Investigation of endocrine diseases

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  • Created by: hadar
  • Created on: 08-02-18 19:44
What is a hormone?
Messenger molecules secreted by endocrine glands- circulate and influence other tissues producing short/long term changes- only if specific target receptor present.
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What are the 3 different types of hormones and give examples of each?
1) peptide hormone- PTH,ACTH,TSH 2)Steroid hormones- testosterone, oestradiol, cortisol 3) Tyrosine-based hormones- thyroxine (T4), triiodothyronine (T3)
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What are the 3 ways a steroid hormones can interact with a cell?
1) classical model 2) receptor-mediated endocytosis 3)signalling through cell-surface receptors
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How do peptide hormones work compared to steroid?
Peptide hormones act via membrane receptors intracellular signalling Steroid homroens fuse into the cell and bind to DNA binding domains  change in transcription and translation
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Thyroid function test interpretaion
Thyroxin is bound to TBG in the body only a small percentage is free only this free thyroxine is active- don't measure total hormone level since influences by TBG level
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What are causes of increased TBG?
1)genetic 2)pregnancy 3)oestrogen
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What are causes of decreased TBG?
1)genetic 2)protein-losing states 3)malnutrition 4)malabsorption 5)acromegaly 6)cushing disease 7)high dose corticosteroids 8)severe illness 9)androgens
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What is the diagnosis if low TSH and low thyroxine?
secondary hypothyroidism--> pituitary failure
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What is the diagnosis if high TSH and low thyroxine?
primary hypothyroidism
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What is the diagnosis if low TSH and high thyroxine?
primary hyperthyroidism
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What is the diagnosis if high TSH and high thyroxine?
Secondary hyperthyroidism--> pituitary gland overproduction or feedback fails
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What would you do if TSH is low and what patient would that pick up?
Do and T3 and T4 test --> picks up hyperthyroid patient
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What would you do if TSH is high and what patient would that pick up?
Do T4 test --> pick up hypothyroid patient
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What patients have normal TSH but a thyroid problem?
secondary hypothyroidism--> normal TSH with low T4
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When are TSH levels/ thyroid function test results affected?
During periods of illness/ recovering from illness--> illness can reduce levels of TBG/ modify capacity to bind to T3+4- increasing free thyroid levels
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How often do you repeat TFT?
Healthy person= 3 years hyperthyroid= 1-2 months after radioactive iodine then 4-6 weeks or 6-8 weeks after thyroidectomy hypothyroidism=1 yearly
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What are the 2 types of adrenal medullary tumours?
1)Phaeochromocytoma (adults) 2)Neuroblastoma (children)
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What is a Phaeochromocytoma?
Tumour of neuroendocrine chromaffin cells – the majority in the adrenal medulla- produce catecholamines
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What are the clinical features of Phaeochromocytoma?
Hypertension, Sweating, pallor, Panic attacks, Headaches, Abdominal pain, can be asymptomatic
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How is Phaeochromocytoma diagnosed? and what follow up tests?
Plasmametanephrines- 24 hour urine fractionated metanephrines--> follow with clonidine suppression test, plasma chromogranin A, MRI/CT adrenals, MIBG scan, genetic counselling/screening
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What is whipple's triad the definition of and what may it indicate?
definition of hypoglycaemia and may indicate insulinoma
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What are the 3 factors in while's triad?
1)resolution of symptoms once glucose level rises 2)low plasma glucose level 3) signs and symptoms of hypoglycaemia
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Why does alcohol cause hypoglycaemia?
co factor used to break down alcohol used for gluconeogenesis so depleted to breakdown alcohol do cannot be used in gluconeogenesis
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Describe insulinoma
Most common tumours arising from islets of Langerhans- Diagnosed through a simple fasting blood test-Insulin should be undetectable in hypoglycemic patient If insulin is present diagnostic of insulinoma
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What are the features of cushings?
obesity- moon face, central, shoulders Skin- thin, purple striae, bruising Hypertension, Glucose intolerance, Menstrual disturbances/impotence, Thin limbs/weak muscles, back pain from osteoporosis, psychiatric disturbances- depression, psychoses
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What are the 4 causes of cushings?
1) exogenous cause- administration of steroids 2)pituitary/ ACTH secreting tumour 3) Tumour/ adenoma of adrenal gland 4)Ectopic ACTH secreting tumour (cushing syndorme)
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What the difference between Cushing disease and syndrome?
ACTH will be high in cushing syndrome more than cushing disease
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What is ectopic ACTH secretion most commonly associated with? (5)
1)Benign carcinoid tumors of the lung 2)Small cell tumours of the lung 3)Islet cell tumours of the pancreas 4)Medullary carcinoma of the thyroid 5)Tumours of the thymus gland
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What is the difference between a secondary and primary endocrine disorder?
Primary= target organ Secondary= problem with higher centre
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Other cards in this set

Card 2

Front

What are the 3 different types of hormones and give examples of each?

Back

1) peptide hormone- PTH,ACTH,TSH 2)Steroid hormones- testosterone, oestradiol, cortisol 3) Tyrosine-based hormones- thyroxine (T4), triiodothyronine (T3)

Card 3

Front

What are the 3 ways a steroid hormones can interact with a cell?

Back

Preview of the front of card 3

Card 4

Front

How do peptide hormones work compared to steroid?

Back

Preview of the front of card 4

Card 5

Front

Thyroid function test interpretaion

Back

Preview of the front of card 5
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