Week 7 - The Endocrine System Flashcards
What types of endocrine diseases can occur?
- underproduction
- overproduction
- mass lesions
What makes up the endocrine system?
Hypothalamus Pituitary gland Thyroid gland Parathyroid glands Adrenal glands
How does the hypothalamus contribute to the endocrine system?
- located in the brain - above brain stem
- links the CNS to the endocrine system
- produces releasing and inhibiting hormones - stop and start the production of other hormones throughout the body
What hormones does the anterior pituitary gland produce?
- growth hormone
- thyroid stimulating hormone
- adrenocorticotrophic hormone
- follicle stimulating hormone
- lutenising hormone
- prolactin
What hormones does the posterior pituitary gland produce?
- ADH
- oxytocin
What pituitary diseases can occur?
Hyperpituitarism-related effects
-adenomas (benign tumours - functionally active)
Hypopituitarism-related effects
-injury, surgery, radiation, inflammation
Local mass effect
-compressing the optic chiasm
What is hyperpituitarism?
Condition due to the primary hypersecretion of pituitary hormones
What causes hyperpituitarism?
Most common:
-adenoma in anterior lobe
Other:
- cancer
- hyperplasia
What are the types of pituitary adenoma?
- functional - prolactinoma
- non-functional
- macroadenomas (>1cm in diameter)
- microadenomas (
What is the effect of having too much ACTH?
Cushing’s disease
-buffalo hump, moon face, poor wound healing, thin skin etc
What is the effect of having too much growth hormone?
- gigantism (children)
- acromegaly (adults)
What is the effect of having too much prolactin?
- galactorrhea/amenorrhea
- sexual dysfunction
- infertility
What is the effect of having too much TSH?
Hyperthyroidism
What is the effect of having too much FSH/LH?
- hypogonadism
- mass effects
- hypopituitarism (occurs with loss of 75% or more of the anterior pituitary parenchyma)
What are the causes of hypopituitarism?
- ischaemic necrosis of the pituitary: Sheehan’s syndrome (post-partum)
- non-functioning adenomas - grow to potentially cause hypopituitarism
- surgery or irradiation - take out too much
- inflammatory lesions - rare
What can be the causes of hyperthyroidism?
- Grave’s disease (autoimmune) - proptosis (bulging eyes, shouldn’t be able to see white at the bottom of the eye, muscle at the back of the eye cause them to bulge)
- over treatment by thyroxine (for hypothyroidism)
- infective - De Quervain’s thyroiditis - related to viral infection
- toxic multinodular goitre
- toxic adenoma - single nodule in the thyroid gland producing thyroxin
What are the symptoms of hypothyroidism?
- intolerance to heat
- fine, straight hair
- bulging eyes
- facial flushing
- enlarged thyroid
- tachycardia
- high systolic BP
- breast enlargement
- weight loss
- muscle wasting
- localised oedema
- menstrual changes (amenorrhea)
- diarrhoea
- tremors
- finger clubbing
Explain why Grave’s disease occurs
- auto-immune condition, stimulates auto-antibodies
- the auto-antibodies attach to TSH receptors, meaning the receptors are constantly stimulated
- however because the antibodies are blocking the TSH receptors, this means that TSH decreases but thyroxine increases (unregulated overproduction)
- negative feedback can’t occur so thyroid hormone production can’t be regulated
How is hyperthyroidism managed?
- testing: clinical and thyroid function tests (blood test)
- treat the cause
- carbimazole/propylthiouracil
- radioiodine therapy (ingest radioactive iodine, kills off thyroid gland - decreases production)
- thyroidectomy
What can cause a goitre and what precautions need to be made?
- iodine deficiency
- could be hyper/hypothyroidism
-ensure trachea is not compressed by it
What are the causes of hypothyroidism?
- iodine deficiency
- autoimmune - Hashimoto’s thyroiditis
- iatrogenic - surgery, radioiodine
- pituitary defects
- congenital
What are the symptoms of hypothyroidism?
-intolerance to cold
-receding hairline
-facial and eyelid oedema
-extreme fatigue
-thick tongue - slows speech
-anorexia
-brittle nails and hair
-hair loss
-apathy
-lethargy
-dry skin
-muscle aches/weakness
-constipation
Late clinical manifestations:
-weight gain
-Bradycardia
-subnormal temp
-thickened skin
-cardiac complications
-decreased LOC
What is Hashimoto’s thyroiditis and who does it effect?
Autoimmune destruction of the thyroid gland
- women > men
- 45-60 years old
How is hypothyroidism managed?
Thyroxine
