patho exam 6: alterations of hormonal regulation

what does failure of feedback systems cause

too much or too little hormone secretion

what does excessive or inadequate hormone production mean

there is a dysfunction of an endocrine gland

what is a positive feedback system

INCREASE the synthesis and secretion of a hormone

- ex. TSH released when thyroid hormone is low

OR

it can increase the target organ beyond its normal function

- ex. during labor oxytocin is secreted exponentially for UC

what is a negative feedback system

glands will respond to stimuli to DECREASE the synthesis and secretion of hormones

- most common form of endocrine control

- ex. HPA axis (hypthalamus (CRH), ant. pituitary (ACTH), adrenal cortex (CORTISOL)

what is target cell dysfunction

failure of target cell to respond to its hormone (hormone insensitivity

target cell dysfunction can also be caused because of what

receptor-associated disorders

ex. decrease in the number of receptors, impaired receptor function, antibody against specific receptors, etc

which hormones does the Anterior Pituitary excrete

ACTH (adrenal cortex)

GH (bones and muscle)

MSH (sin)

TSH (thyroid)

FSH/LH (testis/ovaries)

PRL (breast)

which hormones does the posterior pituitary secrete

ADH (kidneys)

oxytocin (breast/uterus)

what are diseases of the posterior pituitary

hyperfunction or hypofunction

hyperfunction of of posterior pituitary

too much ADH hormone (SIADH)

hypofunction of of posterior pituitary

too little ADH (diabetes insipidus)

syndrome of inappropriate ADH

levels of ADH are abnormally high

- water retention

common causes: malignancy (cancer), head injury, stroke, brain infection

clinical manifestations of SIADH

hyponatremia, urine hyperosmolality, hypervolemia, weight gain

diabetes insipidus

insufficiency of ADH

- can cause polyuria and polydipsia

- neurogenic: insufficient amounts of ADH likely from a head injury

- nephrogenic: insensitivity of renal collecting tubules to ADH, likely from kidney injury

clinical manifestations of diabetes insipidus

polyuria, nocturia, continuous thirst, and polydipsia

what are diseases of anterior pituitary

Hyperfunction

- hyperpituitarism

- hypersecretion of GH (acromegaly, giantism)

Hypofunction

- hypopituitarism

what can cause hypopituitarism

can be for either pituitary

- hypothalamus issue

- damage to pituitary stalk

- inability to produce hormones

- tumor or surgical removal

what are the different types of hypopituitarism

panhypopituitarism (all hormones are affected)

ACTH deficiency

cortisol deficiency

TSH deficiency

altered metabolism

FSH and LH deficiency

lack of secondary sex characteristics

GH deficiency

lack of growth in children (hypopituitary dwarfism)

hyperpituitarism: primary pituitary neuroendocrine tumors

commonly benign (called pituitary adenomas)

clinical manifestations of pituitary adenomas

HA, fatigue, visual changes, hypersecretion of pituitary from tumor/hyposecretion of neighboring anterior pituitary hormones

acromegaly

hypersecretion of GH during adulthood

- can cause in young mortality due to: cardiac hypertrophy, HTN, atherosclerosis, Type II DM, leading to coronary artery disease

what will you see with acromegaly

connective tissue proliferation

- enlarged tongue

bony proliferation

hyperfunction of thyroid

hyperthyroidism

ex. thyrotoxicosis, Graves disease, Thyroid storm

hypofunction of thyroid

hypothyroidism

ex. primary or secondary hypothyroidism, hashimoto disease

what are the primary thyroid gland hormones

T3 and T4 are the primary thyroid hormones

hypothalamus releases TRH --> ant. pituitary release TSH --> stimulates thyroid to release T3 and T4

difference between T3 and T4

T3 is the most potent of thyroid hormone

T4 is the most abundant thyroid hormone

what is primary thyroid function disorder

primary: dysfunction of the thyroid gland (alters TH production)

secondary: conditions cause alterations (alters TSH production)

what are clinical manifestations of hyperthyroidism

increased metabolic rate, heat intolerance, stimulation to the sympathetic NS, enlargement of the thyroid gland (goiter)

what is graves disease

hyperthyroidism

autoimmune disesase, develops antibodies to thyroid hormones

graves disease S/S

tachycardia/palpitations, heat intolerance, exophthalmos (bulging eyes), weight loss, goiter, high T4

what is thyrotoxic crisis (thyroid storm)

rare but life threatening; results from excess stress and have hyperthyroidism

- increased action of T4 and T3

clinical manifestations of thyrotoxic crisis (thyroid storm)

hyperthermia, tachycardia, high-output heart failure, agitation or delirium, N/V or diarrhea

what is hypothyroidism

deficient production of thyroid hormone by the thyroid gland

- primary hypothyroidism (high TSH, low T3 and T4)

- autoimmune thyroiditis (Hashimotos disease)

what is myxedema

hypothyroidism in adults; can lead to myxedema coma which is a medical emergency

- myxedema coma you will see: decreased LOC, hypothermia, hypoventilation, hypoTN

hypothyroidism S/S

fatigue, lethargy, low exercise intolerance, constipation, course/dry hair or hair loss, cold intolerance, dry/rough/cold skin

what does PTH do

"puts calcium into the blood"

what does primary hyperPTH do

excess secretion of PTH from one or more of the parathyroid glands and HYPERCALCEMIA

what are the clinical manifestations of primary hyperPTH

decreased bone density/osteoporosis (increased risk of bone fractures), general weakness, urinary calcium (calculi formation), depressed reflexes

what is secondary hyperPTH

increase in PTH due to chronic disease (chronic renal failure, Vit D deficiency and/or Ca

- HYPERCALCEMIA DOES NOT OCCUR!!

what is hypoPTH

abnormally low PTH levels

- depressed serum Ca levels

- increased serum phosphate levels

usual causes: parathyroid damage, autoimmunity, genetic mechanisms

clinical manifestations of hypoPTH

hypocalcemia, muscle spasms/hyperreflexia, chvostek and trousseau signs, phosphate retention

what is cushing syndrome

chronic excessive cortisol level, regardless of cause

what is cushing disease

overproduction of pituitary ACTH by a pituitary adenoma

- will see loss of diurnal and circadian patterns of ACTH and cortisol secretion

- lack of ability to increase ACTH and cortisol in response to stressors

what are causes of Cushing syndrome/Disease

prolonged steroid use

tumors

carcinoma of lung can lead to excessive secretion of ACTH

what are clinical manifestations of Cushing syndrome/Disease

weight gain of adipose tissue in trunk/face/cervical areas (moon face/buffalo hump)

sodium and water retention, glucose intolerance, HTN (fluid overload)

what is addisons disease

Primary adrenal insufficiency (rare/autoimmune mechanisms)

- inadequate corticosteroid and mineralocorticoid synthesis = elevated ACTH

Secondary adrenal insufficiency

- due to prolonged administration of exogenous glucocorticoids (which supresses ACTH secretion)

what are common causes of addisions disease

autoimmune response (most common) can also be a pituitary disease

what are sx of Addison's disease

sx not there until 90% of adrenal cortex not working

- weakness/fatigue/hypoTN/hyponatremia/hyperkalemia

- bronzed skin, hypoglycemia, weight loss

what is acute adrenocortical insufficiency: "Addisonian Crisis"

life-threatening crisis - aka adrenal crisis due to sudden withdrawal of corticosteroid medications/sudden pituitary gland destruction/following adrenal surgery