pathology of endocrine diseases Flashcards
What regulates the endocrine system
Feedback inhibition
What does the pineal gland secrete
Melatonin - regulates circadian rhythm
Describe a benign neoplasia
Usually circumscribed, localised and cannot invade or transform
Describe a malignant neoplasia
Cancer - invades, metastasises and is fatal if untreated
Where is the pituitary gland located
Sella turnica
What connects the pituitary to the hypothalamus
Pituitary stalk
What is the adenohypophyses
Anterior pituitary
What is the neurohypophyses
Posterior pituitary which is a down-growth of the hypothalamus
What does the pituitary gland secrete
TSH
ACTH
prolactin
FSH
GH
What controls release of hormones from the pituitary gland
Trophic hormones from the hypothalamus
What does the posterior pituitary secrete
ADH and oxytocin
What is the most common cause of hyperfunction of the pituitary
pituitary adenoma
What age group is pituitary adenoma common in
35-60 years old
What does a prolactinoma cause
Galactorrhoea and menstrual disorders
What does excess GH secretion cause
Acromegaly and gigantism
What does excess ACTH secretion cause
Cushings disease
What is a non functioning pituitary adenoma
Does not cause excess secretion of hormones
What is acromegaly
Jaw, hands and feet are enlarged
What happens if the pituitary adenoma is very large
It will cause a build up in pressure and can compress on the optic chiasm which causes visual defects
The increased intercranial pressure can cause nausea, vomiting and headaches
What can cause pituitary hypofunction
Compression by tumours
Trauma
TB and sarcoidosis
Describe thyroid epithelial cells
Arranged in follicles filled with colloid that contains thyroglobulins
C cells which secrete calcitonin
What stimulates hypothalamus to secrete TRH
cold and stress
How does hypothyroidism manifest
mxoedema - physical and mental sluggishness
Cretinism - retardation and failure to grow
What is the most common cause of hyperthyroidism
Grave’s disease
How does graves disease cause hyperthyroidism
It has autoantibodies which bind to the TSH receptor and stimulate it to secrete T3/T4 - this breaks down the negative feedback as the T3/T4 cannot inhibit the autoantibodies
What are the symptoms of grave’s disease
sweating
weight loss
tachycardia
tremor
exopthalmosis
What is the most common cause of hypothyroidism
Hashimotos thyroiditis
Iodine defficiency is also common
What drugs can cause hypothyroidism
Lithium and methimazole
What is hashimotos thyroiditis
Autoimmune destruction of the thyroid epithelial cells
What are the symptoms of hashimotos
lethargy
hairloss
dry skin
muscle aches
constipation
intolerance to cold
slow speech
brittle hair and nails
bradycardia
weight gain
What is the most common cause of multinodular goitre
Iodine deficiency
How does iodine deficiency cause multinodular goitre
Impairs synthesis of T3/T4 causes increased TSH which causes hypertrophy and hyperplasia of the thyroid epithelium
What investigations are done for thyroid nodules
TFT - thyroid function tests
US
Fine needle aspiration and then cytology
What are the risk factors of thyroid carcinoma
Family history
chronic inflammatory conditions
radiation exposure
obesity
Describe thyroid neoplasms follicular adenoma
Most are non functioning
Circumscribed encapsulated tumour
What does circumscribed mean
within limits
Describe follicular carcinomas
Rare and usually solitary but they are malignant and can breach their capsule unlike follicular adenoma
Where do follicular carcinomas commonly metastasise to
blood
bones
What gene abnormalities are associated with follicular carcinoma
RAS mutation
PAX8/PPARG translocation
What gene mutations is papillary carcinoma associated with
RET/PTC GENE REARRANGEMENT
What are thyroid medullary carcinomas
Malignant tumours of the C-cells (calcitonin producing)
What gene abnormalities are associated with thyroid medullary carcinoma
MEN2A , 2B
RET
What is the treatment options for thyroid carcinoma
Surgery
Radioactive iodine
external radiotherapy
chemotherapy
When is radioactive iodine contraindicated
Pregnancy
Fathering a child in the 4 months after treatment
breast feeding
What is the function of parathyroid glands
Produces PTH which regulates plasma calcium
What opposes the effect of PTH
calcitonin
What is the common gene mutation linked to parathyroid hyperfunction
MEN-1
What is MEN1 mutation
MEN1 tumour supressor gene mutation so there is a defect in the protein which regulates cell growth (Menin)
What does MEN1 cause
parathyroid hyperplasia and adenoma
Pancreatic and duodenal endocrine tumours
pituitary adenomas
what is MEN2 mutation
Mutations to proto-oncogene
What does MEN2 cause
Medullary carcinoma of thyroid
Parathyroid hyperplasia
Neuromas
