Endocrine Flashcards
Name the hormones secreted by the anterior pituitary?
FSH, LH, GH, TSH, prolactin, ACTH
Where are ADH and oxytocin secreted from?
posterior pituitary
What is the function of cortisol?
It is a stress hormone. It inhibits the immune system, inhibits bone formation, increases blood glucose, increases metabolism and increases alertness. Therefore there is diurnal variation and it is highest in the morning.
What does GH stimulate and what is the role of this?
It stimulates release of IGF-1 from the liver. This is used for increased muscle growth, cell regeneration and production, increased bone density and strength and increased growth of internal organs
Describe the parathyroid axis?
PTH is released by the four parathyroid glands in response to low serum calcium (and low magnesium and high phosphate). PTH release results in higher numbers of and increased activity of osteoclasts and therefore there is more reabsorption of calcium from bones to blood. PTH also increases the kidney reabsorption and intestinal absorption of calcium.
Describe the renin angiotensin system?
Renin is secreted by the juxtaglomerular cells in the afferent arterioles in response to a low blood pressure. It converts angiotensinogen to angiotensin I in the liver. Angiotensin I is then converted to angiotensin II in the lungs using ACE. ATII causes vasoconstriction and release of aldosterone. Aldosterone then increases the sodium reabsorption in the DT, K secretion and hydrogen secretion. Water is then drawn in and increases volume.
What does prolonged abnormally elevated cortisol result in?
Cushing’s syndrome
What are the signs and symptoms of Cushing’s syndrome?
symptoms: central obesity, round moon face, buffalo hump, limb proximal muscle wasting, abdominal striae
signs: HTN, cardiac hypertrophy, hyperglycaemia, depression, insomnia, poor skin healing, easy bruising, osteoporosis
What are the signs and symptoms of Cushing’s syndrome?
symptoms: central obesity, round moon face, buffalo hump, limb proximal muscle wasting, abdominal striae
signs: HTN, cardiac hypertrophy, hyperglycaemia, depression, insomnia, poor skin healing, easy bruising, osteoporosis
How is Cushing’s syndrome diagnosed?
low dose dexamethasone suppression test and if the morning cortisol returns high then do the high dose dexamethasone suppression test
FBC (increased WCC), U&Es, MRI, CT chest and abdomen
How is Cushing’s syndrome treated?
Life long steroids or transsphenoidal surgery if there is a pituitary adenoma
Describe the types of Adrenal Insufficiency?
Addison’s - damaged adrenals - decreased cortisol and aldosterone - primary or autoimmune
secondary - decreased ACTH due to pituitary damage
tertiary - decreased CRH due to hypothalamic damage
How is adrenal insufficiency diagnosed?
short synacthen test - synthetic ACTH given in morning and cortisol measured at baseline and at 8 hours - less than double is indicative
what investigations are done in adrenal insufficiency?
FBC, U&Es (decreased na, increased K)
early morning cortisol
ACTH
adrenal autoantibodies
CT/MRI adrenals
MRI pituitary
how does adrenal insufficiency present?
fatigue, nausea, cramps, abdominal pain, decreased libido, hyperpigmentation, hypotension
What is an addisonian crisis and how is it treated?
when the patient presents with decreased consciousness, hypotension, low BG and sodium, increased K, and is triggered by infection, trauma, withdrawal of steroids etc
treatment - monitoring, IVF resus, correct hypoglycaemia, parenteral steroids, monitor U&Es
How is Adrenal insufficiency treated?
hydrocortisone to replace cortisol and fludrocortisone to replace aldosterone
What does anti-TPO positive indicate?
autoimmune condition such as grave’s or hashimotos
what does antithyroglobulin indicate?
graves, hashimotos or cancer
what do TSH receptor antibodies indicate?
Graves
what do you look at in TFTs and describe the results?
look at TSH alone first - if abnormal do T3 and T4
hyperthyroidism - high T3 and T4, low TSH
hypothyroidism - low T3 and T4, high TSH if primary, if secondary then low T3,4 and TSH
pituitary adenoma - high TSH
how do you diagnose thyroid disorders?
TFTs
thyroid USS and guided biopsy
radioisotope scan
describe the results of a radioisotope scan?
diffuse high - Graves
focal high - TMNG and adenomas
low - cancer
what is the primary cause of hyperthyroidism?
graves
what are signs specific to graves?
exopthalmos, pretibial myxoedema, thyroid eye disease
what is the presentation of hyperthyroidism?
anxiety, irritability, tachycardia, weight loss, fatigue, frequent loose stools, sexual dysfunction
a patient presents with viral presentation, symptoms of hyper then hypothyroidism, what is condition and how is it treated?
DeQuervains thyroiditis - NSAIDs, BBs - self limiting
what is the management of hyperthyroidism?
carbimazole
change to maintenance or add levothyroxine
propylthiouracil
radioactive iodine
surgery
what are the signs of thyroid storm? what is the management?
hyperthyroidism + delirium, tachycardia and pyrexia
supportive mx with IVf, BBs and anti-arrhythmias
list the causes of hypothyroidism?
hashimotos, iodine deficiency, hypopituitarism, medications
what is the presentation of hypothyroidism?
weight gain, constipation, fatigue, dry skin, coarse thinning hair, fluid retention, heavy/irregular periods
how do you investigate hypothyroidism?
T3, T4 - low
TSH - increase in primary and decrease in secondary