mcg and dose was slowly increased over several weeks. 3 months later TSH level was 38.76 microIU/mL, Free T4 level normalized at 0.9 ng/dL and creatine kinase level normalized at 91 units/L (<143 units/L). Patient reported resolution of her myopathic symptoms and sleep apnea. Conclusion: This is first pediatric case report of rhabdomyolysis and sleep apnea due to hypothyroidism. Hypothyroidism should be considered in the differential diagnosis of rhabdomyolysis, especially if etiology of myopathy is unknown. Prompt thyroxine replacement can prevent further episodes of rhabdomyolysis and in this case also prevented long term complications and morbidity associated with sleep apnea.

Emergence of a latent TSHoma pituitary macroadenoma on a background of primary autoimmune hypothyroidism

SummaryThe coexistence of primary hypothyroidism and thyroid-stimulating hormone (TSH)-stimulating pituitary macroadenoma can be a rare occurrence and can make diagnosis very challenging. We describe a case of a 44-year-old female with a history of fatigue, poor concentration, weight gain and amenorrhoea together with biochemical evidence of primary autoimmune hypothyroidism. Her initial TSH levels were elevated with low normal free thyroxine (T4) levels. Levothyroxine treatment was initiated and the dose was gradually titrated to supraphysiologic doses. This led to the normalisation of her TSH levels but her free T4 and triiodothyronine (T3) levels remained persistently elevated. This prompted a serum prolactin check which returned elevated at 2495 µ/L, leading onto pituitary imaging. A MRI of the pituitary gland revealed a pituitary macroadenoma measuring 2.4 × 2 × 1.6 cm. Despite starting her on cabergoline therapy with a reduction in her prolactin levels, her TSH levels began to rise even further. Additional thyroid assays revealed that she had an abnormally elevated alpha subunit at 3.95 (age-related reference range <3.00). This corresponded to a thyroid-secreting hormone pituitary macroadenoma. She went on to have a transphenoidal hypophysectomy. Histology revealed tissues staining for TSH, confirming this to be a TSH-secreting pituitary macroadenoma. This case highlighted the importance of further investigations with thyroid assay interferences, heterophile antibodies, alpha subunit testing and anterior pituitary profile in cases of resistant and non-resolving primary hypothyroidism.Learning points:Levothyroxine treatment in primary hypothyroidism can potentially unmask the presence of a latent TSH-secreting pituitary macroadenoma, which can make diagnosis very challenging.A high index of suspicion should prompt clinicians to further investigate cases of primary hypothyroidism which despite increasing doses of levothyroxine treatment with normalisation of TSH, the free T4 and T3 levels remain persistently elevated.Clinicians should consider investigating for adherence to levothyroxine, thyroid assay interference, heterophile antibodies, TSH dilution studies, alpha subunit and anterior pituitary profile testing to further clarity the diagnosis in these patients.Although coexistent cases of TSHoma with primary hypothyroidism are rare, it should always be in the list of differential diagnoses in cases of unresolving primary hypothyroidism.

Comparison of three competitive immunoassays for measurement of TSH receptor antibodies in patients with Graves’ disease

Thyrotropin (TSH) receptor antibodies (TRAb) mediate the hyperthyroidism of Graves’ disease (GD). The aim of the study was to compare the diagnostic performance and assay agreement between three immunoassays for the measurement of TRAb in patients with newly diagnosed GD. TRAb was measured with three different assays [H-TRAb (BRAHMS Diagnostica), M22-Man (RSR Limited) and M22-Aut (Roche Diagnostics)] in 387 participants who were recruited from two Danish population-based studies and diagnosed with GD (n = 101), multinodular toxic goitre (n = 88), primary autoimmune hypothyroidism (n = 100) or included as controls (n = 98). Coefficient of variation for duplicate measurements with each of the three assays were H-TRAb: 3.6%, M22-Man: 9.4%, M22-Aut: 7.7%. Frequency of TRAb positivity in patients with GD were H-TRAb: 95%, M22-Man: 94%, M22-Aut: 96%. Receiver operating characteristic analysis revealed a high sensitivity (H-TRAb: 95%, M22-Man: 93%, M22-Aut: 95%) and specificity (H-TRAb: 99%, M22-Man: 99%, M22-Aut: 97%) for the diagnosis of GD with all assays. Comparison of TRAb levels showed inter-assay variability and values were considerably lower with the M22-Man assay. All TRAb assays showed a high diagnostic performance for GD, but a high inter-assay variability was observed limiting the use of different assays in clinical monitoring of patients with GD.