Clinical Aspects of Thyroid & Parathyroid Disorders Flashcards
Distinguish primary, secondary, and tertiary thyroid disorders
Primary = thyroid abnormality d/t thyroid gland issue
Secondary = thyroid abnormality d/t pituitary disease
Tertiary = thyroid abnormality d/t hypothalamic disease
Symptoms of hyperthyroidism
Nervousness, irritability, heat intolerance, excess sweating, palpitations, fatigue, weakness, weight loss with increased appetite, frequent bowel movements, oligomenorrhea
PE findings associated with hyperthyroidism
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
PE findings specific to hyperthyroidism d/t Grave’s disease
Proptosis, periorbital swelling, and ophthalmoplegia
Pretibial myxedema
PE findings specific to hyperthyroidism d/t subacute thyroiditis
Thyroid is tender
Pt may be febrile
Hx of viral URI
Symptoms of hypothyroidism
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
PE findings associated with hypothyroidism
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
What is euthyroid sick?
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]
Formula to correct calcium if albumin is abnormal
Ca[corrected] = measured Ca + 0.8(4.0 - serum albumin)
Drug classically associated with medication-induced thyroid issues since it has structural similarity to thyroid hormone in addition to high iodine content
Amiodarone (type III antiarrhythmic)
May be associated with acute transient suppression of thryoid function, hypothyroidism, or thyrotoxicosis
A decrease in serum calcium leads to an increase in PTH secretion. What are the 3 major effects of this increase in PTH?
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
Signs/symptoms of hypercalcemia
Fatigue, depression, mental confusion, anorexia, nausea, constipation, renal tubular defects, polyuria, short QT interval, and arrhythmias
Signs/symptoms of hypocalcemia
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
In terms of calcium and PO4 levels, what changes would indicate an issue with vitamin D metabolism?
If both Ca and PO4 are altered in the same direction
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?
Primary hyperparathyroidism
[causes include solitary nodule, parathyroid ca, MEN]
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?
Something producing PTH-like substances or substances that include calcium — Malignancy, Granulomatous disease, drugs, mets, multiple myeloma, lymphoma, vitamin D intoxication
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
B. Dehydration
[rapid sxs include polyuria, dehydration, and renal impairment; more chronic symptoms include renal stones, bone issues, psychiatric issues, etc.]
What is the best option to treat hypertension in a patient with hypercalcemia?
Loop diuretics — increase calcium excretion
[do NOT give thiazides — which increase Ca reabsorption]
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
B. Hypovitaminosis D
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
B. 25-OH vitamin D
Because it is the storage form and we want to know how much she has stored
How does calcium vary with respect to albumin?
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%
Effect of physical inactivity on bone and subsequently on PTH and Ca levels
Increased osteoclast activity —> bone resorption —> increased Ca in the blood —> suppression of PTH —> calciuria
Which is a more sensitive/specific test for demineralization of bone/osteoporosis: Central or peripheral DEXA?
Central (of lower spine and hip)
[peripheral DEXA is used for screening only — consists of wrist, heel, leg, fingers]
Calcium replacement therapy options
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
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?
First step is IV fluids to help kidneys excrete excess calcium
Can also consider loop diuretic
For Grave’s disease, which Ab tests support the diagnosis?
A. FT4 Ab
B. TSI Ab
C. TPO Ab
D. Thyroglobulin stimulating Ab
B. TSI Ab
What would a thyroid scan show in the case of Graves disease?
Diffuse, homogenous iodine uptake
[note that only iodine will help determine if actual uptake is increased — not technetium]
________ are of utmost importance in controlling CV and neurologic symptoms associated with hyperthyroidism
Beta blockers [non-selective]
If a pt with hyperthyroidism also has severe asthma and cannot tolerate beta-blockers, a trial of _____ can be given
CCBs
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
Methimazole
If in your initial workup of a thyroid nodule you find that the TSH is low, what is the next diagnostic step?
Do a thyroid scan — because something is suppressing the TSH and you want to check for hot nodule producing thyroid hormone
If in your initial workup of a thyroid nodule you find that the TSH is normal, what is the next diagnostic step?
FNA — because if the TSH is not suppressed, we have to see what the nodule is doing
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
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]
What is your most likely dx in the case of very high TSH and high T4?
TSH-secreting pituitary adenoma
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
A. Bradycardia, decreased systolic and diastolic BP, non-pitting edema
What antibodies are present in 90-95% of autoimmune hypothyroidism?
Anti-TPO
