✅The correct answer is: E.
🔺This patient, with fatigue, sweating, palpitations, and weight loss, has features of hyperthyroidism. The first step in evaluating hyperthyroidism is to measure serum TSH and free T4 levels. In the absence of a TSH-secreting pituitary adenoma (secondary hyperthyroidism), patients with hyperthyroidism will have an elevated T4 and suppressed TSH.
🔺The most common cause of hyperthyroidism is Graves' disease, which is caused by an autoantibody to the TSH receptor and is characterized by a diffuse goiter and ocular abnormalities (proptosis, periorbital edema). Patients with clear features of Graves' disease may be managed accordingly, but those without require further investigation.
⚠️Patients with undiagnosed hyperthyroidism may be evaluated further with radioactive iodine uptake (RAIU), usually with scan. A high RAIU suggests de novo hormone synthesis due to Graves' disease (diffusely increased uptake) or toxic nodular disease (nodular uptake). Iin contrast, a low RAIU suggests either release of preformed thyroid hormone (ie, thyroiditis) or exogenous thyroid hormone intake. In such cases, the serum thyroglobulin level can make the distinction: elevated thyroglobulin is consistent with endogenous thyroid hormone release whereas decreased thyroglobulin suggests exogenous or factitious thyrotoxicosis. In this patient, it is likely that her weight loss supplement contains thyroid hormone derived from porcine or other animal sources.
❎(Choice A) Antithyroid peroxidase antibodies are seen in Hashimoto thyroiditis, which usually presents with a palpable goiter and clinical hypothyroidism (rather than hyperthyroidism). RAIU is not typically part of the evaluation of hypothyroidism but would generally show low uptake in patients with Hashimoto thyroiditis due to autoimmune thyroid destruction. Rarely, patients with Hashimoto thyroiditis can present with a transient hyperthyroid state (due to inflammation) early in the course of the disease. Factitious thyrotoxicosis is much more likely in this patient who developed manifestations of hyperthyroidism shortly after she started taking an over-the-counter weight loss remedy.
❎(Choice B) Subacute thyroiditis (de Quervain's thyroiditis) is characterized by fever, neck pain, thyroid tenderness, and an elevated erythrocyte sedimentation rate. Iln most cases, hyperthyroid symptoms fade in
🔺This patient, with fatigue, sweating, palpitations, and weight loss, has features of hyperthyroidism. The first step in evaluating hyperthyroidism is to measure serum TSH and free T4 levels. In the absence of a TSH-secreting pituitary adenoma (secondary hyperthyroidism), patients with hyperthyroidism will have an elevated T4 and suppressed TSH.
🔺The most common cause of hyperthyroidism is Graves' disease, which is caused by an autoantibody to the TSH receptor and is characterized by a diffuse goiter and ocular abnormalities (proptosis, periorbital edema). Patients with clear features of Graves' disease may be managed accordingly, but those without require further investigation.
⚠️Patients with undiagnosed hyperthyroidism may be evaluated further with radioactive iodine uptake (RAIU), usually with scan. A high RAIU suggests de novo hormone synthesis due to Graves' disease (diffusely increased uptake) or toxic nodular disease (nodular uptake). Iin contrast, a low RAIU suggests either release of preformed thyroid hormone (ie, thyroiditis) or exogenous thyroid hormone intake. In such cases, the serum thyroglobulin level can make the distinction: elevated thyroglobulin is consistent with endogenous thyroid hormone release whereas decreased thyroglobulin suggests exogenous or factitious thyrotoxicosis. In this patient, it is likely that her weight loss supplement contains thyroid hormone derived from porcine or other animal sources.
❎(Choice A) Antithyroid peroxidase antibodies are seen in Hashimoto thyroiditis, which usually presents with a palpable goiter and clinical hypothyroidism (rather than hyperthyroidism). RAIU is not typically part of the evaluation of hypothyroidism but would generally show low uptake in patients with Hashimoto thyroiditis due to autoimmune thyroid destruction. Rarely, patients with Hashimoto thyroiditis can present with a transient hyperthyroid state (due to inflammation) early in the course of the disease. Factitious thyrotoxicosis is much more likely in this patient who developed manifestations of hyperthyroidism shortly after she started taking an over-the-counter weight loss remedy.
❎(Choice B) Subacute thyroiditis (de Quervain's thyroiditis) is characterized by fever, neck pain, thyroid tenderness, and an elevated erythrocyte sedimentation rate. Iln most cases, hyperthyroid symptoms fade in