Endocrine Flashcards
1
Q
Major endocrine glands and hormones
A
- Glands: hypothalamus, pituitary, thyroid, parathyroid, pancreas, & adrenals
- Hormones: a chemical messenger with a target cell; insulin, oral contraceptives, steroids
- Receptors/Effect: intracellular signals (ATP, ADP, cAMP pathways); direct stimulation (transport channels & aquaporin production)
2
Q
Describe the functions of the hypothalamus & pituitary glands
A
- regulates growth hormone both releasing & inhibiting; thyrotropin releasing hormone; & corticotropin releasing hormone
- positive & negative feedback loops
3
Q
Describe the feedback loops related to the hypothalamus
A
- Hypothalamus -> thyrotropin releasing hormone (TRH) -> anterior pituitary -> TSH -> thyroid -> T4 & T3
- Normal body temp. -> increased body temp. -> thermostat in hypothalamus activates cooling mechanism -> blood vessels in skin dilate & sweat -> body temp. decreases -> normal body temp. -> body temp. decreases -> thermostat in hypothalamus activates warming mechanisms -> blood vessels in skin constrict & shivering -> body temp. increases -> normal body temp.
4
Q
Describe a positive feedback loop
A
- the loop will continue with more and more until told to stop (ex: pregnancy won’t stop until birth, blood clot formation to stop bleeding)
5
Q
Describe the functions of the thyroid gland
A
- Free and total thyroid: T4/T3 (mostly makes T4)
- Metabolism
- Temperature management
- Respiration
- Growth & development
- Negative feedback loop
6
Q
Signs and symptoms of hypothyroidism
A
- Fatigue*
- Bradycardia
- Muscle weakness*
- Dry skin
- Neck swelling (Goiter)
- Constipation
- Increased weight gain*
- Cold imbalance*
- Facial edema
- Irregular menstrual period
- Increased cholesterol
- Hair loss
7
Q
Supplementation for hypothyroidism
A
- T4 Synthroid: Levothyroxine
- T3 Cytomel: Liothyronine
- T4/T3 combination: Armour Thyroid
- T4 has a long half life (7-10 days)
- onset of action takes 3-5 days and peaks ~6 wks
- T3 has more side effects
- T4 is metabolized first & because it’s potent you can see if the pt will have any ADRs quicker
8
Q
Describe Hashimoto’s disease
A
- most prevalent hypothyroid disease
- inherited with unknown gene expression
- women more than men
- 40-60 yrs of age
- immune cells target & destroy thyroid tissue
9
Q
Describe Myxedema Coma
A
- severe form of hypothyroidism
- 20-60% mortality rate
- no edema/no coma
- deteriorating mentation
- Tx: supportive care, IV levothyroxine, & reverse underlying cause if known
10
Q
Signs and symptoms of hyperthyroidism
A
- Artial fibrillation
- Heart failure
- Osteoporosis
- Thromboembolism
- Tremor
- Tachycardia/Tachypnea
- Altered mental status
- Fatigue
- Muscle weakness
- Heat intolerance
- Nervousness
- Neck swelling (Goiter)
11
Q
Treatment for hyperthyroidism
A
- Propythiouracil (PTU): blocks new hormone synthesis, blocks T4 -> T3 conversion, preferred agent given dual mechanism, 3x daily, bone marrow suppression & hepatotoxicity
- Methimazole: blocks only new hormone synthesis, minor hepatotoxicity, 1x daily
12
Q
Describe Graves disease
A
- hyperthyroid disease
- autoimmune disorder
- rapid/irregular HR
- osteoporosis
- muscle weakness
- vision changes
- weight loss
13
Q
Describe thyrotoxicosis
A
- 1% prevalence: most common cause of Graves disease, could also be gestational or drug induced
- 1% will experience thyrotoxicosis crisis “Thyroid Storm”: extremely elevated T4 and T3; 20% mortality rate
14
Q
Treatment for thyrotoxicosis “Thyroid Storm”
A
- symptom management with beta blocks (slows HR)
- Thionamides (some side effects): propythiouracial (PTU) & methimazole
- Iodine (some side effects): blocks new hormone synthesis & release; tachyphylaxis ~2 wks
- Radioactive Iodine (permanent)
- Thyroidectomy (permanent)
15
Q
Describe the effect iodine has on the body
A
- gives an overload of the thyroid
- if seen on a patient chart it means they are getting ready to go into a procedure
