Endocrine Flashcards
What’s the difference between an endocrine and an exocrine gland?
An endocrine gland secretes directly into the bloodstream, whereas an exocrine gland secretes into a duct first.
Give 4 causes of primary adrenal insufficiency.
Addison’s disease, surgical removal, ACTH resistance/antibodies, invasion from tumour
Give 4 causes of secondary adrenal insufficiency.
Steroids, ACTH deficiency, basal skull fracture, radiotherapy
What are the 3 first line tests for Cushing syndrome?
Late night salivary cortisol
24 hour free cortisol
Dexamethasone suppression test (followed by serum cortisol level)
How does hyperglycaemia lead to insulin secretion?
Increased uptake of glucose into cells
Glucose is metabolised, increasing ATP
ATP causes K+ channels to close
K+ channels closing depolarises the cell membrane
Ca2+ channels open
Ca2+ enters the cells
Ca2+ entering causes exocytosis of insulin containing vesicles
Insulin is released by the pancreatic beta cells
Which blood values are diagnostic of diabetes?
Random plasma glucose >11mmol/mol
Fasting plasma glucose >7mmol/mol
HbA1c > 48mmol/mol
Give 3 microvascular complications of diabetes.
Nephropathy, neuropathy, retinopathy.
Give 3 macrovascular complications of diabetes.
Cerebrovascular disease, ischaemic heart disease, peripheral vascular disease
Which antibodies are most prominent in graves disease?
Anti-TSH receptor antibodies
What other antibody may be present in patients with Graves’ disease?
Anti thyroid peroxidase antibodies
Give 3 features specific to Graves’ disease.
Pretibial myxoedema
Thyroid acropachy
Eye disease
What is thyroid acropachy?
Finger clubbing, soft tissue swelling, periosteal new bone formation
What are signs of thyroid eye disease?
Exophthalmos (bulging of the eyeballs), ophthalmoplegia (paralysis of extraocular muscles)
How do women with post-partum thyroiditis present?
Initially present with hyperthyroidism after birth, but thyroid levels return to normal or even low.
What is the first line treatment of Grave’s disease?
Radioactive iodine treatment
What other management options are there for Grave’s disease?
Carbimazole, beta blockers, thyroidectomy
Why are beta blockers used in Grave’s disease?
Symptom management
Give 7 signs of Hashimoto’s thyroiditis.
Bradycardia Slow reflexes Moon face Ascites Cold hands Dry/thin skin/hair Drowsiness
What is the first line treatment of hypothyroidism?
Synthetic levothyroxine
What are the two main symptoms of diabetes insipidus?
Polyuria
Polydipsia
What is the gold standard investigation for diabetes insipidus?
Water deprivation test
Which class of diabetes drug can cause hypoglycaemia?
Sulfonylureas
Give an example of a sulfonylurea.
Gliclazide
How do sulfonylureas work?
Increase the pancreatic output of insulin
What is the gold standard investigation for acromegaly?
Oral glucose tolerance test
What findings are seen in secondary hyperparathryoidism?
PTH - high
Calcium - low
Phosphate - high
What findings are seen in primary hyperparathyroidism?
PTH - high
Calcium - high
Phosphate - low
What are the symptoms of hypercalcaemia?
Bones (bone pain), stones (kidney stones/urinary symptoms), moans (depression), groans (constipation, abdominal pain)
What tests are needed for the diagnosis of diabetes?
2 positive tests from the following:
- Random plasma glucose >11
- Fasting plasma glucose >7
- HbA1c > 48
Fasting plasma glucose and HbA1c are preferred
What test is used to monitor diabetes?
HbA1c
What is the first line management of type 2 diabetes?
Lifestyle management
What is the first line medical management of type 2 diabetes?
Metformin
How does metformin work?
Increases sensitivity of cells to insulin
How do sulfonylureas work?
They increase the amount of insulin that the body produces
Give a side effect of sulfonylureas.
Hypoglycaemia
What are the two most common complications of diabetes?
Retinopathy, peripheral neuropathy
What is the first line management of diabetic ketoacidosis?
IV fluids
What is the second line management of diabetic ketoacidosis?
Insulin
What type of tumour is a carcinoid tumour?
Neuroendocrine tumour
What is the triad of symptoms seen in a carcinoid tumour?
Flushing, diarrhoea, palpitations
When do symptoms appear with a carcinoid tumour?
Once it has metastasised to the liver
What is the first line/gold standard investigation for a carcinoid tumour?
Urinary 5-hydroxyindoleacetic acid
What is the first line investigation for acromegaly?
IGF-1
What is the gold standard investigation for acromegaly?
Oral glucose tolerance test
What can be tested for in phaeochromocytoma?
Plasma free metanephrines
What molecule causes hyperpigmentation in Addison’s disease?
POMC - propriomelanocortin
What symptoms does Conn’s syndrome present with?
Weakness, muscle cramps, hyporeflexia, polyuria/polydipsia
What is Conn’s syndrome?
Primary hyperaldosteronism
Which diabetes medication promotes weight loss, and which can cause weight gain?
Metformin promotes weight loss
Sulfonylureas can cause weight gain
What lab results are indicative of diabetic ketoacidosis?
Ketones > 3
Glucose > 11
pH < 7.3
What is the first line treatment of acromegaly?
Transphenoidal surgery
What is the second line treatment of acromegaly?
Somatastatin analogue (ocreotide or lanreotide)
What is the third line treatment of acromegaly?
GH receptor agonist
Give 4 signs of hypothyroidism.
Cold intolerance
Weight gain
Carpal tunnel
Lethargy
Give 5 signs of hyperthryoidism.
Heat intolerance Weight loss Palpitations Tremor Anxiety
What is the most common cause of hypothryoidism in the developed world?
Hashimoto’s
What is the most common cause of hypothryoidism in the developing world?
Iodine deficiency
What does a basal cell carcinoma look like?
Pink, waxy and flat
What does a squamous cell carcinoma look like?
Firm, red and scaly
Give a side effect of coming off long term steroids.
Adrenal insufficiency due to atrophy whilst on steroids
Give 3 types of cancer that can cause SIADH.
Small cell lung carcinoma
Prostate cancer
Pancreatic cancer
What ECG changes take place in hyperkalaemia?
Tall tented T waves
Flattened P waves
Wide QRS
Give 5 signs seen in hyperkalaemia.
Muscle weakness or cramping Palpitations Hyperreflexia Irritability Dyspnoea
Give 4 complications of acromegaly.
Type 2 diabetes
Hypertension
Sleep apnoea
Bitemporal hemianopia
What is the first line investigation for acromegaly?
Serum IGF-1 (raised)
What is the gold standard investigation for acromegaly?
Oral glucose tolerance test
What is the first line treatment of acromegaly?
Transphenoidal resection of pituitary adenoma
What are the second line pharmacological managements of acromegaly?
Dopamine agonists - cabergoline
Somatostatin analogues - ocreotide
Give 4 differentials of polyuria and polydipsia.
Diabetes mellitus, diabetes insipidus, Conn’s, hypercalcaemia
What is the first line investigation of SIADH?
Serum sodium, serum osmolality, serum urea
What is the first line management of SIADH?
IV saline and fluid restriction
What is the most common cause of primary hyperparathyroidism?
A solitary adenoma
What are the symptoms of hypercalcaemia?
Bones, stones, groans, moans, thrones
- Bone pain/fracture
- Renal/biliary stones
- Constipation
- Abdominal pain
- Depression
What is the definitive treatment of primary hyperparathyroidism?
Total parathyroidectomy
What condition can classically cause the symptoms of hypercalcaemia?
Primary hyperparathyroidism (or any other condition where calcium is high really)
What is the first line investigation of Cushing’s syndrome?
Overnight dexamethasone suppression test
What is the most common cause of Cushing’s?
Exogenous causes e.g excessive corticosteroid use
What is the main electrolyte abnormality in Conn’s syndrome?
Hypokalaemia
What is the first line investigation of Conn’s syndrome?
Aldosterone/renin ratio
What is the aldosterone/renin ratio in primary aldosteronism?
High
What is the aldosterone/renin ratio in secondary aldosteronism?
Low
What is seen on ECG in hypercalcaemia?
Short QT interval
Tall T waves
What two tests/signs are positive in hypercalcaemia?
Chvostek’s sign
Trosseau’s sign
What is the pathophysiology of hypercalcaemia of malignancy?
Excess PTHrP secretion from tumour
Give 4 actions of PTH.
Increased renal absorption of calcium
Renal excretion of phosphate
Increased intestinal absorption of calcium
Increases bone turnover to release calcium
What is carcinoid syndrome?
Excess release of serotonin from a tumour
What are the two most common features of carcinoid syndrome?
Diarrhoea and flushing
What is the action of carbimazole?
Blocks thyroid peroxidase from iodinating tyrosine residues
Give 6 signs/symptoms of DKA.
Fruity breath Reduced consciousness Polyuria/polydipsia Tachycardia Kussmauls breathing Abdominal pain
Give 4 symptoms of hypoglycaemia.
Sweating
Palpitations
Shaking
Poor concentration
What is the most common electrolyte disturbance found in Addison’s disease?
Hyponatramie (hyperkalaemia also seen, but not as commonly)
What is the first line pharmacological management of Graves’ disease?
Carbimazole
What is the urine osmolality in diabetes insipidus?
Low urine osmolality
What happens to urine osmolality after desmopressin is given in cranial diabetes insipidus?
Urine osmolality will increase
What happens to urine osmolality after desmopressin is given in nephrogenic diabetes insipidus?
Urine osmolality remains low
What is the first line treatment of an addisonian crisis?
100mg IV hydrocortisone
Which hormone inhibits GH secretion from the anterior pituitary?
Somatostatin
What cells synthesise T3 and T4?
Thyroid follicular cells
Give 5 signs of Cushing’s disease?
Moon face Buffalo hump Osteoporosis Skin thinning Mood change
What are the TFT results seen in primary hypothyroidism?
Low T3/T4, High TSH
What are the TFT results seen in secondary hypothyroidism?
Low T3/T4, Low TSH
Give an example of an alpha blocker used in the treatment of pheochromocytoma.
Phenoxybenzamine
Why is phenoxybenzamine given to pheochromocytoma patients before a removal of the tumour?
To avoid spikes of hypertension during the surgery
What is seen on ECG in hypokalaemia?
Small T waves, ST depression, U waves, short QT
What is the action of DPP-4 inhibitors?
Prevent insulin from being metabolised
What is the action of sulfonylureas?
Stimulate insulin production
What is the action of SGL-2 inhibitors?
Block reabsorption of glucose in the kidneys
What is the action of GLP-1 analogues?
Increase insulin production by increasing the beta cell mass of the pancreas
What is the first line investigation in diabetes insipidus?
Water deprivation test
What is the investigation used to differentiate between cranial and nephrogenic diabetes insipidus?
IM desmopressin test
What would the results be for a desmopressin test in cranial and nephrogenic diabetes insipidus?
The urine is concentrated in cranial DI, whereas it remains diluted in nephrogenic DI.
What is the first line treatment of a prolactinoma?
Dopamine agonist - cabergoline
What is the second line treatment of a prolactinoma?
Transphenoidal resection of tumour
Give 4 causes of diabetic ketoacidosis.
Underlying infection
Disruption of insulin treatment
Binge drinking
New onset of diabetes
What are the contraindications of metformin?
Renal disease
Liver failure
Heart failure
Give 4 side effects of metformin.
Anorexia
Diarrhoea
Nausea
Abdominal pain
What is the pathophysiology of graves disease?
TSH receptor autoantibodies cause thyroid hormone overproduction
What is the first line investigation for graves disease?
Thyroid function tests
What is the gold standard investigation for graves disease?
Anti-TSH antibodies
Give 3 risk factors for Hashimoto’s thyroiditis.
Female
Other autoimmune disease
Down’s syndrome/Turner’s syndrome
What antibodies are most prevalent in Hashimoto’s thyroiditis?
Thyroid peroxidase antibodies
What is the first line management of hypothyroidism?
Levothyroxine
What is De Quervian’s thyroiditis?
Hyperthyroidism usually following a viral illness
What is the treatment of De Quervian’s thyroiditis?
Aspirin
What is primary hypothyroidism?
Problem with the thyroid itself
What TFTs will be seen in primary hypothyroidism?
Low T3/T4, high TSH
What is secondary hypothyroidism?
Problem with the pituitary
What TFTs will be seen in secondary hypothyroidism?
Low T3/T4, low TSH, high TRH
What is tertiary hypothyroidism?
Problem with the hypothalamus
What TFTs will be seen in tertiary hypothyroidism?
Low T3/T4, low TSH, low TRH
What are the clinical effects of a pituitary tumour?
Pressing on other structures
Pressure damage to the normal pituitary leading to hypopituitarism
Effects of excess hormones from functional tumours
What are the commonest biochemical abnormalities in Addison’s disease?
Hypernatraemia
Hypercalcaemia
Hypokalaemia
Decreased glucose
What is the most common cause of an addisonian crisis?
Cessation of long term steroids
What is the action of metformin?
Decreases hepatic glucose production
Decreases intestinal absorption of glucose
Increases peripheral glucose uptake and use
What is the gold standard investigation for phaeochromocytoma?
Serum metanephrines
