Parathyroid Disorders (Exam 3) Flashcards
How many parathyroid glands are there typically? Where are they located?
There are usually 4 parathyroid glands they are located posterior to each pole of the thyroid
What hormone do the parathyroid glands release? What is the function of the hormone?
The parathyroid glands release parathyroid hormone (PTH) which regulates serum calcium levels.
What are the functions of serum Ca 2+?
- Muscle contraction
- Terminal neurons release Ca 2+ ions that bind to activator proteins which signal muscles to contract and relax
- Ca 2+ stabalizes cardiac cell membranes against depolarization in severe hyperkalemia (too much potassium)
- Essentail element of bone mineralization
- Important in blood clotting
Bone has many uses when it comes to Ca 2+ what can is serve as?
A reservoir for Ca 2+
Hypercalcemia and hypocalcemia can lead to issues with which vital organ?
The heart, can cause arrhythmias
To maintain homeostatic levels of Ca 2+ the body needs how many functioning parathyroid glands?
1
In the event of low Ca 2+ serum levels PTH stimulates which cells within bone to break down the bone matrix and release Ca 2+ into the blood stream?
Osteoclasts
Oh snap! Blood serum levels of Ca 2+ are low, the body senses this and the parathyroid releases PTH. PTH reaches the kidneys, they respond by doing two things, what are they?
Reducing Ca 2+ clearance in the urine and stimulating production of 1.25dihydroxyvitaminD (Calcitriol) which stimulates the absorption of Ca 2+ in the GI tract.
DDX for elevated calcium (Hypercalcemia)
- Primary hyperparathyroidism
- Familial hypocalciuric hypercalcemia
- Lithium
- Sarcoidosis
- Genetic disorders: multiple endocrine neoplasia, familial hyperparathyroidism
- Renal failure acute or chronic
- Vitamin D excess
- Granulomatous disease
- Williams syndrome
- Endrocrine disease: thyrotoxicosis, adrenal insufficiency
- Milk-Alkali syndrome
- Thiazide diuretics (She mentioned these a lot!)
- Cancers: Multiple myeloma, head, neck, lung, lymphoma
When serum Ca 2+ levels are high osteo____ activity increases
When serum Ca 2+ levels are low osteo____ activity increases
- Osteoblast activity increases in response to high levels of serum Ca 2+
- Osteoclast activity increases in response to low levels of serum Ca 2+ (Osteoclasts break down bone and release Ca 2+ into the blood)
Cause of 80% of hyperparathyroidism, leading to hypercalcemia
Benign parathyroid adenomas
Most common in women 3:1
Increased incidence after age 50
Besides benign parathyroid adenomas what are otther causes of hypercalcemia?
- Renal failure
- multiple myeloma
- Head, neck, and lung cancers
- TB
- Medications
- lymphoma
- Adrenal insufficiency
- Hyperthyroidism
The sign and symptoms of Hypercalcemia as a result of hyperparathyroidism are best summerized by the mnemonic “Stones, bones, abdominal groans, throans, and psychiatric overtones” What the hell does that mean?
- Stones
- Kidney stones (Calcium Oxalate)
- Bones
- Bone diseases of hyperparathyroidism
- Osteitis fibrosa cystica (some bones become abnormally weak and deformed)
- Osteoporosis
- Osteomalacia (softening of bones)
- Arthritis
- Bone diseases of hyperparathyroidism
- Abdominal groans
- N/V/D
- Constipation (Most common)
- PUD (Peptic ulcer disease)
- Pancreatitis
- Thrones
- Polyuria
- Constipation
- Psychiatric overtones (from effects on the CNS)
- Depresson
- Memory loss
- Psychosis
- Delerium
- Fatigue
Clinical features of hyperparathyroidism
- Thirst
- Anorexia
- Nausea
- Vomiting
- Abdominal pain
- Constipation (A big sign)
- Fatigue
- Anemia
- Wight loss
- PUD (Peptic ulcer disease)
- Pancreatitis
- HTN
Halmark lab finding for a Dx of Hyperparathyroidism
Adjusted total calcium greater than 10.5 mg/dl
Which lab test is needed to see calcium levels
Comprehensive metabolic panel
Findings that can lead you to a Dx of Hyperparathyroidism
- Adjusted total calcium greater than 10.5 mg/dl (Hallmark finding)
- Elevated PTH
- Low phosphate level
- Imaging studies–ultrasound, CT, MRI, sestamibi scan
- EKG may show prolonged PR, shortened QT, bradycardia, heart block, and eventually asystole
Patients who have elevated calcium levels should be screened for what?
Familial hypocalciuric hypercalcemia (Gene mutation that leads to elevated calcium levels)
Treatment for hyperparathyroidism
- Avoid foods and medications that increase calcium levels (thiazide, diuretics, antacids, large doses of vit. A and D)
- Furosemide is a diuretic that may be used as it increases the amount of calcium lost in urine
- Increase fluids
- Exercise
- Monitor with scheduled serum calcium and albumin levels, kidney fxn test, urinary calcium excretion, and bone density
- If hypercalcemic crisis occurs treat with IV fluids and bisphosphonates
- A parathyroidectomy is indicated when symptomatic primary disorder
How would you treat a patient in hypercalcemic crisis
IV fluids and bisphosphonates
When would a parathyroidectomy be indicated
- In symptomatic primary hyperparathyroidism
- If serum Ca2+ is 11.5 mg/dl or greater
- Creatinine clearance less than 60 ml/minute
- Bone mineral density T score less than 2.5 at the hip, spine or wrist and/or history of previous fragility fracture
- Age less than 50
If a parathyroidectomy is not done in a patient for whom it is indicated what needs to be done?
- Closely monitor serum Ca2+ and creatinine levels annually
- Bone density checks every 1-2 years
Which is more common hyperparathyroidism or hypoparathyroidism
Hyperparathyroidism is more common
Findings that indicate hypoparathyroidism
- Decreased PTH
- Low calcium
- Increased phosphate levels
Common causes of hypoparathyroidism
- Aquired most commonly after surgical removal of thyroid or parathyroid glands
- Autoimmunity
- Heavy metal toxicity
- Wilson’s disease
- Genetic disorder that causes the accumulation of copper in the body
- Hemochromatosis
- Accumulation of Iron
- Wilson’s disease
- Thyroiditis
- Hypomagnesemia (caused by alcoholism)
- DiGeorge syndrome
- congenital cause of low Ca 2+ arising from parathyroid hypoplasia
- Congenital pseudohypoparathyroidism
Clinical features of hypoparathyroidism (theres a lot of them)
- Abdominal cramps
- Muscle cramps
- Tetany
- Carpopedal spasm
- Paresthesias
- Numbness/tingling especially around mouth or fingers
- Hyperreflexia
- Teeth, hair, and nail defects
- Lethargy
- Anxiety
- Parkonsonism
- Mental retardation
- Blurred vision from cataracts
- Personality changes
- Bronchospasm
- Seizures
Contraction of eye, nose, or mouth by tapping facial never anterior to ear is what sign?
Chvostek sign (indicates hypocalcemia)
A spasm produced in the hand and wrist with compression to forearm (such as applying a BP cuff).
Trousseau sign (indicates hypocalcemia)
Hallmark signs to make diagnosis of hypoparathyroidism
- Low PTH
- Low adjusted calcium
- Increased phosphate
- EKG may show prolonged QT, T-wave abnormalities
As Ca2+ increases, Phosphate ____
Decreases (vice versa is true too as Ca2+ decreases phosphate increases)
Treatments for hypoparathyroidism
- Directed at increasing Calcium levels (goal calcium level is 8.0-8.6 mg/dl)
- Calcium and vit D supplements
- Monitor adjusted serum calcium levels and urine calcium levels
- Avoid furosemide and other meds that increase calcium loss
- Thiazide diuretics increase calcium levels so they are safe to use
- Emergency treatment with IV calcium gluconate
- May use Teriparatide (recombinant PTH) off label in extreme cases to increase PTH levels.
