Pathology of the parathyroid glands Flashcards Preview

Year 2 Endocrine > Pathology of the parathyroid glands > Flashcards

Flashcards in Pathology of the parathyroid glands Deck (22):
1

what is the most common cause of primary hyperparathyroidism?

parathyroid gland adenoma

2

what characterizes primary hyperparathyroidism?

- lesions WITHIN the parathyroid gland that secrete excessive PTH
- autonomous overproduction of PTH NOT suppressed by the negative feedback inhibition of elevated serum calcium

3

how does excess PTH cause hypercalcemia?

- increased bone resporption and calcium mobilization from bone
- increased renal tubular reabsorption of calcium in urine
- increased urinary excretion of phosphate
- increased renal synthesis of vitamin D - enhancing calcium absorption in gut

4

what is the main cause of flank pain / hematuria / renal stone formation?

filtered load of calcium exceeds kidney's ability for reabsorption - calcium is still excreted in urine

5

what are the clinical symptoms of primary parathyroidism?

STONES - kidney stones
BONES - osteomalacia, cystic lesions, brown tumors (osteitis fibrosa cystica)
GROANS - high calcium - produces gastrin - PUD (most common)
MOANS - depression

6

what type of tumor is a parathyroid adenoma?

SOLITARY

7

how is parathyroid carcinoma diagnosed?

- breaks through capsule
- metastasis

8

what differences are seen between normal parathyroid tissue and parathyroid adenoma?

- no fat cells
- primarily chief cells
- thin rim of normal parathyroid tissue

9

what is the second most common cause of primary hyperparathyroidism? what are the clinical features?

parathyroid hyperplasia

- all 4 glands are enlarged
- hyperplastic glands usually LACK the usual fat cells

10

parathyroid hyperplasia is most common in patients with what syndrome?

MEN syndrome

11

what is MEN syndrome?

parathyroid disease associated with tumors of the pancreas, adrenal, thyroid, and pituitary glands

12

how is parathyroid hyperplasia different from adenoma histologically?

hyperplasia - NO rim of normal parathyroid tissue

13

definition: secondary hyperparathyroidism

what is the most common cause?

parathyroid hyperplasia due to hypocalcemia from some OTHER causes

most common - chronic renal failure (low calcium and high PTH)

14

what constitutes a major problem stemming from secondary hyperparathyroidism?

bone disease ("renal osteodystrophy"leading to brown tumors)

15

parathyroid carcinoma: characteristics

- low malignant potential
- 50% cured by en bloc resection

16

what is the main morphological characteristic of parathyroid carcinoma?

FIBROUS BANDS (90% present)

17

parathyroid carcinoma: histology

- uniform cells resembling normal parathyroid cells
- cells arrayed in nodular or trabecular patterns
- cells enclosed in fibrous bands

18

what are the only reliable criteria for diagnosing parathyroid carcinoma?

invasion of surrounding tissues and metastasis

19

what are the causes of hypoparathyroidism?

- autoimmune disorder (main cause)
- iatrogenic
- DiGeorge syndrome

20

hypoparathyroidism: signs and symptoms?

- mental changes
- circumoral paresthesia
- chvotek sign
- trousseau sign

progresses to convulsions and tetany

21

how is hypoparathyroidism diagnosed?

decreased serum calcium and increased serum phosphate

22

hypoparathyroidism: treatment

- vitamin D
- calcium gluconate cookies
- recombinant human PTH