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Essentials of Diagnosis
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Sweating, weight loss or gain, anxiety, palpitations, loose stools, heat intolerance, menstrual irregularity
Tachycardia; warm, moist skin; stare; tremor
Graves disease
Suppressed TSH in primary hyperthyroidism; usually increased T4, FT4, T3, FT3
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General Considerations
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Causes
Graves disease (most common)
Can be precipitated by chemotherapy with immune checkpoint inhibitors (such as ipilimumab, pembrolizumab, tremelimumab, and atezolizumab) and alemtuzumab (for multiple sclerosis)
Must be distinguished from hyperthyroidism due to destructive autoimmune thyroiditis (silent thyroiditis) that can be caused by these same medications
Autonomous toxic adenomas, single or multiple
Jod-Basedow disease, or iodine-induced hyperthyroidism, may occur with multinodular goiters after significant iodine intake, radiographic contrast, or drugs, eg, amiodarone
Subacute de Quervain thyroiditis: hyperthyroidism followed by hypothyroidism
Autoimmune (Hashimoto) thyroiditis may cause transient hyperthyroidism during initial phase and may occur postpartum
Silent thyroiditis
Also known as subacute lymphocytic thyroiditis or "hashitoxicosis"
Can be caused by chemotherapeutic agents (such as tyrosine kinase inhibitors, denileukin diftitox, alemtuzumab, interferon-alpha, interleukin-2), immune checkpoint inhibitors as well as lithium and amiodarone
Amiodarone-induced thyrotoxicosis
Diagnosed when serum TSH levels are suppressed and serum T3 or FT3 levels are high or high-normal
Categorized as type 1, type 2, or mixed (27%)
Type 1 is caused by the active production of excessive thyroid hormone
Type 2 is caused by thyroiditis with the passive release of stored thyroid hormone
Thyrotoxicosis factitia: excessive exogenous thyroid hormone
High serum human chorionic gonadotropin levels in first 4 months of pregnancy, molar pregnancy, choriocarcinoma, and testicular malignancies may cause hyperthyroidism
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Heat intolerance, sweating
Palpitations
Pruritus
Frequent bowel movements
Weight loss (or gain)
Menstrual irregularities
Nervousness, fine resting tremor
Fatigue
Muscle weakness, muscle cramps, hyperreflexia
Tetany (rare)
Thyroid
Goiter (often with a bruit) in Graves disease
Moderately enlarged, tender thyroid in subacute thyroiditis
Eye
Upper eyelid retraction
Stare and lid lag with downward gaze
Thyroid associated ophthalmopathy (exophthalmos) in 20–40% of patients with Graves disease
Diplopia may be due to coexistent myasthenia gravis
Skin
Heart
Thyrotoxic crisis or "storm"
Hypokalemic paralysis (Asian or Native-American men)
Subclinical hyperthyroidism (suppressed serum TSH with normal FT4) may increase the risk of nonvertebral fractures
Clubbing and swelling of the fingers (acropachy) develop rarely
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Differential Diagnosis
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General anxiety, panic disorder, mania
Other hypermetabolic state, eg, cancer, pheochromocytoma
Exophthalmos due to other cause, eg, ...