Download Endocrine System Overview

9/28/2016
Endocrine System Overview
Negative feedback
• Occurs naturally in the body • “Control mechanism” used to regulate secretion of hormones
• Hormones released when levels are low or there is a need to increase levels; then it “shuts it off”
An example: an event (such as an infection) causes hypothalamus to stimulate pituitary to release ACTH; ACTH causes adrenal cortex to release cortisol, which inhibits inflammation. When cortisol reaches a certain blood level, hypothalamus tells pituitary to stop releasing ACTH, adrenal gland stops production (this is negative feedback mechanism‐ it’s the “shut‐off valve”)
Group of glands that are integrated/interrelated, release hormones & affect every cell
in the body. Many diseases are related to too much/too little of 1 or more hormones.
Pituitary Gland
Other examples….
“Master gland”  Produces hormones that control other glands
 Works in conjunction with hypothalamus (attached to it)
 Part of CNS
 Controls growth, maturity, sexuality, & metabolism  Anterior lobe most productive‐
secretes many hormones such as ACTH (adrenocorticotropic hormone), prolactin, TSH, Growth hormones,… and others Can an autoimmune disease effect negative feedback?
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Adrenal Glands
Adrenal cortex releases Glucocorticoids
Located on each kidney
Have two parts, cortex and medulla (each release different hormones)
They control growth, inflammation, blood pressure, electrolyte balance & sexuality
Cortisol (naturally occuring “steriod”)
Normal adult produces 20 mg of cortisol every day.
This production increases in times of stress ….
(Cortisol helps the body respond to stress- anti-inflammatory)
When body under constant stress, body does not have
a chance to return to normal state. Results include:
High BP, blood sugar imbalances , lowered immunity,
increase in abdominal fat deposits, autoimmune diseases, etc….
A result of a “fast-paced society” ?
Addition of Synthetic Steroids: Dangerous!
Bodybuilders may take anabolic steroids to build muscle
Side effects are many to steroid use (even Rx)‐‐
including irritability & extreme aggressive behavior, impotence, skin changes (such as acne), feminization or masculinization, increased cardio problems, kidney/liver problems, swelling “puffiness” of the tissues, HPB See Haveles p. 214‐215
Glucocorticoids can also be given by Rx for illnesses (Prednisone/hydrocortisone)
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Negative feedback complication
‐Rule of Twos
If a patient takes 20 mg or more of hydrocortisone a day for two weeks, pituitary may not produce adequate ACTH for two years!
This causes a disruption in the naturally occurring negative feedback mechanism. Impaired wound healing & masking of infection
May precipitate adrenal crisis if patient becomes stressed (weakness, syncope, cardiovascular collapse, shock, or death)
This is how Glucocorticoids effect negative feedback!
Adrenal Insufficiency: Primary/Secondary
Cushing’s Syndrome
o Caused by excessive cortisol production
o Moon face, humpback (fat on back)
o Symptoms include: severe fatigue, high BP, high blood sugar, excess hair growth
o Can also be result of a tumor‐ either pituitary gland or adrenal gland (then Cushing’s Disease) or taking Rx cortisol for extended periods of time (i.e. for Rheumatoid Arthritis, Lupus, Diabetes, Hyperthyroidism, Asthma, Graves, Crohns, etc…)
o Diagnosis by a 24‐hour urine test
Adrenal Drugs used in Dentistry
too little cortisol or ACTH
Causes severe fatigue, muscle weakness, low blood pressure‐ can be life threatening (from adrenal crisis)
May be result of tumor, surgery, steroid use or autoimmune disease (destroys the adrenal glands) 3
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Thyroid gland
Thyroid gland effects:
o Produces Thyroid Hormones ‐
controlled by the hypothalamus and the pituitary gland <TSH>
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o T4 & T3
o Controls metabolism‐ and effects almost every cell and organ in the body
o Normal function requires iodine, which helps produce thyroid hormones
o In US, iodine deficiency rare – put in SALT (“iodized”)
Energy
Muscle function
Heart/lungs
Brain chemistry
Stomach/intestines
Skin, hair, nails
Sexual function/cycle/fertility
Bones
Butterfly shape- sits in base
of neck under Adam’s apple; in front
of trachea
How can you detect a goiter?
*use caution- why?
Subacute Thyroiditis vs Hypo • Temporary inflammation of thyroid gland
• Usually tender
• Treat with Ibuprofen
• Symptoms of hyperthyroidism
NORMAL
Thyroid should be
difficult to detect (due to size)
move gently side- to- side
Watch patient swallow
Ask about difficult swallowing (“lump in throat”), breathing, hoarseness, coughing,
etc…
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Hyperthyroidism
• Usually caused by Graves Disease (80‐90%)‐ autoimmune disease
How do they check the Thyroid?
Exopthalmus
• Can also be caused by benign or malignant nodules
• Some degree of Thyroid Eye Disease (TED) usually accompanies Graves
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Goiter (visual)
“Bruit”
Full Thyroid panel
• Severe consequences if left untreated
Treatment for Hypo *note: Hashimoto’s (auto) & Cretenism (congenital)
• Taking thyroid hormones every day
• Getting the right amount (this can be tricky)
• Testing hormone levels on a regular basis
Treatment Hyperthyroidism
 Radioactive Iodine Treatment (RAI) – ablation of thyroid gland
 Surgery- partial or complete removal of thyroid (thyroidectomy)
 Antithyroid medication- (ATD’s) – Methimazole
(Tapazole or Carbimazole) or Propylthiouracil (PTU)
 Other meds may include- Propranolol or Atenolol
(beta blockers for heart/tremors), Prednisone, antidepressants &
anti-anxiety, & insomnia medications
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In Dentistry….
The Hyperthyroid patient
• Epinephrine typically contraindicated with hyperthyroid patients
• Pain tolerance usually much lower (increase in anxiety)
• Be careful of aggressive palpation of the thyroid • Lymph nodes usually chronically swollen/tender (autoimmune disease)
Recognizing who is at Risk for Thyroid Disorders
o Women are affected by thyroid problems much more frequently than men (1:5 chance of developing thyroid issues); obvious hormone relationship
o Thyroid problems often arise after age 30
o About half of all the people with thyroid disorders are undiagnosed
o Pay special attention to children, women who have recently delivered a child or gone through a “crisis” period & elderly ****Myxedema Coma*** Life threatening
• Increased heart rate ‐ tachycardia
What is “Thyroid Storm?”
The majority of patients present with a nodule or goiter which typically does not cause symptoms Occasionally, symptoms such as hoarseness, neck pain, difficulty swallowing, and enlarged lymph nodes do occur
Types of thyroid cancer‐ papillary (most common), follicular, medullary, & anaplastic
**** MAJOR RISK FACTOR– low dose radiation
** The thyroid is very sensitive to radiation (Atomic bomb Japan; Chernobyl –
Ukraine, Russia & Belarus but also Europe where nuclear accident ‘86 & nuclear plant), STRESS, immune system responses, poor diet, environmental exposures, and other hormonal changes, possibly from ESTROGEN. Also Fluoride?!? (debate ongoing‐ blocks iodine); The thyroid gland can often simply “wear out” (similar to the pancreas); Potassium iodide in high doses is given as a “blocking agent” in case of nuclear emergency
Although as much as 50 % of the population will have thyroid nodules (very few are palpable) the vast majority are benign (usually 90%).
Young people usually do not have thyroid nodules However, with age, more develop. By the time we are 80, 90% of us will have at least one nodule!
Treatment includes total thyroidectomy and sometimes RAI
5 year survival rate approx 97% (if hasn’t spread)
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Autoimmune diseases are common,
affecting more than 23.5 million Americans …
No tissue/organ exempt from disease
Body’s IMMUNE system Malfunctions –
develop autoantibodies
Top 10 cause of death in females
$100 Million a year in medical costs
Prevalence increasing
identified at least 80 with possibly 40 additional ones
tend to co‐exist & predisposition in families
Family history?!?
Female Hormones
 Drugs used in Menopause – HRT (pills, patch, creams, Bioidentical, etc…) also for fertility, osteoporosis, menstrual issues, cancer, contraceptive *when does menopause occur (age)?
 Some replace only estrogen, progestin, & others multiple hormones, including testosterone
 Know key terms associated with menses & how dental meds can effect Rx OC ‐ also effects risk of dry socket
 DO effects oral tissues ‐‐ see oral health risk assessment in Wilkins  BMS recommendations– diet modifications, xylitol, avoid TP with SLS
 Can have serious side effects‐ do benefits out way risks?
 Bisphosphonates for osteo (more freq. in men or women?)
can be given by IV but strongly associated with osteonecrosis of jaw
Male Hormones
 Myth or reality?  Male hormones= Androgens
 Drugs used in Andropause or “Male Menopause” – HRT (pills, patch, creams, Bioidentical, etc…)
 Hormones can also be used as treatment for cancer
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