Pituitary gland secretes stimulating hormones

In response to the stimulating hormones, the target gland responds by secreting its hormone.

So... If there are normal to high levels of stimulating hormone present and low levels of target gland hormone available, the cause is the target gland because the target gland is not responding.

Where are growth hormone disorders produced?

Produced in the anterior pituitary gland under the influence of hypothalamic releasing (growth hormone-releasing hormone) and inhibiting (somatostatin) factors.

What is the target of growth hormone disorders?

Liver

What do growth hormone disorders affect?

it affects body mass

What does growth hormone disorders cause?

cause liver to release glucose

What does growth hormone disorder induce?

Lipolysis

What do growth hormone disorders increase?

it increases rate of protein synthesis

what does hypoglycemia stimulate?

It stimulates the release of growth hormones

What causes growth hormone deficiency?

Most relevant in children

HX of prolonged labor

Midline craniocerebral defects

Should be considered in children with nystagmus, retinal abnormalities, cleft lip or palate.

Most of the time is an abnormal growth near the brain

What is the pathogenesis of growth hormone deficiency?

Variety of presentations
Depend on the age at onset
May be caused by failure of hypothalamus to stimulate pituitary GH secretions or failure of the pituitary to produce GH
Midline brain tumors common cause

What does someone with a growth hormone deficiency look like?

Normal birth length and weight

Hypoglycemia

GH needed to maintain adequate glucose levels

Undescended testicles

Delayed dental eruption

Thin hair, poor nails

How do you treat growth hormone deficiencies?

hormone replacement

What causes a growth hormone excess?

Nearly always due to uncontrolled production of the hormone by a benign somatotropic tumor in the pituitary gland.

GH stimulates the liver and this causes an upregulated growth of soft and bony tissues

What is the pathogenesis of growth hormone excess?

Tumor present in childhood before epiphyses are closed: GIGANTISM. Rapid growth. Exceed 95% on growth charts. May be taller than 8 feet. May have heart failure or die

Tumor present after epiphyses are closed: acromegaly (soft tissue gets bigger). Fourth or fifth decade. Growth of short bones

What does someone with growth hormone excess look like?

Acromegaly:
-Increased ring/shoe sz
-Lrg frontal sinus/brow
-Lrg mandible
-Internal organs increase in size
-Increased ICP
-Does NOT affect height in adults

How do you treat someone with growth hormone excess?

Surgical removal of tumor

Medications

Describe growth hormone excess in children.

Increased linear growth and tall stature

Describe growth hormone deficiency in children.

delayed growth, fine features, short stature, proportionate

Describe growth hormone excess in adults.

soft tissue hyperplasia, increased bone density, large hands and feet, coarse facial features, thick leathery skin, weight gain, glucose intolerance

Describe growth hormone deficiency in adults.

may be associated with hypo-secretion of other pituitary hormones

Where are thyroid hormone T3 and T4 secretion controlled?

Secretion of thyroid hormones T3 and T4 is under control of thyroid-stimulating hormone (TSH) secretion from the anterior pituitary gland

What are thyroid hormones important for?

Metabolism; needed for normal growth and development of tissue

What causes hypothyroidism?

Most cases are primary (thyroid gland dysfunction)

Congenital

Irradiation of the Thyroid

Surgical removal of Thyroid

Lithium inhibits TH synthesis

What is the pathogenesis (characterized by) of hypothyroidism?

Lymphocytic thyroiditis (Hashimoto thyroiditis) most common:

Characterized by an enlarged thyroid gland (Goiter) due to lymphocytic infiltration. TH decreased producing increased TSH from pituitary gland.

What does someone with hypothyroidism look like?

*Goiter-growth on side of neck (in both hypo and hyperthyroidism)
*Hypometabolic state
*Weakness
*Lethargy
*Cold intolerance
*Constipation
*Myxedema (Facial edema)- thick hard tissue that develops
*Coarse hair
*Bradycardia

How do you treat hypothyroidism?

return to euthyroid state

Synthroid

Describe hypothyroidism in infants.

Cretinism

Newborns

Congenital

↑TSH↓T4

Deficiency →mental retardation

Psychomotor deficits

Rx - thyroid replacement

Describe myxedema

Occurs in severe prolonged thyroid deficiency

Generalized, non-pitting edema

Fluid retention due to accumulation of glycosaminoglycans in interstitial spaces

What does someone with myxedema present to the emergency room with?

AMS, thermoregulation problems

Hx of sepsis, trauma, certain medication use

What happens if myxedema is untreated?

"Myxedema coma"

medical emergency

60% mortality rate

Describe a myxedema coma

Life threatening

common in Older women

common in Cold months

CO2 retention & hypoxia

F & E imbalances
Hypothermia

What are the signs and symptoms of myxedema coma?

-Hypoventilation
-Lactic acidosis
-Hyponatremia
-Hypoglycemia
-Cardiovascular collapse
-Coma
-Hypothermia

How do you treat myxedema coma?

Prevention is #1

Supportive

No re-warming

Thyroid replacement

What is hyperthyroidism is also called...?

Graves disease

What is the cause of hyperthyroidism?

Thyroid gland hyperfunction with increased synthesis and secretion of T4 and T3

MC is from autoantibodies that stimulate TSH. This causes toxic goiter. End result-Graves Disease

What is the pathogenesis of hyperthyroidism?

More common in women

In response to high circulating T3 and T4 levels, the pituitary stops producing TSH.

TSH then falls very low

What does someone with hyperthyroidism look like?

-Hypermetabolic state
-Insomnia
-Restlessness, palpitations
-Heat intolerance
-Weight loss
-Thyromegaly
-Exophthalmos-(enlarged retro-orbital muscles)
-**Thyroid storm-life threatening (HR 170 BPM)

What causes thyroid storm?

When excessive amounts of hormone are released in circulation. (life threatening surge of TH)
-Stress response:
DKA, Trauma (physical/emotional), thyroid manipulation during surgery

Increased temperature

Severe tachycardia

Cardiac dysrhythmias

N/V/D

Life threatening hypermetabolic state

How do you treat thyroid storm?

Treatment: Beta Blockers

Surgical removal of thyroid

Cooling, supportive measure, steroids, antithyroid meds

What are present in both hyper and hypothyroidism?

Goiters

The adrenal cortex synthesizes what?

three different classes of steroid hormones:
Glucocorticoids (Cortisol)

Mineralocorticoids (Aldosterone)

Sex Steroids (Androgens)
Sugar, Salt, Sex

What do steroid hormones do?

provide negative feedback regulation of the hypothalamus and pituitary gland to suppress "turn off" adrenocorticotropic hormone (ACTH).

What disease is associated with adrenocorticotropic hormone (ACTH)

Addison's disease
*remember you must add stuff to ADDison's dz

What can hypersecretion of adrenocorticotropic hormone (ACTH) result from?

can result from disease of the adrenal cortex (primary adrenocortical insufficiency, Addison disease)

What can cause adrenocorticotropic hormone (ACTH) insufficiency?

Inadequate secretion of ACTH from the anterior pituitary. (secondary) OR

Lack of releasing hormone from the hypothalamus

Caused by destruction of the adrenal gland through idiopathic or autoimmune mechanisms (trauma or hemorrhage)

Addisonian crisis or acute adrenal insufficiency is a true emergency. Could be severe in patients who take corticosteroids routinely and then abruptly stop.

What does someone with adrenocorticotropic hormone (ACTH) insufficiency look like?

Most severe manifestations are r/t inadequate levels of circulation cortisol and aldosterone.

Reduced CO

Diminished vascular tone

Inadequate circulating volume

Early signs:
Weight loss, weakness, malaise, apathy, electrolyte imbalances

How do you treat someone with adrenocorticotropic hormone (ACTH) insufficiency?

Replace the absent of deficient hormone

In adrenal crisis: give glucocorticoids IV

What does addison's dz look like?

Hyperpigmentation of skin:
Darkened skin folds and creases

Oral mucus membranes become bluish

What disease is associated to hypercortisolism?

Cushing disease

What causes hypercortisolism?

Hyperfunction of the adrenal cortex. Adrenal adenoma (primary)

Hyperfunction of anterior pituitary ACTH-secreting cells (secondary).

What is the pathogenesis of hypercortisolism?

Excessive production of pituitary ACTH by adenomas stimulate the adrenal glands to overproduce hormones

In the US, exogenous steroids used in respiratory disease is the most common cause of Cushing syndrome