Endocrinology Flashcards
What are hormones?
Molecules secreted into the blood with regulatory actions at distant sites
How do hormones act via?
Receptors
How are hormones regulated?
Feedback loops
List 5 endocrine glands?
Pituitary gland Thyroid and parathyroid glands Adrenal glands Pancreas Ovaries/testes
Describe the actions leading to the secretion of cortisol
Corticotrophin releasing hormone released from the hypothalamus
This stimulates Adrenocorticotrophic hormone to be released from pituitary gland
This travels in the blood stream to the adrenal cortex which secretes cortisol
When cortisol levels are high this causes negative feedback loop to hypothalamus and CRH stops being made
How is thyroxine produced?
Thyroid-releasing hormone secreted from hypothalamus causes release of thyroid stimulating hormone from pituitary gland
This causes release of thyroxine from thyroid
What hormone does the adrenal medulla secrete?
Adrenaline
What hormone does the parathyroid secrete?
Parathyroid hormone - effects plasma calcium
What does the adrenal cortex release when not governed by the pituitary gland)?
Aldosterone - effects plasma volume
What do the pancreatic islet of langerhans secrete?
Insuline, glucagon
List 5 mechanism of endocrine disease?
Autoimmune destruction of gland Autoimmune stimulation of gland Destruction of gland - surgery, cancer Tumour formation Effects of tumour - hypersecretion
What is the effect of Cushing’s syndrome?
Hypercortisolism - too much cortisol from adrenal cortex
What causes hypercortisolism?
Excess exogenous steroids
Damage to the hypothalamus pituitary axis e.g. ACTH secreting pituitary tumour or Cortisol secreting adrenal tumour
Adrenal clinical features of Cushing’s syndrome?
Moon face - increase adipose tissue Buffalo hump Abdominal obesity Proximal muscle weakness Thin skin Bruising
How is Cushing’s syndrome investigated?
Test cortisol level in urine
Measure ACTH to decide where the abnormality is
How is Cushing’s syndrome treated?
Surgery - adrenalectomy
What is Addisons disease?
Hypo-adrenalism (hypocortisolism) - due to destruction of adrenal cortex
Causes of hypo-adrenalism?
Destruction of adrenal cortex - Addison’s disease
Suppression of hypothalamus-pituitary-adrenal axis following steroid treatment
Adrenal tumour
Pituitary failure - lack of ACTH
Clinical features of hypoadrenalism
Tiredness Weight-loss Pigmentation of skin Hypotension Hypoglycaemia
Features of Addisonian crisis?
Vomiting
Dehydration
Hypotension
Hypoglyaemia
How is hypoadrenalsim investigated?
Low cortisol levels
High ACTH
Adrenal antibodies
How is hypoadrenalism treated?
Replacement of cortisol - hydrocortisone
What is hyperthyroidism?
Excess thyroxine and tri-iodothyronine from thyroid
Causes of hyperthyroidism?
Graves disease
Thyroid adenoma
Features of hyperthyroidism?
Sped up metabolism - too much adrenaline (stimulated when thyroid levels high) - hot - weightloss - increased appetite - poor sleep - loose bowels graves disease
Diagnosis of hyper-thyroidism?
Raised thyroxine and tri-iodothyronine
Suppressed TSH
Thyroid stimulating antibodies
Treatment of hyper-thyroidsim?
Surgical thyroidectomy
Anti-thyroid drugs
Beta-blockers
What is hypothyroidism?
Lack T4 and T3 - high TSH
Causes of hypothyroidism?
Autoimmune destruction of thyroid
Surgical removal of thyroid
Secondary to TSH lack in pituitary disease
Features of hypothyroidism?
Slow metabolism
- cold
- dry skin
- slow, tired
- weight gain
- poor appetite
What is acromegaly?
Excess growth hormone from pituitary gland
What causes acromegaly?
Pituitary tumour
Diagnosis of acromegaly?
High GH, doesn’t suppress with glucose (negative feedback)
Features of acromegaly?
Enlarged hands. feet. jaw, skull Coarse facial features Thick skin Arthritis (TMJ) Hypertension Hyperglycaemia
What is hyperparathyroidism?
Increased calcium production
Caused by hyperparathyroidism?
Tumour, Vit D excess, cancers
Features of hyperparathyroidism?
Dry eyes and mouth
Thirst, polyuria
Loss of lamina dura
Reduced cortical width of mandible and ground glass appearance
Effect of hypoparathyroidism?
Hypocalcaemia
Causes of hypoparathyroidism?
Autoimmune destruction
Damage to parathyroids
Features of hypocalacemia?
Tingling, paraethesiae
Cramps
