thyroid pathophysiology Flashcards
what is the clinical diagnosis of child with too much growth hormone?
gigantism (before fusion of the bone)
what is the clinical diagnosis of adult with too much growth hormone?
acromegaly (after fusion of the bone )
what is the clinical diagnosis of a child with too little growth hormone?
dwarfism
what is the clinical diagnosis of adult with too little growth hormone?
- loss of muscle strength
- sometimes affect cognitive and affective changes
how does thyroid hormone form in the body?
- hypothalamus produces TRH
- stimulates the pituitary gland to produce TSH
- stimulates thyroid gland to combine iodine and tyrosine to produce T3 and 4
what is the function of thyroid hormone?
- controls the body’s metabolism
- proper development of differentiated cells
- heat generation
- regulate, long bone growth, mental development , sexual maturity,
- regulate protein fat and carbohydrate metabolism
- regulate glucose oxidation to provide energy
- regulate blood pressure and increase body sensitivity to catecholamines
what is the clinical diagnosis if baby have too little thyroid hormone?
cretinism
what is the clinical diagnosis when adults have too little thyroid hormone ?
myxedema
endemic goiter if lack of iodine
what are the symptom of hypothyrodism?
- intolerance to cold
- weight gain with poor appetite
- edema
- fatigue, general weakness
- dry skin
- slow pulse rate
- constipation
- poor memory and concentration
- pleural effusion (fluid in the lungs)
- decreased sense of smell and taste
- hair loss
what is the clinical diagnosis of patient with hyperthyroidism?
graves disease (auto immune disease where body produces antibodies that activate the TH secreting cells)
thyroid storm
what are the symptoms of hyperthyroidism?
- heat intolerance
- increase in appetite but weight loss
- goiter
- nervousness
- budging eyes
- finger clubbing
- facial flushing
- frequent bowel movements
- insomnia
- fine tremor
- tachycardia and palpitations
what are the causes of hypothyroidism?
Primary hypothyroidism
- iodine deficiency in diet (cause goiter)
- thyroidectomy (removal of gland)
- chronic autoimmune thyroiditis (hashimoto)
- exposure to radioactive radiation
- use of radioactive iodine
- disorder in pituitary gland or hypothalamus
what is primary hypothyroidism?
when the thyroid gland is the reason
- hashimoto thyroditis
- removal of thyroid gland
- radiation therapy
- iodine therapy
what are the reasons for acquired hypothyroidism?
primary
- thyroidectomy (removal of thyroid gland)
- hashimoto
- radiation therapy
- iodine deficiency
secondary
- disorder in pituitary gland or hypothalamus
what is hashimoto disease?
when your immune system produces antibodies against your own thyroid tissue
therefore your body does not produce enough thyroid hormones and overtime thyroid may enlarge, painless goiter, will shrink many years later
who is hashimoto disease more relevant in?
female 30-40 due to hormonal changes that produces antibody and attack the thyroid
especially pregnant women
what is the myxedema?
severe hypothyroidism where it might cause coma if severe
Primary signs and symptoms of myxedema coma are altered mental status and low body temperature, hypoglycemia, low blood pressure, edema of face, legs and tongue, waxy consistency of skin, weight loss
what will result when there is not enough iodine which causes hypothyroidism?
endemic goiter will be present due to the lack of iodine to produce T3 and T4
therefore the thyroid gland will try to produce more thyroid therefore it will be swollen
how to test for endemic goiter?
ask patient to swallow and feel the presence of nodules
what is the treatment for endemic goiter?
- get enough iodine (150mg per day is the requirement)
- use iodized salt or eat seafood or seaweed
what is the result of children with hypothyroidism?
cretinism
what are the symptoms of cretinism?
- prolonged jaundice
- poor feeding
- constipation
- sleepiness
- decreased crying
- dry rough skin
- protuberant tongue and abdomen , hernia
- mental retardation
what is the diagnostic test for hypothyroidism?
- lab investigation
- radiological investigations
- biopsy of gland
- radioiodine uptake study
what are the lab investigation results to diagnose hypothyroidism?
Primary hypothyroidism (low t4 and high TSH)
Secondary hypothyroidism (low T4 and low TSH)
For autoimmune : check serum antithyroid antibodies
what are the radiological investigations that can be done to test for hypothyrodism?
- ultrasound of gland
- skull xray
- ct scan of thyroid gland
- MRI of thyroid gland
what are the treatment for hypothyroidism
compensate for lack of hormone
provide iodine
what are the causes of primary hyperthyroidism?
- auto immune (graves disease)
- toxic multinodular goiter
- toxic thyroid adenoma
what is graves disease?
autoimmune disorder by thyroid stimulating antibodies where it binds to thyroid to produce hormones and produce excess T3 and T4
what is toxic multinodular goiter ?
when one or more nodules in the thyroid gland make thyroid hormones without responding to the signal to keep thyroid hormone balanced
many swollen parts of the thyroid gland
what is toxic thyroid adenoma ?
increased hormone production coming from a single nodule in the gland
one single swollen part of the thyroid gland
what is the secondary cause of hyperthyroidism?
hypersecretion of TSH
what is thyroid storm?
it is the hypermetabolic state induced by excessive release of thyroid hormones
it is acute and life threatening if left untreated, treatment is critical
what are the symptoms of hyperthyroidism?
- increased heart rate (tachycardia)
- increased BP (hypertension)
- increase body temperature
- neurological
- GI abnormalities
- may lead to congestive heart failure
what are the diagnostic test for hyperthyroidism?
- lab test
- thyroid 123 scan
what are the lab results that diagnose hyperthyroidism?
primary hyperthyroidism: high T4 and low tsh level
secondary hyperthyroidism: high T4 and high tsh and TRH level
autoimmune : check thyroid stimulating anti bodies
what is the treatment for hyperthyrodism?
- drug therapy (PTU and meth)
- radioactive iodine therapy
- surgery to remove thyroid
the body produces more T4 or T3?
more T4, however T3 is more potent so T4 is converted to T3
Which hormone is released by the hypothalamus and controls thyroid hormone secretion?
Thyrotropin-Releasing Hormone (TRH)
Which hormone is released by the pituitary gland and controls thyroid hormone secretion?
Thyroid Stimulating Hormone (TSH)
How are TRH and TSH secretions controlled?
Negative feedback by T4 and T3
