Endocrine part 2 Flashcards
the parathyroid glands are mainly composed of ________ cells. what do these cells do?
- Mostly composed of chief cells
- Secrete parathyroid hormone
what does parathyroid hormone control?
regulator of blood calcium levels
Besides chief cells, parathyroid glands also contain ______ cells
oxyphil
- they have an unknown function
where are the parathyroid glands located?
- Four small glands
- located on the POSTERIOR surface of the thyroid gland
A decreased level of ________ stimulates the synthesis and release of PTH
blood calcium
what are the specific actions of PTH?
↑ renal tubular reabsorption of calcium
↑ urinary phosphate excretion
↑ the renal conversion of vitamin D into its active form
↑ osteoclastic activity which releases calcium from the bones
what is the overall function of parathyroid hormone?
↑ level of free calcium which inhibits further PTH secretion
________________ is an important cause of hypercalcemia
hyperparathyroidism
name the 2 types of hypoparathyroidism, and what causes each:
- Primary
caused by an autonomous spontaneous overproduction of PTH - Secondary
A secondary phenomenon in pts with chronic renal failure
Primary Hypoparathyroidism is usually the result of what 2 disorders?
Usually the result of:
A) parathyroid hyperplasia (multiglandular)
B) an adenoma (solitary)
what groups are most likely to have PRIMARY hyperparathyroidism?
1) Adults
2) Women (4X as likely as men)
what are the “Classic clinical features” of PRIMARY Hyperparathyroidism?
“Painful bones, stones, abdominal groans, and psychic moans”
- fractures from osteoporosis
- kidney stones
- constipation, ulcers, gallstones
- depression/lethargy/seizures
T/F: most cases of primary hyperthyroidism are diagnosed after clinical signs appear
FALSE
- clinically silent hyperparathyroidism is detected early
Secondary hyperparathyroidism is usually the result of what?
Usually due to renal failure
what is hyperphosphatemia ? how does it lead to the production of PTH?
= increased amounts of phosphate in the blood because of decreased excretion
- that decreases serum calcium
- decreased serum Ca = increased PTH
Renal failure not only leads to hyperphosphatemia, but also to the failure to synthesize ______
vitamin D
This reduces calcium absorption in the intestines
Clinical characteristics of Secondary hyperparathyroidism:
Calcium levels are usually near normal
Symptoms dominated by renal disease
Renal osteodystrophy (growth of bone)
why are serum calcium levels usually within the normal range during secondary hyperparathyroidism?
Compensatory increase in PTH levels sustains serum Ca
treatments for Hyperparathyroidism :
Surgical removal of hyperplastic parathyroid glands
Kidney transplant may be beneficial
T/F: Hypoparathyroidism is more common than Hyperparathyroidism
FALSE
hyper = common
hypo = uncommon
causes of hypoparathyroidism:
A) Surgically induced, removed during thyroidectomy
B) Congenital absence
C) Autoimmune
what is Di George Syndrome?
congenital absence of parathyroid glands
clinical signs of hypothyroidism:
1) Hypocalcemia
2) Increased neuromuscular excitability
3) Cardiac arrhythmias
4) Increased intracranial pressure and seizures
The endocrine pancreas is composed of the _____________________
islets of Langerhans
what are the 4 major cell types of the islets of langerhans? what is the function of each type
Beta cells: produce insulin
Alpha cells: produce glucagon
Delta cells: produce somatostatin
PP cells: produce VIP, a pancreatic polypeptide
Somatostatin suppresses both __________ and _________ release
insulin and glucagon
VIP (a peptide produced by the pancreas) exerts several effects on what?
the G-I tract
_____________ is a group of metabolic disorders resulting in hyperglycemia (excessive amounts of glucose in the blood)
Diabetes Mellitus
Diabetes Mellitus is the leading cause of what other medical conditions?
Leading cause of:
- ESRD (renal failure)
- blindness
- lower limb amputation
what are normal blood glucose levels? what levels do diabetics have?
Normal = 70-120 mg/dL
Diabetic if either:
1) A random glycemia of ≥ 200mg/dL
2) Fasting glucose levels of ≥ 126mg/dL
3) abnormal glucose tolerance test
what causes type 1 diabetes? what does it result in?
Beta cells of the pancreas get destroyed by self-reactive T cells & autoAntiboides
Results in absolute deficiency in insulin production
Clinical features of Type 1 diabetes:
- diagnosed before age 20 in patients who have a normal weight
- Characterized by decreased blood insulin
- autoAbs are detectable in the blood of 70-80% of pt’s
name the 4 symptoms of type 1 diabetes:
1) Polydipsia (thirsty)
2) Polyuria (peeing)
3) Polyphagia (hungry)
4) Ketoacidosis (acetone breath)
what is the prognosis for type 1 diabetes?
guarded
- because of all the possible complications
T/F: Type 2 diabetes is an autoimmune-related disease
FALSE
it is NOT autoimmune
type 2 diabetes may be the result of what 2 conditions?
1) Insulin resistance (failure of target tissues to respond normally to insulin)
2) Decreased insulin secretion (may be normal in amount, but inadequate for the patient’s size if they are obese)
clinical features of type 2 diabetes:
1) Onset after age 40 (usually, but not always)
2) Obesity
3) Insulin levels in the blood may be normal or increased
4) Increased susceptibility to infection, periodontal disease
the symptoms of Type 2 diabetes are the same symptoms as type 1, but it is rare to have ______________
ketoacidosis
mainly found in type 1
Type 1 diabetes makes up ____% of all diabetes forms
10%
the other 90% is type 2
what happens to the pancreas during diabetes mellitus?
- Destruction of Islets
- Heavy inflammatory infiltrate
- Amyloid (protein fragments)
_____________ is responsible for 80% of the diabetes related deaths
Vasculopathy
what types of vasculopathy can result from Diabetes mellitus?
A) Atherosclerosis
B) Myocardial infarction, stroke
C) Gangrene of lower extremities
D) Microangiopathy (thickening of basement membrane)
diabetic nephropathy is the 2nd most common cause of diabetes-related death, and leads to what 2 conditions?
leads to:
1) hypertension
2) end stage renal disease (ESRD)
characteristics of Diffuse glomerulosclerosis:
A) 90% of diabetics within 10 years; not specific to diabetics
B) Microangiopathy around glomerular capillaries and deposition of matrix
C) Proteinuria, total renal failure
Characteristics of Nodular glomerulosclerosis:
A) 15-30% of persons with long-term diabetes
B) Ball-like deposition of matrix at the periphery of the glomerulus
C) Total renal failure
which form of glomerulosclerosis is specific to diabetics?
Nodular glomerulosclerosis
in which form of glomerulosclerosis would you see protienurea?
Diffuse glomerulonephritis
__________ due to diabetes is the 4th leading cause of blindness
Retinopathy
characteristics of diabetic retinopathy:
- Microangiopathy and microaneurysms
- Retinal detachment and vision loss
what 2 types of nerves are effected by diabetic neuropathy?
1) Can affect the peripheral sensorimotor nerves
2) Autonomic neuropathy
what are the clinical manifestations of diabetic autonomic neuropathy?
- causes disturbances in bowel and bladder function
- sexual impotence
what types of infections are more likely in patients with diabetes?
- infections of the skin
- TB, pneumonia
- deep fungal infections
- pyelonephritis
T/F: most Islet cell tumors arise from the endocrine pancreas
FALSE
most are from exocrine pancreas
______________ are functional tumors that arise in duodenum, peripancreatic tissues, or pancreas
Gastrinomas
characteristics of gastrinomas:
- gastric acid hyper secretion
- cause 90-95% of recalcitrant peptic ulcers
- cause Zollinger-Ellison Syndrome
what is Zollinger-Ellison Syndrome? how is it treated?
- Pancreatic islet cell tumor that causes
1) hypersecretion of gastric acid
2) severe peptic ulcers - Most are MALIGNANT (60%)
- treated by surgical resection
name the hormones secreted by the adrenal cortex:
1) Cortisol/cortisone
2) Aldosterone
3) Estrogen and Progesterone
what is secreted by the adrenal medulla?
Catecholamines
- Epinephrine (adrenaline)
- Norepinephrine
- Dopamine
T/F: the outer portion of the adrenal gland produces hormones, while the inner portion produces catecholamines
true
what are the 2 types of hyperadrenalism?
1) Hypercortisolism (Cushing Syndrome)
2) Hyperaldosteronism
Name the causes of Cushing’s Syndrome:
AKA Hypercortisolism
A) Excess administration of exogenous glucocorticoids
B) Primary adrenal hyperplasia or neoplasm
C) Primary pituitary source
D) Ectopic ACTH secretion by neoplasm
what is Cushing’s DISEASE?
- hypercortisolism due to primary pituitary source
- ACTH oversecretion
what site is a common ECTOPIC source of ACTH secretion? (that causes cushing’s)
the lungs
called “paraneoplastic cushing’s syndrome”
____________ cushing’s syndrome is caused by ingestion of exogenous glucocorticoids
Iatrogenic cushing’s syndrome
Short term effects of Cushing’s syndrome:
A) weight gain and hypertenstion
B) “Moon face” (accumulation of fat in the face)
C) “Buffalo hump” (accumulation of fat in the posterior neck & back)
what are the 2 “main” features of long-term Cushing’s syndrome?
Osteoporosis
mood swings
what is the result of Hyperaldosteronism ?
what effect does excess aldosterone have
Sodium retention, potassium excretion
Hypertension and hypokalemia
characteristics of Primary Hyperaldosteronism:
Very rare
Hyperplasia, neoplasm, idiopathic
**Decreased levels of plasma renin
characteristics of secondary Hyperaldosteronism:
Aldosterone release in response to activation of renin-angiotensin system
**Increased levels of plasma renin
what causes secondary hypoadrenalism?
Decreased stimulation of adrenals from deficiency of ACTH
secondary hypoadrenalism does not appear until ____% of adrenal gland has been destroyed
90%
what causes Acute Adrenocortical Insufficiency?
- occurs in patients that abruptly stop taking exogenous steroids
- rapid withdrawal of steroids or failure to increase steroids in response to an acute stress can precipitate an adrenal crisis
Can also be caused by adrenal hemorrhage or stress
effects of Acute Adrenocortical Insufficiency:
- Vomiting, abdominal pain, hypotension, coma, death
Acute Adrenocortical Insufficiency can also be triggered by stress in patients with ______________
Addinson’s disease
what is Addison’s disease?
- Primary Chronic Adrenocortical Insufficiency
- Progressive destruction of adrenal cortex
- Destruction of cortex prevents response to ACTH
clinical characteristics of Addison’s Disease:
A) Hyper-pigmentation (due to increased serum ATCH)
B) Progressive weakness
C) GI disturbances
D) craving for salt
causes of Addison’s disease:
1) Autoimmune destruction of steroid-producing cells
* Most common, 60-70% of cases**
2) TB
3) AIDS
4) Metastatic disease
what is the definition of Secondary Adrenocortical Insufficiency?
Any disorder of hypothalamus of pituitary that reduces output of ACTH
what key clinical sign is MISSING in patients with secondary adrenocortical insufficiency?
(its in primary, but not secondary)
no skin/mucosa pigmentation
primary will have ELEVATED ACTH, secondary will have lowered production
characteristics of Pheochromocytomas:
- neoplasm of chromaffin cells (adrenal glands)
- these cells make epinephrine - F > M, 30-60 yrs
- ** Hypertension
- surgically correctable
what percent of Pheochromocytomas are malignant? bilateral? extra-adrenal? familial?
each category has a 10% prevalence
- its why Pheochromocytomas are called the “10% tumor”
what are the 3 types of Multiple Endocrine Neoplasia (MEN) Syndromes
Types I, 2A, and 2B
Multiple Endocrine Neoplasias appear in what organs?
o Medullary Thyroid Carcinoma o Pheochromocytoma (chromaffin cells) o Parathyroid o Pituitary o Pancreas
what proto-onconogene is mutated in patients with MEN?
mult endocrine neoplasias
RET proto-onconogene
Mult endocrine neoplasia type 2B notable for its ________ manifestations
orofacial
characteristics of type 2B MEN:
- Mucosal neuromas (tongue, labial commisure)
- Large, blubbery lips
- Marfanoid body habitus
