Endocrinology Flashcards
Which hormones are released by anterior pit
FLAT GP FSH LH ACTH TSH GH Prolactin
Which hormones are released by post pit
Oxytocin
ADH
Describe the thyroid axis
Hypothalamus releases TRH
Ant pit releases TSH
Thyroid releases T4-> T3
Symptoms of hypothyroidism
- Weight gain
- Fatigue/weakness
- Cold
- Depression
- Hair loss
Causes of hypothyroidism
- Autoimmune (hashimotos, atrophic)
- Treatment of hyper (iodine, surgery)
- Natural course of thyroiditis and graves
- Drug (amiodorone, lithium, phenytoin)
- Central - hypopituitarism
WORLDWIDE = iodine deficiency
Diagnosis of hypothyroidism
- TSH high
- T4 and T3 low
MAY SEE
TPO antibodies raised
Treatment of hypothyroidism
100-150mcg Levothyroxine or 25 for elderly/IHD
Rare SE
interacts with warfarin
Symptoms of hyperthyroidism
Weight loss/inc appetite Heat intolerance/sweating Fatigue/cant seep tremor Palpitations/nervousness Irregular periods Eye problems
Causes of hyperthyroidism
- Graves disease
- TNG
- Thyroiditis (autoimmune or viral)
- Drug induced (amiodarone)
- Iodine induced Jod basedow
Diagnosis of hyperthyroidism
- Low TSH
- High T4/3
MAY SEE
anti TSH antibodies (TRab)
Treatment of hyperthyroidism
GRAVES - long course carbimazole 20mg 1 daily - radioiodine TNG - radioiodine - surgery -long term carbimazole
BRIDGE = beta blocker for 1st month propanolol = mild nadolol = severe
Graves disease natural history, presentation and assd conditions
strong genetic asscn
Spontaneous remission 1-2 yrs common. then long term remission, R+R, hypo (TRab)
Can present with dermopathy, smooth diffuse goitre, eye signs assd with smoking
ASSD with addisons, pernicious anaemia and vitiligo
RF for hyperthyroidism to elicit in history
- FH of autoimmunity
- Female
- Smoking
if post partum thyroiditis suspected ask about t1 diabetes
Describe hypothalamic- adrenal axis (EDIT)
hypothalamus releases ARH
Ant pit releases ACTH
Adrenal glands release cortisol and androgens
Functions of cortisol
- Stress response- alert
- Inc blood glucose
- Inc metabolism
- Suppress immune response
- Suppress bone formation
Causes of primary adrenal insufficiency
- Autoimmune = Addison’s disease
- Infective = TB, HIV
- Congenital = CAH
- Neoplastic = adrenal, mets from RCC, lung
- Non malignant infiltration = sarcoidosis, amyloidosis, haemochromatosis
Symptoms of primary adrenal insufficiency
Low aldosterone: - fatigue, weakness - orthostatic hypo Abdo signs: - weight loss - N/V - abdo pain
XS ACTH = hyperpigmentation
TANNED TIRED TEARFUL TUMMY
Causes of Cushing syndrome
- Cushing disease = acth secreting pituitary adenoma
- Exogenous steroids= long term tx
- Ectopic source = paraneoplastic syndrome eg SCLC ACTH secreting
- Cancer- Adreno-cortical carcinoma
Growth hormone axis
Hypothalamus releases GHRH
ant pit releases GH
Liver releases insulin like growth factor 1 IGF1
IGF1 acts everywhere - bone density, muscle mass, cell turnover and organ growth
What is function of somatostatin
Growth hormone inhibiting hormone
What is ghrelin
Hormone released by digestive organs onto Ant pit to stimulate GH release
Describe PTH axis
- Low calcium, low magneisum and high P04 cause PTH release from 4 glands on thyroid
- Inc in number and activity of osteoclasts -> Ca release
- Kidneys reabsorb calcium
- Kidneys activate vit D -> inc calcium absorption from food in gut
Describe PTH axis
- Low calcium, low magneisum and high P04 cause PTH release from 4 glands on thyroid
- Inc in number and activity of osteoclasts -> Ca release
- Kidneys reabsorb calcium
- Kidneys activate vit D -> inc calcium absorption from food in SI
Describe RAAS
- low circ volume detected
- renin released from kidney
- acts on angiotensin 1 (liver)-> 2
- angiotensin 2-> angitoensinogen by ACE
- angiotensinogen causes vasoconstriction and aldosterone release (adrenal)
- aldosterone = water and Na reaborsption DT and H,K secretion?
Carbimazole indication, SE and alternative
Used to control Graves, TNG
Works by blocking TPO from organifying the iodine
RISK = agranulocytosis = low neutrophils = check fbc in pxs on this drug when ill
SE- rash, GI
Teratogenicity
Alternative in preg esp 1st trimester: propylthiouracil
SE: hepatotoxicity and fulminant hepatitis
How does thyroid cancer present, diagnosis, treatment
Asymptomatic, palpable nodule in 30-40 year old women
risk - previous head /neck radiation
Diagnose: USS and FNAC
Tx: thyroidectomy, radioiodine ablation, TSH suppressing dose of levothyroxine
rare but good prognosis for most types
Role of steroids in thyroid problems
If treating px with thyroid eye disease with radioactive iodine need to give prophylactic steroids
Can give prednisolone in severe thyroiditis symptom management
What is T1 diabetes
Autoimmune or idiopathic destruction of beta cells that result in complete loss of insulin
So there is no uptake of glucose from blood, no glyconeogenesis, no inhibition of glycogenolysis
Diagnosis of diabetes
HbA1c > 48
Fasting bgc > 7
Random bgc or OGTT > 11
If T1 symptomatic = 1 test is enough
if T2 need 2 tests
Diagnosis of pre-diabetes
HBA1c > 38
Fasting > 5.5
Random > 7.8
Treatment of T1 diabetes
Insulin injection or subcut infusion
Never stop, inc when ill (hyperglycaemic)
Take a mixture of long and short acting
Monitor 3 monthly with Hba1c or fructosamine if blood disorder
What is DKA
- Hyperglycaemic or known diabetic
- Ketonaemia >3 bloods or urine >2
- Metabolic acidosis VBG > 7.3 pH or Hc03 <15
Cause
- forgot to take insulin/infection
Presentation of DKA
ACUTE < 24 HOURS T1 DIABETIC Usual t1 symptoms + N+V Abdo pain Reduced conciousness,low bp, excessive tiredness, headache Hyperventilation Hot dry skin Hypothermic
Presentation of DKA
ACUTE < 24 HOURS T1 DIABETIC Usual t1 symptoms + N+V Abdo pain Reduced conciousness,low bp, excessive tiredness, headache Hyperventilation Hot dry skin Hypothermic
Treatment of DKA
- 500ml of 0.9% NaCL
- FRII 0.1unit/kg/hour of insulin
- Potassium if <5.5 because insulin lowers K risk of hypokalaemia
- VTE prophylaxis
- Glucose if bgc <14
What is T2 diabetes
Beta cell of pancreas dysfunction = reduced sensitivity to and production of insulin
Presentation of T2 diabetic
Asymptomatic
Chronic fatigue, may have blurred vision
RF for T2 diabetes
Non modifiable:
- age
- ethnicity
- FH
- PCOS
- exisitng CVD
Modifiable:
- activity, weight status (BMI 25-30 over, 30+ obese)
- hypertension
- hyperlipidaemia
Management of T2 diabetes other than OHA
Conservative: activity = reduce cv risk, directly use glucose, inc glycogen stores, directly inc sensitivity to insulin change diet stop smoking = cvd alcohol = risk hypo
DRUGS
- BP
- Lipid
- Antiplatelet asprin, clopidogrel CV risk
What is HHS
- Hyperosmolar ( >320 mosmol/kg)
- Marked Hyperglycaemic (>30)
- Hypovolemic
- non ketotic
Causes - old diabetic who is ill or poorly controlled
Present - confused, dehydrated over a few days
Treat HHS
SLOW fluid replacement, naturally lowers glucose
if not -> insulin
Watch for hypernatraemia with saline replacement
Watch for hypokalaemia
VTE and ulcer protection
OHA for T2 diabetes
- Metformin
- SU eg gliclazide
- Pioglitazone
- Incretin based - gliptins, exenatide
- Acarbose
- SGLT2 inhibitors
How does metformin work, benefits and SE
Increases insulin sensitivity by
- inc glucose uptake into muscle
- reduce gluconeogensis
- decrease gut absorption of glucose
Benefit: cannot cause hypo or weight gain
BUT risk of lactic acidosis so check LFT and U+E before.
SE- GI, impaired B12 absorption
How do SU’s work, examples, side effects.
Name a similar drug
Change electrochemical gradient accross B cells via K = MORE INSULIN secreted
EG gliclazide, tolbutamide (s), glibenclamide (l)
SE- hypo, weight gain
CI- pregnancy/breastfeeding
SIMILAR- REPAGLINIDE
but shorter half life, less risk of hypo
What is pioglitazone an example of, how does it work and what are its SE
Thiazolidinediones
Increases lipid metabolism -> secondary glucose uptake
SE- weight gain, peripheral oedema, inc risk bladder cancer, reduce bone density
How do gliptins work, examples, SE
Gliptins = inhibit DPP4 = inhibit incretin(GLP1) breakdown = inc glucose mediated insulin release SE- pancreatitis CANT cause hypo Eg Linagliptin, Alogliptin, Saxagliptin
What kind of drug is exanatide, how does it work for diabetes and SE
Exanatide is a GLP1 analogue (mimetic) = glucose mediated insulin release increases
also : impaired glucagon secretion, slow gastric emptying
Benefit = only one good for obese px except acarbose
SE- subcut injection, N+V, pancreatitis
How do SGLT2 inhibitors work for diabetes, examples, SE
Reduce renal resorption of glucose
Gliflozins
SE- DKA, peripheral vasc disease
Eg dapagliflozin, clanagliflozin
Risk factors/associations of primary adrenal insufficiency
- Hypothyroidism
- Female
- Hypercoaguable state
Symptoms of Cushing’s syndrome
- Central adiposity, buffalo hump
- Purple striae
- Think skin, bruising
- Facial plethora
- Diabetes symptoms
- Prem osteoporosis
How to investigate cushing syndrome
PMH: steroid use, cancers
DEXAMETHASONE suppression test
Low dose = fails to suppress axis, cortisol still high
High dose = lowers cortisol in cushings disease. Ectopic or endogenous = stay high.
MRI pituitary for disease
How is cushings syndrome treated
DISEASE: trans-sphenoidal hypophysectomy, radiotherapy
SYNDROME: metyrapone, ketoconazole, etomidate ICU, mitotane (ACC)
How is primary adrenal insufficiency diagnosed
Low sodium, high potassium
SHORT SYNACTHEN TEST
primary = low or no cortisol response
How is secondary adrenal insufficiency diagnosed
high suspicion -> treat
Early morning cortisol
May do a synacthen if stable later
How is adrenal insufficiency treated
- Replace aldosterone if primary = fludrocortisone
2. Replace cortisol = hydrocortisone
What is an adrenal crisis and how is it prevented
Emergency situation where a patient has insufficient cortisol response to stress They will be - hypotensive, tachycardic - hypoglycaemic - hyponatraemic -> confused hyperkalaemic
PREVENT = sick day rules, pxs on cortisol should take more when ill
Causes of secondary adrenal insufficiency
- Exogenous steroid use
- Ectopic ACTH secretion
- Hypopituitarism
What are the causes of primary hyperaldosteronism/Conn’s syndrome?
- Aldosterone secreting adenoma of adrenals
2. Idiopathic (familial)
How does Conn’s present
- Hypertensive (always consider)
- headaches
- retinopathy
- weakness/tired - Hypokalaemic (can be normal, but they can end up swapping H,K for Na)
risk of met acidosis
could also present with hypertensive complications eg stroke
Diagnosis of conn’s
- Plasma aldosterone: renin ratio= increased
2. Fludrocortisone suppression test = would expect aldosterone to drop but it doesn’t
How is conn’s treated
- Excise adenoma
2. Spironolactone (gynae SE), triamterene for K preservation + amiloride diuretic for fluid overload
What is phaeochromocytoma
Excess catecholamines (ad,nad, dop) due to adrenal medullary tumour
Symptoms of phaeochromocytoma
random
- sweating
- palpitation
- headache
-tremor
-pallor
- weakness
hypertension
How is phaeochromocytoma diagnosed + tx
No consensus for diagnostic test
Tx- alpha and beta blockers, excise tumour
Causes of secondary hyperaldosteronism
- Benign JMA growth = inc renin
- RAS = false activation
Causes of primary hyperparathyroidism and blood results
- benign PT adenoma
- Hyperplasia
- Cancerous tumour
PTH high
Calcium high
Phosphate low
vit d high
Causes of secondary hyperparathyroidism and blood results
- renal disease
- vit d deficiency
- malabsorption eg pancreatitis
PTH high
calcium low
Phosphate high
low vit d (renal fail)
Causes of tertiary hyperparathyroidism and blood results
Continued secondary, px given tx but axis doesnt respond PTH high calcium high phosphate high vit d low
Symptoms of hypercalcaemia
Stones
Bones
Abdo moans
Pyschic groans(confusion)
Symptoms of hypocalcaemia
CATs go numb convulsions arrhythmias tetany numb hands, feet, around mouth = chvosteks sign = trosseau sign
