Disorders of the Parathyroid

Ca2+ and phosphates

What does parathyroid hormone regulate?

bones, intestine, kidneys

What organs does PTH act on?

stimulates osteoclast

PTH action at the bones

increases calcium reabsorption (also needs calcitriol)

PTH action on the intestines

Ca2+ conservation, calcitriol release

PTH action on the the kidneys

hypoparathyroidism

An endocrine disorder characterized by low serum PTH leading to hypocalcemia

post-surgical (most common), autoimmune, functional

Acquired causes of hypoparathyroidism

polyglandular autoimmune syndrome, systemic lupus erythematosus

Common autoimmune causes of hypoparathyroidism

low Mg (parathyroids need mag to function)

Functional causes of hypoparathyroidism

tetany (hypocalcemia)

What is the hallmark of acute hypoparathyroidism?

chvostek (facial twitch), trousseau (arm spasm), muscle cramps, stridor, carpopedal spasm, seizures, hyperactive deep tendon reflexes, prolonged QT

Signs of severe hypoparathyroidism

Increased bone density, osteosclerosis, craniofacial abnormalities, dental abnormalites, cataracts (irreversible)

Signs of chronic hypoparathyroidism

Anything that has hypocalcemia (resp alkaosis, epilepsy, loop diuretics, phenytoin, alndronate, pancreatitis)

DDX for hypoparathyroidism

Serum Ca + (0.8 x (4 - albumin))

Formula for corrected Ca2+

45% of calcium binds albumin so low serum may be due to hypoalbuminemia

Why do we need to “correct” ca levels when looking at lab work?

PTH (low), Serum Ca (low), Serum phosphate (high), urinary Ca (low), EKG (Qt prolongation), Mg (maybe low)

Diagnostics for hypoparathyroidism

ABCs, IV calcium (Ca Glutamate OR CaCl), vitamin D, Mg

45 y/o male patient presents to the ER after a seizure. Past medical hx is positive for thyroid cancer which was removed via complete thyroidectomy 1 week ago. Physical exam shows a positive chvostek and trousseaus sign. Vitals WNL. Lab work is as follows PTH low, corrected calcium under 7.5 mg/dl, high serum phosphate, low Mg. What is your treatment plan?

Oral calcium, oral vitamin D (taper after 3 weeks), oral Mg (taper after 3 weeks), Human PTH (teriparatide - severe cases)

45 y/o male patient presents to the clinic for numbness of the hands and feet. Past medical hx is positive for thyroid cancer which was removed via complete thyroidectomy 1 week ago. Vitals WNL. Lab work is as follows PTH low, corrected calcium low, high serum phosphate, low Mg. What is your treatment plan?

increased risk of osteosarcoma

BBW for teriparatide (human PTH)

urinary/serum calcium, serum phosphate weekly until stable then q3-6 months

Monitoring plan for hypoparathyroidism

hypercalcemia, nephrolithiasis, nephrocalcinosis, renal failures

Side effects of hypoparathyroidism treatments

Primary hyperparathyroidism

increase in the secretion of the parathyroids, causing elevated serum calcium, decreased serum phosphorus, and increased excretion of both calcium and phosphorus

Single parathyroid adenoma (most common), hyperplasia of 2+ parathyroid gland, MEN association, carcinoma

What are some causes of primary hyperparathyroidism?

asymptomatic hypercalcemia, hypercalcuria, possible kidney stones, cortical demineralization (excess PTH), pathological fractures, cystic bone lesion

Signs of primary hyperparathyroidism

secondary hyperparathyroidism

hypocalcemia due to non-parathyroid disorder (probs the kidneys) leads to chronic PTH hypersecretion

Tertiary hyperparathyroidism

Parathyroids are autonomous in their secretion of PTH - unrelated to serum calcium concentration in patients with long-standing secondary hyperparathyroidism

CKD (kidneys start throwing out everything (including calcium - loss of feedback, more PTH)), vitamin D deficiency

Causes of secondary/tertiary hyperparathyroidism

Asymptomatic or mild, symptoms may arise due to hypercalcemia (bones, stones, groans, psychic moans, fatigue overtones)

Presentation of Hyperparathyroidism

low bone density, arthralgia, pathologic fracture (loss of cortical bone loss)

Skeletal symptoms of hyperparathyroidism - hypercalcemia

Nephrogenic DI (polyuria, polydipsia), nephrolithiasis

Renal symptoms of hyperparathyroidism - hypercalcemia

N/V, constipation, weight loss

GI symptoms of hyperparathyroidism - hypercalcemia

fatigue, HA, insomnia, irritability, depression

Neuropsychiatric symptoms of hyperparathyroidism - hypercalcemia

hypertension, brady, shortened QT

Cardiovascular symptoms of hyperparathyroidism - hypercalcemia

elevated serum and/or urine calcium (usually above 10.5), elevated PTH, low/normal serum phosphate, ALP normal/elevated

*Labs for primary hyperparathyroidism

Look for underlying (probably kidney labs BUN/Creat), elevated PTH, serum calcium may be normal

*Labs for secondary hyperparathyroidism

Xray, U/S (kidney stones), DXA (determine bone density)

What imaging would you get for pre-op hyperparathyroidism

salt and pepper skull, brown tumor (cystic lesion), osteopenia

XRAY red flags for calcium disorders

lab error, dehydration, malignancy, multiple myeloma, sarcoidosis, Supplementation (Vitamin D and calcium), prolonged physical immobilization (Wolff's Law)

DDX for hyperparathyroidism

parathyroidectomy

Definitive treatment plan for symptomatic/meets asymptomatic guidelines hyperparathyroidism

Cinacalet (severe hypercalcemia - inhibit PTH secretion), bisphosphanates (osteoporosis)

For nonsurgical candidates, what is the treatment plan for hyperparathyroidism

thiazide diuretics (increase Ca reabsorption), calcium containing antacids, immobilization/bed rest

What are we avoiding with hyperparathyroidism peeps?

osteoporosis, osteopenia

What may be able to be reversed if primary hyperparathyroidism is cured?