Endocrinology Flashcards
What do meglitinides (e repaglinide) do?
Increase pancreatic insulin secretion but binding to an ATP dependant potassium channel of the cell membranes of pancreatic beta cells
What is the treatment of severe hypocalcaemia?
10ml of 10% calcium gluconate over 10 minutes
Where is prolactin secreted from?
The anterior pituitary gland
What drugs cause a raised prolactin?
Metclopramide, domperidone
Phenothiazines (Chlorpromazine)
Haloperidol
How do sulfonylureas work?
Increase pancreatic insulin secretion by binding to an ATP dependant potassium channel
Why do patients with cushings syndrome get metalbolic alkalosis?
Excess aldosterone increased acid and pottasium secretion in the kidney
Why do patients with addisons get a hyperkalaemic metabolic acidosis?
Insufficiency of aldosterone which decreases acid secretion in the kidney and leads to the retention of potassium
What tests are used to confirm cushings syndrome?
Overnight dexamethasone suppression test
24 hr urinary cortisol
What are the main complications of acromegaly?
Hypertension
Diabetes
Cardiomyopathy
Colorectal cancer
What is the first line investigation for primary aldosteronism?
Renin/aldosterone ratio
What is the diagnostic criteria for type 2 diabetes?
If the patient is symptomatic:
- Fasting glucose greater than 7
- Random glucose greater than 11.1
(if asymptomatic then the same criteria but must be demonstrated on two occasions )
An HbA1c of 48 or above in diagnostic of diabetes
What is the criteria for impaired fasting glucose?
Glucose of greater than 6.1 but less than 7
What is the criteria for impaired glucose tolerence?
Fasting glucose less than 7 and oral glucose tolerence test equal or greater than 7.8 but less than 11.1
What thyroid cancerare you more at risk of if you have hashimotos thyroiditis?
Thyroid lymphoma - due to chronic infiltration of the thyroid gland with B lymphocytes which are prone to clonal proliferation
What is the most common type of thyroid cancer?
Papillary
What is the first hormone secreted in response to hypoglycaemia?
Glucagon
How do fibrate drugs work?
Acivation of PPAR alpha receptors which result in an increase in LPL activity reducing triglyceride levels.
What do you need to increase thyroxine too if a women falls pregnant?
Increase dose by 50% by 4 - 6 weeks of pregnancy
In what groups of patients is a QRISK2 score contraindicated?
Type 1 diabetics
eGFR less than 60ml/min
Patients with a history of familial hyperlipidaemia
What is liddle’s syndrome?
A rare autosomal dominant condition that causes hypertension and hypokalaemia acidosis. It is thought to be caused by disordered sodium channels in the distal tubules leading to an increased reapsoprtion of sodium
What is the first line drug treatment for painful diabetic neuropathy?
Amitriptyline, duoloxetine, gabapentin or pregabalin
What antibodies are seen in hashimotos thyroiditis?
Anti TPO antibodies
Anti thyroglobulin antibodies
What kind of drug is octreotide?
A somatostatin analogue - this directly inhibits the release of growth hormone
What is the usual first line treatment for acromegaly?
Trans-sphenoidal surgery
What are the options for drug treatment of acromegaly?
Somatostatin analogue (eg ocreotide) GH receptor antagonists such as pegnisomant. This prevents dimerization of the GH receptor
What is the medical management of phaechromocytoma?
Alpha Blocker (phenoxybenzamine) THEN Beta blocker
What cells in the parathyroid secrete PTH?
Chief cells
What does PTH do in response to low calcium?
- Increased absorption of calcium from the gut
- Increase reabsorption of calcium from he kidneys
- Increasing the osteoclast activity in the bone (breakdown of bone)
- Acts on vitamin D to convert it to its active form
What is primary hyperparathyroid hormone?
Uncontrolled PTH secretion (usually by a ademona/tumour of the PTH glands) This results in hypercalcaemia
What is secondary hyperparathyroidism?
Chronic renal failure or reduced vitamin D leads to reduced calcium absorption . This causes hypocalcaemia and causes an increase in the secretion of PTH. This then causes hyperplasia.. Blood results show a low or normal calcium with a high PTH
What is tertiary hyperparathyroidism?
When secondary hyperparathyroidism is fixed by the glands are so hypertrophied that they continue to secrete lots of PTH and cause hypercalcaemia
What are the causes of primary hyperparathyroidism?
Solitary adenoma (80%)
Hyperplasia (15%)
Multiple adenoma (4%)
Carcinoma (1%)
What type of thyroid cancer is associated with MEN 2?
Medullary thyroid cancer
What is the cause of hyperlipidaemia that is mostly due to hypertriglyceridaemia?
Diabetes (Type 1 and 2_ Obesity Alcohol Chronic renal failure Liver disease Oestrogen Thiazides
What are the causes of hyperlipidaemia with predominantly hypercholesterolaemia?
Nephrotic syndrome
Cholestasis
Hypothyroidism
What is the mechanism of action of Thiazolidinediones
eg pioglitazone
Agonists of the PPAR gamma receptor and they reduce peripheral unsulin resistance
What is the mechanism of action of gliptins (DPP 4 Inhibitors)?
Reduce the peripppheral breakdown of incretins such as GLP 1
How is MEN inherited?
Autosomal dominant
What is in MEN 1?
Parathyroid hyperplasia
Pituitary tumours
Pancreas tumours (eg insulinoma)
Adrenal and thyroid also!
What is the most common biochemical abnormality seen in MEN 1?
Hypercalcaemia
What is in MEN 2a?
Medullary thyroid cancer
Parathyroid
Phaechromocytoma
What is in MEN 2b?
Medually thyroid cancer
Phaemchromocytoma
Marfanoid body
Neurma
What does the aldosterone/renin ratio show in primary hyperaldosteronism?
High aldsterone and low renin
What is the treatment for a toxic multinodular goitre?
Radioiodine therapy
What is subacute thyroiditis?
Occurs after a viral infection and there are 4 phases
- ( lasts 3 - 6 weeks) Hyperthyroidism, painful goitre
- (Lasts 1 - 3 weeks) Euthyroid
- (weeks - months) hypothyrodisim
- Normal
What do you see on thyroid scintigraphy or subacute thyroiditis?
Globally reduced uptake of iodine 131
What is the treatment for a thyroid storm?
Beta blockers Anti thyroid drugs such as methimazole ot propylthiouracil
Dexamethasone
What autoantibodies are seen in graves disease?
TSH receptor stimulating antibodies
Anti thyroid peroxidase antibodies
Where about in the kidney does aldosterone act?
Distal convoluted tubule
What conditions can cause a falsely low HBa1c?
Sickle cell anaemia
G6PD deficiency
Hereditary spherocytosis
What conditions can cause a falsely high level of HbA1c?
Vitamin B12/folic acid deficiency
In deficiency anaemia
Splenectomy
What is riedels thyoiditis?
A rare case of hypothyroidism characterised by dense fibrous tissue replacing the normal thyroid parenchyma . It is associated with retroperitoneal fibrosis
Why is dexamethasone given in thyroid storm?
It blocks the conversion of T4 to T3
How should graves disease be treated in pregnancy?
propylthiouracil in the first trimester in place of carbimazole. At the start of th second trimester switch back to cabimazole
