Endocrinology Flashcards
What drug can be used in the management of SIADH? What is its mechanism?
Demeclocycline (decreases the responsiveness of collecting tubules to ADH)
How do loop diuretics work?
inhibit NKCC2 co-transporter in ascending loop of Henle
commonest cause of Conn’s syndrome? Second commonest?
Bilateral adrenal hyperplasia
second: adrenal adenoma
How does aldosterone work?
Hypokalaemia
increases Na/H20 abdorption kidney –> hypertension
Commonest cause of primary hyperparathyroidism?
Single parathyroid adenoma
Explain the management of conn’s?
Depends on the cause
If bilateral adrenal hyperplasia - use aldosterone antagonist (spironolactone)
If adrenal adenoma –> adrenelectomy
What is barttle’s syndrome and how do you remember it?
A.R. condition affecting the NKCC2 co-transporter in the ascending loop of henle
Causes hypokalaemia, polyuria, polydipsia etc
It is like giving loads of furosemide which blocks the same co-transporter
What does a normal short synacthen test not exclude when assessing for adrenocortical insufficiency?
Pituitary failure
What metabolic derangements
Hyperkalaemia
Hyponatraemia
Hypoglycaemia
Metabolic acidosis
What autoantibody may be seen in addisons disease?
anti- 21,hydroxylase
How do sulfonylureas work? What are 2 side effects
Give an example
Bind to pancreatic beta cells ATP dependent K+ channel (closes it) –> increasing insulin release
weight gain + hypoglycaemia
Example: Gliclazide
Give an exmaple of an SGLT2 inhibitor + how does it work
Reversibly inhibit sodium glucose co transporter 2 in renal prox conv tubule (reduce glucose reabsorption)
Example: dapagliflozin
Which two diabetic classes can cause weight loss
SGLT2 inhibitors
GLP-1 analogues
In T1DM patients with BMI >25 what should you consider adding into their medications?
metformin
Causes of hypocalcaemia
vitamin D deficiency (osteomalacia)
chronic kidney disease
hypoparathyroidism (e.g. post thyroid/parathyroid surgery)
pseudohypoparathyroidism (target cells insensitive to PTH)
rhabdomyolysis (initial stages)
magnesium deficiency (due to end organ PTH resistance)
massive blood transfusion
acute pancreatitis
Two main causes of hypercalcaemia. Give some other causes
1) Primary hyperparathyroidism
2) Malignancy (bone mets lytic, myeloma, PTHrP from SCC)
Other:
sarcoidosis/TB/histoplasmosis (all cause granulomas)
vitamin D intoxication
acromegaly
thyrotoxicosis
Milk-alkali syndrome
drugs: thiazides, calcium containing antacids
dehydration
Addison’s disease
Paget’s disease of the bone (usually normal initially)
Complication of type 1 renal tubular acidosis
Hypokalaemia, Nephrocalcinosis + renal stones
Complication of type 2 renal tubular acidosis
hypokalaemia, osteomalacia
What is the commonest gene is defect in MODY?
HNF-1 alpha gene
What diabetic medication increases risk of Fournier’s gangrene and how does it work?
SGLT-2 inhibitors
Inhibits sodium-glucose co-transporter –> prevents reabsorption of glucose and therefore increases urinary glucose excretion (n.b. this increases risk of urinary/genital infections)
Give some adverse effects of SGLT-2 inhibitors
Give one benefit
UTI (secondary to glycosuria)
Normoglycaemic ketoacidosis
Increased risk of lower limb amputation
Benefit: weight loss
What thyroid cancer is associated with Hashimoto’s?
Thyroid lymphoma
What type of renal histological finding is seen diabetic retinopathy?
Nodular glomerulosclerosis + thickening of BM + Kimmelstiel-Wilson nodules
What type of renal histological finding is seen in amyloidosis?
Apple-green birefringence under polarised light
What is the treatment of hyperthyroid in pregnancy?
Propylthiouracil is used in the first trimester of pregnancy in place of carbimazole, as the latter drug may be associated with an increased risk of congenital abnormalities. At the beginning of the second trimester, the woman should be switched back to carbimazole
What maternal free thyroxine level should a pregnant lady be kept at when treating hyperthyroid and why?
thyroxine levels should be kept in the upper third of the normal reference range to avoid fetal hypothyroidism
What is the urinary sodium in SIADH?
> 20mmol/L
What drugs might prevent absorption of levothyroxine (hence patient presenting with hypothyroidism despite being on treatment)?
ferrous sulfate/iron tablets + calcium carbonate
should be given 4 hours apart
What is a contraindication for pioglitazones?
Previous bladder cancer (increases risk) or macroscopic haematuria (univestigated)
Heart failure
What anti diabetic meds have extra benefit in those with CVD?
SGLT-2 inhibitors (gliflozins)
What vision defect is seen in full scatter pan retinal photocoagulation in diabetic retinopathy?
Tunnel vision
What is MEN I linked to?
parathyroid (95%): hyperparathyroidism due to parathyroid hyperplasia
pituitary (70%)
pancreas (50%, e.g. Insulinoma, gastrinoma)
also: adrenal and thyroid
What is zollinger ellison syndrome?
excessive levels of gastrin, usually from a gastrin producing tumour
