Endo E2- Thyroid

What cells secrete PTH?

Chief cells

PTH is stimulated in response to what?

Hypocalcemia

What is the most important hormone in Ca homeostasis?

PTH

*raises Ca level in the blood

How does PTH increase blood Ca levels?

Increases release of Ca & phosphate from bone

Increases Ca resorption from kidney

Increases renal production of vit D → increased intestinal absorption

How does PTH affect phosphate?

excrete phosphate (phosphaturia)

*dec serum levels

What is primary hyperparathyroidism?

unregulated overproduction of PTH resulting in abnormal Ca homeostasis

What is secondary hyperparathyroidism?

overproduction of PTH due to chronic abnormal stimulus for its production

What are the MCCs of secondary hyperparathyroidism?

chronic renal failure & vit D deficiency

What is the MCC of primary hyperparathyroidism?

single adenoma of parathyroid gland

The chronic excessive resorption of calcium from bone caused by excessive PTH can result in what?

Osteopenia

What can cause osteitis fibrosa cystica?

severe cases of hyperparathyroidism

What is fibrosa cystica characterized by?

subperiosteal resorption of distal phalanges, tapering of distal clavicles, salt-and-pepper appearance of skull, brown tumors of long bones

What causes the majority of sx of hyperparathyroidism?

Hypercalcemia

What are other sx of hypercalcemia?

muscle weakness, fatigue, PUD, volume depletion, N/V, neuro sx, severe → coma, death

What are the RF for hyperparathyroidism?

> 50 yo (avg. 52-56), W > > M, hx neck irradiation/surgery

What cardiac sx can hyperparathyroidism cause?

HTN w/ shortened QT, prolonged PR

What labs support hyperparathyroidism dx?

serum calcium is >10.5 mg/dL on 2 occasions

low serum phosphate, but high urine phosphate

inc serum PTH

low vit D

inc Ca:Cr ratio

What lab findings are diagnostic of primary hyperparathyroidism?

Elevated PTH with elevated serum calcium

What saying helps w/ sx of hyperparathyroidism?

"Bones, stones, abdominal groans, psychic moans, with fatigue overtones"

renal calculi, HTN, constipation, fatigue, mental changes, bone pain/fx

When does hyperparathyroidism NOT require tx?

If asymptomatic

What is the tx for hyperparathyroidism?

surgery (parathyroidectomy), IV hydration for dehydration, Vit D 800-2000 U/day

What medication class can be used in tx hyperparathyroidism to improve BMD? (no change in PTH or Ca levels)

Bisphosphonates (-dronate)

What medication used to tx hyperparathyroidism decreases PTH secretion & serum Ca, but NO effect on BMD?

Calcimimetics- cinacalcet hydrochloride (Sensipar)

For asymptomatic hyperparathyroidism patients who are being monitored, how frequently should serum calcium & creatinine be checked?

Every 6 months

For asymptomatic hyperparathyroidism patients who are being monitored, how frequently should BMD be checked?

Annually

What is hypoparathyroidism?

deficiency of PTH

*leads to hypocalcemia

Why would a pt with hypoparathyroidism have hoarseness, wheezing, and dyspnea?

Laryngospasm & bronchospasm

What are sx of hypoparathyroidism?

muscle cramps of lower back & LE, paresthesia, hyperirritability, fatigue, anxiety, seizures, mood swings, personality disturbances

What can develop if hypocalcemia is severe?

tetany

What is Chvostek sign?

*hypoparathyroidism

Facial twitching, especially around the mouth, induced by gently tapping the ipsilateral facial nerve as it courses just anterior to the ear

What is Trousseau sign?

*hypoparathyroidism

Carpal spasm is induced by inflating a BP cuff around the arm to a pressure 20 mmHg above obliteration of the radial pulse for 3-5 min

What is the MCC of hypoparathyroidism?

S/p thyroidectomy

What are RF of hypoparathyroidism?

Wilson's disease, hemochromatosis, neck surgery/trauma, head/neck malignancies

In hypoparathroidism, DTRs are (hyperactive/hypoactive)

Hyperactive

What labs indicate hypoparathyroidism?

low Ca & Magnesium

low PTH

high serum phosphate, low urine Ca

What diagnostic studies indicate hypoparathyroidism?

XR: inc bone density; cutaneous calcifications

CT skull: calcification of basal ganglia

What EKG changes indicate hypoparathyroidism?

prolonged QT interval, T wave abnormalities

What is the mainstay tx for hypoparathyroidism?

Ca & vit D

What do pts undergoing parathyroidectomy have a high risk for?

permanent primary hypothyroidism → lifelong risk of symptomatic tetany

What are complications of hypoparathyroidism?

cataracts, parkisonian sx, permanent mental damage; w/o access to Ca pt may die

What is the 1st line tx for acute tetany related to hypoparathyroidism?

Airway management

In addition to airway management, what else should be given to patients with acute tetany related to hypoparathyroidism?

IV calcium gluconate, IV mag sulfate

What is thyrotoxicosis?

hyperthyroidism

What labs indicate hyperthyroidism?

Low TSH + Elevated T4, FT4, T3, FT3

What are sx of hyperthyroidism?

wt loss, sweating, irritabilty, fatigue, palpitations, exophthalmos, lid lag, diarrhea, heat intolerance, tachycardia, hyperreflexia

What arrhythmia may be seen in elderly patients with hyperthyroidism?

Afib

What does an increase in TSH-R Abs indicate?

Graves disease

What does an increase in TPO antibodies?

Hashimoto's disease

How are potassium and calcium affected in hyperthyroidism?

Hypokalemia & Hypercalcemia

What is the DOC for hyperthyroidism in first 12 wks of pregnancy & thyroid storm?

Propylthiouracil (PTU)

What is the DOC for hyperthyroidism (except in first trimester of preg)?

Methimazole

What is definitive therapy for hyperthyroidism?

Thyroid ablation with oral radioactive iodine (I3II)

What is the MCC cause of hyperthyroidism?

Grave's disease

What are sx Grave's disease?

pretibial myxedema, pernicious anemia, myasthenia gravis, DM, “orange peel" appearance of LE

What is the DOC for Grave's disease in pregnancy/breast feeding?

Propylthiouracil (PTU)

What is the tx for Grave's disease?

Endo referral, Propanolol, Methimazole

What are sx of thyroid storm?

delirium, severe tachy, vomiting/diarrhea, dehydration, high fever, HTN

What might precipitate a thyroid storm?

DKA, hypoglycemia, PE, childbirth, MI/stroke, and infection

What is the tx for thyroid storm?

High-dose PTU, iodine compounds, BB, hydrocortisone

What medication should be D/C in patients who present with thyroid storm?

ASA

What tx is NOT effective in thyroid storm tx?

Radioactive iodine

What labs indicate Hashimoto's thyroiditis?

CD8+ mediated follicular cell destruction

anti-TSH

anti-TPO

Tg Ab

What drug is a risk factor for Hashimoto's thyroiditis?

Amiodarone

In Hashimoto's thyroiditis, which comes first: hyperthyroidism sx, or hypothyroidism sx?

Hyperthyroidism, then hypothyroidism sx

What are sx of Hashimoto's thyroiditis?

asymmetrically enlarged thyroid, xerostomia, + keratoconjunctivitis sicca

What does Hashimoto's thyroiditis almost always progress to?

hypothyroidism

What are sx of hypothyroidism?

Constipation, cold intolerance, Bradycardia, delayed/slow DTRs; TSH elevated, FT4 low

What are sx of hyperthyroidism?

diarrhea, wt gain

What labs indicate untx hyperthyroidism?

Low TSH, High T4, High T3

What labs indicate Hyperthyroidism, T3 toxicosis?

Low TSH, Normal T4, High T3

What labs indicate Primary hypothyroidism?

High TSH, Low T4, Low/normal T3

What labs indicate Secondary hypothyroidism?

Low/normal TSH, Low T4, Low/normal T3

What sodium disorder is seen in hypothyroidism?

Hyponatremia

What is the 1st line tx for hypothyroidism?

Levothyroxine

The majority of thyroid nodules are (malignant/benign)

Benign

What labs should be ordered first for a pt with thyroid nodules?

TSH, T3, FT4

High or low index of suspicion for malignancy:

Soft nodule, older female, adenoma on FNA biopsy

Low

High or low index of suspicion for malignancy:

Firm nodule, lymph nodes, young male

High

High or low index of suspicion for malignancy:

Papillary carinoma, follicular neoplasm, medullary or anaplastic carcinoma on FNA biopsy

High

High or low index of suspicion for malignancy:

“Hot” nodule, cystic lesion on US

Low

High or low index of suspicion for malignancy:

"Cold" nodule, solid lesion on US

High

High or low index of suspicion for malignancy:

Decrease in size w/ thyroxine suppression therapy

Low

High or low index of suspicion for malignancy:

Increase in size w/ thyroxine suppression therapy

High

What is the MC type of thyroid carcinoma?

Papillary

What is the most deadly type of thyroid carcinoma?

Anaplastic