Endocrine notes Flashcards
What kind of receptors do hormones bind to in order to bring about a specific response
Cognate receptors
How is hormone action typically terminated
By enzyme-mediated inactivation in the liver
What is the rate-limiting step in synthesis of steroid hormones
Conversion of Cholesterol to Pregnenolone
Name 3 important carrier proteins and what they bind
Cortisol-binding-globulin (CBG)
Thyroxine-binding-globulin (TBG)
Sex steroid-binding-globulin (SSBG) - testosterone/ estradiol
Name 2 general carrier proteins and what they bind
Albumin - many steroids + thyroxine
Transthyretin - thyroxine
Name the 3 classes of nuclear receptor and what activates them
Class 1 - Steroids
Class 2 - Lipids
Hybrid class - T3
What do PP cells of the pancreas islets release
Pancreatic Polypeptide
What is Leprechaunism-Donohue syndrome
Mutations in the gene for insulin receptor
Cause growth retardation, muscle loss and fat loss
Which three things are seen in Rabson Mendenhall syndrome
Severe insulin resistance
Hyperglycaemia
Hyerinsulinaemia
Which derm condition can be seen in Rabson Mendenhall
Acanthosis Nigricans
What chemical excess is converted to ketone bodies
Acetyl-CoA
What are three useful tests to differentiate between Type 1 and Type 2 diabetes
Anti-GAD/ islet cell antibody test
Ketones
Plasma C-peptide
Children diagnosed under the age of 6 are more likely to have which form of diabetes
Monogenic
What is Bardet-Beidl syndrome
Genetic disorder with diabetes, obesity, retinitis pigmentosa, polydactyly, hypogonadism
What are the 4 types of neuropathy
Peripheral
Autonomic
Proximal
Focal
What is Kimmelstiel-Wilson syndrome
Diffuse scarring of glomeruli seen in long-standing diabetes
What ratio is used to screen for nephropathy
Albumin-creatinine ratio (ACR)
What is the main cause of death in children, secondary to DKA
Cerebral Oedema
How is Hyperglycaemic Hyperosmolar syndrome
Hypovolaemia
Hyperglycaemia (BG > 30)
Hyperosmolar (osmolarity > 320)
Where does GLP-1 act on in the brain
Hypothalamus
To reduce appetite
What normally binds to the SUR1 subunit in a beta cell to open the K+/ATP channel
ADP-Mg2-
How many micrograms of T3 equal 100 ug of T4
20
What is struma ovarii
A teratoma containing thyroid tissue
What is the treatment for thyroid storm
Lugol’s iodine
Steroids
B-blockers
Fluid
Which drug can cause agranulocytosis
Carbimazole
Which cardio drug can cause thyroiditis
Amiodarone
When should you always treat subclinical hypothyroidism
In pregnancy
If TSH > 10
Which cells of the anterior pituitary release Prolactin
Lactotroph cells
What does AMES stand for with regard to thyroid cancer
Ages
Mets
Extent of primary tumour
Size of primary tumour
What are the side effects of thyroid remnant ablation
Increased risk of AML(acute myelogenous leukaemia)
What drug treatments are available for Cushing’s
Metyrapone (adrenal suppression)
Pasireotide (somatostatin analogue)
How is Diabetes Insipidus diagnosed
Water Deprivation test
How is diabetes insipidus treated
Desmopression (synthetic vasopressin)
What are some side effects of somatostatin analogues
Flatulence
Diarrhoea
Abdominal pain
Where is most Na in the body
Extra-cellular fluid
What values of sodium can be classed as hyper and hyponatraemia
<120 mmol/L = Hyponatraemia
>155 mmol/L = Hypernatraemia
What is the anterior pituitary derived from
Rathke’s Pouch
Name the acidophil cells of the anterior pituitary
Somatotrophs (GH)
Mammotrophs (PRL)
Name the basophil cells of the anterior pituitary
Corticotrophs (ACTH)
Thyrotrophs (TSH)
Gonadotrophs (FSH/LH)
What are Zellballen
Tumour cells forming nests in a phaeochromocytoma
What are the tubular components of the testes
Sertoli cells
Germ cells
What are the interstitial components of the testes
Leydig cells
Capillaries
What is the treatment of Polycystic Ovarian Syndrome
Oral pill
Regulates cycle & decreases androgens
What is the scan used to image the parathyroid glands
Sestamibi scan
What values for serum calcium & eGFR indicate a need for parathyroidectomy
Calcium - > 2.85mmol/L
eGFR - < 60mL/min
What hypertension pattern would make you think of phaeochromocytoma
Labile hypertension - resistant to treatments
Postural hypotension
How does orlistat work
Pancreatic lipase inhibitor
Name an oral steroid with a relatively low mineralocorticoid activity
Dexamethasone
What does mineralocorticoid activity mean
Na retention in exchange for K+/H+ ions
What is the threshold for HbA1c which indicates adding a second oral therapy
58mmol/L
Which diabetes drug should be avoided in severe renal failure
Metformin
Which triad of symptoms suggests an Addisonian crisis
Hyponatremia
Hyperkalaemia
Hypoglycaemia
What should you think of if a patient presents with a tender goitre and thyrotoxicosis
De Quervain’s thyroiditis
What is the 1st line treatment for cerebral metastases and why
Dexamethasone to decrease cerebral oedema
What are some side effects of radioiodine therapy for thyrotoxicosis
Hypothyroidism
Exacerbation of thyroid eye disease
What are the blood pressure targets for someone with diabetes ± end-organ damage
< 140/80
< 130/80 if end-organ damage
Pioglitazone is contraindicated in heart failure, over 65’s and which other PMH
History of bladder cancer
What is the most common cause of Addison’s
Autoimmune Adrenalitis
How often should blood glucose be monitored in a type 1 diabetic
At least 4 times a day
Before each meal and before bed
Which thyroid pathology can have a ‘rich lipid core’
Benign adenoma
Cushing’s can put the body into what biochemical state
Hypokalaemic Metabolic Alkalosis
Which 3 hormones are decreased as part of the stress response
Insulin
Testosterone
Estrogen
What should be done to hydrocortisone and fludrocortisone doses on admission to hospital for an Addison’s patient
Double Hydrocortisone
No change to Fludrocortisone
Which heart failure medication can cause hypercalcaemia
Thiazide diuretics
What does a High T4 and a High TSH suggest in a person on levothyroxine
Poor compliance -> they have taken extra levothyroxine before the review but the TSH hasn’t had time to change
What is the pathology of Nelson’s syndrome
Rapid enlargement of an ACTH producing pituitary adenoma following a bilateral adrenalectomy
Why would an arrhythmia arise in DKA
Hyperkalemia
What kind of iodine uptake is seen in De Quervain’s thyroiditis
Decreased
What is the recommended insulin regime for a newly diagnosed type 1 diabetic
Basal-Bolus regime + long-acting insulin(detemir) twice daily
What should you think of when hypocalcaemia remains resistant to replacement therapy
Magnesium deficiency
What is the commonest cause of hypercalcaemia (and thus renal calculi)
Dehydration
What are the waking and pre-meal blood glucose targets for type 1 diabetics
4-7mmol/l for pre-meal
5-7mmol/L for waking
3 Antibodies associated with type 1 diabetes
Anti GAD
Anti IA2
Anti islet cell
Adrenaline, Cortisol and Glucagon are increased as part of the stress response. What two things are they trying to prevent
Hypoglycaemia
Hypokalaemia
How many ATP molecules can be produced from one glucose molecule
36 ATP molecules
What is the threshold after which beta cells physiologically begin releasing insulin
blood sugar over 5mmol/L
Which condition presents with severe insulin resistance and acanthosis nigricans
Rabson-Mendenhall syndrome
Insulin can be a hexamer or a monomer - which is the active form
Monomer
Which syndrome classically presents with very low muscle mass, growth retardation and severe insulin resistance
Donohue Syndrome
What is the normal level of 2-hour blood glucose for an oral glucose tolerance test
Less than or equal to 7.7mmol/l
What blood glucose after 2 hours will be diagnostic of diabetes in an Oral Glucose Tolerance Test
Greater than or equal to 11.1mmol/l
How might biochemistry results look like in anaemia in diabetes
Low albumin
Low Calcium
What are the two types of basal insulins
Isophane
Analogue
What is the target blood sugar level when a patient is on IV insulin and how often should this be checked
5-12mmol/l
Checked hourly
What happens to the efficacy of sulphonylureas as you increase the dose
Decreases
Metformin can interfere with the absorption of which two substances
Vit B12
Folic Acid
What is the name given to the weakening of the legs seen in proximal neuropathy
Amyotrophy
What is the 1st line treatment for painful neuropathy
Duloxetine
What is the fluid treatment pathway for DKA
0.9% NaCl saline until glucose drops to 15
then switch to dextrose
What should you give for alcohol-induced ketoacidosis
Pabrinex (high-dose vitamins)
What does carbimazole inhibit
Thyroid Peroxidase
prevents iodine binding to tyrosine residues to form MIT and DIT
Which hypothalamic secretion requires thyroid hormones to be present
GnRH
What kind of receptor is the TSH receptor
G-coupled
How does deiodinase work
Removes or adds an iodine atom from the outer ring of T3/4
What do T3 and T4 become after the action of deiodinase
T3 -> T2
T4 -> rT3 (reverse)
What is the most active/abundant deiodinase and where are the others found
D2
(D1 -> kidneys & liver)
(D3 -> placenta & brain)
What is a satisfactory level of serum GH after surgery
< 0.4 ug
