Step-Up To Medicine: Endocrine/metabolic

Front 1

What are the primary causes of hyperthyroidism?

Back 1

(1) Graves' disease (80%)
(2) Plummer's disease (multinodular toxic goiter; 15%)
(3) Toxic thyroid adenoma (single nodule; 2%)
(4) Hashimoto thyroiditis (transient)
(5) Subacute (granulomatous) thyroiditis (transient)
(6) Postpartum thyroiditis
(7) Iodine-induced hyperthyroidism
(8) Excessive doses of levothyroxine

Front 2

What are the symptoms of hyperthyroidism?

Back 2

(1) Nervousness, insomnia, irritability
(2) Hand tremor, hyperactivity, tremulousness
(3) Excessive sweating, heat intolerance
(4) Weight loss despite increased appetite
(5) Diarrhea, frequent defectation
(6) Palpitations (due to tachyarrhythmias)
(7) Muscle weakness

Front 3

What are the clinical signs of hyperthyroidism?

Back 3

Thyroid
(1) Graves': diffusely enlarged, nontender; bruit may be present
(2) Subacute thyroiditis: exquisitely tender, diffusely enlarged
(3) Plummer's and Hashimoto's: bumpy, irregular, asymmetric
(4) Toxic adenoma: single nodule with otherwise atrophic gland

Extrathyroidal:
(1) Eyes: Proptosis, irritation and excessive tearing, lid retraction, lid lag
(2) CV: arrhythmias (sinus tach, AFib, PVC), elevated BP
(3) Skin: warm and moist, pretibial myxedema
(4) Neurologic: brisk deep tendon reflexes

Front 4

What sequence of tests would you order to diagnose the cause of hyperthyroidism?

Back 4

(1) Serum TSH (test of choice)
(2) Thyroid hormone: T4, free T4 assay
(3) T3 can be helpful but is usually unnecessary
(4) Radionuclide T3 uptake gives information regarding TBG

Front 5

How is free thyroxine index (FTI) calculated?

Back 5

FTI = (radioactive T3 uptake x serum total T4)/100
FTI = (patient's radioactive T3 uptake/normal radioactive T3 uptake) x total T4
Normal values between 4 and 11

Front 6

What are the various treatment types for hyperthyroidism?

Back 6

Pharmacologic:
(1) Thionamides: methimazole, PTU
(2) Beta-blockers
(3) Sodium ipodate or iopanoic acid

Radioiodine 131
(1) Most common Tx in US for Graves'
(2) Main complications include hypothyroidism
(3) Contraindicated during breast feeding and pregnancy

Surgical
(1) Subtotal thyroidectomy
(2) Only 1% of pts treated with this method due to side effects (permanent hypothyroidism, 30%; recurrence of hyperthyroidism, 10%; recurrent laryngeal nerve palsy, 1%; permanent hypoparathyroidism, 1%)
(3) Watch for post-op hypocalcemia

Front 7

What treatment modality is used for immediate relief of symptoms related to hyperthyroidism?

Back 7

beta-Blocker therapy

Front 8

Describe the treatment regimen for a patient with Graves' disease. What are contraindications associated with this treatment?

Back 8

(1) Start methimazole and beta-blocker.
(2) Taper beta-blocker after 4-8 weeks (once methimzole begins to work).
(3) Continue methimzole for 1-2 years.
(4) Measure thyroid-stimulating Ab at 12 months and re-evaluate therapy.
(5) Consider radioiodine tx if recurs or refractory.

PREGNANCY is a major contraindication to the above therapeutic algorithm.

Front 9

How should you manage hyperthyroidism in a pregnant patient with Graves' disease?

Back 9

(1) Obtain an endocrinology consult.
(2) PTU is preferred to methimazole.

Front 10

What are the clinical manifestations of thyroid storm?

Back 10

(1) Marked fever
(2) Tachycardia
(3) Agitation or psychosis
(4) Confusion
(5) GI symptoms (nausea, vomiting, etc.)

Front 11

Describe treatment for thyroid storm, both supportive and disease-directed.

Back 11

Supportive therapy:
-IV fluids, cooling blankets, glucose

Antithyroid agents:
-PTU every 2 hours
-Give iodine to inhibit thyroid hormone release

Beta-blockers:
-control of heart rate

Dexamethosone:
-Impairs peripheral conversion of T4 to T3 and provides adrenal support

Front 12

What are common precipitating factors of thyroid storm?

Back 12

(1) DKA
(2) Infection
(3) Stress (severe trauma, surgery, childbirth, etc.)

Front 13

What are the primary causes of hypothyroidism (95% of cases)?

Back 13

(1) Hashimoto's thyroiditis (most common)
(2) Iatrogenic (second most common)
A. Radioiodine therapy
B. Thyroidectomy
C. Medications (e.g. lithium)

Front 14

What are the secondary and tertiary causes of hypothyroidism (5%)?

Back 14

(1) Pituitary disease
(2) Hypothalamic disease

Front 15

What are the symptoms of hypothyroidism?

Back 15

(1) Fatigue, weakness, lethargy
(2) Menorrhagia, slight weight gain
(3) Cold intolerance
(4) Constipation
(5) Slow mentation, inability to concentrate, dull depression
(6) Muscle weakness, arthralgias
(7) Depression
(8) Diminished hearing

Front 16

What are the clinical signs of hypothyroidism?

Back 16

(1) Dry skin, coarse hair, thickened, puffy features
(2) Hoarseness
(3) Nonpitting edema
(4) Carpal tunnel syndrome
(5) Slow relaxation of deep tendon reflexes
(6) Loss of lateral portion of eyebrows
(7) Bradycardia
(8) Goiter

Front 17

Describe the diagnosis of hypothyroidism.

Back 17

(1) High TSH level is the most sensitive indicator of hypothyroidism
(2) Low TSH level indicates secondary hypothyroidism
(3) Low free T4 level (or low FTI) in pts w/ clinically overt hypothyroidism
(4) Increased anti-microsomal antibodies (Hashimotos)
(5) Other labs that might support dx include elevated LDL and decreased HDL and anemia (mild normocytic)

Front 18

What is the treatment of hypothyroidism?

Back 18

Levothyroxine (T4) is treatment of choice
(1) highly effective in achieving euthyroid state
(2) treatment is continued indefinitely
(3) monitor TSH and clinical state periodically

Front 19

What are the clinical features of subacute (viral) thyroiditis?

Back 19

(1) Prodromal phase of a few weeks (fever, flu-like illness)
(2) Can cause transient hyperthyroidism due to leakage of hormone from inflamed thyroid, followed by euthyroid then hypothyroid states
(3) Painful, tender thyroid gland

Front 20

Describe the tests that are useful in diagnosing subacute viral thyroiditis.

Back 20

(1) Radioiodine uptake is low (due to damaged follicular cells)
(2) Low TSH level secondary to suppression by increased T4 and T3
(3) High ESR

Front 21

What is the appropriate treatment for subacute (viral) thyroiditis?

Back 21

(1) NSAIDs and aspirin for mild Sx
(2) Corticosteroids of pain is more severe
(3) Most pts have recovery of thyroid function within a few months to 1 year

Front 22

Describe the general characteristics of pituitary adenomas.

Back 22

(1) Account for about 10% of all intracranial neoplasms
(2) Almost all are benign
(3) May cause parasellar signs and symptoms
(4) Size: microadenoma (</= 10mm); macroadenoma (>/=11mm)

Front 23

What are the clinical features of pituitary adenomas?

Back 23

Hormonal effects occur due to hypersecretion of one or more of the following pituitary hormones:
(1) Prolactin
(2) GH, leading to acromegaly or gigantism
(3) ACTH, resulting in Cushing's
(4) TSH, resulting in hyperthyroidism

Hypopituitarism due to compression of the hypothalamic-pituitary stalk
(1) GH deficiency and hypogonadotropic hypogonadism are the most common problems

Mass effects
(1) HA
(2) Visual defects, including bitemporal hemianopsia (compression of optic chiasm) is most common

Front 24

What is the workup in a patient suspected of having a pituitary adenoma?

Back 24

(1) MRI is imaging study of choice
(2) Pituitary hormone levels

Front 25

What is the treatment of choice in pituitary adenomas?

Back 25

(1) Transsphenoidal surgery is indicated in most pts. (except pts with a prolactinoma, for which medical management can be attempted first

Front 26

What are the causes of hyperprolactinemia?

Back 26

(1) Prolactinoma-most common cause; also most common type of pituitary adenoma (40%)
(2) Drugs (psychiatric meds, H2 blockers, metoclopramide, verapamil, estrogen)
(3) Pregnancy
(4) Renal failure
(5) Suprasellar mass lesions
(6) Hypothyroidism
(7) Idiopathic

Front 27

What are the clinical features of hyperprolactinemia in men and in women?

Back 27

Men
(1) Hypogonadism, decreased libido, infertility, impotence
(2) Galactorrhea or gynecomastia (uncommon)
(3) Parasellar signs and symptoms (visual defects and HA)

Women
(1) Premenopausal: menstrual irregularities, oligomenorrhea or amenorrhea, anovulation and infertility, decreased libido, dyspareunia, vaginal dryness, risk of osteoporosis, galactorrhea
Postmenopausal: parasellar signs and symptoms