Parathyroid Disease Flashcards by tcarlso 3

What are the two major anatomical variations that can occur with the inferior parathyroid glands?

May sometimes follow the thymus and end up in the superior mediastinum

5th PT gland development

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What is the chromosome that has the PTH gene?

Chromosome 11

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What is the half life of PTH?

2-4 minutes

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What two organs clear PTH?

Liver and kidney

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What is significance of the breakdown products of PTH?

Fragments are thought to have their own receptors and biological activity

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What are the modern iPTH assays useful for?

Assaying for the intact PTH

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True or false: modern iPTH assays are able to detect both high and low levels of iPTH

True

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Where are CaR receptors found?

Ubiquitous

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What, besides [Ca] cause secretion of PTH? (3)

Mg
Vit D
Catecholamines

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What is the effect of PTH on the proximal tubule? Distal?

Proximal = Decreases phosphate reabsorption

Distal = increases Ca reuptake

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Where is most of the Ca in the renal tubules reabsorbed? What is the role of PTH in this?

Most reabsorbed in the proximal tubule, which is NOT affected by PTH

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Where does PTH act in the kidney (proximal or distal tubule)?

Distal

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Most Ca reabsorption in the kidney occurs where? Is this regulated? What about the fine tuning of Ca? What is this usually brought in with?

Proximal tubule where most occurs (and is not regulated), but fine tuning in the distal nephron

H2CO3 + Na

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What is the effect of PTH in the proximal tubule of the kidney in terms of phosphate reabsorption?

Inhibits phosphate

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What type of metabolic disturbance (acidosis/alkalosis) can occur with abnormally elevated PTH levels?

Hyperchloremic metabolic acidosis

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What are the three main causes of decreased PTH hormone?

Hypoparathyroidism
Hypercalcemia of malignancy
Hypomagnesemia

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What is the most common cause of increased PTH levels in ambulatory patients?

Hyperparathyroidism

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What is the most common cause of increased PTH levels in hospitalized patients?

Malignancy

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What is the first line test for a hypercalcemic patient?

PTH levels

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What are the components of the VITAMINS TRAP mnemonic for hypercalcemia (just vitamins bit)?

Vits A and D xs
Immobilization
Thyrotoxicosis
Addison’s ds
Milk-alkali/metastatic ds
Inflammatory ds
Sarcoid

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What are the components of the VITAMINS TRAP mnemonic for hypercalcemia (just TRAP bit)?

Thiazides
Rhabdo
AIDS
Paget’s ds

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What type of diuretics may cause hypercalcemia?

Thiazide diuretics

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Which gender more commonly gets primary hyperPTH? What is the most common cause of this?

Female

Single PTH adenoma

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What genetic disease may lead to primary parathyroid adenomas?

MEN2A/2B

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What happens to [Ca] with primary hyperPTH? [Phosphate]? [iPTH]? Urine [Ca]?

- Increased serum [Ca] - Decreased or = serum [phosphate] - Increased PTH - Increased urine Ca

What are the classical x-ray findings of hyperparathyroidism (hands, skull)?

Loss of cortical bones (wrists much greater than hip/spine on DXA scan) Salt and pepper skull

What is the cure for primary hyperPTH?

Surgical

True or false: it is necessary to look at ALL parathyroid glands if there is hyperPTH

True

What is the treatment for PT hyperplasia?

Subtotal parathyroidectomy, leaving 50 mg of PT tissue in situ OR in forearm

What is Hungry bone syndrome?

In pts treated for severe PTH bone disease, the bones mop up Ca as the parathyroid drive ceases

How do you monitor for a loss of a parathyroid gland during surgery? What should this show if you excised the right gland?

Intraoperative PTH More than 50% drop

What is the medical therapy for primary hyperPTH? (3)

- Avoid diuretics - Hydrate - Calcimimetics

Why is estrogen not used for treating hyperPTH?

Side effects

What is the role of bisphosphonates in the medical therapy of hyperPTH?

Decrease bone turnover

How often should you monitor pts with primary PTH pts undergoing medical therapy? What should be measured?

6 months -Serum [Ca], DXA scans

What are the two major secondary causes of hyperPTHism?

- Vit D deficiency | - Renal failure

What is familial hypocalciuric hypercalcemia?

Inactivating mutation in Ca sensor/receptor in the kidney/parathyroids, leading to mild hypercalcemia and normal to elevated iPTH

What is the treatment for asymptomatic familial hypocalciuric hypercalcemia?

nothing

How do you differentiate familial hypocalciuric hypercalcemia from hyperparathyroidism?

Familial will have normal urine Ca levels

What are the two general causes of hypoPTH?

Decrease production or response

What are the causes of hypoPTH?

- Surgical complications - Infiltrative ds - Autoimmune destruction

What is the autoimmune ds that can lead to hypoPTH?

AI Polyglandular syndrome type 1

What congenital syndrome may cause hypoPTHism?

DiGeorge syndrome

What metabolic disturbance can cause hypoparathyroidism?

Hypomagnesemia

What do the ssx of hypoparathyroidism depend on?

Degree and rapidity of onset of hypocalcemia

What are the acute ssx of hypoparathyroidism? Chronic?

- Acute = Paresthesias, Tetany | - Chronic = Apathy/depression

What are the brain CT findings with hypoparathyroidism?

Calcification of basal ganglia and benign intracranial HTN

What are the GI ssx of hypoparathyroidism?

Nausea/vomiting/ abdo pain

What are the EKG findings of hypocalcemia?

Prolonged QT

What are the eye effects of hypoparathyroidism?

Cataracts

What other diseases can mimic hypoparathyroidism

- Vit D resistance - Malabsorption - Decrease Ca mobilization from bone 2/2 metastatic ds

What GI organ complication can cause hypocalcemia?

pancreatitis

What hematological disturbance can cause a hypocalcemia?

albumin

What other ion should be measured with hypocalcemia?

A decrease in 25 vit D3 indicates what organ pathology?

Liver

A decrease in 1, 25 vit D3 indicates what organ pathology?

Kidney

How do you correct Ca levels with low albumin?

Nl [Alb] - pts [alb]x0.8 + [Ca]

What is the treatment for hypocalcemia?

- IV Ca gluconate | - Vit D3

Who should be treated for hypocalcemia?

If symptomatic or has complications

What is the new drug for treating hypocalcemia? How is this administered?

NATPARA (synthetic PTH analog) SQ QD

What is the role of NATPARA in treating hypocalcemia?

Reduces the dose of Vit D and Ca needed

True or false: NATPARA decreases the risk of renal calculi

True

What is pseudohypoparathyroidism types 1A and 1B?

End organ resistance to PTH d/t defects in the Gs subunits

What are the lab findings of pseudohypoparathyroidism types 1A and 1B? (Ca, phosphate, PTH)

- Hypocalcemia - Hyperphosphatemia - High iPTH

What is Albright's hereditary osteodystrophy pseudohypoparathyroidism type 1 A? SSx?

Type 1 pseudohypoparathyroidism that causes: - short stature - short metacarpals - Calcified basal ganglia - mild mental subnormality

What are the characteristic hand findings of Albright's hereditary osteodystrophy?

- Dimples over the MCPs - Brachydactyly of the hand - Short, wide thumb

What is the difference between pseudohypoparathyroidism types 1A and 1B?

Same, but no physical findings with 1b

What is pseudo-pseudohypoparathyroidism?

Same phenotype of pseudohypoparathyroidism type 1A, but NO biochemical abnormalities

What causes the super high PTH levels in pseudohypoparathyroidism?

Resistance to PTH, NOT deficiency

Salt and pepper skull is seen in what disease?

Primary hyperparathyroidism

What is the treatment for parathyroid hyperplasia?

Remove 3.5 glands

True or false: if a patient is symptomatic from primary hyperparathyroidism, you have to do surgery

True

What is the CrCl level that indicated the need for surgery with primary hyperparathyroidism? What other renal symptom indicates the need for surgery?

Less than 70%, OR have a h/o stone

What is the serum [Ca] level that indicated the need for surgery with primary hyperparathyroidism?

More than 1 mg/dL above the normal limits

What is the bone mineral density T score that indicated the need for surgery with primary hyperparathyroidism? What bone(s) must this be?

Less than 2.5 SD at ANY site

What is the age that indicated the need for surgery with primary hyperparathyroidism?

Less than 50 y.o.

What is tertiary hyperparathyroidism?

Continuous parathyroid stimulation in secondary leads to an autonomous parathyroid gland

Parathyroid Disease Flashcards

(77 cards)