Thyroid Function Test Results Research Articles

Langerhans cell histiocytosis of the thyroid gland

Objectives A case is reported in which Langerhans cell histiocytosis was found in the thyroid gland. Although the thyroid gland is frequently affected with multiple common diseases, a search of the English language literature suggests that Langerhans cell histiocytosis in the thyroid gland is rarely reported. Study Design The study design was of a case report and literature review. Setting Academic tertiary referral practice. Methods A case was reported, and the literature was reviewed. Results A 31-year-old woman presented with an enlarged, diffusely firm, nontender, nonmobile, and not particularly nodular thyroid gland with mild compressive symptoms. She had intermittent skin papules and 1 episode of gingival ulceration. Ultrasound showed diffusely, hypoechoic thyroid with dimensions of 36 × 20 × 16 mm on the right and 36 × 16 × 17 mm on the left. No distinct nodules were noted, and thyroid function test results were normal. Laboratory testing for autoimmune abnormalities of the thyroid was negative for antithyroid peroxidase, antiparietal cell, and anti–smooth muscle cell antibodies. She tested positive for serum antithyroglobulin antibodies. A computed tomographic scan demonstrated abnormal low attenuation of her thyroid gland without any distinct nodules or masses. A fine-needle aspiration and core biopsy confirmed the diagnosis of Langerhans cell histocytosis. Dissection was technically challenging because of the firm and nonmobile lobes. Densely adherent strap musculature was encountered bilaterally, and the rare presence of a nonrecurrent laryngeal nerve was noted on the right. Histologically, thyroid parenchyma was largely obliterated by a diffuse infiltrate of mononuclear spindled to epithelioid histiocytes with few residual thyroid follicles. These histiocytes had moderate to abundant pale to eosinophilic cytoplasm, and some had prominent nuclear grooves and indentation/clefts, consistent with Langerhans histiocytes. Plasma cells and lymphocytes were sparsely dispersed. Immunohistochemistry showed that these histiocytes were positive for S-100, and rare lesional histiocytes were also positive for CD1a. Eosinophils were not readily identified in this lesion. Conclusions Langerhans cell histiocytosis in the thyroid gland is a rarely reported disease, with controversy over its management. This disease should be considered in the differential diagnosis of a diffusely irregular and firm thyroid gland, and multidisciplinary team cooperation is important for its diagnosis and management.

Atrial Fibrillation Induced by Post-Parathyroidectomy Transient Thyrotoxicosis

We describe a 59-year-old Japanese woman with post-parathyroidectomy transient thyrotoxicosis and atrial fibrillation. She underwent parathyroidectomy for secondary hyperparathyroidism due to chronic renal failure. Three days after surgery, she complained of palpitation and chest pain due to atrial fibrillation. Results of thyroid function tests were compatible with thyrotoxicosis. Twelve days after parathyroidectomy, the elevated level of free thyroxine decreased spontaneously to the normal range. These features were compatible with post-parathyroidectomy transient thyrotoxicosis. No further recurrences of thyrotoxicosis or atrial fibrillation were observed for one year. This is the first report of atrial fibrillation induced by post-parathyroidectomy transient thyrotoxicosis.

Atrial Fibrillation due to Late Amiodarone-Induced Thyrotoxicosis

A 60-year-old male patient complaining of palpitations, fatigue, weakness and weight loss of 1 month's duration was hospitalized in our cardiology department for atrial fibrillation. Thyroid function test results were compatible with thyrotoxicosis. The patient had been taking amiodarone for 2.5 years for hypertrophic obstructive cardiomyopathy and non-sustained ventricular tachycardia episodes. However, amiodarone had been discontinued after follow-up examinations revealed that the patient's ventricular arrhythmias were no longer present, and he had been taking metoprolol only for the preceding 6 months. In this patient, amiodarone-induced thyroiditis had developed 6 months after cessation of treatment, demonstrating that adverse effects may occur after discontinuation of amiodarone. Detection of the condition requires assessment of thyroid function before treatment initiation, during treatment and at regular intervals after treatment cessation. The type of hyperthyroidism induced by amiodarone cannot be determined in most cases. Patients with this condition should be referred to an experienced endocrinologist. Our case of delayed amiodarone-induced thryoiditis occcurred approximately 6 months after termination of amiodarone treatment.

口底部異所性甲状腺の１例

We report a 61-year-old man with ectopic thyroid tissue in the left side of the oral floor. He had a painless and elastic hard mass suspected to be a sublingualgland tumor in the left side of the floor of the mouth. On MRI, the mass clearlyshowed low density areas on T1 and T2 images. On dynamic studies, the mass was enhanced in the early stage, suggesting a malignant tumor. On plain CT, however, the lesion was high density as compared with the muscles, and there was no thyroid gland in the normal position. Then, thyroid scintigraphy (99mTc O4-, 201T1-Cl, and 123I) was performed and confirmed that there was no uptake in the neck, but in the left side of oral floor. Thyroid function test results were within the normal range. We diagnosed the mass to be ectopic thyroid tissue. This patient was followed without treatment for about 3 years.

Diagnosing unsuspected hypopituitarism in adults from suggestive thyroid function test results

The typical pattern of thyroid function tests (TFTs) associated with hypopituitarism consists of subnormal free T4 (fT4) or total T4 and normal or marginally elevated thyroid-stimulating hormone (TSH). A previous study calculated an incidence of hypopituitarism of 3.2 cases/100,000/year by following up abnormal TFTs. The aim of this study was to verify the incidence of unsuspected hypopituitarism diagnosed by reflective testing on such samples in a Scottish population. Prospective audit of TFT results over 15 months. Individuals with suitable results (fT4 < 9 pmol/L, TSH < 10 mU/L) were identified by the laboratory information system at the Biochemistry Department, Glasgow Royal Infirmary, serving a population of 200,000. fT4 (repeat analysis following assay recalibration), total T3, testosterone (males), luteinizing hormone, follicle-stimulating hormone, prolactin and cortisol were analysed on appropriate samples. Three hundred and eleven suitable results from 266 adult individuals were identified from a total of 73,650 TFT results, leading to the diagnosis of 10 new cases (age range 28-90 years) of hypopituitarism (approximately 4 cases/100,000/year). Nine patients now attend endocrine clinics. Pituitary imaging was abnormal in five cases (2 large pituitary tumours, one macroadenoma, 2 empty sellae), normal in three cases and two patients were not scanned. A significant number of cases of unsuspected hypopituitarism can be diagnosed by reflective testing on appropriate samples. fT4 should be an integral part of frontline TFTs as TSH alone cannot assist in the identification of possible hypopituitarism. Laboratories are in an excellent position to assist in early identification of hypopituitarism, which may lead to improved outcomes in such patients.

Graves' Disease with Intractable Diarrhea, Chylous Ascites, and Chylothorax: A Case Report

A 50-year-old woman was admitted to our hospital because of severe diarrhea, irritableness, and severe pitting edema of the legs. The patient had been well until 5 years before admission, when a tremor and tachycardia developed and a diagnosis of Graves' disease was made. Treatment with methimazole was effective in reducing her tremor and tachycardia; however, she was often nonadherent with her antithyroid medication because of improvement of her symptoms. On admission, a thyroid swelling, exophthalmos, a pleural effusion, and ascites were observed. The results of thyroid function tests (free triiodothyronine: 21.5 pg/mL; free thyroxine: 7.17 ng/dL; thyroid-stimulating hormone (TSH): <0.01 microIU/mL; TSH receptor antibodies: 95.9%) were consistent with Graves' disease. Biochemical analysis of pleural and ascitic fluid was consistent with chylothorax and chylous ascites, respectively. Serum calcium, total protein, and albumin were very low. Her symptoms and signs except severe diarrhea, edema, pleural effusion, and ascites disappeared after receiving intravenous drip infusion of fluid replacement, and methimazole and iodine. Because of malnutrition, she was given a high-calorie intravenous infusion. Three months after admission, her pleural effusion and ascites began to improve, as did her diarrhea and hypoalbuminemia. An appropriate treatment of Graves' disease is crucial to avoid serious sequelae of longstanding, poorly controlled hyperthyroidism.

Second-Trimester Reference Intervals for Thyroid Tests: The Role of Ethnicity

Thyroid function changes during pregnancy, complicating the diagnosis of thyroid disorders. Maternal thyroid dysfunction has been associated with a variety of adverse outcomes. We evaluated thyroid function test results by ethnicity and week of gestation during the 2nd trimester of pregnancy. We collected 3064 blood specimens in serum tubes from Asians (13%), blacks (22%), Hispanics (23%), and whites (42%). We measured thyroid-stimulating hormone (TSH), total and free thyroxine (TT4 and FT4), total and free triiodothyronine (TT3 and FT3), thyroglobulin autoantibodies (TgAb), and thyroid peroxidase autoantibodies (TPOAb) by use of an ARCHITECT i2000(SR) (Abbott Diagnostics). The TSH reference interval was calculated for samples negative for both TgAb and TPOAb and reference intervals for TT4, FT4, TT3, and FT3 in antibody-negative samples with normal TSH. Serum samples were positive for TgAb in 10.6%, 1.8%, 6.2%, 6.5%, and 5.9% of Asian, black, Hispanic, white, and combined groups, respectively. Samples were positive for TPOAb in 12.4%, 4.1%, 11.8%, 12.3%, and 10.4% of the same groups, respectively. The nonparametric reference intervals for all participants were 0.15-3.11 mIU/L (TSH), 9.3-15.2 pmol/L (0.72-1.18 ng/dL; FT4), 89.0-176.3 nmol/L (6.90-13.67 mug/dL; TT4), 3.82-5.96 pmol/L (2.48-3.87 pg/mL; FT3), and 1.82-3.68 nmol/L (118-239 ng/dL; TT3). Blacks had lower prevalences of TgAb and TPOAb positivity and of increased serum TSH. The prevalence of TgAb and TPOAb positivity was highest in Asians. Whites had the highest prevalence of increased TSH. The lower and upper reference limits of TT3 were significantly lower for Asians. Reference intervals for women in the 2nd trimester were different from those of nonpregnant individuals.

Diffuse Alopecia in a Child Due to Dietary Zinc Deficiency

A 4-year-old girl was evaluated for hair loss of a few weeks' duration. History of the present illness, medical history, and review of systems were obtained from the parents, who described progressive diffuse hair loss with hair dryness and brittleness, with no change in the child's eating habits or any other unusual symptoms. No fever, weight loss, diarrhea, vomiting, abdominal pain, chronic cough, dyspnea, change in appetite, change in bowel habit, or urinary symptoms were noted. On further questioning, her nutritional history revealed that she always favored cow's milk in her diet. The patient has been healthy with no significant medical history, surgical history, psychiatric history, or history of hospitalization. She was taking no medications. Her mother's pregnancy and the child's birth history were uneventful. The child was up-to-date on her vaccinations. Her physical examination showed a healthy-appearing child who was at 50% on the height chart and 70% on the weight growth chart. She was afebrile with a respiratory rate of 24 breaths per minute, pulse rate of 110 beats per minute, and pulse oximetry of 99% on room air. Skin examination revealed interstitial diffuse patchy alopecia with very dry hair and nonscarred, normal-appearing scalp. The hair pull test was normal, with 4 hairs extracted. Results of examination of her eyes (including visual acuity) and lungs were normal, and no abnormalities were found on heart, abdominal, musculoskeletal, and neurologic examinations. Laboratory workup showed normal electrolytes, blood urea nitrogen, creatinine, and blood sugar levels. Her complete blood cell count with differential was normal, ferritin concentration level was 110 ng/mL (reference, 40-200 ng/mL), iron level was 75 microg/dL (reference, 35-175 microg/dL), and total iron-binding capacity was 310 microg/dL (reference, 245-400 microg/dL). Levels of liver enzymes, total bilirubin, serum protein, and albumin were normal, as were the results of urinalysis. Thyroid function test results were normal and levels of vitamins A and D were also normal. Low levels of serum zinc were measured repeatedly at 48 and 61 microg/dL (reference, 66-144 microg/dL) at 2 different laboratories. She was started on zinc supplement (50 mg daily) for 6 months and her diet was modified. The hair loss stopped in 3 weeks. Follow-up in 4 months showed no evidence of alopecia, with normal-looking hair.

Thyroid Function Abnormalities in HIV-Infected Patients

Abnormal thyroid function test results are common among human immunodeficiency virus (HIV)-infected patients. Although the prevalence of overt thyroid disease does not appear to be significantly increased in HIV-infected patients, compared with the general population, specific patterns of abnormal thyroid function test findings are more frequently identified among HIV-infected patients. Among patients with advanced acquired immunodeficiency syndrome, nonthyroidal illness (i.e., euthyroid sick syndrome) is common. During antiretroviral therapy, the prevalence of 2 generally asymptomatic conditions (subclinical hypothyroidism, which is characterized by isolated elevated thyroid-stimulating hormone levels, and isolated low free thyroxine levels) is increased. In addition, Graves disease, which is marked by low thyroid-stimulating hormone and elevated thyroxine levels, may occur during immune reconstitution. Testing for thyroid disease among symptomatic patients should begin with measurement of the thyroid-stimulating hormone level. However, there is insufficient evidence to recommend routine thyroid screening of asymptomatic HIV-infected individuals. This review summarizes the current evidence regarding the optimal laboratory evaluation of thyroid function; highlights the causes, presentation, and treatment of thyroid dysfunction in HIV-infected patients; and discusses the controversies regarding screening.

Hypothyroidism in Patients With Metastatic Renal Cell Carcinoma Treated With Sunitinib

Sunitinib is an inhibitor of the vascular endothelial growth factor and platelet-derived growth factor receptors, and it has antitumor activity in metastatic renal cell carcinoma and gastrointestinal stromal tumors. To further investigate the fatigue associated with sunitinib therapy, thyroid function tests were performed on patients with metastatic renal cell carcinoma who were receiving sunitinib. Seventy-three patients with metastatic renal cell carcinoma were treated with sunitinib at the Cleveland Clinic Taussig Cancer Center, and 66 of them had thyroid function test results available. Fifty-six (85%) of the 66 patients had one or more abnormality in their thyroid function test results, consistent with hypothyroidism, and 47 (84%) of the 56 patients with abnormal thyroid function tests had signs and/or symptoms possibly related to hypothyroidism. Thyroid hormone replacement was undertaken in 17 patients, and symptoms improved in nine of them. Thyroid function test abnormalities appear to be common in patients with metastatic renal cell carcinoma treated with sunitinib, and routine monitoring is warranted.

Hypothyroidism in a breast-fed preterm infant resulting from maternal topical iodine exposure

Hypothyroidism developed in a preterm infant, whose initial screening thyroid function test results were normal, at 2 weeks of life. The infant's mother was packing her Caesarian incision with iodine soaked gauze, resulting in a markedly increased breast milk iodine concentration. Treatment with oral L-thyroxine normalized thyroid function tests.

Late Effects in Survivors of Childhood Cancer

1. Mandy M. Meck, MD* 2. Margaret Leary, MD* 3. Richard H. Sills, MD* 1. *Albany Medical College, Department of Pediatrics, Division of Pediatric Hematology/Oncology, Albany, NY After completing this article, readers should be able to: 1. Describe common late effects in children who are treated for cancer. 2. Know the common clinical presentations for the more serious late effects. 3. Explain how to monitor survivors of childhood cancer for late effects. 4. Recognize when to refer patients to a pediatric oncologist or other specialist. A 19-year-old male was treated for cerebellar medulloblastoma at 3 years of age. Therapy included total resection followed by craniospinal radiation in a dose of 3,600 cGy, with a boost to 5,040 cGy to the tumor bed, as well as chemotherapy with vincristine, cyclophosphamide, and cisplatin. School was a struggle, and he was held back in the 8th grade. One physician suggested methylphenidate therapy, but the boy’s mother refused. He has just graduated from high school but is having difficulty obtaining employment. Now he presents with his fiancee because they want to know if he can father children. He shows no evidence of recurrent disease or complications of his tumor. Physical examination documents a weight of 60 kg (16th percentile) and height of 158 cm (<3rd percentile). Abnormalities include a 3×4 cm area of alopecia over his occipital region and a posterior midline craniotomy scar. His only neurologic deficit is a mild impairment in upward gaze bilaterally. He has no lymphadenopathy or thyroid abnormalities. He is at Sexual Maturity Rating (SMR) 5. Results of complete blood count, chemistry profile, and thyroid function tests are normal; the insulin-like growth factor value is low. Semen analysis is normal. Audiogram demonstrates mild-to-moderate bilateral sensorineural hearing loss. The combined radiation and chemotherapy administered to the boy at a relatively young age would be expected to cause neurocognitive dysfunction. School problems are common for children treated with craniospinal irradiation (even older children), who should be evaluated and problems addressed promptly to …

Serum Thyroglobulin Levels After Fine-Needle Aspiration of Thyroid Nodules

To investigate whether a minor insult to the thyroid gland attributable to fine-needle aspiration (FNA) or external thyroid palpation can cause a release of serum thyroglobulin (Tg) into the circulation. We determined serum Tg levels before and at 60 minutes and 15 days after FNA in 25 patients with thyroid nodules. Results were compared with those obtained in 25 patients with thyroid nodules, in whom serum Tg concentrations were determined before and 60 minutes after palpation of the thyroid, and in 15 healthy subjects without thyroid disease, who had no thyroid palpation and no FNA, from whom 2 blood specimens were obtained 60 minutes apart. All participants had normal results of thyroid function tests and no detectable antithyroglobulin or thyroid peroxidase antibodies. After FNA, 22 of 25 patients had significant elevation of serum Tg concentrations. The Tg levels returned to baseline values 15 days after FNA. In 4 of the 25 patients with thyroid nodules who had palpation of the thyroid, a significant increase in serum Tg levels was elicited. None of the 15 healthy subjects with normal thyroid glands (and with no FNA or thyroid palpation) had significant Tg elevations. FNA causes a significant increase in serum Tg concentrations, which may persist for 15 days. Therefore, Tg assay should not be scheduled prematurely after FNA.

Neurocognitive function in children with compensated hypothyroidism: lack of short term effects on or off thyroxin

BackgroundAlthough thyroxin therapy clearly is beneficial to children with frank hypothyroidism there is little data on the effects of thyroxin in children with compensated or subclinical hypothyroidism. The objective of this study was to determine the effect of thyroxin therapy on cognitive function in children with compensated hypothyroidism. The hypothesis was that thyroxin therapy would change neuropsychological function.MethodsEleven patients with a history of sub clinical hypothyroidism entered the study. At the start of the study, six out of the 11 were on thyroxin therapy, while 5 were off therapy. All patients underwent a battery of neuropsychological testing and thyroid function tests at the start of study. Based on the results of thyroid function tests, two of the 5 patients who were off thyroxin were started back on thyroxin. All of the 6 patients who were on thyroxin were taken off thyroxin. All patients then underwent repeat neuropsychological testing and thyroid functions after an average of 91 days.ResultsThyroxin therapy could not be shown to have an effect on neuropsychological function in this short term study. Our patients had attention problems as compared to the normal population. No significant differences were found between our subjects and normal population standards in verbal processing, visual processing, motor speed/coordination and achievement.ConclusionIn this small, short term study, thyroxin therapy could not be shown to affect neuropsychological function in children with compensated hypothyroidism. These children may have attention problems but appear to have normal verbal and visual processing, motor speed/coordination and achievement.

Outcomes of pregnancy complicated by thyroid disease

To perform a case note review of pregnancies complicated by thyroid dysfunction to determine management and therapeutic intervention in relation to pregnancy outcome. A retrospective case note analysis of 81 ongoing pregnancies in 70 pregnant women with a history of thyroid dysfunction over a period of 5 years at the Glasgow Royal Maternity Hospital (GRMH), Glasgow, Scotland, United Kingdom. The results of thyroid function tests and whether a change in treatment was instituted were recorded. Thyroid function was assessed by standard laboratory reference ranges for free thyroxine (FT4) and thyroid stimulating hormone (TSH) in all trimesters. Other parameters were also noted. Medication levels needed to be increased in the hypothyroid group (45%), and decreased (38%) in the hyperthyroid group. Pregnancy outcome was good in majority of cases given appropriate replacement therapy for stated reference values.

Severe coronary artery spasm can be associated with hyperthyroidism

Coronary artery spasm is not infrequently seen in Korea. Most of the patients with coronary spasm show a focal spasm in coronary angiography. However, the cause of the disease is not well known. There have been a few anecdotal case reports of coronary artery spasm associated with hyperthyroidism, but there has not been a report concerning a large series of such patients. Over a period of 5 years and 8 months, we experienced eight patients having the diffuse or severe type of coronary artery spasm in association with hyperthyroidism. We investigated the characteristics of the patients with coronary artery spasm, which was diagnosed by coronary angiography or by provocation with an intracoronary injection of acetylcholine or ergonovine. The demographic data, coronary angiographic findings, thyroid function test results, and the follow-up clinical data of the eight patients having coronary artery spasm associated with hyperthyroidism were analyzed. All eight patients had Graves' disease. In six patients, the coronary arterial vasoconstriction developed during the coronary angiography without an injection of ergonovine. In three patients, the left main stem coronary artery was involved in the spasm. Among these eight patients, five were female, and all of these female patients were < or = 51 years old. All of the patients were treated with anti-thyroid medications, calcium channel blockers, and long-acting nitroglycerines; they all remained free of chest pain during the median follow-up period of 5 years. A severe form of coronary artery spasm could be associated with hyperthyroidism. A high level of suspicion and the thyroid function study should be mandatory for patients with coronary artery spasm, especially for the young female patients.

Serum thyroid hormone concentrations and thyroglobulin autoantibodies in trained and non-trained healthy whippets

Numerous factors including non-thyroidal systemic diseases and drug administration can significantly alter canine thyroid function test results. Furthermore, the importance of breed specific variations has probably been underestimated. In this study, total thyroxine (TT4), free thyroxine (FT4), canine endogenous thyroid stimulating hormone (cTSH) serum concentrations and thyroglobulin autoantibodies (TgAA) were determined in a population of healthy whippets and compared to a control group of different breeds. Mean TT4 values were significantly lower in the whippets but no significant differences were seen between whippets and control dogs for FT4 and for cTSH. The prevalence of serum TgAA in the whippets was 2%, and this was not significantly different from the controls. The results suggest a breed variation for TT4, but not for FT4, cTSH and TgAA serum concentrations in whippets. Serum thyroid hormone concentrations were also compared between trained and non-trained whippets and it was concluded that regular training did not seem to have any significant influence.

Dermopathy of Graves' Disease

A 51-year-old woman presented with weight loss (despite good appetite), palpitations, tremor, and heat intolerance. On examination, she had typical features of Graves' disease, including a diffusely enlarged thyroid, periorbital edema, and proptosis, as well as mild thickening of the skin in the pretibial area. The diagnosis was confirmed by the results of thyroid-function tests, which showed a thyroid-stimulating hormone level of less than 0.1 mU per milliliter (normal range, 0.5 to 5.15); a triiodothyronine level of 557 ng per deciliter (8.5 nmol per liter; normal range, 100 to 190 ng [1.5 to 2.9 nmol]); and a thyroxine level of . . .

Increased prevalence of subclinical and clinical hypothyroidism in persons with chronic kidney disease

Previous studies have suggested a higher prevalence of thyroid abnormalities in persons with end-stage renal disease. However, little is known regarding the epidemiology of thyroid disorders in persons with less severe kidney dysfunction. We used data from the Third National Health and Nutrition Examination Survey to examine the prevalence of hypothyroidism (clinical and subclinical) at different levels of estimated glomerular filtration rate (GFR). We used multivariable logistic regression to evaluate the association between GFR and prevalent hypothyroidism. Among 14,623 adult participants with serum creatinine and thyroid function test results, the mean age was 48.7 years, and 52.6% were women. The prevalence of hypothyroidism increased with lower levels of GFR (in units of mL/min/1.73 m(2)), occurring in 5.4% of subjects with GFR >/=90, 10.9% with GFR 60-89, 20.4% with GFR 45-59, 23.0% with GFR 30-44, and 23.1% with GFR <30 (P < 0.001 for trend). Overall, 56% of hypothyroidism cases were considered subclinical. Compared with GFR >/=90 mL/min/1.73 m(2), reduced GFR was associated with an increased risk of hypothyroidism, after adjusting for age, gender, and race/ethnicity: adjusted odds ratio 1.07 (95% confidence interval: 0.86-1.32) for GFR 60-89, 1.57 (1.11-2.22) for GFR 45-59, 1.81 (1.04-3.16) for GFR 30-44, and 1.97 (0.69-5.61) for GFR <30 mL/min/1.73 m(2) (P= 0.008 for trend). Among a nationally representative sample of adults, reduced glomerular filtration rate was associated with a higher prevalence of hypothyroidism, with many subclinical cases. Future studies are needed to determine the potential adverse effects of subclinical and clinical hypothyroidism in persons with chronic kidney disease.

Sleepwalking Associated with Hyperthyroidism

To report several cases of hyperthyroidism in patients presenting with the unusual symptom of sleepwalking and to discuss the possible pathophysiologic basis for this novel association. After encountering and reporting the first case of new-onset somnambulism in a patient presenting with thyrotoxicosis at our institution, we routinely inquired about the sleep history of patients with thyrotoxicosis, questioning both the patients and family members when applicable. Those patients who actually had sleepwalking episodes coinciding with the onset of thyrotoxicosis underwent close follow-up, and the relationship between the sleepwalking and the results of thyroid function tests was analyzed. In addition, we reviewed the literature on psychiatric disorders and sleep problems, and the pathophysiologic rationale for a cause-and-effect relationship is discussed. We collected 8 cases of patients with new-onset sleepwalking episodes that coincided with the start of thyrotoxicosis. The disappearance of the sleepwalking with successful achievement of euthyroidism supports a cause-and-effect relationship. This hypothesis is further supported by the absence of a family history, the adult onset, and the relapse of sleepwalking in 2 of the patients when their thyrotoxicosis became poorly controlled as a result of noncompliance with medications and its subsequent disappearance with reachievement of euthyroidism. Of note, such a presentation was seen only in patients with thyrotoxicosis caused by diffuse toxic goiter or Graves' disease and never in patients with other causes of thyrotoxicosis. New-onset sleepwalking could be caused by thyrotoxicosis or, more specifically, by thyrotoxicosis resulting from diffuse toxic goiter. The mechanism is hypothesized to be related to the combination of prolongation of non-rapid eye movement sleep and the associated fatigue. Specific inquiry about this unusual presentation of thyrotoxicosis is encouraged, and more studies are needed to confirm and evaluate its extent.