Endocrine Flashcards
What hormones are released by the anterior pituitary?
LH/FSH GH TSH Prolactin ACTH
What hormones are released by the posterior pituitary?
Vasopressin
Oxytocin
Where do paracrine, autocrine and endocrine hormones act?
Paracrine - nearby cells
Autocrine - cells of origin
Endocrine - distant site
What are the microvascular and macrovascular complications of DM?
Micro - retinopathy, nephropathy, neuropathy
Macro - stroke, MI, renovascular disease, limb ischaemia
What are some atypical causes of DM?
Steroids, anti-HIV drugs, antipsychotics
Pancreatitis, trauma, CF, cancer
Cushing’s - acromegaly, phaechromocytoma, hyperthyroidism, pregnancy
What are the criteria for impaired glucose tolerance?
OGTT >7.8mmol/L
DM = >11.1mmol/L
What are the criteria for impaired fasting glucose?
Impaired = >6.1mmol/L DM = >7mmol/L
What is metabolic syndrome?
2 of:
- BP >130/85
- Triglycerides >1.7mmol/L
- Fasting glucose >5.6mmol/L or T2DM
What are the features of metformin?
Biguanide drug, increases insulin sensitivity
Helps with weight loss
SE: nausea, diarrhoea, abdo pain
What are some features of DPP4 inhibitors?
Inhibit enzymes that breakdown incretin (hormone that decreases blood glucose)
e.g. Sitagliptin
What are some features of glitazone?
Increases insulin sensitivity
SE: hypoglycaemia, fractures, fluid retention, abnormal LFTs
What are some features of sulphonyureas?
Increase insulin secretion
e.g. gliclazide
SE: hypoglycaemia, weight gain
What are some features of SGLT inhibitors?
Blocks reabsorption of glucose in the kidneys
e.g. empagliflozin
What are the stages of diabetic retinopathy?
- Background - micro aneurysms, haemorrhages, exudates
- Pre-proliferative - cotton wool spots, haemorrhages
- Proliferative - new vessel formation
What are the different types of diabetic neuropathy?
Symmetrical sensory polyneuropathy
Mononeuritis multiplex
Amyotrophy - painful wasting of quads and pelvic muscles
Autonomic neuropathy - postural BP drop, gastroparesis, urine retention, ED, diarrhoea
What is the triad of diabetic ketoacidosis?
Acidaemia
Hyperglycaemia >11
Ketonaemia or ketonuria
What is the management of DKA?
- ABCDE
- Cannulae and fluid bolus
- VBG, glucose, ketones, UEs, FBC, CRP
- 50 units insuline in 50ml saline
- Check glucose and ketones hourly
- Find and treat cause
What are non-DM causes of hypoglycaemia?
EXogenous drugs Pituitary insufficiency Liver failure Addison's Islet cell tumours Non-pancreatic neoplasms
What are some signs of hyperthyroidism?
Tachycardia, AF, tremor, palmar erythema
Thin hair, lid lag
Goitre, nodule, bruit
Graves - exophthalmos, ophthalmoplegia, pre-tibial myxoedema, clubbing
What are some causes of hyperthyroidism?
Graves Toxic multi nodular goitre Toxic adenoma Ectopic thyroid tissue - ovarian teratoma Idoine excess De-Quervian's thyroiditis Amiodarone, lithium Post-partum
What are the signs of hypothyroidism?
Ascites, weight gain
Pallor, puffy lids, coarse hair
Ataxia, hyporeflexia
What are some causes of hypothyroidism?
Hashimoto’s thyroiditis
Iodine deficiency
Post-thyroidectomy
Amiodarone, lithium
What is the action of PTH?
Secreted in response in decreased Ca levels
Increases osteoclast activity
Ca and phosphate released from bones
Increased Ca and decreased phosphate reabsorption in the kidney
Net = increased calcium, decreased phosphate
What are the causes and features of primary hyperparathyroidism?
80% caused by solitary adenoma
All gland hyperplasia
- Hypercalcaemia - weak, tired, depressed, thirsty, renal stones
- Bone reabsorption - pain, fractures, osteoporosis
- Hypertension
What are the causes of secondary hyperparathyroidism?
Low vitamin D, chronic renal failure - low calcium
What is the cause of tertiary hyperparathyroidism?
Occurs after prolonged secondary due to gland hyperplasia
High calcium, high PTH - no negative feedback
What are the causes and signs of primary hypoparathyroidism?
Autoimmune, Di George
Spasms Paraesthesia Anxiety Seizures Muscle tone increased Orientation impairment Dermatitis Impetigo Cardiomyopathy
What are the causes of secondary hypoparathyroidism?
Radiation, surgery, hypomagnesaemia
What is multiple endocrine neoplasia?
Functioning hormone-producing tumours in multiple organs
Autosomal dominant
Includes: MEN 1 and 2, neurofibromatosis, Von-hippel Lindau and Peutz Jegher
What is the tumour pattern in MEN1?
Parathyroid adenoma
Pancreas insulinoma or gastronoma
Pituitary prolactinoma
MEN1 = tumour suppressor gene
What is the tumour pattern in MEN2?
A - Thyroid medullary carcinoma, phaeochromocytoma, parathyroid hyperplasia
B - similar to A, + mucosal neuromas and Marfinoid appearance, - hyperparathyroidism
MEN2 = oncogene
What does the adrenal cortex produce?
- Glucocorticoids e.g. cortisol
- Mineralocorticoids e.g. aldosterone
- Androgens
What are some ACTH dependent causes of Cushing’s syndrome?
Cushing’s disease i.e. pituitary adenoma
Ectopic ACTH production e.g. SC lung cancer, carcinoid tumours
What are some ACTH independent causes of Cushing’s syndrome?
Iatrogenic - taking steroids
Adrenal adenoma/carcinoma
Adrenal hyperplasia
McCune-Albright syndrome
What are some symptoms of Cushing’s syndrome?
Weight gain, acne, proximal weakness
Depression, irritability, lethargy, psychosis
Irregular menses, hirtuism, erectile dysfunction
What are some signs of Cushing’s syndrome?
Central obesity
Bruises, purple abdominal striae
Osteoporosis, hypertension, hyperglycaemia, frequent infections
What initial investigation should be done for Cushing’s syndrome?
- Overnight dexamethasone suppression test
- 1mg dex at midnight
- Measure cortisol at 8am
- Normally suppresses to <50nmol/L
What are the next line tests for Cushing’s syndrome?
- 48 hour dexamethasone suppression test
- Plasma ACTH
- If undetectable think adrenal tumour - CT
- If detectable do high dose suppression test - MRI pituitary
- Bilateral inferior petrosal sinus blood sampling
What are the causes of primary adrenal insufficiency (Addison’s)?
Autoimmune
TB, lymphoma, APS, SLE
What is Waterhouse-Freiderichsen syndrome?
Bilateral adrenal cortex haemorrhage in meningococcal sepsis
What causes secondary adrenal insufficiency?
Suppression of the pituitary adrenal axis from chronic steroid use
What are the signs and symptoms of Addison’s?
Lean, tanned, tired, tearful, weak, anorexia, faints, dizziness
Depression, psychosis
Nausea and vomiting, abdominal pain, diarrhoea or constipation
Pigmented palmar creases and buccal mucosa
Postural hypotension
What investigations should be done for Addison’s?
U and Es
Low sodium, high potassium
