Endocrinology Flashcards
What is type 1 diabetes mellitus?
Autoimmune destruction of pancreatic beta cells within the Islets of Langerhans resulting in insulin deficiency
What is type 2 diabetes mellitus?
Insulin resistance
Give some risk factors for type 2 diabetes.
- Older
- Central obesity
- Sedentary lifestyle
- Hypertension and/or hyperlipidaemia
- African/Caribbean ancestry
Describe the clinical presentation of diabetes.
- Polyuria
- Polydipsia
- Weight loss
How is type 2 diabetes diagnosed?
Symptomatic individual:
ONE glucose result in diabetic range (fasting/random)
Asymptomatic individual:
TWO separate glucose results in diabetic range (fasting/random/2 hr postprandial)
Symptomatic/asymptomatic individual:
ONE HbA1c result in diabetic range
Diabetic values:
- Fasting > 7 mmol/L
- Random or 2 hr postprandial > 11.1 mmol/L
- HbA1c > 48 mmol/L
Describe the conservative management of type 2 diabetes.
Lifestyle advice, e.g. weight loss, take regular exercise etc.
Describe the pharmacological management of type 2 diabetes.
- 1st line = Metformin (Biguanide)
- 2nd line = Metformin + Gliclazide (Sulfonylurea)
- 3rd line = Metformin + Gliclazide + Sitagliptin (DPP4i)
- 4th line = insulin therapy
Side effects of pharmacological therapies for type 2 diabetes.. which cause weight gain/loss?
- Biguanides = weight LOSS (also cause GI disturbance: nausea, anorexia)
- Sulfonylureas/glitazones = weight GAIN
- DPP4 inhibitors = no change
How is type 1 diabetes diagnosed?
Signs of hyperglycaemia (polydipsia, polyuria) AND ONE of the following:
- Ketosis
- Rapid weight loss
- Age of onset <50 years
- BMI <25 kg/m2
- Personal/family history of autoimmune disease
Describe the management of type 1 diabetes.
Insulin
What are the microvascular and macrovascular complications of diabetes mellitus?
Microvascular =
Diabetic neuropathy, retinopathy, nephropathy
Macrovascular =
CVD
What is hyperthyroidism?
Excess thyroid hormone
What are the causes of hyperthyroidism?
- 2/3 cases = GRAVES DISEASE
- Toxic multinodular goitre
- Toxic thyroid adenoma
What are the symptoms and signs of hyperthyroidism?
Symptoms:
- Weight loss
- Diarrhoea
- Sweating, palpitations, tremor (anxiety)
- Amenorrhoea
Signs:
- Tachycardia
- Lid lag/retraction
- Exophthalmos
- Onycholysis
How is hyperthyroidism investigated?
Thyroid function tests:
- Primary = low TSH and high T3/T4
- Secondary = high TSH and high T3/T4
Thyroid autoantibodies:
- Thyroid peroxidase
- Thyroglobulin
- TSH receptor antibody
Radioactive iodine isotope uptake scan
Describe the pharmacological management of hyperthyroidism.
- Beta blockers for rapid symptom control
- Carbimazole (antithyroid drug)
Describe the interventional management of hyperthyroidism.
Thyroidectomy
What is Graves’ disease? Extra signs present with Graves’ disease?
Autoimmune induced excess production of thyroid hormone (via TSH receptor antibody)
Signs - Graves’ ophthalmology:
- Extraocular muscle swelling
- Eye discomfort
- Excessive lacrimation
- Diplopia
What is hypothyroidism?
Too little thyroid hormone
What are the causes of hypothyroidism?
- Hashimoto’s thyroiditis
- Iodine deficiency
What are the symptoms and signs of hypothyroidism?
Symptoms:
- Weight gain
- Constipation
- Fatigue, myalgia
- Menorrhagia
Signs:
- Bradycardia
- Reflexes relax slowly
- Ataxia
Describe the pharmacological management of hypothyroidism.
Synthetic thyroid hormone (levothyroxine)
What is acromegaly? What is gigantism?
Acromegaly = Increased production of growth hormone occurring in adults (after fusion of epiphyseal growth plates)
Gigantism = Increased production of growth hormone occurring in children
What is the main cause of acromegaly?
Pituitary adenoma
What are the symptoms and signs of acromegaly?
Symptoms:
- Acroparasthesia
- Arthralgia
- Sweating
- Headache
Signs:
- Massive growth of hands, feet and jaw
- Widely spaced teeth
- Puffy lips, eyelids and skin
- Deep voice
How is acromegaly investigated?
NOT random growth hormone test - GH is a pulsatile protein and levels vary throughout day
Administer glucose:
- Normally glucose suppresses GH levels
- If given glucose and GH levels still high, this is diagnostic for acromegaly
MRI pituitary fossa for adenoma
Describe the pharmacological/interventional management of acromegaly.
- Transsphenoidal surgery to remove adenoma
- GH antagonist, e.g. pegvisomant
What is hyperaldosteronism?
Excess aldosterone production, independent of RAAS
Aldosterone works in kidney to cause potassium loss- excess causes hypokalaemia and sodium + water retention
What are the causes of hyperaldosteronism?
- 2/3 cases = CONN’S SYNDROME (a solitary, benign adrenocortical adenoma)
- Bilateral adrenocortical hyperplasia
What are the symptoms of hyperaldosteronism?
Symptoms of hypokalaemia =
- Cramps
- Constipation
- Paraesthesia
- Arrhythmias
How is hyperaldosteronism investigated?
U+E = hypokalaemia
ECG - signs of hypokalaemia:
No POT and no T, but a long PR and a long QT
ADRENAL CT is diagnostic
Describe the pharmacological/interventional management of hyperaldosteronism.
Depends on cause…
- Treat hypokalaemia (give K+)
- Pharmacological = spironolactone (aldosterone antagonist)
- Interventional: laparoscopic adrenalectomy
What is Cushing’s syndrome? What is Cushing’s disease?
Cushing’s syndrome = excess cortisol + loss of hypothalamic pituitary axis feedback + loss of circadian rhythm
Cushing’s disease = all of above + CAUSED by pituitary adenoma
What are the causes of Cushing’s syndrome?
ACTH independent causes:
- Iatrogenic - STEROIDS!!
- Adrenal adenoma
ACTH dependent causes:
- Cushing’s disease (pituitary adenoma)
Describe the symptoms of Cushing’s syndrome.
- Weight gain/truncal obesity
- Hirsuitism
- Acne
- Moon face/buffalo hump
- Striae
How is Cushing’s syndrome investigated?
Dexamethasone suppression test:
- Dexamethasone usually suppresses cortisol levels
- Failure of dexamethasone to suppress cortisol levels over 24 hr period is diagnostic of Cushing’s syndrome
MRI for pituitary adenoma
Describe the management of Cushing’s syndrome.
Depends on cause:
- If iatrogenic then stop steroids
- Adrenal adenoma = adrenalectomy, radiotherapy
- Cushing’s disease (pituitary adenoma) = transsphenoidal removal of pituitary adenoma
What is Addison’s disease?
- Autoimmune destruction of the adrenal cortex resulting in primary adrenal insufficiency (adrenal impairment resulting in low cortisol and low aldosterone levels)
What are the leading causes of primary adrenal insufficiency in the UK and worldwide?
- Worldwide = TB
- UK = Addison’s disease
Describe the symptoms of Addison’s disease.
- Hyperpigmentation of the skin
- Depression
- Abdominal pain, nausea and vomiting
Describe the investigation of Addison’s disease.
ACTH stimulation test:
- Give ACTH (synacthen) and measure cortisol levels
- Normally, ACTH would cause a rise in cortisol levels; in Addison’s, cortisol remains low after giving ACTH
Test for 21-hydroxylase adrenal autoantibodies
U+E: hyperkalaemia and hyponatraemia (due to low levels of aldosterone)
Addison’s disease can result in hyperkalaemia…
a) Describe the ECG changes you would see with hyperkalaemia
b) Describe the non-urgent and urgent management of hyperkalaemia
a) Small P waves, tall T waves, wide QRS complex
b) Non-urgent = polystyrene sulfonate resin
Urgent = calcium gluconate, insulin
Describe the pharmacological management of Addison’s disease.
- Hydrocortisone to replace cortisol
- Fludrocortisone to replace aldosterone
What is diabetes insipidus?
EITHER
- Too little ADH secretion from posterior pituitary (cranial DI)
- OR kidney not responding to ADH (nephrogenic DI)
What are the causes of diabetes insipidus?
Cranial DI:
- Head trauma
- Pituitary adenoma
Nephrogenic DI:
- Drugs, e.g. Lithium
What are the symptoms of diabetes insipidus?
- Polyuria
- Polydipsia
- Dehydration
How is diabetes insipidus investigated?
Water deprivation test:
- Restrict fluid
- Measure urine osmolarity - +ve for DI if urine osmolarity remains low
- Differentiate between cranial and nephrogenic DI by using desmopressin (ADH analogue)
Describe the pharmacological management of diabetes insipidus.
- Cranial DI - desmopressin
- Nephrogenic DI - bendroflumethiazide, NSAIDs
What is SIADH?
SIADH stands for ‘syndrome of inappropriate secretion of ADH’
Too much ADH being secreted from posterior pituitary
What are the causes of SIADH?
- Malignancy
- Drugs
- CNS disorders
What are the symptoms and signs of SIADH?
Symptoms:
- Confusion
- Nausea
- Anorexia
Signs:
- Concentrated urine
How is SIADH investigated?
Measure urine osmolarity (v high) and plasma osmolarity (v low)
Describe the management of SIADH.
- Treat underlying cause if possible
- Restrict fluid intake
- Vasopressin receptor antagonists (‘vaptans’)
What is hyperparathyroidism? What are the types of hyperparathyroidism? Give examples of what causes each type
Too much PTH secreted from parathyroid glands into bloodstream
- Primary, most commonly caused by parathyroid adenoma
- Secondary - when a condition such as kidney failure or vitamin D deficiency lowers calcium levels, so parathyroid glands produce more parathyroid hormone
Does PTH reduce/increase serum calcium levels? Describe the mechanisms by which it achieves this
PTH increases serum calcium levels by…
- Stimulating osteoclasts to resorb bone to release calcium into blood
- Stimulating kidneys to reabsorb more calcium from urine into blood
- Stimulating gut to absorb more calcium
Describe the serum PTH and calcium results for…
a) primary hyperparathyroidism
b) secondary hyperparathyroidism
a) high PTH, high calcium
b) high PTH, low calcium
Describe the management of hyperparathyroidism
Primary = surgery to remove parathyroid adenoma Secondary = treat underlying condition, e.g. kidney disease, vit D deficiency
What are the symptoms of hyperparathyroidism?
STONES, BONES, MOANS, GROANS
Kidney stones
Bone pain/tenderness
Depression/fatigue
Abdominal pain, constipation
What is hypoparathyroidism?
What are the causes of hypoparathyroidism?
Too little PTH secreted from parathyroid glands into bloodstream
Causes:
- Surgical (removal of parathyroid glands)
- Autoimmune
What are the symptoms and signs of hypoparathyroidism?
HYPOcalcaemia:
Symptoms:
- Paraesthesia (especially around mouth and lips)
Signs:
- Chvostek’s sign (twitching of facial muscles when ficial nerve is tapped)
- Trousseau’s sign (spasm caused by inflating BP cuff around upper arm)
- Long QT interval
Describe the management of hypoparathyroidism
Treat hypocalcaemia:
- Urgent = IV calcium glucoronate
- Maintenance = Adcal D3
Treat underlying cause, e.g. autoimmune with steroids
Give some signs of DKA
Kussmaul’s breathing
Vomiting
Loss of consciousness
Pear drop breath
