What is your diagnosis (6)


A 26-year-old man comes to the office for a periodic health maintenance examination. He has no complaints at this time and does not take any medications. His temperature is 37 C (98.6 F), blood pressure is 110/70 mm Hg, pulse is 70/min, and respirations are 12/min. Physical examination reveals a single, firm nodule in the left lobe of the thyroid gland. It is fixed and placed with swallowing. The remainder of his examination is normal. Radioactive iodine thyroid scintiscanning reveals that the nodule is "cold". Thyroid function tests show TSH 1.14 mU/mL, T3 134 nmol/L, thyroxine 8 nmol/L. The most appropriate next step is to:


A. advise the patient to return in 3 months to evaluate the nodule for change in size

B. begin 6 months of suppressive therapy with thyroxine

C. begin therapy with propylthiouracil

D. order a thyroid ultrasound in 3 months to evaluate for additional nodules

clip_image004E. perform a fine needle aspiration of the nodule

 

A 54-year-old woman comes to the office complaining of "sluggishness", decreased concentration, depression, and weight gain of 11 pounds over the last 7 months despite dieting and exercising 3 days a week. Her temperature is 37 C (98.6 F), blood pressure is 110/70 mm Hg, pulse is 70/min, and respirations are 12/min. Physical examination reveals a diffuse goiter, dry skin, and a slightly hoarse voice. The remainder of her physical exam is normal with the exception of "hung up" ankle jerk reflexes bilaterally. Laboratory studies show:

clip_image001

The most appropriate next step in management is to

A. begin therapy with fluoxetine

B. begin therapy with levothyroxine

C. begin therapy with lovastatin

D. begin therapy with propylthiouracil (PTU)

E. begin therapy with vitamin B12 and folate

 

A 35-year-old woman comes to the office because of tremors, weakness, weight loss despite an increased appetite, frequent bowel movements, and "itchy legs." She does not drink alcohol or caffeine and she does not smoke cigarettes. She appears anxious and fidgety, and has a "frightened" look. Her blood pressure is 120/80 mm Hg and pulse is 88/min. Physical examination shows a proptosis with stare and lid lag. The thyroid gland is lobular and asymmetrically enlarged. There are waxy, infiltrated plaques over the dorsum of her legs and the affected area has a peau d’orange appearance. An ECG shows sinus tachycardia. Laboratory studies show:

clip_image001[5]

Treatment options are discussed, and she decides upon radioactive iodine. In discussing radioactive iodine therapy with the patient, you should inform her that

A. continuous or repeated doses of radioiodine are usually necessary

B. hepatitis, arthralgias, agranulocytosis, and a rash are common side effects of radioiodine therapy

C. patients treated with radioiodine will often require replacement doses of thyroid hormone within 10 years

D. radioiodine therapy is the treatment of choice if she is currently pregnant

E. there is plenty of evidence that the dose of radioiodine that she will receive has leukemogenic effects

9 thoughts on “What is your diagnosis (6)

  1. answer:

    1. A – i dunno what to explain for diz one.. he just needs regular monitoring of the nodule to check for any change of size..

    2. B – pt most likely (or definitely? hehe) has Hashimoto thyroiditis. and the Sx and Sm and lab data (hypercholesterolemia, macrocytic anemia, autoantibodies, hi-TSH) are typical for Hashimoto thyroiditis and hypothyroidism . so yeah, for treatment, we give replacement therapy.

    3. C – aim for radioisotope therapy is destruction of thyroid tissue. so there will be hypothyroid state and patient will need replacement therapy.

    happy?😛

  2. The correct answer is E. This patient presented with a thyroid nodule that is suspicious for malignancy. Risk factors for thyroid cancer include radiation therapy to the neck in childhood and family history of thyroid cancer. The fact that the nodule is firm and fixed in place is suggestive of malignancy. Thyroid malignancies are more common in men than in women and more nodules in young patients are malignant than in older patients. Radioactive iodine thyroid scintiscanning is a test which tells us which areas of the thyroid gland are more active and which are less active. Most thyroid malignancies are less active (i.e., cold). The appropriate management of this patient is a fine needle aspiration of the nodule. This can be done safely in experienced hands and has very few complications. It is of great benefit to the physician because it provides tissue to make a definitive diagnosis and guide treatment.

    Serial neck exams (choice A) for change in size of the nodule is inappropriate because thyroid cancer found in its early stages is often curable.

    Thyroxine therapy (choice B) is important in the management of thyroid cancer and is often used after the thyroid cancer is removed with surgery. Since TSH can stimulate cancers to grow more rapidly it is beneficial to suppress TSH after someone is diagnosed with a thyroid cancer. The dose of Levothyroxine used is the highest dose possible to suppress TSH without causing the patient to be symptomatically hyperthyroid.

    Propylthiouracil (choice C) inhibits the oxidation of iodide thereby decreasing the production of thyroid hormone and inhibiting peripheral conversion of T3 to T4 in the blood. It is used in the management of Graves disease as well as other hyperthyroid states. It is not useful in the management of a thyroid nodule.

    Thyroid ultrasound (choice D) is sometimes valuable in the work-up of a thyroid nodule. An ultrasound can detect small nodules that even very experienced hands cannot palpate. However these small nodules rarely have malignant potential and a biopsy of these nodules hasn’t been shown to improve mortality. Also, there is no reason to wait 3 months for this evaluation. A FNA should be performed with or without an ultrasound at this visit or as close to this time as possible, not in 3 months.

  3. Explanation:
    The correct answer is B. This patient has subclinical hypothyroidism (elevated TSH with a normal free T4). Treatment is recommended if the patient has symptoms. Ordering further studies such as thyroid function test or thyroperoxidase antibody will help support your diagnosis. Clues to the diagnosis of hypothyroidism include weight gain, difficulty concentrating, hoarse voice, dry skin, thinning of the eye brows laterally, goiter, etc. Treatment with levothyroxine should be initiated in our patient since she has many of the classic symptoms of hypothyroidism. It is likely that this patient, if untreated, would develop clinical hypothyroidism in the future, which would require treatment. In a young, otherwise healthy person, therapeutic doses of levothyroxine can be started initially. In older patients or patients with heart disease low-dose levothyroxine should be started with a slow titration to therapeutic doses to avoid cardiac complications.

    Depression is often a part of hypothyroidism and the two disorders can often mimic each other. Prior to starting a patient on an SSRI (choice A), reversible causes of depression (such as hypothyroidism) need to be excluded. Since depression is so prevalent, it is reasonable to reevaluate this patient for depression after she is euthyroid.

    Therapy with a statin drug (choice C) is not appropriate at this time. This patient does have an elevated LDL and total cholesterol but two things need to be remembered: first, hypothyroidism can cause high cholesterol so it is necessary to recheck the patient’s cholesterol when euthyroid. Second, this patient needs a trial of exercise and diet prior to being placed on a lipid-lowering drug.

    Propylthiouracil (choice D) is a therapy for hyperthyroidism, not hypothyroidism. It acts by inhibiting the iodination of thyroid hormone and acts to block the peripheral conversion of T3 to T4.

    This patient has a macrocytic anemia, which is often associated with B12 and folate deficiency (choice E). A less common cause of macrocytic anemia is hypothyroidism. This patient’s anemia may resolve once treatment with levothyroxine is initiated.

  4. The correct answer is C. This patient has Grave’s disease, which is a common cause of hyperthyroidism, and it important to discuss the advantages and disadvantages of the treatment options. The major disadvantage of radioiodine therapy is that 40-70% of patients will develop hypothyroidism and require thyroid hormone replacement within 10 years. Grave’s disease is characterized by diffuse goiter, dermopathy, and ophthalmopathy. The clinical manifestations are that of hyperthyroidism and include palpitations, tremors, weakness, weight loss despite an increased appetite, frequent bowel movements, heat intolerance, and oligomenorrhea or amenorrhea. Proptosis, lid lag, and stare are often present. The dermopathy, which is called pretibial myxedema, is usually characterized by waxy, infiltrated plaques over the dorsum of the legs and a peau d’orange appearance. Laboratory studies show low or undetectable levels of TSH, and elevated levels of T4, T3, and the RAIU and RT3U. Radioactive iodine therapy is a good choice for treating hyperthyroidism in adult patients, patients with previous thyroid surgery, and those who cannot undergo surgery. Long-term antithyroid therapy with methimazole or propylthiouracil is usually used in children.

    It would be incorrect to inform her that continuous or repeated doses of radioiodine is usually necessary (choice A). Continuous or repeated therapy with antithyroid drugs (methimazole or propylthiouracil) is often necessary.

    It would be incorrect to inform her that hepatitis, arthralgias, agranulocytosis, and a rash are common side effects of radioiodine therapy (choice B) because these are associated with antithyroid drugs, not radioiodine therapy.

    It would be incorrect to inform her that radioiodine therapy is the treatment of choice if she is currently pregnant (choice D) because radioiodine therapy should never be given to pregnant women. Antithyroid drugs are usually used during pregnancy.

    It would be incorrect to inform her that there is plenty of evidence that the dose of radioiodine that she will receive has leukemogenic effects (choice E) because this is not true. There is no evidence to support this statement (in adults).

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