Thyroid Disease And Endocrinology Chapter 26 Paauw

Front 1

What are the most likely causes of hyperthyroidism?

Back 1

1. Graves' disease
2. Toxic multinodular goiter
3. Subacute thyroiditis
4. Silent thyroiditis

Front 2

Describe Grave's disease.

Back 2

Graves' disease is commonly seen in young women and is due to an antibody that turns on the TSH receptor.

Front 3

Describe toxic multinodular goiter.

Back 3

Toxic multinodular goiter is seen in the elderly and occurs when one or more clones of cells grown into nontender, autonomously functioning nodules.

Front 4

Describe subacute thyroiditis.

Back 4

Subacute thyroiditis follows viral respiratory infection and causes a painful enlarged thyroid gland, elevated ESR and transient HYPERthyroidism followed by transient HYPOthyroidism.

Front 5

Describe silent thyroiditis.

Back 5

This occurs postpartum and may be a nonpainful variant of subacute thyroiditis. There may be no preceding viral infection or elevated ESR.

Front 6

What is the most common cause of hypothyroidism in DEVELOPED nations?

Back 6

Iatrogenic hypothyroidism from ablation or removal of the thyroid gland is the most common cause

Front 7

What is the most common cause of hypothyroidism worldwide?

Back 7

Iodine insufficiency is the most common cause of hypothyroidism worldwide and causes diffuse thyroid enlargement or goiter.

Front 8

What is Hashimoto's thyroiditis?

Back 8

It is a hypothyroid condition; an autoimmune disease associated with antimicrosomal antibodies against thyroid peroxidase.

Front 9

Hashimoto's thyroiditis may coexist with what other autoimmune disorders?

Back 9

1. Sjogren's disease
2. diabetes
3. pernicious anemia
4. lupus

Hashimoto's thyroiditis can be complicated by lymphoma, especially in the few men with Hashimoto's.

Front 10

Why is it important to diagnosis secondary hypothyroidism (from pituitary failure) even though it represents less than 5% of the cases of hypothyroidism?

Back 10

This diagnosis is important to make since thyroid replacement in panhypopituitarism can precipitate fatal adrenal insufficiency if no mineralocorticoids or glucocorticoids are given.

Front 11

Thyroid nodules:

Though thyroid nodules are recognized in only 5% of causes, autopsies should 50% prevalence. Aprroximately 5-10% of ______ thyroid nodules are maligant, the majority of which are _________ or _________ carcinomas - well-differentiated, slow-growing, and curable by resection when found early.

Back 11

Thyroid nodules:

Though thyroid nodules are recognized in only 5% of causes, autopsies should 50% prevalence. Aprroximately 5-10% of SOLITARY thyroid nodules are malignant, the majority of which are PAPILLARY or FOLLICULAR carcinomas - well-differentiated, slow-growing, and curable by resection when found early.

Front 12

__________ thyroid carcinoma is uncommon and may be sporadic or inherited as part of a multiple endocrine neoplasia syndrome ________ .

Back 12

MEDULLARY thyroid carcinoma is uncommon and may be sporadic or inherited as part of a multiple endocrine neoplasia syndrome MEN-2.

Front 13

Anaplastic thyroid carcinoma is rare but aggressive with average survival ______________ .

Back 13

Anaplastic thyroid carcinoma is rare but aggressive with average survival LESS THAN ONE YEAR.

Front 14

What questions are pertinent if I suspect hyperthyroidism?

Back 14

Ask about:
1. weight loss despite a healthy appetite
2. nervousness
3. emotional lability
4. excessive sweating
5. tremor
6. palpitations
7. heat intolerance
8. frequent bowel movements
9. diarrhea
10. altered menses (usually amennorrhea)
11. insomnia

Front 15

__________ patients may present less typically, with "apathetic" hyperthyroidsim manifesting as anorexia, weakness, blunted affect, depression or slowed mentation.

Back 15

ELDERLY patients may present less typically, with "apathetic" hyperthyroidsim manifesting as anorexia, weakness, blunted affect, depression or slowed mentation.

Front 16

_____ , ______ or ________ may be precipitated or worsened by thyroid disease, so do a good cardiopulmonary review of systems (ROS).

Back 16

CHF, ANGINA or ARRHYTHMIAS may be precipitated or worsened by thyroid disease, so do a good cardiopulmonary review of systems (ROS).

Front 17

Symptoms of Hyperthyroidism include:

Back 17

1. Weight loss
2. Fatigue, insomnia
3. Palpitations
4. Tremor
5. Weakness
6. Sweating, heat intolerance
7. Nervousness, irritability
8. Diarrhea, frequent stools
9. Menstrual irregularities (usually amenorrhea)

Front 18

Signs of Hyperthyroidsim include:

Back 18

1. Tachycardia, afib, CHF, HTN
2. Abnormal thyroid gland exam
3. Proximal muscle weakness
4. Lid lag (all causes)
5. Proptosis (Grave's only).
6. Pretibial myxedema (Grave's only).

Front 19

What is a thyroid storm?

Back 19

Thyroid storm is a life-threatening presentation of extreme hyperthyroidism.

Decompensation in one or more organ systems occurs with fever as high as 106, delirium or even frank psychosis, seizures, tachyarrhythmia, angina, high output cardiac failure or cardiogenic shock.

Front 20

What are precipitants of thyroid storms?

Back 20

1. infection
2. surgery
3. iodine contrast dyes
4. ablative therapy
5. amiodarone
6. trauma

Front 21

On physical exam (when you suspect hyperthyroidism):

Observe for agitation, fine tremor, nail clubbing, and __________ (fingernail separation from the nail bed).

Back 21

On physical exam (when you suspect hyperthyroidism):

Observe for agitation, fine tremor, nail clubbing, and ONYCHOLYSIS (fingernail separation from the nail bed).

Front 22

On physical exam (when you suspect hyperthyroidism):

Feel for velvety moist skin from ___________ .

Back 22

Feel for velvety moist skin from EXCESSIVE SWEATING.

Front 23

On physical exam (when you suspect hyperthyroidism):

Palpate the thyroid. Multiple nodules suggest __________ . Diffuse enlargement is consistent with ___________ . A tender hard gland suggests ______________ .

Back 23

Palpate the thyroid. Multiple nodules suggest MUTLINODULAR GOITER. Diffuse enlargement is consistent with GRAVE'S DISEASE. A tender hard gland suggests VIRAL THYROIDITIS.

Front 24

On physical exam (when you suspect hyperthyroidism):

Ask patients to rise from chair with arms crossed to detect _____________ .

Back 24

Ask patients to rise from chair with arms crossed to detect PROXIMAL MUSCLE WEAKNESS.

Front 25

On physical exam (when you suspect hyperthyroidism):

Check for signs of ____________ overstimulation: tachycardia, arrhythmias, hyperreflexia, lid lag on oculomotor test (white sclera visible above the iris with downward gaze, and widened palpebral fissures causing a frightened stare.

Back 25

Check for signs of SYMPATHETIC overstimulation: tachycardia, arrhythmias, hyperreflexia, lid lag on oculomotor test (white sclera visible above the iris with downward gaze, and widened palpebral fissures causing a frightened stare.

These reverse with therapy for the hyperthyroid state.

Front 26

On physical exam (when you suspect hyperthyroidism):

Check for exophthalmos (protrusion of the eyeballs) due to infiltration of eye muscles in ____________ .

Back 26

Check for exophthalmos (protrusion of the eyeballs) due to infiltration of eye muscles in GRAVE'S DISEASE.

Unlike lid lag, exophthalmos does not reverse with treatment.

Front 27

On physical exam (when you suspect hyperthyroidism):

Look for _________ , an infiltrative dermopathy seen on the anterior shins due to ____________ .

Back 27

Look for PRETIBIAL MYXEDEMA, an infiltrative dermopathy seen on the anterior shins due to GRAVE'S DISEASE.

Front 28

What history and exam suggests hypothyroidism?

Onset is often insidious and may be overlooked by patients and physicians because hypothyroidism can mimic normal aging.

Hypothyroid patients are often fatigued (although most fatigued patients do not have hypothyroidism). Ask about dry skin, slowed speech, hoarseness, _____ intolerance, myalgias, weakness, muscle cramps, depression, constipation, altered menses (usually _____________ ), and weight gain.

Paradoxical weight loss may occur from poor bowel motility and anorexia, especially in the _________ .

Back 28

Hypothyroid patients are often fatigued (although most fatigued patients do not have hypothyroidism). Ask about dry skin, slowed speech, hoarseness, COLD intolerance, myalgias, weakness, muscle cramps, depression, constipation, altered menses (usually MENORRHAGIA), and weight gain.

Paradoxical weight loss may occur from poor bowel motility and anorexia, especially in the ELDERLY.

Front 29

What history and exam suggests hypothyroidism?

On exam, look for hypothermia, bradycardia, pale cool doughy skin, pitting edema in the lower extremities, __________ edema, coarse skin and hair, macroglossia, pleural effusion, and distant heart sounds suggesting a percaridal effusion.

Neurologic manifestations can include impaired mentation, dementia, ataxia, psychosis, deafness, ______________ syndrome, "hung-up" reflexes with a delayed relaxation phase, and bradykinesia.

Severe hypothyroidism may cause _________ or _________.

Back 29

On exam, look for hypothermia, bradycardia, pale cool doughy skin, pitting edema in the lower extremities, PERIORBITAL edema, coarse skin and hair, macroglossia, pleural effusion, and distant heart sounds suggesting a percaridal effusion.

Neurologic manifestations can include impaired mentation, dementia, ataxia, psychosis, deafness, CARPAL TUNNEL syndrome, "hung-up" reflexes with a delayed relaxation phase, and bradykinesia.

Severe hypothyroidism may cause CARDIAC FAILURE or COMA.

Front 30

What studies do I order if I suspect thyroid disease?

Back 30

Order a TSH. If the TSH is low, then check a free T4.

Other lab abnormalities that may accompany hypothyroidism include anemia, hypercholesterolemia, hyponatremia, elevated SGOT, LDH and CPK.

Front 31

What may CXR reveal in hypothyroidism?

Back 31

CXR may reveal cardiomegaly in hypothyroid patients due to pericardial effusion.

Front 32

What may EKG reveal in hypothyroidism?

EKG may show bradycardia or decreased ________ , if pericardial effusion is present.

Back 32

EKG may show bradycardia or decreased VOLTAGE, if pericardial effusion is present.

Front 33

What may the EKG show in hyperthyroidism?

Sinus tachycardia or possibly _____________ may accompany hyperthyroidism.

Consider bone density testing in patients with prolonged hyperthyroidism to assess for bone loss.

Back 33

Sinus tachycardia or possibly ATRIAL FIBRILLATION may accompany hyperthyroidism.

Front 34

What does it mean if my patients has a high TSH?

TSH cannot be interpreted alone. The most common cause of a ______ TSH is an underactive thyroid gland (primary HYPOthyroidism). A concomitant _____ free T4 confirms this.

Back 34

TSH cannot be interpreted alone. The most common cause of a HIGH TSH is an underactive thyroid gland (primary HYPOthyroidism). A concomitant LOW free T4 confirms this.

Front 35

What does it mean if my patients has a high TSH?

Since TSH is very sensitive to small changes in T4, it may ______ before a drop in T4 is detected. This situation is called subclinical hypothyroidism because patients are usually asymptomatic.

In rare cases, both T4 and TSH are high, implicating a TSH-producing pituitary or GYN ______ .

Back 35

Since TSH is very sensitive to small changes in T4, it may RISE before a drop in T4 is detected. This situation is called subclinical hypothyroidism because patients are usually asymptomatic.

In rare cases, both T4 and TSH are high, implicating a TSH-producing pituitary or GYN TUMOR.

Front 36

TSH takes _______ weeks to reflect changes in thyroid hormone replacement.

Back 36

TSH takes 4-6 weeks to reflect changes in thyroid hormone replacement.

Front 37

Does a low TSH imply primary HYPERthyroidism?

Yes, usually. This is confirmed by the clinical picture and a ______ free T4.

In the rare instance where both TSH and free T4 are low with hypothyroid symptoms, secondary hypothyroidism from __________ failure is likely.

Back 37

Does a low TSH imply primary HYPERthyroidism?

Yes, usually. This is confirmed by the clinical picture and a HIGH free T4.

In the rare instance where both TSH and free T4 are low with hypothyroid symptoms, secondary hypothyroidism from PITUITARY failure is likely.

Front 38

When do I need to check a free T3?

T4 is the ______ form of hormone produced in the thyroid and converted to _______ T3 in the periphery. Elevated T3 can be missed if not specifically measured.

If TSH is low in the setting of HYPERthyroid symptoms but free T4 is normal or _____ , obtain a free T3 to look for T3 toxicosis.

Back 38

When do I need to check a free T3?

T4 is the INACTIVE form of hormone produced in the thyroid and converted to ACTIVE T3 in the periphery. Elevated T3 can be missed if not specifically measured.

If TSH is low in the setting of hyperthyroid symptoms but free T4 is normal or LOW, obtain a free T3 to look for T3 toxicosis.

Front 39

When do I need to check for antithyroid antibodies?

Most Hashimoto's and many Grave's disease patients have anti-microsomal and/or anti-thyroglobulin antibodies.

Grave's patients may also have anti-thyroid receptor antibodies.

Occasionally, Grave's opthalmopathy causes proptosis without hyperthyroidism. The presence of thyroid antibodies obviates the need for further work-up for retro-orbital mass or vascular lesion.

Patients with other __________ disorders can be checked for antithyroid antibodies to determine if frequent TSH monitoring is warranted.

Back 39

Grave's patients may also have anti-thyroid receptor antibodies.

Occasionally, Grave's opthalmopathy causes proptosis without hyperthyroidism. The presence of thyroid antibodies obviates the need for further work-up for retro-orbital mass or vascular lesion.

Patients with other AUTOIMMUNE disorders can be checked for antithyroid antibodies to determine if frequent TSH monitoring is warranted.

Front 40

How do I tell the difference between malignant and benign thyroid nodule?

The strongest risk factor for thyroid malignancy is prior head and neck __________ : one third of nodules are malignant in these high-risk patients.

Other risk factors include: male gender, family history, childhood onset, rapid growth, hard fixed nontender nodules larger than 4 cm, hoarseness, local compressive symptoms, and ipsilateral adenopathy or a Delphian node in the midline just about the thyroid isthmus.

Back 40

How do I tell the difference between malignant and benign thyroid nodule?

The strongest risk factor for thyroid malignancy is prior head and neck IRRADIATION: one third of nodules are malignant in these high-risk patients.

Other risk factors include: male gender, family history, childhood onset, rapid growth, hard fixed nontender nodules larger than 4 cm, hoarseness, local compressive symptoms, and ipsilateral adenopathy or a Delphian node in the midline just about the thyroid isthmus.

Front 41

How do I tell the difference between malignant and benign thyroid nodule?

Fine needle aspiration (FNA), the initial nodule evaluation of choice, yield a benign diagnosis in 70%-80% of patients and a malignant diagnosis in 5%. The remaining 10%-20% are nondiagnostic and require further work-up, usually by surgical removal. Although ultrasound distinguishes solid from cystic lesions, this is not useful as either of these lesions could be ________ .

Radioactive iodine scan identifies the 10% of nodules that are "hot" nodules (take up radiolabeled iodine) and therefore are unlikely to be malignant. Of the remaining 90% of nondiagnostic-FNA nodules, surgical exploration is mandatory as 2 out of 10 are malignant.

Back 41

How do I tell the difference between malignant and benign thyroid nodule?

Fine needle aspiration (FNA), the intial nodule evaluation of choice, yield a benign diagnosis in 70%-80% of patients and a malignant diagnosis in 5%. The remaining 10%-20% are nondiagnostic and require further work-up, usually by surgical removal. Although ultrasound distinguishes solid from cystic lesions, this is not useful as either of these lesions could be MALIGNANT.

Radioactive iodine scan identifies the 10% of nodules that are "hot" nodules (take up radiolabeled iodine) and therefore are unlikely to be malignant.
Of the remaining 90% of nondiagnostic-FNA nodules, surgical exploration is mandatory as 2 out of 10 are malignant.

Front 42

What are the symptoms of HYPOthyroidism?

Back 42

Symptoms:
1. Weight gain
2. Fatigue, hypersomnolence
3. Weakness, myalgias, muscle cramps
4. Hoarseness
5. Cold intolerance
6. Impaired mentation, depressed mood
7. Peripheral and periorbital edema
8. Dry skin
9. Coarse hair
10. Constipation
11. Menstrual irregularities (usually menorrhagia)

Front 43

What are the signs of HYPOthyroidism?

Back 43

1. Altered mental status, coma, depression, psychosis
2. Bradycardia, hypotension, CHF
3. Edema
4. Pleural effusion
5. Pericardial effusion
6. Reflexes with a delayed relaxation phase

Front 44

What are the options for treatment of HYPERthyroid patients?

Hyperthyroidism causes unpleasant and potentially dangerous symptoms in the short-term, and long-term may cause osteoporosis, cardiac arrthymias, and CHF.

Medications for symptom management include ___________ to block sympathetic stimulation and thereby decrease tremor, palpitations, and tachycardia. The negative inotropy may worsen CHF, however.

In acute thyroiditis, _________ shorten the course and decrease thyroid pain but are rarely needed.

Antithyroid medications _______ and ________ decrease thyroid hormone production and release. ________ also blocks peripheral conversion of T4 to active T3.

Back 44

What are the options for treatment of HYPERthyroid patients?

Hyperthyrodism causes unpleasant and potentially dangerous symptoms in the short-term, and long-term may cause osteoporosis, cardiac arrthymias, and CHF.

Medications for symptom management include PROPANOLOL to block sympathetic stimulation and thereby decrease tremor, palpitations, and tachycardia. The negative inotropy may worsen CHF, however.

In acute thyroiditis, GLUCOCORTICOIDS shorten the course and decrease thyroid pain but are rarely needed.

Antithyroid medications PROPYLTHIOURACIL (PTU) and METHIMAZOLE decrease thyroid hormone production and release. PTU also blocks peripheral conversion of T4 to active T3.

Front 45

What are the options for treatment of HYPERthyroid patients?

Although most patients achieve a euthyroid state by 6 weeks on these medication, 35%-40% experience relapse. Because these antithyroid drugs rarely cause agranulocytosis, CBC monitoring is important especially in older patients.

__________ is effective for both Grave's disease and multinodular goiter but leads to iatrogenic hypothyroidism in 75% of the cases.

Check TSH periodically after ablation.

____________ of thyroid gland is reserved for local compressive symptoms, failure to respond to other therapies, or possible malignancy.

Back 45

What are the options for treatment of HYPERthyroid patients?

Although most patients achieve a euthyroid state by 6 weeks on these medication, 35%-40% experience relapse. Because these antithyroid drugs rarely cause agranulocytosis, CBC monitoring is important especially in older patients.

RADIOIODINE ABLATION is effective for both Grave's disease and multinodular goiter but leads to iatrogenic hypothyroidism in 75% of the cases.

Check TSH periodically after ablation.

SURGICAL REMOVAL of thyroid gland is reserved for local compressive symptoms, failure to respond to other therapies, or possible malignancy.

Front 46

How do I treat HYPOthyroid patients?

Asymptomatic patients with subclinical hypothyroidism (normal free T4 and mildly elevated TSH) can be followed without therapy, although patients may feel better if treated with low-dose ________.

Start clearly hypothyroid patients on oral ________ at around 100 ug/day. Start more gingerly at 25 ug/day in ______ patients and those with known __________ ; this avoids precipating angina or MI.

IV thyroxine is reserved for ____________ .

Back 46

How do I treat hypothyroid patients?

Asymptomatic patients with subclinical hypothyroidism (normal free T4 and mildly elevated TSH) can be followed without therapy, although patients may feel better if treated with low-dose THYROXINE.

Start clearly hypothyroid patients on oral THYROXINE at around 100 ug/day. Start more gingerly at 25 ug/day in ELDERLY patients and those with known CORONARY ARTERY DISEASE ; this avoids precipating angina or MI.

IV thyroxine is reserved for LIFE-THREATENING COMA.

Front 47

When should I hospitalize a patient for thyroid disease?

Hypothyroid myxedema coma

Back 47

Hypothyroid myxedema coma is an endocrine emergency with stupor, hypothermia, bradycardia and hypoventilation. It may be associated with hypoglycemia, anemia, hyponatremia, or adrenal insufficiency.

Treat the patient in hospital with parenteral levothyroxine, high dose glucocorticoids to prevent adrenal crisis, and intensive supportive therapy.

Myxedema coma may develop insidiously or may be precipitated by infection, cold exposure, sedative drugs, or failure to take thyroid replacement.

Front 48

When should I hospitalize a patient for thyroid disease?

Life-threatening hyperthyroidism or thyroid storm.

Back 48

This requires hospitalization for monitoring and initiating antithyroid drugs, iodine to inhibit hormone release, and beta-blockers to decrease adrenergic effects and block peripheral conversion of T4 to T3.

Glucocorticoids may have a role.

Iopanoic acid or ipodate (radiographic contrast agents) can be added to block hormone release and decrease peripheral T4 to T3 conversion.