Graves disease

Vignette says a 38 year old female presents to her primary care physician with a 3 month history of weight loss despite good appetite, palpitations, and difficulty sleeping; She also reports of feeling increasingly anxious and has noticed a tremor in her hands; Vital signs shows heart rate of 110 beats per minute, and blood pressure of 140/80 mmHg; Examination shows exophthalmos (bulging eyes), a diffusely enlarged, non-tender thyroid, and a fine tremor in her hands; Thyroid function tests show low TSH and high free T4 and free T3 levels; Serology shows positive thyroid-stimulating immunoglobulin (TSI); Radioactive iodine uptake shows diffuse uptake; Diagnosis? 

Diagnosis is Graves disease. 

Graves disease is an autoimmune disease that occurs due to autoantibodies against TSH receptors of the thyroid gland, causing overproduction of thyroid hormone. It is the most common cause of hyperthyroidism in the United States.

Clinical features:-

1. Diffuse, enlarged thyroid glands; thyroid bruit is heard on auscultation.

2. Features of hyperthyroidism (i.e. anxiety, tremor, tachycardia, AFib, systolic HTN, weight loss

despite good appetite, hyperdefecation, heat intolerance, increased sweating, onycholysis, moist skin and fine hair).

3. Graves ophthalmopathy; It is characterized by upper eyelid retraction, lid lag, periorbital swelling, conjunctivitis, and bulging eyes (exophthalmos or proptosis).

4. Pretibial myxedema.

Diagnosis:-

1. Thyroid function test (TFT) shows low TSH and high fT3/fT4.

2. Anti thyroid receptor antibodies is positive (i.e. Thyroid stimulating immunoglobulins is positive).

3. Radioactive iodine uptake (RAIU) shows diffuse uptake.

4. Thyroid ultrasonography shows diffuse enlarged thyroid gland.

5. Histology shows follicular hyperplasia, intracellular colloid droplets, cell scalloping, a reduction in follicular colloid, and a patchy lymphocytic infiltration.

6. MRI of orbit for evaluating ophthalmopathy.

Management:-

1. Beta blockers are used (e.g. propranolol) for symptoms due to sympathetic overactivity.

2. Anti thyroid drugs are used  (e.g. methimazole, propylthiouracil) to block thyroid hormone synthesis and release; The recommended starting dose is 0.5–1.0 mg/kg/day for methimazole and 5–10 mg/kg/day for propylthiouracil. 

3. Radioactive iodine (RAI) ablation therapy.

4. Total or subtotal thyroidectomy.