Pathophys Exam 2

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Cellular mechanism of Thyroid Hormones
- Iodine is transfered into cell
- Iodine is transfered out of cell with Thryoglobulin
- T3 and T4 are synthesized and moved back into cell
- T3 and T4 are secreted
T4
- must be converted to T3
- 90% of thyroid hormone
T3
- 10%
- ready to use form
Protein binding of T3 and T4

99% is protein bound
Hypothalamus
- secretes TRH to the Anterior Pituitary gland
- Inhibited by T3 and T4
Anterior pituitary

Releases TSH when stimulated by TRH from the hypothalamus
Thyroid gland

Releases T3 and T4 inresponse to TSH from the anterior pituitary gland.
Actions of thyroid hormones are in all tissues except
- spleen
- retina
- lungs
- testes
Actions of thyroid hormones include increased metabolism of:
- glucose
- protein
- fat
- vitamins
Thyroid hormones are important in children for

growth and development
metabolism of thyroid hormones in cardiovascular tissue
- oxygen
- vasodilation
metabolism of thyroid hormones in the GI tract
- motility
- secretions
- appetite
- activity
- weight loss
Metabolism of thyroid hormones in the neuromuscular system
- Skeletal muscle tone
- Sympathetic activity
- tachycardia
- palpitations
- sweating
Tests of thyroid function screening
- T3 level
- T4 level
- Free T4 level
- TSH level
Test of known thyroid problem
- Anti-TPO
- Radioiodine uptake
Hypothyroidism

underactive thyroid characterized by not producing enough hormone
Congenital Hypothyroidism
- Prenatal
- 1/5000 births
Acquired Hypothyroidism
- Primary, Secondary and Tertiary
- 4-10% of Americans
Primary Hypothyroidism

Thyroid gland misfunction
Secondary and Tertiary Hypothyroidism

Anterior Pituitary or hypothalamus problem
Metabolic changes with Hypothyroidism
- weight gain
- fatigue
- cold intolerance
Skin changes with hypothyroidism
- cool, pale rough, cracked
- coarse hair
- brittle nails
- potential hair loss
Changes in eyes with hypothyroidism

Graves' opthalmopathy
Cardiovascular changes in hypothyroidism
- Reduced cardiac output
- decreased exercise capacity
- shortness of breath
GI changes with hypothyroidism

constipation
Hallmark sign of thyroid issues

goiter
thyrotoxicosis

dangerously high levels of T3
Complications of a goiter
- swallowing
- blood flow
- breathing
Risk factors for hypothyroidism
- age
- family history of thyroid or autoimmune problems
- pregnancy
- smoking
- radiation exposure
- iodine exposure
- neck trauma
- stress
Women vs. men hypothyroidism
- Women 5:1
- Men 8:1
Diagnosis of Hypothyroidism
- History
- Physical Exam
- Lab tests
Lab test for Hypothyroidism
- TSH and T4
- T3 and Free T4
Low Levels in Hypothyroidism
- T3
- T4
- Free T4
High levels in hypothyroidism

TSH
Hypothyroidism Treatments
- Synthetic T3 and T4
- mostly T4
- Start low and go slow
- Do not change brands
Monitoring TSH
- every 6-8 weeks until normalized
- every 8-12 weeks after dosage changes
- every 6-12 months througout therapy
- watch for hyperthyroidism
Hyperthyroidism
- Overactive thyroid characterized by producing too much hormone
- thyrotoxicosis
Types of Hypothyroidism
- Graves' disease
- Goiter
- Thyroid Storm
Thyroid Storm
- accute
- increased mortality rate
- usually a co-morbidity
General Metabolic changes with hyperthyroidism
- weight loss
- increased appetite
- excessive sweating
- heat intollerance
Sympathetic nercous changes in hyperthyroidism
- nercousness
- irritablity
- fatigability (crash)
Cardiovascular effects of hyperthyroidism
- Tachycardia
- palpitations
- shortness of breath
Neuromuscular effect of hyperthyroidism
- muscle cramps
- fine tremor
- eyelid retraction
- infrequent blinking
GI changes with hyperthyroidism

diarrhea
Graves' Disease
- onset at 20-40 years
- women 5x as likely
- autoimmune overstimulation of TSH antibodies
Laboratory Tests for Hyperthyroidism
- TSH and T4
- T3 and free T4
Low levels in hyperthyroidism

TSH
High levels in hyperthyroidism
- T3
- T4
- Free T4
Hyperthyroidism treatment directed at reducing thyroid hormone
- eradication through radioactive iodine (most common)
- surgical removal of gland
Propylthiouracil

blocks conversion of T4 to T3
Methimazole

block oxidation of iodine in the thyroid gland to stop producettion of T4 and T3
Beta Blockers

suppress sympathetic nervous system
Hyperthyroidism follow ups
- 2-4 weeks then 6-8 weeks until normalized
- follow hypothyroidism monitoring
Surgical removal of thyroid gland may result in
- hypothyroidism
- may still have bulging eyes

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Anonymous

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Card Set

Pathophys Exam 2

Description

Thyroid Disorders

Updated

2010-10-07T23:29:38Z

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