hyperthyroid

Question 1

2 broad groups of disorders

Answer 1

-Abnormal function
-Abnormal growth (nodules) in the gland

Question 2

thyroid diseases

Answer 2

-Common problems in the general population -> Older people and women
-Functional disorders
-Related to the gland producing too little thyroid hormone (hypothyroidism)
-Or too much thyroid hormone (hyperthyroidism)
-Benign nodules in the thyroid gland are common; do not USUALLY cause serious health problems
-Occur when the cell growth within the nodule is abnormal
-Nodules can occasionally put pressure on the neck -> cause difficulty swallowing, breathing or speaking

Question 3

testing for different disease

Answer 3

-screening- TSH (most sensitive for primary hypo and hyper) and T4
-hypothyroidism- TSH (high in primary and low in secondary) and anti-TPO

-hyperthyroidism:
-TSH (suppressed except in TSH secreting pituitary tumor or pituitary hyperplasia)
-T3 or free T4 - elevated
-123-I uptake and scan- increase uptake, diffuse versus hot foci on scan
-anti-TPO- elevated in graves
-TSI- 65% + in graves

-thyroid nodules:
-FNA bx- best dx for thyroid cancer
-123-I uptake and scan- cancer is usually cold, less reliable than FNA
-99m-Tc scan- vascular versus less vascular
-U/S- assist with FNA bx, assesses risk of malignancy , monitor nodules and pts after thyroid surgery for carcinoma

Question 4

hyperthyroidism types

Answer 4

-Graves’ Disease
-Thyroiditis
-Acute Thyroiditis
-Subacute Thyroiditis
-Hashimoto’s Thyroiditis- small period before when its hyper and then becomes hypo
-Toxic adenomas
-Multi nodular goiter
-Thyrotoxicosis factitial (abusing levothyroxine for wt loss) vs. Struma ovarii (teratoma)
-Pituitary tumor
-Pregnancy & trophoblastic tumors
-Thyroid carcinoma – rare cause of thyrotoxicosis
-Jodbasedow disease
-Amiodarone-induced thyrotoxicosis

Question 5

thyrotoxicosis vs hyperthyroidism

Answer 5

-Thyrotoxicosis
Is defined as the state of thyroid hormone excess
Is not synonymous with hyperthyroidism??? -> she said in class they are the same thing

-Hyperthyroidism is result of excessive thyroid function
-However, the major etiologies of thyrotoxicosis are hyperthyroidism -> Caused by Graves’ disease, toxic multinodular goiter, and toxic adenomas

Question 6

hyperthyroidism

Answer 6

-Refers to conditions caused by excessive thyroid hormone produced by the thyroid gland
-Signs and symptoms generally result from stimulation of the adrenergic nervous system
-hx of radiation on the neck? lymphoma?
-nodules are usually non-tender (dont hurt)

-The MC causes of hyperthyroidism
-Graves’ disease
-Toxic multinodular goiter
-Toxic uninodular goiter
-Thyroiditis

-Less common causes
-Thyroid-stimulating hormone producing tumors
-Pituitary resistance to thyroid hormone
-Trophoblastic disease
-Iodine ingestion

Question 7

graves disease

Answer 7

-toxic diffuse goiter
-MC cause, familial predisposition
-autoimmune disease
-thyroid gland is being stimulated by Thyrotropin receptor antibodies
[also known as thyroid-stimulating immunoglobulin]
-60 to 80% of thyrotoxicosis
-Prevalence varies among populations -> Typically occurs between 20-50 years of age, but also in elderly
-Genetic factors and environmental factors contribute to susceptibility to GD; Indirect evidence - stress - important environmental factor
-Smoking:
-minor risk factor for Graves’ disease
-major risk factor for ophthalmopathy
-Sudden increases in iodine intake may precipitate Graves’ disease
-3-fold increase in the occurrence of Graves’ disease in the postpartum period

Question 8

toxic multinodular goiter

Answer 8

-toxic several nodules
-Multiple areas in the thyroid gland are overproducing thyroid hormone independently of TSH

Question 9

toxic unimodular goiter

Answer 9

-adenoma
-A solitary nodule in the thyroid gland overproducing thyroid hormone independently of TSH

Question 10

subacute thyroiditis

Answer 10

-often idiopathic
-but sometimes virally mediated inflammation and destruction of the thyroid gland
-Consequently, the stored thyroid hormones are released into the circulation, causing a transient hyperthyroid state

Question 11

rare causes

Answer 11

-TSH-secreting pituitary adenoma or pituitary resistance to thyroid hormones
-Pituitary adenoma - benign neoplasms of the anterior pituitary
-Functioning trophoblastic tumors - this includes hydatidiform mole, choriocarcinoma, or metastatic embryonal carcinoma of the testis
-Iodine-induced hyperthyroidism (Jod-Basedow’s disease) - occurs when supplemental iodine is given to patients with iodine-deficiency goiter

Question 12

epidemiology

Answer 12

-Genetics- Graves’ disease has a familial predisposition and can overlap clinically and immunologically with Hashimoto’s disease
-Graves’ disease has a genetic predisposition that is polygenic in nature
-Increased frequency in human leukocyte antigen (HLA)
-Geography- Iodine-induced hyperthyroidism - outbreaks of thyrotoxicosis have occurred when thyroid supplements added into diets of previously iodine-deficient populations

Question 13

iodine

Answer 13

-give radioactive iodine
-whole gland lights up- graves
-overactive thyroid
-if its a nodule- only that nodule shows up
-radioactive iodine can be a treatment to kill overactive thyroid cells (last resort before removal) -> can make you hypothyroid

-Five different scintigrams taken from thyroids with different syndromes: (A) Normal thyroid; (B) Graves disease, diffuse increased uptake in both thyroid lobes; (C) Plummer disease (toxic multinodular goiter); (D) Toxic adenoma; (E) Thyroiditis (marker 99Tc).

Question 14

thyroid nodule

Answer 14

-<1mm - monitor
-1-2mm - monitor, bx

Question 15

symptoms

Answer 15

-Nervousness
-Sweating
-Sensitivity to heat
-Palpitations
-Fatigue
-Dyspnea
-Increase in appetite
-Eye irritation
-Swelling in legs
-Increased frequency of bowel movement, or diarrhea
-pretibial myxedema ** (dont confuse myxedema)

Question 16

signs

Answer 16

-Cardiovascular manifestations
-Fever
-Warm, moist skin
-Tremor
-Bruit over thyroid
-Goiter
-Dermopathy (GD)
-Weight loss (although weight gain can occur in 5% of patients due to increased appetite)
-Splenomegaly
-Gynecomastia
-Oligomenorrhea/amenorrhea/menorrhagia
-Thymic hyperplasia can rarely occur
-Palmar erythema
-Onycholysis
-Less commonly:
-Pruritus
-Urticaria
-Diffuse hyperpigmentation

-Hair texture may become fine
-Diffuse alopecia occurs in up to 40% of patients
-Persisting for months after restoration of euthyroidism

Question 17

graves ophthalmopathy

Answer 17

-Eye signs (erythema, lid retraction, stare)
-The earliest manifestations:
-Usually a sensation of grittiness
-Eye discomfort
-Excess tearing

-In severe cases - corneal exposure and damage can occur, especially if the lids fail to close during sleep
-Periorbital edema, scleral injection, and chemosis are also frequent
-Exophthalmos: Thyroid stare and Lid lag
-These are due to adrenergic stimulation, not infiltrative disease
-About 1/3 of pts have PROPTOSIS
-Best detected by visualization of the sclera between the lower border of the iris and the lower eyelid, with the eyes in the primary position
-Can be measured using an exophthalmometer
-Unilateral exophthalmos should not be attributed to Graves’ disease (tumor)
-Lid retraction, causing a staring appearance, can occur in any form of thyrotoxicosis -> result of sympathetic over activity
-eye symptoms are also called thyroid-associated ophthalmopathy -> Most of these pts have autoimmune hypothyroidism or thyroid antibodies
-onset of Graves’ ophthalmopathy occurs within year before or after dx of thyrotoxicosis in 75% of pts -> Can sometimes precede or follow thyrotoxicosis by several years, accounting for some cases of euthyroid ophthalmopathy

Question 18

graves: dermopathy

Answer 18

-Almost always in the presence of moderate or severe ophthalmopathy
-Most frequent over the anterior and lateral aspects of the lower leg (hence the term pretibial myxedema), skin changes can occur at other sites, particularly after trauma
-The typical lesion is a noninflamed, indurated plaque with a deep pink or purple color and an “orange-skin” appearance

Question 19

graves: thyroid acropachy

Answer 19

-Refers to a form of clubbing
-It is so strongly associated with thyroid dermopathy that an alternative cause of clubbing should be sought in a Graves’ patient without coincident skin and orbital involvement

Question 20

neurologic manifestations

Answer 20

-Common neurologic manifestations include
-Hyperreflexia (brisk), muscle wasting, and proximal myopathy without fasciculation
-Chorea is a rare feature
-Sometimes associated with a form of hypokalemic periodic paralysis -> This disorder is particularly common in Asian males with thyrotoxicosis

Question 21

other effects: graves

Answer 21

-The direct effect of thyroid hormones on bone resorption leads to osteopenia in long-standing thyrotoxicosis
-Mild hypercalcemia occurs in up to 20% of patients
-Hypercalciuria is more common
-There is a small increase in fracture rate in patients with a previous history of thyrotoxicosis

Question 22

presentation and Mx in the elderly and children

Answer 22

-In the elderly:
-Congestive heart failure
-Atrial fibrillation - Digoxin, beta-blockers, and anticoagulants, may be required
-Management of these complications need to be done early or in conjunction with treatment of GD

-Proximal muscle weakness

-In children:
-Accelerated linear growth
-Eye signs are more common

Question 23

differential dx

Answer 23

Anxiety
Thyroiditis
Pheochromocytoma
Autoimmune Deficiency Syndrome (AIDS)
Malignancy
Accelerated Hypertension
Orbital Tumors
Cushing’s Syndrome

Question 24

lab studies

Answer 24

-TSH level is suppressed and total and unbound T3 & T4 levels increased.
-In 2–5% of patients (and more in areas of borderline iodine intake), only T3 is increased (T3 toxicosis).
-Measurement of TPO antibodies is useful in differential diagnosis.
-Associated abnormalities that may cause diagnostic confusion in thyrotoxicosis include elevation of bilirubin, liver enzymes, and ferritin.
-Microcytic anemia and thrombocytopenia may occur

Question 25

management of hyperthyroidism

Answer 25

-For hyperthyroidism include
-Antithyroid medications
-Radioactive 131-iodine
-Subtotal thyroidectomy

-Each choice has disadvantages and advantages

-Therapy should be individualized for each patient

Question 26

antithyroid medications

Answer 26

-Thioureylene
-Propylthiouracil (PTU); methimazole; carbimazole -> Decrease output of thyroid hormone from thyroid gland and
Inhibits thyroperoxidase; Inhibit thyroid hormone biosynthesis

-They offer patients a chance of permanent remission and their advantages include:
-No risk of permanent hypothyroidism
-Low cost, and only minor adverse effects
-They may be used as monotherapy in patients with mild disease, or to treat symptoms before patients are treated with radioactive iodine or surgery
-Pregnancy – Category D

Question 27

adjunctive therapies

Answer 27

-Beta-blockers - reduce adrenergic manifestations of hyperthyroidism
-Propanolol - often beta-blocker of choice
-Thought to have the additional benefit of blocking the peripheral conversion of T4 to T3
-due to afib

-Educate patient about relevant lifestyle changes
-Such as iodine consumption
-Avoidance of tobacco, especially in the setting of Graves’ disease

Question 28

follow up

Answer 28

-Therapy with antithyroid can continue for 6 months to 2 years for Graves’ disease
-Monitor - CBC, LFT’s & thyroid function tests every 3 months
-Maintain thyroid function tests in the high-normal range
-Patients free from symptoms

-Beta-blockers - discontinue when tachycardia abates
-Patients receiving radioactive 131-iodine should be seen 6 weeks after therapy was received, at which time thyroid function tests need to be checked for hypothyroidism
-TFT’s need to be monitored again at 3 months, 6 months, one year, and annually thereafter

Question 29

radioactive 131-iodine

Answer 29

-Very effective at ablating hyperthyroidism
-Is generally the treatment of choice except in- Pregnant women and children
-It achieves permanent hypothyroidism
-Has lower costs and complications when compared to surgery
-However, there is a risk of permanent hypothyroidism and thyroiditis, as well as the usual risks associated with radiation
-Contraindicated in pregnancy or breast-feeding
-Safety not yet established in children <10 years of age
-Elderly patients should receive antithyroid drugs prior to radioactive iodine and for several weeks after to decrease any risk of worsening hyperthyroidism from post radiation thyroiditis

-Moderate orbitopathy may worsen
-Avoid in: Patients with active orbitopathy (and especially cigarette smokers)
-Associated with aggravating the eye disease

Question 30

chart

Answer 30

-T3 thyrotoxicosis is rare

Question 31

subtotal or total thyroidectomy

Answer 31

-Rarely the treatment of first choice
-Often recommended in
-Young children
-Pregnant women who have had an adverse reaction to pharmacotherapy
-Patients with compressive symptoms
-Patients in whom there is a concern about the possibility of thyroid cancer
-When rapid control of hyperthyroidism is needed or avoidance of exacerbation of symptoms is required (i.e. cardiac patients)

-Risk of permanent hypothyroidism and severe adverse effects
-Cost may also be an issue with surgery

Question 32

goiter rx

Answer 32

-Patients with toxic uninodular and multinodular goiter
-Do not go into remission
-Require surgery
-Or radioactive 131-iodine after stabilization with -> Thioureylenes and/or beta-blockers

Question 33

management of pregnancy and hyperthyroidism

Answer 33

-Hyperthyroidism in pregnancy results in increased rates of fetal loss
-Propylthiouracil is the drug of choice initially -> Crosses the placenta less than methimazole
-In 2nd trimester – often methimazole may be preferred
-Frequently, pregnancy has an ameliorative effect - can be maintained on a low dose
-Thyroid-stimulating antibodies can be checked at the end of the pregnancy -> Will help predict neonatal hyperthyroidism
-Patients should be seen 6 weeks postpartum because Graves’ is likely to worsen then

Question 34

foods to monitor

Answer 34

-iodized salt
-cauliflower

Question 35

thyroid storm

Answer 35

-A life-threatening condition
-Characterized by
-Exaggerated signs and symptoms of -hyperthyroidism:
-A fib./shock
-Fever»>104
-Hypotensive
-Altered mental status

-Usually precipitated by a concurrent illness or injury
-Also occurs following withdrawal of antithyroid medications

-Treatment requires
-Aggressive therapy for the concurrent illness
-Bring temperature down [cold fluids, cool them down]

-Aggressive antithyroid therapy
-Beta-blocker, a thionomaides (PTU or methimazole) glucocorticoids

Question 36

toxic adenomas

Answer 36

-Single - Plummer’s disease
-Multiple – toxic multinodular goiter
-No infiltrative ophthalmopathy or dermopathy
-Tests
-Antithyroid antibodies – negative
-TSH-R -negative

Question 37

pituitary tumor

Answer 37

-Pituitary adenoma →TSH hypersecretion→ hyperthyroidism
-Rare cause
-Neoplastic inappropriate secretion of thyrotropin vs. non-neoplastic
-Symptoms of Thyrotoxicosis
AND
-TSH assay – normal or elevated
-No ophthalmopathy
-Antithyroid antibodies TSH-R Ab – normal

-Management
-Sphenoidal surgery – if large tumor
-Propranolol
-Radioactive iodine/thyroid surgery

Question 38

jodbasedow disease

Answer 38

-Iodine-induced hyperthyroidism
-Multinodular goiters:
-after large amount of iodine in diet
-or in radiographic contrast material

-Or drugs – e.g. amiodarone

Question 39

thryotoxicosis factitia

Answer 39

-Due to ingestion of excessive amount of exogenous thyroid hormone
-Contaminated ground beef
-‘hamburger thyrotoxicosis’

Question 40

struma ovarii

Answer 40

-Thyroid tissue in: 3% of ovarian dermoid tumors
-Teratomas
-Autonomous secretion of hormones due to a toxic nodule
-Or in addition to a woman’s thyroid gland in Graves’ disease
-Or toxic multinodular goiter

Question 41

pregnancy and trophoblastic tumors

Answer 41

-Post partum thyroiditis
-Mild gestational hyperthyroidism – in first 4 months when hCG levels are very high
-More likely to have thyrotoxicosis and hyperemesis gravidarum
-Molar pregnancy
-Chorio-carcinoma
-Testicular malignancies

Question 42

referrals

Answer 42

-Patients with significant ophthalmopathy require urgent referral
-Patients suspected of thyroid storm should be referred for specialist care in an ICU
-Infiltrative orbitopathy of Graves’ disease may follow an independent course; may be uninfluenced by treatment -> Nonsurgical therapies
-Significant hyperthyroidism in the elderly is poorly tolerated and may lead to psychosis, cardiac ischemia, or arrhythmia, which can be difficult to manage with conventional therapies unless hyperthyroidism is controlled
-(e.g. weakness in the extraocular muscles, diplopia, corneal ulcerations, papilledema, venous congestion, and visual field defects)