Clinical Aspects of Thyroid & Parathyroid Disorders

Question 1

Distinguish primary, secondary, and tertiary thyroid disorders

Answer 1

Primary = thyroid abnormality d/t thyroid gland issue

Secondary = thyroid abnormality d/t pituitary disease

Tertiary = thyroid abnormality d/t hypothalamic disease

Question 2

Symptoms of hyperthyroidism

Answer 2

Nervousness, irritability, heat intolerance, excess sweating, palpitations, fatigue, weakness, weight loss with increased appetite, frequent bowel movements, oligomenorrhea

Question 3

PE findings associated with hyperthyroidism

Answer 3

Pt appears anxious, restless, and fidgety; skin is warm and moist and fingernails may separate from nail bed (Plummer’s nails). Eyelid retraction and lid lag may be present

CV findings include tachycardia, systolic HTN, systolic murmur and afib

Fine tremor, hyperreflexia, and proximal muscle weakness may also be present

Question 4

PE findings specific to hyperthyroidism d/t Grave’s disease

Answer 4

Proptosis, periorbital swelling, and ophthalmoplegia

Pretibial myxedema

Question 5

PE findings specific to hyperthyroidism d/t subacute thyroiditis

Answer 5

Thyroid is tender

Pt may be febrile

Hx of viral URI

Question 6

Symptoms of hypothyroidism

Answer 6

Lethargy, dry hair and skin, cold intolerance, hair loss, difficulty concentrating, poor memory, constipation, mild weight gain and poor appetite, dyspnea, hoarse voice, muscle cramps, menorrhagia

Question 7

PE findings associated with hypothyroidism

Answer 7

Bradycardia, mild diastolic HTN, prolongation of relaxation phase of DTRs, cool peripheral extremities

May or may not have goiter; thyroid may also not be palpable at all

Question 8

What is euthyroid sick?

Answer 8

Abnormalities in circulating thyroid hormone levels or TSH during any acute, severe illness in the absence of underlying thyroid disease

Considered an adaptive response to a catabolic state

[most common pattern is a decrease in total and free T3 levels, with normal levels of TSH and T4]

Question 9

Formula to correct calcium if albumin is abnormal

Answer 9

Ca[corrected] = measured Ca + 0.8(4.0 - serum albumin)

Question 10

Drug classically associated with medication-induced thyroid issues since it has structural similarity to thyroid hormone in addition to high iodine content

Answer 10

Amiodarone (type III antiarrhythmic)

May be associated with acute transient suppression of thryoid function, hypothyroidism, or thyrotoxicosis

Question 11

A decrease in serum calcium leads to an increase in PTH secretion. What are the 3 major effects of this increase in PTH?

Answer 11

Increased tubular reabsorption of Ca by the kidney

Resorption of Ca from bone

Increased renal 1,25-OH2 vitamin D production —> increased intestinal Ca absorption

Question 12

Signs/symptoms of hypercalcemia

Answer 12

Fatigue, depression, mental confusion, anorexia, nausea, constipation, renal tubular defects, polyuria, short QT interval, and arrhythmias

Question 13

Signs/symptoms of hypocalcemia

Answer 13

Peripheral and perioral paresthesia, muscle spasms, carpopedal spasm, tetany, laryngeal spasm, seizure, respiratory arrest, increased ICP, papilledema, irritability, depression, psychosis, intestinal cramps, chronic malabsorption, prolonged QT interval

Positive Chvostek and Trousseau signs

Question 14

In terms of calcium and PO4 levels, what changes would indicate an issue with vitamin D metabolism?

Answer 14

If both Ca and PO4 are altered in the same direction

Question 15

A 45 y/o male presents for a well check and denies complaints. Labs are normal except an elevated calcium and low phosphorus. PMHx is negative and PE is normal. If further lab workup reveals high PTH, what is your working dx?

Answer 15

Primary hyperparathyroidism

[causes include solitary nodule, parathyroid ca, MEN]

Question 16

A 45 y/o male presents for a well check and denies complaints. Labs are normal except an elevated calcium and low phosphorus. PMHx is negative and PE is normal. If further lab workup reveals low PTH?

Answer 16

Something producing PTH-like substances or substances that include calcium — Malignancy, Granulomatous disease, drugs, mets, multiple myeloma, lymphoma, vitamin D intoxication

Question 17

Which of the following clinical findings is associated with rapid development of hypercalcemia?

A. Pulmonary edema
B. Dehydration
C. Psychiatric issues
D. Kidney stones
E. Pneumonia

Answer 17

B. Dehydration

[rapid sxs include polyuria, dehydration, and renal impairment; more chronic symptoms include renal stones, bone issues, psychiatric issues, etc.]

Question 18

What is the best option to treat hypertension in a patient with hypercalcemia?

Answer 18

Loop diuretics — increase calcium excretion

[do NOT give thiazides — which increase Ca reabsorption]

Question 19

An 84 y/o female resides in a nursing home and requires help with ADLs. Labs reveal normal renal and hepatic function. Electrolytes are normal except low calcium and low phosphorus. Albumin is normal. Which of the following is most likely driving this pt’s calcium issue?

A. Hypoparathyroidism
B. Hypovitaminosis D
C. Excess phosphate ingestion
D. Munchausen by proxy

Answer 19

B. Hypovitaminosis D

Question 20

An 84 y/o female resides in a nursing home and requires help with ADLs. Labs reveal normal renal and hepatic function. Electrolytes are normal except low calcium and low phosphorus. Albumin is normal. She most likely has hypovitaminosis D. Of the following, which lab test would you order first?

A. 1,25-OH vitamin D
B. 25-OH vitamin D
C. 25, 26-OH vitamin D
D. CBC
E. LH/FSH

Answer 20

B. 25-OH vitamin D

Because it is the storage form and we want to know how much she has stored

Question 21

How does calcium vary with respect to albumin?

Answer 21

Free (ionized) Ca is metabolically active (50%)

Calcium bound to anions like bicarb, lactate, phosphate, and citrate makes up 10% of calcium

Calcium bound to plasma proteins (typically albumin) makes up 40%

Question 22

Effect of physical inactivity on bone and subsequently on PTH and Ca levels

Answer 22

Increased osteoclast activity —> bone resorption —> increased Ca in the blood —> suppression of PTH —> calciuria

Question 23

Which is a more sensitive/specific test for demineralization of bone/osteoporosis: Central or peripheral DEXA?

Answer 23

Central (of lower spine and hip)

[peripheral DEXA is used for screening only — consists of wrist, heel, leg, fingers]

Question 24

Calcium replacement therapy options

Answer 24

Calcium Carbonate (recommended) - can cause constipation and upset stomach

If pt is on H2 blockers, PPIs, or other acid-reducers, the recommendation is Calcium citrate

Question 25

A 78 y/o pt with right hilar mass on CXR is subsequently dx with SCC of the lung. Bloodwork demonstrates albumin of 2.5 and calcium of 16. His EKG shows shortened QT segment. What would your initial tx be in this hospitalized pt?

Answer 25

First step is IV fluids to help kidneys excrete excess calcium

Can also consider loop diuretic

Question 26

For Grave’s disease, which Ab tests support the diagnosis?

A. FT4 Ab
B. TSI Ab
C. TPO Ab
D. Thyroglobulin stimulating Ab

Answer 26

B. TSI Ab

Question 27

What would a thyroid scan show in the case of Graves disease?

Answer 27

Diffuse, homogenous iodine uptake

[note that only iodine will help determine if actual uptake is increased — not technetium]

Question 28

________ are of utmost importance in controlling CV and neurologic symptoms associated with hyperthyroidism

Answer 28

Beta blockers [non-selective]

Question 29

If a pt with hyperthyroidism also has severe asthma and cannot tolerate beta-blockers, a trial of _____ can be given

Answer 29

CCBs

Question 30

The anti-thyroid drugs Methimazole and PTU will take 2-8 weeks for their most significant effects on hyperthyroidism. Note that ____ should not be used in preganncy d/t high rate of placental transfer

Answer 30

Methimazole

Question 31

If in your initial workup of a thyroid nodule you find that the TSH is low, what is the next diagnostic step?

Answer 31

Do a thyroid scan — because something is suppressing the TSH and you want to check for hot nodule producing thyroid hormone

Question 32

If in your initial workup of a thyroid nodule you find that the TSH is normal, what is the next diagnostic step?

Answer 32

FNA — because if the TSH is not suppressed, we have to see what the nodule is doing

Question 33

Which of the following helps to support a benign nodule dx?

A. Being very young
B. Male gender
C. Tenderness
D. Firm, fixed nodule(s)
E. Being very old

Answer 33

C. Tenderness

[benign features include family hx of benign nodules, tenderness, mobile nodule, concomitant dx of hypo or hyperthyroidism; malignant features include age extremes, male gender, hx of neck irradiation, firm/fixed nodules, and LAD]

Question 34

What is your most likely dx in the case of very high TSH and high T4?

Answer 34

TSH-secreting pituitary adenoma

Question 35

A 47 y/o female complains of having a hard time motivating herself and has been feeling cold and complaining of GI upset, including constipation and a bloated feeling. Which of the following findings are consistent with a non-infectious cause of her condition?

A. Bradycardia, decreased systolic and diastolic BP, non-pitting edema
B. Increased perspiration, excess hair growth, weak proximal muscles
C. SOB, tachycardia, lower extremity edema
D. Telangiectasias, hyperhidrosis, large pulse pressure

Answer 35

A. Bradycardia, decreased systolic and diastolic BP, non-pitting edema

Question 36

What antibodies are present in 90-95% of autoimmune hypothyroidism?

Answer 36

Anti-TPO