Term
| Where is the parathyroid derived from? |
|
Definition
| pharyngeal pouches along w/the thymus |
|
|
Term
| What are the 3 functional cell types of the parathyroid? |
|
Definition
chief cells: pale, eosinophilic; main source of PTH
oxyphil cells: granular eosinophilic cytoplasm due to mitoch
water clear cells: optically clear cytoplasm due to glycogen |
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Term
| What usually triggers suspicion of hyperparathyroidism? What other findings might there be? |
|
Definition
elevated serum calcium
also:
renal calculi
nephrocalcinosis
osteitis fibrosa cystica (from over re-sorption of bone)
pancreatitis
peptic ulcer
muscle atrophy
emotional disorders |
|
|
Term
| What test do you use to distinguish between hyperparathyroidism and other causes of hypercalcemia? |
|
Definition
corticosteroid suppression test
If due to hyperPTH, hypercalcemia is not suppressed
suppressed if secondary to sarcoidosis, vit d toxicity, myeloma or other causes |
|
|
Term
| describe a typical parathyroid adenoma |
|
Definition
| solitary and encapsulated w/ a rim of normal glad; decreased fat content |
|
|
Term
| what is diagnostic of malignancy for parathyroid tumor? |
|
Definition
| invasion into surrounding tissues (skeletal muscle) |
|
|
Term
| What symptoms are seen with hypoparathyroidism? |
|
Definition
eye problems: cataracts, spiculate opacities of the lens
mental retardation
fungal infections of the nails and mouth
patchy alopecia
dental hypoplasia |
|
|
Term
| What stimulates secondary hyperparathyroidism? |
|
Definition
| low serum calcium and possibly high serum phosphate |
|
|
Term
| Explain what happens in secondary hyperparathyroidism |
|
Definition
PTH is increased and glands become hyperplastic
PTH promotes CA reabsorption in the tubules, but very little CA makes it to the tubules
main source of CA becomes the bones
PTH stimulates osteoclastic activity leading to subperiosteal resorption and cyst formation |
|
|
Term
| What happens in pseudohypoparathyroidism |
|
Definition
short stature, shortened metacarpals and ectopic bone
phosphate continues to be reabsorbed
CA may be bound in the gut due to high levels of serum phosphate
bones may be normal or show resorptive changes |
|
|
Term
| clinical manifestations of pseudohypoparathyroidism |
|
Definition
short stature with a thickset figure
shortening of the 4th and 5th metacarpals
knuckle dimpling
subperiosteal bone resorption
soft tissue nodules with ulceration
shortened metatarsals |
|
|
Term
| primary hyperaldosteronism |
|
Definition
increased EC fluid, increased NA and decreased K (alkalosis)
polydypsia
polyuria
HTN
Chvostek's sign
Trousseau's sign |
|
|
Term
|
Definition
tapping the facial nerve induces contractions of the muscles of the eye mouth or nose
seen in hyperaldosteronism |
|
|
Term
| What is Trousseaus' sign, and when is it seen? |
|
Definition
occluding blood flow to the forearm and hand for several minutes induces carpal spasm which disappears the moment blood is allowed to flow
seen in primary hyperaldosteronism |
|
|
Term
|
Definition
| aldosterone producing adenomas of the adrenal cortex |
|
|
Term
| What is the most common cause of primary hyperaldosteronism? |
|
Definition
|
|
Term
| What is glucocorticoid suppressible hyperaldosteronism? |
|
Definition
runs in families
mutation causes a developmental derangement of the cortical zones and formation of hybrid cells
responds to dexamethasone suppression |
|
|
Term
| What are the clinical findings in adult adrenogenital syndrome? |
|
Definition
| baldness, acne, hirsutism, small breasts, variable pigmentation |
|
|
Term
| What hormone is deficient in congenital adrenal hyperplasia? |
|
Definition
|
|
Term
| What are acute causes of adrenal cortex hypofunctioning? |
|
Definition
waterhouse friedrichsen
rapid withdrawal of exogenous steroids
massive adrenal hemmorhage
DIC |
|
|
Term
| What causes waterhouse friedrichsen? |
|
Definition
| most often infection w/neisseria meningitides (but also pseudomonas, pneumococci, haemophilus influenza) that leads to DIC, adrenal hemorrhage and hypotension |
|
|
Term
| What are the clinical findings in acute adrenal cortical insufficiency |
|
Definition
| hypotension, purpura and cyanosis, spiking fevers; maybe a meningococcal rash |
|
|
Term
| What are the clinical manifestations of chronic adrenocortical insufficiency (Addison's)? |
|
Definition
pigmentation of mucous membranes
hyperpigmentation of skin creases and scars as well as nipples and areas exposed to friction
freckling and vitiligo
small breasts
hypogonadism
hypotension
weight loss
muscle weakness |
|
|
Term
| What is the etiology of Addison's disease? |
|
Definition
atrophy of the adrenal cortices due to autoimmune adrenalitis
infection, especially TB(necrotizing granulomatous inflammation) or fungal infection
metastatic tumors |
|
|
Term
| secondary adrenocortical insufficiency |
|
Definition
reduced output of ACTH due to dysfunction of the hypothal or pituitary
similar to addison's but hypopigmentation |
|
|
Term
| What are the functions of catecholamines? |
|
Definition
| increase BP and CO, bronchial dilation, intestinal inhibition, increased glycogenolysis (inducing hyperglycemia), CNS excitability |
|
|
Term
| What is the clinical presentation of pheochromocytoma? |
|
Definition
| abrupt onset of HT associated w/tachcardia, palpitations, headache, sweating, anxiety |
|
|
Term
| What is pheochromocytoma the 10% tumor? |
|
Definition
10% familial, often bilateral
10% of sporadic cases are bilateral
10% are malignant |
|
|
Term
| What is seen microscopically and on EM in a pheochromocytoma? |
|
Definition
large cells with granular cytoplasm arranged in nests (zellballen)
cells may be pleiomorphic
EM: electron dense neurosecretory granules that contain catecholamines |
|
|
Term
| Where do you see zellballen? |
|
Definition
|
|
Term
| What is the most common tumor of childhood outside the skull? |
|
Definition
neuroblastoma
may originate anywhere in sympathetic nervous system, but 25-30% arise in the adrenal medulla |
|
|
Term
| What is the histology of a neuroblastoma? |
|
Definition
small, primitive cells w/little cytoplasm arranged in sheets
Homer-Wright psuedorosettes- tumor cells palisading aroudn a central space containing fibrillar extensions of the cells |
|
|
Term
| What is the difference in clinical symptoms between primary and secondary adrenal insufficiency? |
|
Definition
| secondary shows hypopigmentation instead of hyperpigmentation |
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