Pituitary and Thyroid Flashcards
what is an endocrine disease
dysfunction of hormone secreting gland
what controls hormone secretion
negative feedback regulation
More hormone secretes less hormone is allowed to be secreted
Switches off secretion to keep blood level at same level
what is the spread of hormones
widespread
multisystem
(unlike nerve)
where is hormone effect determined
where receptors are located
what are the 2 types of endocrine failure
gland failure (primary)
control failure (secondary)
what is primary endocrine faillure
gland failure
gland can make but not being asked to
what is secondary endocrine failure
control failure
gland cannot make
multiple endocrine neoplasia is
Tumour or cancers in one gland are prone to getting different endocrine tumour/cancer in other glands
where is the pituitary gland
in the sella turcica in the skull
what is the function of the pituitary gland
controls many other gland activities
what controls the pituitary gland
hypothalamic control - releasing hormones
Triggers other hormones for other body functions – fire to particular areas particular glands, trigger other pathways
4 anterior pituitary hormones
TSH - Thyroid Stimulating Hormone
ACTH - Adrenocorticotrophic Hormone
Encourage adrenal gland to make cortisol
GH - Growth Hormone
LH, FSH, Prolactin
2 posterior pituitary hormones
ADH - Anti Diuretic Hormone
diabetes insipidus
control of body fluids – concentrate urine
Oxytocin
how is the pituitary gland controlled
Controlled by a mixture of endocrine and neurogenic stimuli
Hypothalamus – allows messenger hormones to pass to pituitary to venous plexus to
Tumour in pituitary gland
- cannot grow in size as in bony space
- Squash gland – so cannot make other hormones
Tends to be multi system disease
what type are pituitary tumours
adenomas
are pituitary tumours benign or malignant mainly
benign
functional adenoma
make hormone as well as being tumour
functional adenoma of prolactin/ACTH above 40 yrs causes
Amenorrhoea-Galctorrhoea syndrome or Cushing’s disease
Producing excess ACTH
Not switched off by normal feedback as tumour don’t respond to normal trigger
functional adenoma of growth hormone above 40 yrs causes
Acromegaly
Growth hormone in excess
Stop growth agree – nose, ears, forehead, fingers, feet
non functional adenoma
squash gland but doesn’t make hormones, space occupying
non functional adenoma effect above 60 yrs
Mass effects - visual field defects, other hormone deficiencies
Gradually spread out of sella turcica
- Pushes on brain above – optic chiasm (eye nerves cross – affect vision, particular peripheral end up with tunnel vision)
- –Take out nasal fields from both eyes so only get lateral field
how to remove a pituitary tumour
Transsphenoidal surgery to remove tumour
- Through nose
- Remove most of tumour and pressure easily
what happens if a child lacks growth hormone
Growth failure in children
reduced height (not dwarf but child like – correct proportions but small)
what happens if an adult lacks growth hormone
increased fat
reduced vitality
not really notice to same extent as fully grown,
causes subtle changes, anabolic, build body up – maintain blood sugar, fat levels
what happens is there is excess growth hormone in a child
giantism’ in children
Apparent – child very large but correct proportion (giantism)
giantism
excess growth hormone in a child
giantism’ in children
child very large but correct proportion (giantism)
what happens if there is excess growth hormone in an adult
Acromegaly in Adult
all stopped growth plates cannot change (limbs, spine) but membranous bone can continue to grow (skull thicker, hand and feet bigger, mandible will get bigger (dentures don’t fit, teeth become spaced), and so will soft tissue)
how to assess Growth hormone levels
measure IGF-1
(insulin like growth factor 1)
and compare to old photographs
what type of onset does acromegaly have
insidious
what is the peak incidence for acromegaly
30-50yrs
can take 10-15 yrs till changes obvious enough
what is a possible cause of acromegaly
benign pituitary tumour (functional adenoma)
- MEN-1
what are general presenting features of acromegaly
coarse features
enlarged supra-orbital ridges
Broad nose, thickened lips & soft tissues
enlarged hands
- carpal tunnel syndrome - finger numbness,
Type 2 diabetes mellitus
- insulin resistance from increased GH
- Raise blood sugar in growth hormone
- Can get type 2 diabetes
- Fighting against insulin trying to reduce blood sugar
Cardiovascular disease
- ischaemic heart disease
- —Heart will increase in size and become less efficient
- acromegalic cardiomyopathy
- —-Acromegalic – heart muscle changed in size and function so inefficient
Change in lipid balance in blood
Enlarged tongue
- Bite and catch on teeth
Interdental spacing
‘shrunk’ dentures
Reverse overbite
- Becomes class 3
- Wear facets don’t make sense in occlusion
Visual field defects
- III, IV and VI nerve palsies possible as well
Hyperprolactinaemia
- Prolactin tumour
Hypopituitarism
- not making other hormones to right level (ACH, FSH and LH – upset menstrual cycle)
reduced life span
what is acromegalic cardiomyopathy
heart muscle changed in size and function so inefficient
excess thyroid
hyperthyroidism
deficiency in thyroid
hypothyroidism (a.k.a. Myxoedema)
what is the common cause for hyperthyroidism
primary (gland failure)
secondary is rare
thyrotoxicosis without hyperthyroidism is different
what is the common cause for hypothyroidism
primary (gland failure)
secondary less common
myxoedema is
hypothyroidism (deficient)
Graves disease
autoimmune disease that causes 70-80% cases in hyperthyroidism
how does graves disease cause hyperthyroidism
Auto antibodies stimulating the TSH receptor
- Immune system making hormone (protein) which fits receptor for TSH on thyroid gland
- So makes more thyroid hormone
Gets exercised and increase in size gland – Goitre
Control still working fine
- But no chance to take effect as been overridden by TSH receptor activation
2 classes of tumours in pituitary gland that can cause excess thyroid
Toxic multi-nodular goitre
Toxic adenoma
effects of hyperthyroidism
Increased metabolism
- Makes metabolism run too fast
hot & excess sweating,
weight loss
diarrhoea
Lower blood sugar quicker
palpitations
- Tachycardia and atrial fibrillation
- Lost normal rhythm
- Increased BP and heart failure
- Tendency for heart failure - extra oxygen demand will worsen
muscle weakness
irritable/manic/anxious
- brain excitable
Eye retraction and lid lag
- eyelid is further back as muscle more excited can see white layer of sclera above eyelid
where is the thyroid gland
at the base of the neck
characteristic sign of Grave’s disease
diffuse goitre
what chemical is needed for thyroid hormones
Need iodine for thyroid hormones
- Gland increases in size if low iodine so increases blood flow so more chance for blood to be caught
organ specific autoimmune diseases
run in families
- if have one more likely to have another, genetically coded
vitiligo, PA, Type 1 DM, Coeliac, Myaesthenia gravis, Graves disease
non thyroid effects of Graves disease
Opthalmopthy (Swelling in soft tissue around eye)
- Fat cells in orbit
- Antibody triggers inflammation– get red, hot swollen fat cells in orbit
- Volume to increases
- Pushes eyeball out of socket
- Inflammation around eye
- Same antibody causing graves’ disease
- Scleral injection
- Propotosis
- Periorbital oedema
Conjunctival oedema
- chemosis
how to treat graves disease
Block thyroid hormone effect
Will not improve eye – caused by antibody causing high thyroid levels
- Only way to stop is by stopping immune reaction is steroid
7 primary causes of hypothyroidism
Autoimmune (Hashimoto’s) thyroiditis (90% cases!)
- Organ specific
- Gland eaten away by immune cells in inflammatory process
Idiopathic atrophy
Radioiodine treatment/thyroidectomy surgery
- iodine concentrated in gland and causes cell damage when alpha released, goes over active to normal to underactive with age
Iodine deficiency
Drugs
- carbimazole, amiodarone, lithium
congenital
- gland not going to work
- tested when born
- can lead to developmental problems
Take off too much gland if hyperthyroidism excessively treated
secondary causes of hypothyroidism
hypothalamic/ pituitary disease
- tumours squashing cells making TSH
effects of hyperthyroisim
Reduced metabolism
- tired
- bradycardia, hyperlipidaemia
cold intolerance
weight gain
constipation
hoarse voice
goitre (Hashimoto’s)
- as gland inflamed and attacked by immune system
puffed face & extremities
angina
‘slow’, poor memory,
- psychiatric or confusion
hair loss
- common lateral 1/3 of eyebrow
dry coarse skin
delayed reflexes
what is myxoedema
Swelling within the tissue caused by hypothyroidism
- Often in leg
hashimoto’s thyroiditis effects
Middle aged and elderly women
- Presents at later age but start young
Idiopathic atrophy
- Can lead to loss of gland
2 presenting features of Hashimoto’s thyroiditis
Goitre
Hypothyroid features
associations of Hashimoto’s thyroiditis
All familial auto immune diseases (few exception) effect women more than men
- Vitiligo, PA, Type 1 DM, Addison’s disease
Down’s syndrome
idiopathic atrophy of thyroid gland incidence
Increased incidence with age
10x more in females
likely autoimmune cause
- lymphocyte infiltrate
- associated with organ specific autoimmune disease
effect of idiopathic atrophy of gland
loss of gland
3 investigations for thyroid disease
Blood
- TSH,T3 &T4
Imaging
- ultrasound scan (cysts)
- radioisotope scans - gland uptake
Tissue
- fine needle aspirate/biopsy (FNA & FNB)
FNB take some gland cells out via need
- Quick biopsy without surgery
TSH
thyroid stimulating hormone from anterior pituitary
blood investigation for thyroid disease
TSH, T3 and T4
2 imaging investigations for thyroid disease
- ultrasound scan (cysts)
- radioisotope scans - gland uptake
tissue investigation for thyroid disease
fine needle aspirate/biopsy (FNA & FNB)
FNB take some gland cells out via need
- Quick biopsy without surgery
how to read radioisotope scans
To see if gland is working carry out a radioisotope scan
- radioactive concentrated in gland see if taken out of blood and back in
Normal gland makes hormone – brighter colour
Missing part
- Lobe on both sides – left missing part – tumour or cyst not producing hormone
Goitre
- Non functional as no hormone release
So much hormone in small area pituitary switched off TSH production but tumour is still making excess (functional adenoma)
- Hyperthyroid due to one tumour
investigation results for hyperthyroid pituitary cause
T3 and TSH raised
rare (primary??)
investigation results for hyperthyroid graves disease causes
Stimulation of gland not from pituitary
- TSH is low
But T3 still high
- as auto antibody signalling
common (Secondary??)
investigation results for hypothyroid pituitary cause
Not asking to make thyroxin
TSH and T4 are low
rare (Secondary??)
investigation results for hypothyroid gland failure causes
Negative feedback to make more thyroxin
TSH high
- but gland being destroyed by disease so cannot cause effect
T4 low
common (primary??)
5 types of hyperthyroidism treatment
Carbimazole - titration block & replace - T4 as required - Drug blocks effect of hormone - Make hormone less effective - Take back to normal and be less effected
β-blockers
- treat effects of hyperthyroidism
- —anxiety, increased BP
Radioiodine - 131I
- hypothyroid risk with time - review!
Surgery - partial thyroidectomy
- usually follows drug therapy to stabilise
Graves’ ophthalmopathy
- Graves disease- largest causes
- —Ophthalmopathy not fixed as caused by antibody not hormone – harder
carbimazole drug treatment of hyperthyroidism
- titration block & replace - T4 as required - Drug blocks effect of hormone - Make hormone less effective - Take back to normal and be less effected
treatment of hypothyroidism
Give hormone (T4 tablets) - Hormone replacement therapy – return physiology to normal
Increase dose slowly
- IHD
- Slowly over 6 month – as heart and metabolic tissues need to adapt
- –increase metabolic rate – diet pills (get effects hyperthyroidism)
Recheck using TSH as a guide if gland failure
- TSH will reduce to normal level – can use to tell when normal placement
how to assess if successful hypothyroidism treatment
Recheck using TSH as a guide if gland failure
- TSH will reduce to normal level – can use to tell when normal placement
why does hormone replacement therapy for hypothyroidism need to be gradual
Increase dose slowly
- IHD
Slowly over 6 month – as heart and metabolic tissues need to adapt
—increase metabolic rate – diet pills (get effects hyperthyroidism)
2 causes of thyroid enlargement
Goitre
Solitary nodule enlargement
solitary nodule enlargement of thyroid
- adenoma, carcinoma, cyst formation possible
- low cancer risk – suspicious/more in children or elderly
goitre of thyroid
Diffuse enlargement of the thyroid gland – often Iodine deficient
—-mountainous areas of developing countries
diffuse, nodular
Drug related?
thyroid cancer
Usually with a thyroid swelling
Young or Elderly
- papillary (80%) or folicular in younger
- undifferentiated in elderly
‘Cold’ nodules on radioisotope scans
often TSH sensitive - give T4 post surgery
generally a good prognosis in young
- 5% 10 year mortality in Papillary but
- 80% 10 year mortality in Folicular
new treatments available
hyperthyroid impact on dental care
High energy – hard to be seated, state may not be best for making decisions on treatment
pain anxiety and psychiatric problems
caution for treatment until controlled
- Can do emergency treatment whilst waiting to settle
hypothyroid impact on dental care
avoid the use of sedatives if severe
treated thyroid problem or on hormone replacement therapy
treat patient as normal
what is the dentist’s role in goitre detection
Goitre detectable to the dentist
If find goitre in examination refer to GP immediately
