MNT Endocrine Flashcards
hypothyroidism
> fatigue
weight gain
constipation
increased sensitivity to cold
dry skin
depression
muscle aches
reduced exercise tolerance, >irregular or heavy menses
Hashimotos
-there are no signs or symptoms that are unique to
Hashimoto’s thyroiditis” except elevated TPO (thyroid peroxidase) antibodies detected in blood tests.
Hyperthyroidism
> nervousness
-irritability
-increased sweating
-heart racing
-anxiety
-difficulty
-sleeping
-thinning of skin
-fine brittle hair
-weakness in muscles (upper arms and thighs)
-more frequent bowel movements (but diarrhea is uncommon)
-lose weight despite good appetite
-menstrual flow may lighten/periods may occur less
-Initially the patient has more energy but as the body breaks down, they become fatigued.
-Graves’ dermopathy (skin condition on shins
Graves disease
eye symptoms, such as Graves’ ophthalmopathy or orbitopathy
(1/3 of all individuals diagnosed) “bulging Eyes”
Nonmodifiable risk factors (Thyroid)
● There is a “genetic predisposition for the development of Hashimoto’s Thyroiditis in patients with positive family history of the disease (43.59% of patients with positive family history developed Hashimoto’s Thyroiditis themselves).
● Exposure to Epstein Barr Virus 7
● THEA Score: Verified, Predictive Score for the Occurence of Events in a Euthyroid Cohort of Women with First- or Second-Degree Relatives with Proven AITD
General nutrients of concern
Iodine
● Magnesium
● Selenium
● Vitamin D
● Iron
● Zinc
● Vitamin C
● Vitamin E
● Vitamin B12
General lifestyles of concern
● Overnight shifts
● Smoking
● Environmental, Toxin and Heavy Metal Exposure
● Stress; history of trauma
● Gut microbiota
● Other infections
● Prior use of medications
Role of nutrition professional (Thyroid)
-Inside scope of practice
○ Educate client on thyroid function
○ Support thyroid through food and supplementation
○ Support thyroid through lifestyle changes
○ Ensure client is taking prescription medication as directed
○ Communicate, if appropriate consent has been received, with endocrinologist or
PCP regarding client’s care plan
● Outside scope of practice
○ Recommend to a client change or stop prescription medicine
○ Diagnosis a client with a form of thyroiditis
Basics of Thyroid
Thyroid Stimulating Hormone (TSH) is the “test first” marker; this marker is inversely associated with thyroid function; TSH is a component of the metabolic pathway to ensure sufficient release of thyroid hormone
● Graves’ disease is the autoimmune disorder associated with hyperthyroidism (but not all hyperthyroidism is Graves’)
● Hashimoto’s disease is the autoimmune disorder
associated with hypothyroidism (but not all hypothyroidism is Hashimoto’s)
Thyroid hormones explained
- Low blood level of thyroid hormones or low metabolic rate stimulates release of TRH (Hypothalamus)
- TRH carried by hypophyseal portal veins to anterior pituitary stimulates release of TSH (anterior pituitary gland)
- TSH released into blood stimulates thyroid follicular cells
- Thyroid hormones released into blood by collicular cells
- Elevated level of thyroid hormones inhibits release of TRH and TSH
- Where is the Thyroid gland located? What shape is the thyroid gland?
Butterfly shaped structure that lies on the windpipe below the Adam’s apple. Wings wrap themselves around the windpipe. The Thyroid isthmus (body) lies over the second and third ring of the trachea and opposite the fifth, sixth and seventh cervical vertebrae. Right lobe larger than left. Sheath attaches thyroid to trachea and larynx. Pyramidal lobe is present in the center.
- Define and describe the roles of TSH, TGB, TRH, Including secreting gland for each.
- Low blood level of thyroid hormones or low metabolic rate stimulates release of TRH (Hypothalamus)
o Low T4 levels are the biggest stimulant of TRH - TRH stimulates the pituitary to produce a hormone called Thyroid stimulating Hormone (TSH) (Anterior pituitary)
- TSH released into blood stimulates thyroid follicular cells
- Thyroid hormone released into blood by follicular cells
- Elevated level of thyroid hormones inhibits release of TRH and TSH
o High T3 is the strongest inhibitor of TRH - TRH (Hypothalamic Releasing Hormone) in Hypothalamus
- TSH (regulatory hormone) produced in the pituitary to control Thyroid function
- Pituitary responds to T3, T4, and TSH
- TBG Thyroid binding globulin:
o The main binding protein (produce in the liver)
- What hormone(s) does the thyroid gland manufacture?
T4 (90%),T3 (10%), rT3 (1 %), T2 (very small amount)
Thyroid gland is the only gland to store its own hormone. 100 day supply.
- What are the roles of thyroid hormones?
- Thyroxine (T4) is the primary hormone your thyroid makes and releases.
o Produced in Thyroid in response to TSH
o Converted into T3(triiodothyronine) or Reverse T3 (rT3) deiodination.
o T4 is a stored in follicle or released into blood stream.
*Triiodothyronine (T3): produces lesser amounts of T3 than T4 but much greater affect on metabolism than T4. - Reversed Triiodothyronine (RT3): very small amounts, reverses the effects of T3
*Calcitonin: Helps regulate the amount of calcium in your blood
To make thyroid hormone, you must need iodine. Your thyroid gland traps iodine.
What function does the thyroid regulate
- metabolism: increase basal metabolic rate (BMR), amount our body uses during rest.
- Heart rate: increase the heart rate, stroke volume, and cardiac output.
- Body temperature
- Digestion: affect how quickly food moves through your digestive tract.
- Muscle strength: cause the development of fast twitch muscle fibers.
- Brain development: and maturation
- Bone maintenance and growth.
- Nervous system, increased alertness, attention, and quicker reflexes.
- Reproductive health:
- Menstrual cycle
The Thyroid gland produces thyroid hormones.
- Where (in the body) does the conversion of T4-T3 take place?
peripheral tissue
Of the four iodinated molecules, which are biologically active?
T3 is considered the most metabolically active thyroid hormone.
- Why is tyrosine important?
Non essesntial amino acid that body produces from Phenylanine. It plays a role in many vital bodily functions: Neurotransmitters (dopamine, norepinephrine, epinephrine which affect mood, memory and alertness) Melanin : pigment that protects skin from sunburn
Hormones: helps adrenal, thyroid and pituitary glands produce and regulate hormones
Protein structure:
Cognitive function: improve especially under stress.
Why is 5’-doiodinase important?
- Enzyme responsible for the conversion of T3 (selenium dependent enzyme)
- Responsible for conversion of rT3 (not selenium dependent)
What is the function of the enzyme thyroid peroxidase (TPO
enzyme primarily found in the thryoid gland. Plays a crucial role in the production of thyroid hormones by facilitating the process of adding iodine to a protein call thyroglobulin.
-Assists in the chemical reaction that adds iodine to a ptoetin called thyroglobulin.
What is iodination?
*The substitution or addition of iodine atoms in organic compounds.
Iodination of thyroglobulin, synthesis of thyroid hormone, extracellular process that takes place inside the thyroid follicles.
What minerals are necessary for the conversion of thyroid hormones?
Iodine and selenium *Iodine ( key component of the thyroid hormone itself
* Selenium (crucial for the enzyme that converts the inactive T4 hormone to the active T3 form.
Other minerals that play a role:
Iron: deficiency can be linked to hypothyroidism (proper conversion of T4 and T3)
Zinc: important for conversion.
Copper: important for normal function.
What is the parathyroid?
Set of four pea sized glands that sit on the back of the thyroid gland in the neck.
-produce and release parathyroid hormone(PTH)
-PTH regulates calcium levels in the blood.
-When calcium levels are low, parathyroid releases PTH(works with Vitamin D) to increase calcium absorption from food.
-When calcium increase, the parathyroid glans stop releasing PTH.
Disorders: Hyperparathyroidism, Hypoparathyroidism,