Endocrinology Flashcards
Refeeding syndrome electrolyte disturbances
Hypophosphatemia Hypomagnasemia Hypokalemia (Hyperglycaemia) (Fluid retention)
Growth hormone (GH) stimulation
Deep sleep Exercise Trauma / sepsis Malnourishment / hypoglycaemia High protein meal Oestrogen Dopamine
Growth hormone (GH) inhibition
Hyperglycaemia
Leptin
Glucocorticoid excess
Most common endocrinopathies post pituitary radiotherapy
Growth hormone - most common
Gonadotroph - 2nd most common
ACTH / TSH - least common
Pregnancy - hormone levels
FSH - low LH - low Prolactin - high Oestrogen - high Testosterone - high
Polycystic ovarian syndrome (PCOS) - hormone levels
Testosterone - high
Oestrogen - high or normal
FSH - low or normal
LH - high (in 50%) relatve to FSH
Congenital adrenal hyperplasia (CAH) - hormone levels
17-hydroxyprogesterone - high, with exaggerated ACTH stimulation test increase
Renin - low
Aldosterone - low
Hydatiform mole - hormone levels
B-hCG - high (higher than intrauterine/ectopic pregnancy)
Prolactinoma - hormone levels
Prolactin - high
Primary ovarian insufficiency (POI) - hormone levels
FSH - high
Oestradiol - low
Mature onset diabetes of youth (MODY) 1
HNF-4 alpha defect
- (Chromosome 20q)
Mature onset diabetes of youth (MODY) 2
Glucokinase defect
- 2nd most common - 15%
- Mild hyperglycaemia
- Can be taken off treatment due to minimal complications
Mature onset diabetes of youth (MODY) 3
HNF-1 alpha defect
- Most common - 70%
- Very sensitive to sulfonylurea treatment
- Offspring diabetes risk 50%
- High HDL cholesterol
Indications to treat diabetic foot ulcers
Shock Bacteraemia Marked necrosis / gangrene Ulceration of deep tissue Severe cellulitis Osteomyelitis Septic arthritis
Indications to treat diabetic foot ulcers
Shock Bacteraemia Marked necrosis / gangrene Ulceration of deep tissue Severe cellulitis Osteomyelitis Septic arthritis
Contraindications to bisphosphonate therapy for osteoporosis
Recent fracture (4-6 weeks)
Oesophageal disorders
Gastrointestinal intolerance
Chronic kidney disease - eGFR less than 30
Hyperprolactinaemia - presentation
Hypogonadotrophic hypogonadism Reduced libido Impotence Infertility Gynaecomastia Galactoorrhoea
Hyponatraemia - BSL correction
+2 mmol/L serum Na for each 5.5 mmol/L BSL (over 10 mmol/L)
Primary aldosteronism - hormone levels
Renin - low
Aldosterone - high
Aldosterone/renin ratio - more than 20
Phaeochromocytoma - hormone levels
Metanephrine - high
Urinary catecholamines - high
Secondary hyperaldosteronism - hormone levels
Renin - high
Aldosterone - high
Aldosterone/renin ratio - approx. 10
Causes of secondary hyperaldosteronism
Renovascular hypertension Diuretic use Renin secreting tumour Malignant hypertension Coarctation of the aorta
Glucocorticoid excess - hormone levels
eg. Cushing’s syndrome, exogenous mineralcorticoid, glucorticoid resistance
Renin - low
Aldosterone - low
Biguanide - mechanism of action
eg. metformin
- Increase insulin action
- Decrease hepatic gluconeogenesis
- Increase peripheral glucose uptake
- Minor decrease in gut glucose absorption
Biguanide - indications for T2DM
eg. metformin
- 1st line initial therapy
- Reduced weight
- Reduced CVS events - in overweight patients
- Reduced all-cause mortality
Sulfonylurea - mechanism of action
eg. gliclazide
- Stimulate relase of insulin from β-cells
- Used in early T2DM, less effective in advanced / progressive T2DM
Sulfonylurea - indications for T2DM
eg. gliclazide
- 1st line - if metformin intolerant
- 2nd line - in addition to metformin
- Side effects - weight gain, hypoglycaemia
Glucosidase inhibitor - mechanism of action
eg. acarbose
- Inhibit saccharide breakdown at brush border of gut
- Reduces post-prandial hyperglycaemia
Glucosidase inhibitor - indications for T2DM
eg. acarbose
- 3rd line - if post-prandial hyperglycaemia
- Side effects - diarrhoea / flatulence, malabsorption
Thiozolidinedione - mechanism of action
eg. pioglitazone
- Binds and activates PPAR-gamma receptor
- Decreased hepatic gluconeogenesis
- Increased peripheral insulin sensitivity
Thiozolidinedione - indications for T2DM
eg. pioglitazone
- 3rd line - if no congestive heart failure
- Side effects - weight gain, fluid retention / CCF, fractures, cardiovascular disease / MI (except pioglitazone)
Incretin mimetic - mechanism of action
eg. exenatide
- GLP-1 analogue, stimulates β cells, inhibits α cells
- Increases insulin
- Decreases glucagon
- Slows stomach emptying
Incretin mimetic - indications for T2DM
eg. exenatide
- 3rd line - if BMI more than 30, desire to lose weight, can self-inject
- Improves glycaemic control
- Reduces weight
- No difference in CVS outcomes
Dipeptidyl peptidase-4 (DDP-4) inhibitor - mechanism of action
eg. sitagliptin
- Inhibits DPP-4 inactivation of GLP-1
- Dependent on endogenous GLP-1 production
Dipeptidyl peptidase-4 (DDP-4) inhibitor - indications for T2DM
eg. sitagliptin
- 3rd line - if weight gain concerning
SGLT-2 inhibitor - mechanism of action
eg. dapagliflozin
- Blocks sodium-glucose transport protein 2
- Reduces glucose reabsorption from urine in tubules
- Increased efficacy as BSL increases
SGLT-2 inhibitor - indications for T2DM
eg. dapagliflozin
- 3rd line - when other drugs contraindicated
- Reduces all-cause mortality, CVD events, CCF admissions, and weight
- Contraindicated in renal impairment eGFR less than 45
- Side effects - genital infections / candidiasis (not UTIs), syncope / hypotension, euglycaemic DKA
Most common secretory hormone in silent / non-functioning adenoma
Gonadotrophin (80-90%)
Most common secretory hormone in functioning adenoma
Prolactin (50% all adenomas, typically microadenoma)
Most common type of macroadenoma
Gonadotroph adenoma
Most common factors associated with thyroid opthalmology
Genetic factors
Smoking
Female sex
Causes of metabolic acidosis - with increased anion gap
Lactic acidosis Ketoacidosis (diabetes, alcohol, starvation) Drugs/toxins (salicylates, biguanides) Renal failure (urate)
Causes of metabolic acidosis - with normal anion gap
Renal tubular acidosis Diarrhoea Drugs (acetazolamide) Ammonium chloride ingestion Addison's disease Pancreatic fistula
Causes of metabolic alkalosis
Vomiting
Burns
Potassium depletion (eg. diuretics)
Ingestion of base
Primary hyperparathyroidism - hormone levels
PTH - inappropriately normal
Ca - high
PO4 - low
Vitamin D (calcitriol) - high
Secondary hyperparathyroidism - hormone levels
PTH - high
Ca - low
PO4 - high
Vitamin D (calcitriol) - low (in vit D deficiency) or normal
Pseudohyperparathyroidism - hormone levels
PTH - high
Ca - low
PO4 - high
Vitamin D (calcitriol) - low
