Endocrine Flashcards
1
Q
Describe the mechanisms of endocrine control?
A
- Hormones: chemical messengers that control the flow of information between different tissues and organs
- Integrate and regulate body functions
- Released from endocrine glands
- Some organs contain endocrine cells and tissue
- Kidneys, heart, liver, stomach
2
Q
What does the Hypothalamus do?
A
- Hypothalamus controls release of anterior pituitary hormones
- Hypothalamus communicates with posterior pituitary gland via nerve tracts
3
Q
Examples of Hypothalamic hormones?
A
- Somatostatin
- Dopamine
4
Q
What does the Posterior Pituitary gland do?
A
- Posterior Pituitary gland (2 p’s)
- Secretes 2 hormones:
- Antidiuretic hormone (ADH/vasopressin)
- Oxytocin
5
Q
How does the Negative Feedback Loop work?
A
- Hypothalamus produces releasing hormone that stimulates production of tropic hormone by anterior pituitary
- Tropic hormone stimulates peripheral target gland to secrete hormone, which acts on target cells to produce physiologic response
- ↑ in blood levels of target hormone travel back to hypothalamus and AP leading to a ↓ in tropic hormone
- Maintains narrow range of target hormone in blood
6
Q
Example of Negative Feedback Loop?
A
- Thyroid hormone (T3, T4) levels lower than setpoint
- Hypothalamus secretes TRH
- TRH stimulates AP secretion of TSH
- TSH signals thyroid to produce T3 and T4
- ↑ in T3 and T4 turns off TRH and TSH signaling in hypothalamus and anterior pituitary gland
7
Q
Example of Positive Feedback Loop?
A
- Baby moves deeper into mother’s birth canal
- Cervix of uterus is stretched
- Nerve impulses are sent to hypothalamus
- Hypothalamus sends impulses to posterior pituitary, where oxytocin is stored
- Posterior pituitary releases oxytocin to blood; oxytocin travels to uterine muscle
- Uterus responds to oxytocin by contracting more vigorously
- At birth, stretching of cervix lessens and positive feedback cycle is broken
8
Q
Disorders of Anterior Pituitary are related to?
A
- GH
- TSH
- ACTH
9
Q
What causes Gigantism?
A
Hypersecretion of GH in children prior to closing of epiphyseal plates
10
Q
What is Acromegaly?
A
- Hypersecretion of GH during adulthood
- GH-secreting pituitary adenoma
- Enlarged body parts
- ↑ risk of HTN, CAD, and stroke
- GH affects glucose, lipid, and protein metabolism → hyperglycemia, insulin resistance, type 2 DM
11
Q
Acromegaly manifestations?
A
- Enlarged tongue
- Broad nose
- Protruding lower jaw
- Slanting forehead
- Enlarged hands and feet
- Nerve entrapment
- Kyphosis
12
Q
Acromegaly treatment?
A
- Correct metabolic abnormalities
- Remove or reduce pituitary tumor mass
- Relieve pressure to nerves
- Pharmacotherapy
- Somatostatin
- Inhibits GH secretion
- Dopamine agonists
- ↓ release of GH and prolactin
- Somatostatin
13
Q
What causes Diabetes Insipidus (DI)?
A
Central:
- Pituitary gland is not releasing enough ADH (antidiuretic hormone)
-or-
Nephrogenic:
- Kidneys are not responding to ADH
14
Q
Diabetes Insipidus (DI) manifestations?
A
- “Dry Inside”
- ↑ sodium, ↑ urine output
- ↓ BP (orthostatic hypotension)
- Neuro status (restlessness, weakness, agitation, seizures, coma)
15
Q
What causes SIADH?
A
- Hypersecretion of ADH
- Tumors
- CNS (pain, stress)
- Drugs
16
Q
SIADH manifestations?
A
- “Soaked Inside”
- ↓ sodium, ↓ urine output
- ↑ BP
- Neuro status (seizures, coma, death)
- GI effects (cramps, N/V)
- Edema
17
Q
SIADH treatment?
A
- Diuretics
- Loop diuretics, mannitol
- Hypertonic 3% saline
- Drugs that inhibit action of ADH in the kidneys
- conivaptan, tolvaptan
18
Q
What does the Thyroid Hormone do?
A
- ↑ metabolic rate
- ↑ cardiorespiratory demands
- ↑ GI motility and appetite
- ↑ skeletal muscle tone and reflexes
- ↑ CNS and SNS effects
19
Q
What is Hashimoto Disease?
A
- ↓ T3/T4 and ↑ TSH/TRH
- Autoimmune thyroiditis
- Inflammatory destruction of thyroid tissue by autoreactive T lymphocytes and thyroid autoantibodies
- Goiter due to inflammation
20
Q
Hypothyroidism manifestations?
A
↓ TH → ↓ metabolism and heat production
- Thickened skin
- Hair loss
- Constipation
- Lethargy
- Weight gain
- Bradycardia
- Sleepy all the time
- Anorexia (no appetite)
21
Q
Hyperthyroidism manifestations?
A
↑ TH → ↑ metabolism and heat production
- Diarrhea
- Increased appetite
- Weight loss
- Muscle weakness
- Altered menstrual flow
- Flushing
- Fatigue
- Palpitations
- Nervousness
- Irritability
Heat intolerance
Excitement (insomnia)
Angina
Restless
Tachycardia/Tremor
22
Q
What is Myxedema Coma?
A
- Life threatening condition: severe end-stage hypothyroidism
- ↓ cellular metabolism
23
Q
Myxedema Coma manifestations?
A
- Hypothermia
- Hypoventilation
- Hard, non-pitting edema
- ↓ level of consciousness/coma
- Hypotension, hypoglycemia, and lactic acidosis
- ↑ risk in older adults with comorbid conditions
24
Q
What is Graves Disease?
A
- ↑ T3/T4 and ↓ TSH/TRH
- Goiter due to hyperplasia of thyroid gland
25
Graves Disease manifestations?
- ↑ metabolic rate, heat intolerance
- ↑ cardiovascular function
- ↑ appetite, weight loss
- ↑ neuromuscular effects
- Exopthalmos
- Corneal dryness and conjuctivitis
26
What is Thyroid Storm?
- Rare but potentially life-threatening
- Fatal within 48 hours if untreated
- Hyperthyroid condition plus stressor → ↑↑↑ T3 and T4
- Ex. Infection, trauma, seizure, surgery, dialysis, emotional distress, pulmonary or cardiovascular disorder, OB complications
27
Thyroid storm manifestations?
- Hyperthermia
- ↑ HR, HF, ↓ BP → shock
- Neuro (restlessness, agitation, seizures, coma)
- GI (abdominal pain, N/V/D)
28
Thyroid storm treatment?
- Antithyroid meds
- Propylthiouracil (PTU), Methimazole
- Blocks conversion of T4 to T3
- Iodine
- Large doses inhibit production and release of T3 and T4
- Radioactive iodine therapy
- Surgery
29
What is Cushing Disease?
- ↑ secretion of ACTH due to pituitary tumor → ↑ cortisol
30
Cushing Disease manifestations?
- Chronically elevated cortisol levels
- Altered fat metabolism → adipose accumulation – ‘buffalo hump’ and ‘moon face’
- ↑ androgen levels, ↑ blood glucose levels, ↑ BP
- Visceral obesity
- Purple striae on chest and abdomen
- **Insomnia**
31
How to treat Cushing Disease?
Treat cause:
- Pituitary tumor
- Transsphenoidal endoscopic surgery
- Adrenal tumor
- Adrenalectomy
- Other ACTH secreting tumors
- Lung or pancreas
Lifetime hormone replacement therapy.
32
Post-op care Pituitary Tumor Removal?
Post-op assessment:
- Neuro
- Dressing
Complications:
- Diabetes insipidus
- CSF drainage
- Halo effect
- Glucose
Education:
- Hormone replacement therapy
- GH, TSH, ACTH
33
Post-op care for Cushing Disease?
- Transsphenoidal endoscopic surgery
- CSF leakage, prevent sneezing, and/or nose blowing
- Adrenalectomy
- Monitor for ↑ risk of hemorrhage
- Monitor BP, fluid overload, or diuresis
- Critical period for circulatory instability
- 24 – 48 hours
34
What is Addison Disease?
- Deficient adrenal cortical hormones
- Autoimmune destruction of adrenal cortical cells
- Inadequate corticosteroid and mineralocorticoid synthesis (↓ cortisol and aldosterone)
35
Addison Disease manifestations?
- Fatigue, orthostatic hypotension, weight loss
- Hypoglycemia, anorexia, N/V/D
- hyponatremia, hyperkalemia
- Vascular collapse and shock (Addisonian or adrenal crisis)
36
Addison Disease treatment?
- Lifetime hormone replacement therapy
- Glucocorticoid and mineralocorticoid supplements
- Hydrocortisone for cortisol deficiency
- Alendronate (Fosamax) to prevent osteoporosis caused by corticosteriods
- Regular schedule for meals and exercise
37
Addisonian Crisis treatment?
- Shock management
- Treat hypotension and electrolyte imbalances
- Corticosteroid therapy
- High-dose hydrocortisone replacement
- Protect against exposure to infection and triggers
