Parathyroid Pathology- LM

Question 1

What are the 2 types of parathyroid cells.

One is more pink, which one?

Which one secretes PTH

Answer 1

chief cells- purplish-PTH producing

oxyphil cells PINK

Question 2

Who want to talk through the various effects of PTH on the body?

Answer 2

Question 3

What is the cause of primary hyperparathyroidism?

Answer 3

Primary hyperparathyroidism: an autonomous overproduction of parathyroid hormone (PTH), usually resulting from an adenoma or hyperplasia of parathyroid tissue

Question 4

What is secondary parathyroidism caused by?

Answer 4

Secondary hyperparathyroidism: compensatory hypersecretion of PTH in response to prolonged hypocalcemia, most commonly from chronic renal failure.

Question 5

What is tertiary Hyperparathyroidism cause by?

Answer 5

Tertiary hyperparathyroidism: persistent hypersecretion of PTH even after the cause of prolonged hypocalcemia is corrected, for example after renal transplant

Question 6

What are the types and % occurrance of endocrine disorders causing hyperparathyroidism?

Answer 6

Adenoma: 85% to 95%

Primary hyperplasia (diffuse or nodular): 5% to 10%

Parathyroid carcinoma: ~1%

Question 7

What is a sestamibi scan?

How would and adenoma look different from hyperplasia on the scan?

Answer 7

a technitium radionucleotide is given and uptake is measured at the parathyroid glands.

Adenoma would most likely only have uptake in one place as opposed to mult places.

Question 8

WHat should you always see in a normal parathyroid gland?

Answer 8

Fat

The picture show the rim of the normal tissue with an adenoma above.

Question 9

WHat characteristic finding on histology of the bone would be present in hyperparathyroid disease?

Answer 9

Railroad tracking from osteoclast burrowing into the bone.

ALso called disected osteitis.

Question 10

How are most cases of primary HPT discovered?

What age group?

Answer 10

As many as 80% of patients with this condition are identified in the outpatient setting, when hypercalcemia is discovered incidentally on a serum electrolyte panel. Most cases occur in the 50s or later in life.

Question 11

The most common cause of primary hyperparathyroidism is a solitary parathyroid adenoma arising

Answer 11

Sporadically

Question 12

Familial syndromes are a distant second to sporadic adenomas as causes of primary hyperparathyroidism. WHat are the mutation present?

Answer 12

Multiple Endocrine Neoplasia, types 1 and 2, caused by germline mutations of MEN1 and RET, respectively

Question 13

Symptomatic, untreated primary hyperparathyroidism manifests with three interrelated skeletal abnormalities: What are they?

Answer 13

1.Osteoporosis- DUH

For unknown reasons, the increased osteoclast activity in hyperparathyroidism affects cortical bone (subperiosteal and endosteal surfaces) more severely than medullary bone.

2. Brown spots
3. osteitis fibrosa cystica (von Recklinghausen disease of bone).

Question 14

How are brown tumors formed?

Answer 14

The bone loss predisposes to microfractures and secondary hemorrhages that elicit an influx of macrophages and an ingrowth of reparative fibrous tissue, creating a mass of reactive tissue, known as a brown tumor. The brown color is the result of the vascularity, hemorrhage, and hemosiderin deposition, and it is not uncommon for the lesions to undergo cystic degeneration.

Question 15

WHat is osteitis fibrosa cystica (von Recklinghausen disease of bone).

Answer 15

The combination of increased osteoclast activity, peritrabecular fibrosis, and cystic brown tumors is the hallmark of severe hyperparathyroidism

Question 16

You thought you were done, there is one more biggy that you should know?

Hint: Ca+2

Answer 16

Kidney stones, no wait, stones, yep stones.

PTH-induced hypercalcemia favors formation of urinary tract stones (nephrolithiasis) as well as calcification of the renal interstitium and tubules (nephrocalcinosis). Metastatic calcification secondary to hypercalcemia may also be seen in other sites, including the stomach, lungs, myocardium, and blood vessels.

Question 17

Discuss as a group what the PTH and Calcium levels would be for malignancy and hyperparathyroidism?

Answer 17

Question 18

See how many causes of hypercalcemia you can get, a piece of candy to anyone who can get more than 4?

Answer 18

Question 19

Most people that have PT ademonas are asymptomatic, BUT what is the pneumonic for symptomatic people?

Answer 19

Question 20

We talked about renal failure being the main cause of secondary HPT, what are some other causes?

Answer 20

Although several other diseases, including inadequate dietary intake of calcium, steatorrhea, and vitamin D deficiency, may also cause this disorder

Question 21

What is the clinical course of secondary HPT?

What is the prognosis?

Answer 21

Basically the same as primary but dominated by the renal failure and not as severe.
Calcifications of heart, lung, stomach, blood vessels - pH changes

Can regress with control.

Question 22

WHat is calciphylaxis?

Answer 22

The vascular calcification associated with secondary hyperparathyroidism may occasionally result in significant ischemic damage to skin and other organs,

Question 23

How are pt with secondary HPT treated

Answer 23

Patients with secondary hyperparathyroidism often respond to dietary vitamin D supplementation, as well as phosphate binders, which decrease the prevailing hyperphosphatemia.

Question 24

WHat is tertiary HPT?

How would you treat?

Answer 24

parathyroid activity may become autonomous and excessive, with resultant hypercalcemia,

Parathyroidectomy may be necessary to control the hyperparathyroidism in such patients.

Question 25

WHat are the clinical sighs of Hypo PT?

Answer 25

The hallmark of hypocalcemia is tetany, which is characterized by neuromuscular irritability, resulting from decreased serum calcium levels. The symptoms range from circumoral numbness or paresthesias (tingling) of the distal extremities and carpopedal spasm, to life-threatening laryngospasm and generalized seizures.

Question 26

What are 2 names signes of Hypo PT?

What are they?

Answer 26

Chvostek sign and Trousseau sign.

1. Chvostek sign is elicited in subclinical disease by tapping along the course of the facial nerve, which induces contractions of the muscles of the eye, mouth, or nose.
2. Trousseau sign refers to carpal spasms produced by occlusion of the circulation to the forearm and hand with a blood pressure cuff for several minutes.

Question 27

WHat is hypo PT usually cause by?

Answer 27

Acquired hypoparathyroidism is almost always an inadvertent consequence of surgery, usually they think they are lymph nodes.

Question 28

Autoimmune hypoparathyroidism

WHat is it associated with?

Gene mutation?

Progression?

Answer 28

1. Autoimmune hypoparathyroidism is often associated with chronic mucocutaneous candidiasis and primary adrenal insufficiency;
2. mutations in the autoimmune regulator (AIRE) gene.
3. The syndrome typically presents in childhood with the onset of candidiasis, followed several years later by hypoparathyroidism and then adrenal insufficiency during adolescence.

Question 29

What does the CASR gene have to do with Autosomal-dominant hypoparathyroidism?

Answer 29

gain of function mutation that causes inappropriate CASR activity due to heightened calcium sensing suppresses PTH, resulting in hypocalcemia and hypercalciuria.

Question 30

How are dominant and recessive forms of familial isolated hypoparathyroidism different?

Answer 30

Autosomal-dominant FIH is caused by a mutation in the gene encoding PTH precursor peptide, which impairs its processing to the mature hormone.

Autosomal-recessive FIH is caused by loss-of-function mutations in the transcription factor gene glial cells missing-2 (GCM2), which is essential for development of the parathyroid.

Question 31

When does congenital abscence usually occur?

Answer 31

In conjunction with other malformations, such as thymic aplasia and cardiovascular defects, or as a component of the 22q11 deletion syndrome.

Question 32

WHat are some clinical features of hypo PT?

Answer 32

1. Mental status changes
2. Intracranial manifestations include calcifications of the basal ganglia, parkinsonian-like movement disorders, and increased intracranial pressure with resultant papilledema.
3. Ocular disease takes the form of calcification of the lens and cataract formation.
4. QT prolongation
5. Dental abnormalities.

Question 33

What is pseudo hypo PT?

Answer 33

end-organ resistance to the actions of PTH

SO it will have the same symptoms as Hypo PT but the PTH will also be high.