Conditions Effecting the Endocrine System and Pharmacology Flashcards
Exam 3
A&P of thyroid gland:
Where is the thyroid located?
Located at the base of the neck below the larynx
A&P of thyroid gland:
What does the thyroid wrap around?
Wraps around the trachea
A&P of thyroid gland:
What does the thyroid consist of?
Consists of two lobes, one on either side of the trachea, connected by a thin band of tissue
A&P of thyroid gland:
What does the thyroid regulate?
Regulates metabolic rate, heart and digestive function, muscle control, and bone maintenance
A&P of thyroid gland:
What does the thyroid contain?
A vascular gland, containing several functional units (follicles) that secretes hormones:
A&P of thyroid gland:
What hormones does the thyroid secrete?
Thyroxine (T4) and Triiodothyronine (T3)
A&P of thyroid gland:
Thyroxine (T4) and Triiodothyronine (T3): What do they stimulate?
Stimulates cell growth and tissue differentiation
Stimulate energy use
Stimulate the heart – increased rate/force of ctx
A&P of thyroid gland:
How does the Thyroxine (T4) and Triiodothyronine (T3) stimulate energy use?
Raises BMR, heat production, oxygen consumption
A&P of thyroid gland:
What does Thyroxine (T4) and Triiodothyronine (T3) do to the heart when it stimulates the heart?
– increased rate/force of ctx better CO, increased O2 demand
A&P of thyroid gland:
What percent of circulating hormones are Thyroxine (T4) and Triiodothyronine (T3)?
95% of circulating thyroid hormones
A&P of thyroid gland:
What are Thyroxine (T4) and Triiodothyronine (T3) needed for?
Needed for normal brain & nervous system development
A&P of thyroid gland:
What is the process in which T3 and T4 are made?
Hypothalamus stimulates pituitary gland to produce the thyroid-stimulating hormone (TSH), which stimulates T3 and T4.
Regulation of Hormone Release :
Hormones are released in response to what?
In response to an alteration in the cellular environment
Regulation of Hormone Release :
Hormones are released to maintain what?
To maintain a regulated level of certain substances or other hormones
Regulation of Hormone Release:
What are hormones regulated by?
Hormones are regulated by chemical, endocrine, or neural factors
Regulation of Hormone Release:
Where are hormones released and distributed?
Hormones are released into the circulatory system by endocrine glands and distributed throughout body
Regulation of Thyroid Hormone Release (2 of 2):
Positive feedback: What is it?
Response to stimulus increases synthesis and secretion of hormone
Regulation of Thyroid Hormone Release (2 of 2):
Example of Positive feedback with thyroid hormone?
Thyrotropin-releasing hormone (TRH) released from the hypothalamus in response to low thyroid levels
Regulation of Thyroid Hormone Release (2 of 2):
Where does secretion of thyroid hormone occur?
Stimulates secretion of thyroid stimulating hormone (TSH) from anterior pituitary
Regulation of Thyroid Hormone Release (2 of 2):
Positive Feedback: What kind of hormone is secreted?
stimulates secretion of Thyroid Hormone (TH) T3 & T4
Monitoring Thyroid Function:
What are the thyroid hormones? Which is more active?
T3 (more active form), T4
Regulation of Thyroid Hormone Release (2 of 2):
Negative feedback: What is it?
Response to stimulus decreases synthesis and secretion of hormone
Regulation of Thyroid Hormone Release (2 of 2):
Negative feedback: What happens?
Increased T3 & T4 levels feedback on pituitary & hypothalamus to inhibit TRH & TSH
Decreased synthesis of thyroid hormones
Monitoring Thyroid Function:
What is 1st line for screening, diagnosis and treatment monitoring?
Serum TSH
Monitoring Thyroid Function:
What does Serum TSH distinguish between?
Distinguishes primary VS secondary disorders
Monitoring Thyroid Function:
1° disorder: Thyroid gland is at fault
What do primary disorders cause?
These disorders cause 2ndry feedback of pituitary TSH
Monitoring Thyroid Function:
What are primary disorders?
1° disorder: Thyroid gland is at fault
Monitoring Thyroid Function:
1° disorder: Thyroid gland is at fault
What happens when the TH is high?
When TH is high (hyperthyroid), TSH secondarily decreases because of neg feedback
Monitoring Thyroid Function:
What happens when TH is low?
When TH is low (hypothyroid), the TSH will be elevated because it’s trying to increase thyroid gland production of TH
Monitoring Thyroid Function:
What is a secondary disorder?
2° disorder: related to pituitary gland disorder
Monitoring Thyroid Function:
What occurs in secondary disorder?
Excessive TSH production –> TH is elevated secondary to the primary elevation of TSH concentration
Monitoring Thyroid Function:
2° disorder: related to pituitary gland disorder
What does low TSH production lead to?
Low TSH production –> TH decreased
Alterations of Thyroid Function:
Primary thyroid disorders: What is it?
Dysfunction or disease of thyroid
Alterations of Thyroid Function:
Primary thyroid disorders: What happens to TH levels?
Increased or decreased thyroid hormone (TH)
Alterations of Thyroid Function:
Primary thyroid disorders: How is it caused?
Idiopathic, caused by autoimmune mechanisms
Alterations of Thyroid Function:
Primary thyroid disorders: What do these cause?
These disorders will cause secondary feedback effects on pituitary TSH
Alterations of Thyroid Function:
Primary thyroid disorders: These disorders will cause secondary feedback effects on pituitary TSH
What is an example?
E.g. Decreased TH from thyroid–> Ant. Pit. TSH increases
Alterations of Thyroid Function:
Central (secondary) thyroid disorders: What are they?
Disorders of pituitary gland thyroid stimulating hormone (TSH) production
Alterations of Thyroid Function:
Central (secondary) thyroid disorders: What does this lead to?
Inadequate TSH –> TH level low
Hypothyroidism: How are T3 and T4 levels?
Decreased T3 and T4
Hypothyroidism: What occurs with T3 and T4?
Destruction of thyroid
Hypothyroidism: What can it cause?
Endemic goiter,
Hashimoto’s
thyroiditis
Cretinism
Hypothyroidism: Patho & Diagnosis:
What age does it occur?
Can occur at any age
Hypothyroidism: Patho & Diagnosis
Primary Thyroid disorder: How is it?
Deficient production of TH and increase TSH and TRH
Hypothyroidism: Patho & Diagnosis
Primary Thyroid disorder: What are most common causes of it?
Autoimmune thyroiditis (Hashimoto’s)
Surgical or radioactive treat of hyperthyroid
Head/neck radiation
Iodine deficiency congenital defects
Meds
Hypothyroidism: Patho & Diagnosis
Primary Thyroid disorder: What occurs with hormone levels?
TH is decreased, TSH elevated
Hypothyroidism: Patho & Diagnosis
Secondary disorder:
2°: pituitary failure to produce adequate amts of TSH or lack of TRH
Hypothyroidism: Patho & Diagnosis
Secondary disorders: How common are they?
Much less common
Hypothyroidism: Patho & Diagnosis
Secondary disorder: What are examples?
Eg: pit tumors compressing pituitary cells or consequences of their tx,
traumatic brain injury,
subarachnoid hemorrhage
Hypothyroidism: Patho & Diagnosis
Secondary disorder: How are levels of TH, TSH and TRH?
Low levels of TH, TSH, TRH
Hypothyroidism: Patho & Diagnosis
What is a third cause of hypothyroidism? Not primary or secondary disorder
Subclinical- mild thyroid failure
Pathophysiology of Primary Hypothyroidism:
How is the thyroid normally supposed to work?
Pituitary gland –> TSH –> Thyroid gland –> T3 and T4
Pathophysiology of Primary Hypothyroidism:
How does the thyroid work in hypothyroidism? (What it the process)
Pituitary –> TSH–> Thyroid gland is unable to respond to TSH stimulation –> Thyroid gland does not produce T3 and T4–> Thyroid tissue is destroyed and hypothyroidism occur?
Hypothyroid conditions:
What is the most common cause of thyroid conditions?
Hashimoto DX (thyroiditis)
Hypothyroid conditions
Hashimoto DX (thyroiditis): What causes it?
Genetic risk factors & associated with other autoimmune conditions
Hypothyroid conditions:
What occurs in Hashimoto’s (thyroiditis)?
T lymphocytes, antithyroid Abs, NK cells infiltrate thyroid –> gradual inflammatory destruction of thyroid tissue
Hypothyroid conditions:
In Hashimoto’s, T lymphocytes, antithyroid Abs, NK cells infiltrate thyroid, What does this lead to?
T lymphocytes, antithyroid Abs, NK cells infiltrate thyroid –> gradual inflammatory destruction of thyroid tissue
Hypothyroid conditions:
What happens to the thyroid gland? What does this lead to?
Destruction of the gland reduces the production of T3 and T4
Hypothyroid conditions:
What does it result from?
Results from the body’s production of antibodies that attack the thyroid gland
Low levels of iodine lead to what?
Low levels of iodine → Endemic goiter
What kind of goiter is an endemic goiter?
Nontoxic goiter
Low levels of iodine → Endemic goiter:
Where is this seen? What conditions?
Usually seen in areas where there are low iodine levels in the soil and food
Use of non-ionized salt in the diet instead of iodized salt
Low levels of iodine → Endemic goiter:
Why is iodine important for thyroid?
Iodine is the fuel used by the thyroid gland to synthesize T3 and T4.
Low levels of iodine → Endemic goiter:
What does decreased iodine intake lead to (having to do with T3 and T4)?
With decreased iodine intake, the production of T3 and T4 decreases.
Low levels of iodine → Endemic goiter:
With decreased iodine intake, the production of T3 and T4 decreases: What does this lead to?
The hypothalamus then compensates by increasing its production of thyrotropin releasing hormone (TRH) to stimulate the pituitary to release thyroid stimulating hormone (TSH) to increase the production of T3 and T4.
Low levels of iodine → Endemic goiter:
Decreased iodine= low T3/T4 = hypothalamus makes more TRH = stimulates pituitary thyroid stimulating hormone (TSH) to increase T3 and T4: What does this lead to?
The increased TSH produces hyperplasia and hypertrophy in the thyroid gland which results in goiter formation.
Look at picture on slide 20
Goiter:
Enlargement of thyroid gland
Goiter: Enlargement of thyroid gland
What are the types of goiters?
Nontoxic goiter
Toxic goiter
Goiter: Enlargement of thyroid gland
Nontoxic goiter: What is it?
Enlargement of thyroid not associated with overproduction of TH
Goiter: Enlargement of thyroid gland
What are the types of nontoxic goiters?
Simple or Diffuse Nontoxic Goiter:
Multinodular Nontoxic Goiter:
Nontoxic Goiter:
Simple or Diffuse Nontoxic Goiter: What is it?
thyroid gland is uniformly enlarged.
Nontoxic Goiter:
Multinodular Nontoxic Goiter: What is it?
Multiple nodules are present but do not result in hormone overproduction
Goiter: Enlargement of thyroid gland
Nontoxic goiters: What can be causes?
Iodine deficiency, genetics, exposure to goitrogens (cabbage, broccoli)
Thyroiditis
Hormonal changes
Goiter: Enlargement of thyroid gland
Toxic Goiter: What is it associated with?
Associated with hyperthyroidism
Goiter: Enlargement of thyroid gland
Toxic goiter: What occurs with this?
Thyroid gland produces an excess amount of thyroid hormones (T4 and T3)
Goiter: Enlargement of thyroid gland
Toxic goiter: What are the types of goiters?
Toxic Multinodular Goiter (Plummer’s Disease):
Toxic Adenoma:
Goiter: Enlargement of thyroid gland
Toxic goiter: Toxic Multinodular Goiter (Plummer’s Disease): What is it?
Multiple nodules in the thyroid produce excess thyroid hormones.
Goiter: Enlargement of thyroid gland
Toxic goiter: Toxic Adenoma: What is it?
A single nodule in the thyroid becomes overactive and produces excess hormones.
Goiter: Enlargement of thyroid gland
Toxic goiter: Toxic Adenoma: What causes it?
Graves’ & nodules (Autonomous functioning secrete TH despite normal regulatory mechanisms
Cretinism: Who does it occur in?
Infants
Cretinism: What is the issue with the thyroid?
Thyroid tissue absent or hereditary defects
Cretinism:
What is TH essential for (in general not having to do with disease)?
TH essential for fetal growth, brain development
Cretinism: What can this lead to if left untreated?
Can lead to developmental & cognitive disabilities if untx’d
Cretinism:
What are symptoms of cretinism?
Protruding tongue,
potbelly,
dwarfish stature,
hypothermia,
constipation,
lethargy,
cold mottled skin,
bradycardia
Cretinism: What happens to skeletal growth in this disease? WHy?
Skeletal growth stunted due to impaired protein synthesis, poor nutrient absorption, lack of bone mineralization
Cretinism: What happens to development of nervous system?
Impaired development of nervous system, bones, teeth, brain tissue, difficulty feeding, lethargy
Cretinism: What develops on the abdomen?
Umbilical hernia due to hypotonic abdominal muscles
Cretinism: When will it be evident?
May not be evident until 4 months of age
Cretinism: What is needed for cretinism?
Immediate TX necessary
Cretinism: How long is treatment?
Continued treatment until 3yo then stopped for 4 weeks to r/o permanent or transient deficiency
Cretinism: What is something that can be lifelong with cretinism?
↑ TSH & ↓ T4 ~ continued lifelong
Clinical Manifestations of Hypothyroidism:
What does hormone levels do to metabolic rate?
↓ T3, T4resulting in a decreased metabolic rate
Clinical Manifestations of Hypothyroidism:
Why does ↓ T3, T4 resulting in a decreased metabolic rate occur?
Hyposecretion of thyroid hormones
Clinical Manifestations of Hypothyroidism: What may or may not be present with hypothyroidism?
Goiter (enlarged gland) may or may not be present; may have hoarseness if present
Clinical Manifestations of Hypothyroidism: Why is Goiter (enlarged gland) may or may not be present; may have hoarseness if present?
Overstimulation of thyroid gland from TSH released from pit. in response to low TH levels; pressure on vocal cord leads to changing voice
Clinical Manifestations of Hypothyroidism:
How is the skin? How is the hair?
How do they tolerate the cold?
Pale, cool skin
Loss of hair, coarse, brittle hair
Cold intolerance
Clinical Manifestations of Hypothyroidism: Why does pale, cool skin, occur in Hypothyroidism?
Decreased metabolic rate, bradycardia, and decreased blood flow to skin
Clinical Manifestations of Hypothyroidism: Why does loss of hair, coarse, brittle hair, cold intolerance and weight gain with decreased appetite occur in Hypothyroidism?
Decreased metabolic rate
Clinical Manifestations of Hypothyroidism: How is weight and appetite?
Weight gain with decreased appetite
Clinical Manifestations of Hypothyroidism:
How does the face appear?
Myxedema (nonpitting edema seen as facial puffiness, periorbital edema, and thick tongue)
Clinical Manifestations of Hypothyroidism: Why does Myxedema (nonpitting edema seen as facial puffiness, periorbital edema, and thick tongue) occur?
Increased mucopolysaccharides in the dermis and other tissues from lack of thyroid hormones and improper metabolism
Clinical Manifestations of Hypothyroidism: How is the heart?
Bradycardia (less than 60 beats per minute),
enlarged heart,
heart failure
Clinical Manifestations of Hypothyroidism: Why does bradycardia occur?
Decreased cardiac contractility
Clinical Manifestations of Hypothyroidism:
Effects on GI, Muscles, reflexes?
Constipation, muscle weakness, hyporeflexia
Clinical Manifestations of Hypothyroidism:
Why does constipation, muscle weakness, hyporeflexia occur?
Hypotonic muscles
Clinical Manifestations of Hypothyroidism:
How are they intellectually?
Lethargic, slow intellectual functions
Clinical Manifestations of Hypothyroidism:
Why does lethargy, slow intellectual functions occur in hypothyroidism?
Decreased mental alertness from decreased metabolic rate and decreased blood flow from bradycardia
Myxedema coma- What is it?
Myxedema coma = severe hypothyroidism with severely decreased metabolic rate which slows everything down into a coma
Myxedema coma: How is it viewed?
Myxedema coma – med emergency
Myxedema coma: What is it a clinical manifestation of?
Severe deficiency, profound presentation of hypothyroidism
Myxedema coma (in severe hypothyroidism): What causes it?
Hypotension, hypoglycemia, respiratory depression, hypothermia, lethargy –> coma
Myxedema coma:
Hypotension, hypoglycemia, respiratory depression, hypothermia, lethargy –> coma:
Why does hypotension occur?
Hypotension due to hypotonic (flabby) heart muscle from decreased metabolism
Myxedema coma:
Hypotension, hypoglycemia, respiratory depression, hypothermia, lethargy –> coma:
Why does hypoglycemia occur?
Hypoglycemia due to decreased production of glucose from low levels of thyroid hormones
Myxedema coma:
Hypotension, hypoglycemia, respiratory depression, hypothermia, lethargy –> coma:
Why does hypothermia occur?
Hypothermia without shivering due to decreased metabolic rate
Myxedema coma:
Hypotension, hypoglycemia, respiratory depression, hypothermia, lethargy –> coma:
Why does hypoventilation occur?
Hypoventilation due to decreased metabolic rate and hypotonic respiratory muscles
Myxedema coma: When can it occur?
May occur after acute illness
Myxedema coma:
Why does loss of consciousness occur?
Loss of consciousness due to decreased perfusion to brain from hypotension
Myxedema coma:
Who is at risk for developing this?
At risk: older adults with comorbidities & mod or untreated hypothyroidism
Myxedema coma:
Why else would it occur (having to do with drugs)?
May occur after overuse of narcotics or sedatives
Myxedema coma:
What is treatment for this?
Adjunct TX w/ GCs
Myxedema coma:
What is the adjunct treatment for this?
Treatment – IV Levothyroxine (SyntheticT4)
Hypothyroidism: Life Span Issues
During Pregnancy: How can it effect first trimester?
In first trimester can result in permanent neuropsychologic deficits in the child
Hypothyroidism: Life Span Issues
During Pregnancy: What are the signs and symptoms?
Minimal s/s or asymptomatic
Hypothyroidism: Life Span Issues
During pregnancy: What is the treatment?
Early-DX & TX necessary
Hypothyroidism: Life Span Issues
During pregnancy: If diagnosis is before pregnancy, how should dosing be?
For prior DX ~ ↑ supplement dose by 50%
Hypothyroidism: Life Span Issues
During pregnancy: When is increased dosage of thyroid supplements needed?
Increased dosage of thyroid supplements needed between 4-8 wks gestation, levels off by week 16
Hypothyroidism: Life Span Issues
In infants: How are effects of hypothyroidism?
May be permanent or transient
Hypothyroidism: Life Span Issues:
In infants: What are the effects of hypothyroidism?
Can cause intellectual disability and derangement of growth
Hypothyroidism: Life Span Issues
Older adults: What is important to remember about symptoms?
Hypothyroid symptoms should never be attributed to normal age-related changes
TX for Hypothyroidism: Thyroid Supplementation
What are the meds?
Levothyroxine (Synthroid)
TX for Hypothyroidism: Thyroid Supplementation
What is the drug of choice for all forms of hypothyroidism regardless of cause?
Levothyroxine (Synthroid)-
DOC for all forms, regardless of cause
TX for Hypothyroidism: Thyroid Supplementation
What is Levothyroxine (Synthroid)- its ingredient?
Synthetic preparation of thyroxine (T4)
TX for Hypothyroidism: Thyroid Supplementation
PKs: How is it absorbed?
Absorption reduced by food
TX for Hypothyroidism: Thyroid Supplementation
PKs: How should they be taken?
Take on empty stomach in AM, 30-60 min before breakfast
TX for Hypothyroidism: Thyroid Supplementation
PKs: What does it do?
Med is converted to T3 –> normal levels of T3 & T4
TX for Hypothyroidism: Thyroid Supplementation
PKs: How is it bound to protein? How does this effect half life?
Highly protein bound –> prolonged half-life of 7d
TX for Hypothyroidism: Thyroid Supplementation
PKs: How are hormone levels with dosing?
Hormone levels remain steady with daily dosing but takes 1 month to reach a plateau so delayed onset of full effects
TX for Hypothyroidism: Thyroid Supplementation:
? interchangeability: What does this mean?
Inconclusive results between FDA & endocrinology society regarding equivalence of brand-name & generic products
TX for Hypothyroidism: Thyroid Supplementation
Dosing & administration: How is it normally taken? How is it take for myxedema coma?
PO for most
IV - myxedema coma 200-500mcg
pts who can’t take PO
TX for Hypothyroidism: Thyroid Supplementation:
Dosing & administration: How are therapeutic effects evaluated?
Resolution of s/sx
TSH
TX for Hypothyroidism: Thyroid Supplementation:
Dosing & administration: How are TSH levels with treatment of hypothyroidism?
When should you evaluate effects of meds on TSH levels?
Levels fall (but effect is slow)
Don’t evaluate until 6-8 wks after starting tx, lags behind TH
TX for Hypothyroidism: Thyroid Supplementation
Dosing & administration-Evaluating Therapeutic effect: How are T3 and T4?
T3 & T4 (normal to high range)
TX for Hypothyroidism: Thyroid Supplementation
Dosing & administration: For most people, how long is treatment?
What kind of treatment is it?
For most people tx is lifelong
Symptomatic relief only (not cure)
TX for Hypothyroidism: Thyroid Supplementation
Dosing & administration: Even if symptoms improve, what should you NOT do?
Although sx improve, do not stop tx
Thyroid Supplementation cont. Levothyroxine:
What are adverse effects of this medication?
Hyperthyroidism
Thyroid Supplementation cont. Levothyroxine:
What rare hyperthyroidism symptoms that can occur with levothyroxine use?
Tachycardia, angina, tremor,
Nervousness, insomnia,
Hyperthermia
Heat intolerance, sweating
Thyroid Supplementation cont. Levothyroxine:
Geriatric ADEs, precautions
Accelerated bone loss –> fracture risk
A. fib
Thyroid Supplementation cont. Levothyroxine
What can occur? What is this called? (A negative effect)
Acute overdose
thyrotoxicosis
Thyroid Supplementation cont. Levothyroxine:
Interactions: What type of drugs does it cause interactions with? So how should these drugs be taken?
Drugs that reduce it’s absorption ~ separate 4h, most PO
Drugs that accelerate it’s metabolism
Warfarin
Stimulant, sympathomimetics, EPI
Thyroid Supplementation cont. Levothyroxine:
Drugs that reduce it’s absorption ~ separate 4h, most PO: What are the drugs?
H2RA
PPIs
Sucralfate
AL-containing antacids
Ca & Fe supplements
Mg salts
Thyroid Supplementation cont. Levothyroxine
Drugs that accelerate it’s metabolism include:
Seizure drugs:
Rifampin, sertraline (Zoloft)
Thyroid Supplementation cont. Levothyroxine
Drugs that accelerate it’s metabolism include: Seizure drugs
What are examples of seizure drugs?
phenytoin,
carbamazepine,
phenobarbital,
Thyroid Supplementation cont. Levothyroxine:
Interactions:
Drugs that accelerate it’s metabolism- What should you do with levothyroxine?
↑ dose of levothyroxine dose when taking these drugs (while taking drugs that accelerate its metabolism)
Thyroid Supplementation cont. Levothyroxine:
Warfarin- effect on levothyroxine?
Levothyroxine accelerates the breakdown of Vit K clotting factors –> enhanced warfarin effects
Thyroid Supplementation cont. Levothyroxine:
Warfarin: What may you have to do with warfarin dose?
Warfarin dose may need to be reduced
Thyroid Supplementation cont. Levothyroxine:
Stimulant, sympathomimetics, EPI: What does it cause with levothyroxine use?
Increase cardiac responsiveness to catecholamines
Thyroid Supplementation cont. Levothyroxine:
Stimulant, sympathomimetics, EPI: What medical condition should you be cautious of when taking this with levothyroxine?
Caution dysrhythmias
Hyperthyroidism/Thyrotoxicosis: Patho & Diagnosis: What occurs?
Excess amts of TH (T3 & T4) secreted from thyroid gland
Hyperthyroidism/Thyrotoxicosis: Patho & Diagnosis:
Primary causes:
1°: most caused by Graves disease (autoimmune TSIs mimic TSH),
toxic multinodular goiter (Plummer DX),
& solitary toxic adenoma
Hyperthyroidism/Thyrotoxicosis: Patho & Diagnosis:
1°: most caused by Graves disease (autoimmune TSIs mimic TSH), toxic multinodular goiter (Plummer DX), & solitary toxic adenoma
What are diagnostic labs of this?
Elevated T3, T4 & suppressed TSH are diagnostic
Hyperthyroidism/Thyrotoxicosis: Patho & Diagnosis:
Secondary cause:
2°: less common, caused by TSH-secreting pituitary adenoma
Hyperthyroidism/Thyrotoxicosis: Patho & Diagnosis:
Secondary cause: What are labs?
Normal to increased TSH despite elevated TH concentrations
Hyperthyroidism/Thyrotoxicosis: Patho & Diagnosis:
What is treatment in general do?
Tx: control excessive TH production, secretion, or action
Hyperthyroidism/Thyrotoxicosis: Patho & Diagnosis:
Treatment: control excessive TH production, secretion, or action
How is this done?
Antithyroid drug tx,
radioactive iodine tx,
surgical removal of nodules or part of thyroid gland
Hyperthyroidism/Thyrotoxicosis: Patho & Diagnosis:
What is a major complication of treatment?
Major complication of treatment is hypothyroidism
Hyperthyroid conditions include:
- Graves disease (most common)
- Toxic multinodular goiter (Plummer disease)
- Toxic adenoma
- Thyroid medication
Hyperthyroid conditions: What is the most common hyperthyroid condition?
- Graves disease (most common)
Hyperthyroid conditions:
Graves disease (most common): What kind of response is this?
Autoimmune response
Hyperthyroid conditions:
Graves disease (most common):
What occurs?
Thyroid stimulating Abs (TSIs) attach to TSH receptors
Hyperthyroid conditions:
In Graves disease when Thyroid stimulating Abs (TSIs) attach to TSH receptors, what does this act like?
Thyroid stimulating Abs (TSIs) attach to TSH receptors
Acts like pit hormone TSH, stimulates thyroid to release TH
Hyperthyroid conditions:
In Graves disease, what does TSIs stimulate thyroid to do? What does this cause?
TSIs stimulate thyroid to make T3 and T4, overriding negative feedback cycle –> overproductions
Hyperthyroid conditions:
In Graves disease, TSIs stimulate thyroid to make T3 and T4, overriding negative feedback cycle –> overproductions;
What does this result in?
Results in hyperplasia & goiter from growth of the thyroid and increased secretion of T3 and T4.
Hyperthyroid conditions:
In Graves Disease, what happens to metabolic rate? Why?
Metabolic rate is increased from the excessive release of TH
Hyperthyroid conditions:
Graves disease is what type of hypersensitivity reaction?
Type II hypersensitivity reaction
Hyperthyroid conditions:
Toxic multinodular goiter (Plummer disease): What happens?
Several hyperfunctioning nodules
Normally, in what circumstances would a thyroid gland enlarge?
Normally, thyroid gland enlarges in response to increased demand (eg pregnancy, puberty, iodine-deficient states) for TH
Normally, thyroid gland enlarges in response to increased demand for TH: What are examples of increased demand?
(eg pregnancy, puberty, iodine-deficient states)
Normally, when would normal thyroid gland size return after it was enlarged?
When condition resolves, TSH secretion subsides, and normal thyroid size returns
Hyperthyroid conditions:
What occurs in Toxic multinodular goiter (Plummer disease)? Be specific
Irreversible changes occur in follicular cells, TSH receptor mutated, nodules form, function autonomously & produce excessive TH
Hyperthyroid conditions:
Toxic multinodular goiter (Plummer disease)- What would several hyperfunctioning nodules lead to?
Several hyperfunctioning nodules –> toxic multinodular goiter
Hyperthyroid conditions:
How is Toxic multinodular goiter (Plummer disease) similar to Graves Disease?
Same clinical sx as Graves’ except exophthalmos
Hyperthyroid conditions:
- Toxic adenoma- what occurs with nodule (s)?
1 hyperfunctioning nodule
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
How are T3 and T4 levels? What does this lead to?
↑ T3, T4 leading to an increased metabolic rate
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why are there ↑ T3, T4 leading to an increased metabolic rate?
Overstimulation to TSH receptors –> increased production of thyroid hormone
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
What are major distinguishing features of this disease?
Exophthalmos (major distinguishing feature)
Pretibial edema (major distinguishing feature)
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why are there Exophthalmos and decreased blink and eye movements?
Increased tissue mass (fat and fluid) in the orbit pushing the eyeball forward
Increased sympathetic stimulation affecting the eyelids
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
What occurs with the eyes?
Decreased blink and eye movements
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why does pretibial edema occur?
Lumpy, swollen appearance on the anterior and lateral aspects of the legs resulting from accumulation of connective tissue, pinkish purple discoloration
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
What develops?
Toxic goiter
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why does toxic goiters occur?
Hyperplasia and hypertrophy of thyroid from overactive thyroid
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
How is the skin? How is heat/cold tolerance?
How is hair?
Skin flushed and warm, sweaty palms, heat intolerance
Thin hair
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why is skin flushed and warm, sweaty palms, heat intolerance?
Increased metabolic rate & vasodilation for heat loss
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why does thin hair occur?
Increased metabolic rate with excessive metabolism of macronutrients –> thinning hair
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
How is heart? Bp?
Tachycardia, increased blood pressure, eventually heart failure
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why does tachycardia, increased bp, and eventual heart failure occur?
Increased tissue sensitivity to the sympathetic nervous system from increased thyroid hormones and increased metabolism
Over time, the heart cannot meet body’s metabolic demands –> heart failure
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
What happens with weight and appetite?
Weight loss, with increased appetite
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why does weight loss and increased appetite occur?
Increased catabolism from increased metabolic rate leads to weight loss even though appetite is often increased
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
What are other symptoms of hyperthyroidism?
Restless, nervous tremors
Hyperreflexia
Diarrhea
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why does diarrhea occur?
Hypermotility of gastrointestinal tract
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why does hyperreflexia occur?
Hyperexcitability of reflexes
Clinical Manifestations of Hyperthyroidism (Graves’ Disease):
Why does restlessness and nervous tremors occur?
Increased tissue sensitivity to the sympathetic nervous system from increased TH
What is Exophthalmos?
Exophthalmos (large and protruding eyeballs)
Hyperthyroid conditions cont’d:
What is another name for Thyrotoxic storm?
Thyrotoxic crisis (AKA thyroid storm)
Hyperthyroid conditions cont’d:
Thyrotoxic crisis (AKA thyroid storm): How common is it?
Rare but dangerous, TH levels rise dramatically
Hyperthyroid conditions cont’d:
Thyrotoxic crisis (AKA thyroid storm): How long can it take death to occur?
Death can occur within 48hrs w/o tx
Hyperthyroid conditions cont’d:
Thyrotoxic crisis (AKA thyroid storm): When does it happen?
Happens in undx’d/partially tx’d Graves & subject to physiologic stressors/triggers
Hyperthyroid conditions cont’d:
Thyrotoxic crisis (AKA thyroid storm): Happens in undx’d/partially tx’d Graves & subject to physiologic stressors/triggers.
What is an example?
E.g. infection
Hyperthyroid conditions cont’d:
Thyrotoxic crisis (AKA thyroid storm)
What are symptoms?
Sx:
hyperthermia,
tachycardia,
heart failure,
atrial tachydysrhythmias,
agitation/delirium,
n/v/d
Hyperthyroid conditions cont’d:
Thyrotoxic crisis (AKA thyroid storm): What are treatments?
Tx: drugs that block TH synthesis (PTU & methimazole),
beta-blockers (for cardiac sx),
glucocorticoids,
radioactive iodine (shrinks the gland),
supportive care (F&E, cooling measures, nutritional support)
Hyperthyroid conditions cont’d:
Thyrotoxic crisis (AKA thyroid storm): If there is no response to treatment drugs, what must be done?
If no response –> surgical tx –> thyroidectomy
Complications of HyperthyroidismThyrotoxic crisis or thyroid storm
Manifestation:
How is temperature?
Severe hyperthermia, over 104◦F
Complications of HyperthyroidismThyrotoxic crisis or thyroid storm:
Why does Severe hyperthermia, over 104◦F occur?
Excessive release of thyroid hormones, increasing metabolic rate
Complications of HyperthyroidismThyrotoxic crisis or thyroid storm:
Manifestation: What happens with the heart?
Severe tachycardia, over 140 beats per minute
Heart failure (shortness of breath, edema, fatigue)
Complications of HyperthyroidismThyrotoxic crisis or thyroid storm:
Why does Severe tachy, over 140 bpm occur?
Excessive release of thyroid hormones, increasing sensitivity of tissues to sympathetic nervous system stimulation and excessive catecholamine release
Complications of HyperthyroidismThyrotoxic crisis or thyroid storm:
Why does Heart failure (shortness of breath, edema, fatigue) occur?
Heart cannot continue to meet the high oxygen demand needed for an increased metabolic rate
Complications of HyperthyroidismThyrotoxic crisis or thyroid storm:
Manifestation: What happens with the consciousness/alertness?
Delirium
Complications of HyperthyroidismThyrotoxic crisis or thyroid storm:
Why does delirium occur?
Decreased neurological functioning
Drugs for HyperthyroidismAntithyroid drugs include:
Methimazole
Propylthiouracil
Hyperthyroidism: What is the first line drug for this condition?
Methimazole
Hyperthyroidism: Methimazole
Mode of action: What does it inhibit?
Inhibits synthesis of thyroid hormones
Hyperthyroidism: Methimazole
Mode of action: What does destroy/not destroy?
Does not destroy existing stores of thyroid hormone, suppresses thyroid synthesis
Hyperthyroidism: Methimazole
Mode of action: How long does it take for effects to occur?
May take 3 to 12 weeks for euthyroid state
Hyperthyroidism: Methimazole
What is it used for?
Uses: Graves, adjunct to radiation, suppress TH in prep for thyroid surgery, thyrotoxic crisis
Hyperthyroidism: Methimazole
Kinetics: How is it absorbed?
Well absorbed,
crosses placenta,
Half life 6 -13 hours, so dosing is once a day
Hyperthyroidism: Methimazole
Kinetics: How often is maintenance dose?
Maintenance tx daily
Hyperthyroidism: Methimazole
Administration:
How is treatment done? When is it dc’d
Tx for 1-2 yrs –> d/c–> 30-40% of pts will go into remission, others relapse in 1-4 wks
Hyperthyroidism: Methimazole
ADR and when should this drug be avoided?
Pregnancy – avoid during 1st trimester
Agranulocytosis!!!!
Hypothyroid state in high doses
Hyperthyroidism: Methimazole
ADR: Why should this drug be avoided in the first trimester of pregnancy?
Can cause neonatal hypothyroidism, goiter, congenital hypothyroidism
Hyperthyroidism: Methimazole
Agranulocytosis!!!! what symptoms associated with this should be reported?
Report sore throat & fever immediately, med must be d/c’d
Develops rapidly
What is the second line drug for Graves’ disease?
Propylthiouracil (PTU)
Propylthiouracil (PTU):
What does it do?
Inhibits thyroid hormone synthesis
Propylthiouracil (PTU):
How long is the half life? How many doses does it require?
Short half-life (about 90 minutes)
Requires 2 or 3 daily doses
Propylthiouracil (PTU):
How long does it take for full benefits of drugs to occur?
Full benefits may take 6 to 12 months
Propylthiouracil (PTU):
How does it cross placenta? What does this mean?
Crosses placenta less readily
Used in 1st trimester
Propylthiouracil (PTU):
What are therapeutic uses?
Graves’ disease
Adjunct to radiation therapy
Preparation for thyroid gland surgery
Thyrotoxic crisis/thyroid storm (preferred initially)
Propylthiouracil (PTU):
Therapeutic uses: Thyrotoxic crisis/thyroid storm (preferred initially)- What does it do?
Blocks conversion T4 –> T3
Propylthiouracil (PTU):
What are adverse effects:
Agranulocytosis (most serious)
Hypothyroidism
Can cause severe liver damage
Propylthiouracil (PTU):
Can cause severe liver damage: How is progression? What should you teach the patient?
Onset sudden & progression rapid so routine LFTs check won’t help
Teach pt to report sx
TX for Hyperthyroidism: What is another treatment?
TX for Hyperthyroidism: Radioactive Iodine-131
TX for Hyperthyroidism: Beta Blockers
TX for Hyperthyroidism: Radioactive Iodine-131
What is the mode of action:
Destructive gamma rays & beta particles on thyroid cells
TX for Hyperthyroidism: Radioactive Iodine-131:
Where is I-131 concentrated?
I-131 is concentrated in thyroid gland
TX for Hyperthyroidism: Radioactive Iodine-131
What does it help to do?
Helps to reduce thyroid hormone production by selectively destroying overactive thyroid cells
TX for Hyperthyroidism: Radioactive Iodine-131
What are uses for it?
Graves’ DX in adults (some require 2 treatments)
ALT for non-response to antithyroid drugs or subtotal thyroidectomy
Toxic multinodular goiter or solitary toxic adenoma (thyroid gland produces excess thyroid hormones)
Diagnostic use (tracer)
Some forms of thyroid cancer
TX for Hyperthyroidism: Radioactive Iodine-131:
What are misconceptions?
⍉ tissue damage outside thyroid
TX for Hyperthyroidism: Radioactive Iodine-131:
How does this treatment effect surrounding tissue?
Minimal damage to surrounding tissue
Beta particles limited to travel to other tissues outside thyroid
TX for Hyperthyroidism: Radioactive Iodine-131:
Adverse Drug Reactions:
Dry mouth,
sore throat,
altered taste,
neck tenderness
TX for Hyperthyroidism: Radioactive Iodine-131
Radiation precautions:
https://www.thyroid.org/radioactive-iodine/
TX for Hyperthyroidism: Radioactive Iodine-131:
How fast are effects?
Delayed full effects ~ 1-3m
Initial effects apparent in days/weeks
TX for Hyperthyroidism: Radioactive Iodine-131:
What is a complication?
Delayed hypothyroid is complication
TX for Hyperthyroidism: Radioactive Iodine-131
Avoid in who?
Pediatrics, risks of delayed
hypothyroidism & slight risk of cancer
Pregnancy, R/O prior
Lactation
TX for Hyperthyroidism: Beta Blockers
Uses:
Management of s/s in Graves’ DX
Adjunct TX for thyrotoxicosis
Administration may be oral or IV
TX for Hyperthyroidism: Beta Blockers
MOA:
Suppress tachycardia
Some effect on T3 (small & slow)
TX for Hyperthyroidism: Beta Blockers:
What is the first line beta blocker?
Propranolol
TX for Hyperthyroidism: Beta Blockers
Propranolol: how is it?
Non-selective BB
