Parathyroid Study Questions Flashcards
Where are the parathyroid glands?
4 small paired glands located in the back of each thyroid lobe
What does the parathyroid secrete?
Parathyroid hormone (PTH)
What does PTH do?
Regulates calcium
Stimulates bone resorption & inhibition of bone formation -> Ca+ & PO4 release into blood
In kidneys: Increases Ca+ reabsorption & PO4 excretion
Stimulates renal conservation of Vit. D (enhances absorption)
What happens when serum Ca+ levels are low?
PTH secretion increases
What happens when serum Ca+ levels are high?
PTH secretion is inhibited
What other high level can inhibit PTH?
Vitamin D
What other low level can stimulate PTH?
Magnesium
If calcium levels rise above the set point, what does the thyroid gland secrete to inhibit PTH?
Calcitonin
What is hyperparathyroidism?
Increased levels of PTH
What is the most common cause of hyperparathyroidism?
Benign adenoma
What are the main s/s of hyperparathyroidism?
Osteoporosis
Constipation
Risk for renal calculi
How are the symptoms tx?
No tx for hyper; symptomatic tx only
What type of hyperparathyroidism is due to hyperplasia of the glands?
Primary
What type of hyperparathyroidism is due to disorders causing hypocalcemia?
Secondary (vit D deficiency, malabsorption, CRF, hyperphosphatemia)
What type of hyperparathyroidism is due to an increased release of PTH even though Ca+ levels are normal?
Tertiary (often seen after kidney transplant following long standing dialysis tx for CRF)
What can chronic hypercalcemia in hyperparathyroidism cause?
Bones (skeletal changes / osteoporosis / fx) Stones (renal damage/ kidney stones) Groans (Abd/GI malfunction) Moans (psychiatric developments) Neuromuscular changes
Remember the tx for risk of renal calculi?
Strain urine; force fluids (cranberry juice)
What is the goal of hyperparathyroid tx?
Relieve symptoms; prevent complications
Since hyperparathyroidism is linked to hypercalcemia, what should tx include?
Drink 4-5 liters water daily
Limit Ca+ & Vit D
Give Phosphorus supplements (except w/ CRF)
What needs to be increased in the diet?
Na+ (8-10 grams/day)
What tx measures should be taken for hyperparathyroidism?
IV saline Lasix (NOT thiazides) Steroids (decrease GI absorption of Ca+) Anti-resorption agents (inhibit bone resorption/loss) Calcitonin
What are the two types of Calcitonin?
Salmon (2x stronger)
Human (used when sensitive to non-human)
What are other anti-resorption agents?
Mithramycin Etidronate disodium (Didronel) Pamidronate sodium (Aredia)
What are calcimimetic agents [Cinacalcet (Sensipar)] used for?
To ↑ sensitivity to Ca+ receptor on parathyroid gland
Increases PTH secretion & Ca+ serum levels (spares Ca+ stores in bone)
What other disorders are this drug used for?
Pagets disease
Postmenopausal osteoporosis
Hypercalcemia
Who should NOT take Salmon Calcitonin?
Allergic to salmon & fish
How can therapeutic effects of salmon calcitonin be alleviated?
Ensure adequate diet & do small frequent feedings
Alternate nostrils daily if intranasal form
What levels should be checked prior to starting & then ongoing?
Calcium & Vit D levels
NOTE: Calcitonin’s are sub-Q & IM drugs – Teach pt how to do injections
What may be done to prevent injury r/t osteoporosis with the hyperparathyroid pt?
Keep bed low
Assist w/ activity
Implement exercise program to prevent bone loss
What kind of diet should the hyperparathyroid pt be on?
Low Ca+ diet; avoid milk/dairy products
What may be done to prevent constipation?
Fluids, increased activity, fiber, stool softeners
What may be given to decrease the risk of peptic ulcers?
Antacids or H2 receptor antagonists
What disorder may be seen when T3 levels are increased?
Pancreatitis
What is the most effective tx of primary & secondary hyperparathyroidism?
Parathyroidectomy
What is the criteria for a parathyroidectomy?
Calcium level > 12mg/dL
Hypercalciuria (> 400 mg/day)
Marked reduced bone density
Overt symptoms (i.e. renal calculi, neuro changes)
What is usually done when a parathyroidectomy is performed to allow for continued PTH secretion?
Autotransplantation of normal parathyroid tissue in Forearm or near sternocleidomastoid muscle)
If autotransplantation isn’t possible or fails, what must be done?
Lifelong calcium supplements
What is the greatest risk after a parathyroidectomy?
Same as thyroidectomy – HYPOcalcemia
What needs to be at bedside in case tetany occurs?
IV Calcium gluconate
What signs should you be monitoring post-parathyroidectomy?
Chvosteks, Trousseaus
What drug should be administered with caution?
Digitalis (Lanoxin)
What causes “hungry bone syndrome”?
Rapid bone rebuilding post-parathyroidectomy
What is hypoparathyroidism?
Decreased PTH secretion
Failure to respond despite normal to high PTH levels (pseudohypoparathyroidism)
What are iatrogenic causes of hypoparathyroidism?
Accidental removal, infarction, strangulation
What are idiopathic causes of hypoparathyroidism?
Autoimmune
What other abnormal electrolyte can cause hypoparathyroidism?
Hypomagnesemia (alcoholic, prolonged TPN use, malabsorption disorders)
What occurs with lowered levels of PTH?
Serum Ca+ levels fall
PO4 levels increase
May have calcification of eyes (irreversible)
What manifestations may be seen with hypoparathyroidism? (Focused assessment)
Hypocalcemic s/s – Tetany,seizures, laryngeal spasm, neuromuscular excitability
How is hypoparathyroidism diagnosed?
Low serum Ca+
Low serum PTH
High serum PO4
What may be used for maintenance therapy in the pt with hypoparathyroid?
Calcium Supplements
When should calcium supplements be given?
30 minutes to 1 hour after meals with a FULL glass of water
What may need to be administered to decrease PO4 & increase Ca+?
PO4 binders (Amphogel/Basogel)
What is the tx for acute hypocalcemia?
Tx tetany w/ IV calcium gluconate
Monitor for hypotension & cardiac arrest
What drugs are given for long-term mgt of hypoparathyroidism?
Antihypocalcemics: Vitamin D analogues Calcitriol Oral Ca+ supplements Calcium carbonate Oyster shell Ca+ PTH replacement
What do vitamin D analogues do?
Promote Ca+ absorption from GI/renal tubules
Promote secretion of Ca+ from bone
What education should pt be given about Calcitriol?
Swallow tablets whole High Ca+/Low PO4 diet Normal sunlight exposure Avoid Vit D! Avoid Mg containing antacids Have Ca+ level assessed weekly at first S/S dehydration
