Hyperthryoidism Flashcards
thyrotoxicosis
clinical, pysiological and biochemical state arising when the tissues are exposed to excess thyroid hormones
hyperthyroidism
refers specifically to conditions in which over activity of the thyroid glands leads to thyrotoxicosis
heart
force and rate increased as TH increase the responsiveness of receptors to catecholamines (adrenaline and noradrenaline)
patients may also suffer from tachycardia and atrial fibrillation
rarely, cardiac failure
what is used to treat heart symptoms
B blockers eg propanolol
heat
thermogenesis is 30% due to thyroid hormones - increase in secretion results in heat intolerance
complications may arise from this, patients may also have moist, itchy skin
movement
tremor, especially in the hands. due to effects of thyroid hormones on CNS
hyperkinesis - excessive bodily movement
muscle weakness, especially thighs and upper arms
basal metabolic rate
increases (growth hormone) meaning patients will have bigger appetites and a tendency to lose weight
the metabolic rates of proteins, fats and carbohydrates are boosted
what cellular changes occur with increased BMR
increase in number and size of mitochondria
increased oxygen use and rate of ATP hydrolysis
increased synthesis of respiratory chain enzymes
sleep
patient may find it difficult to sleep as they are constantly agitated and irritable
may also have lots of energy at night
menstrual cycle
irregular (oligomenorrhoea) and may also complain of loss of libido
light bleeding and less frequent periods, they can disappear completely
behaviour
tremor
agitation - feeling on edge
apparent restlessness
behavioural changes - emotional lability
GI
Diarrhoea
frequent, loose bowel movements
vision
lid retraction
double vision
thyroid eye disease
medical term for double vision
diploplia
hair and skin
hair becomes brittle and thin
rapid fingernail growth
normal TSH and TH levels
TSH: 0.4-4.0 mU/L
T3: 9.9-22
fT4: 0.9-2.6
goitre
enlargment of the thyroid gland
causes of goitre
iodine deficiency, hypo and hyper thryoidism, Grave’s disease
nodular causes: adenoma, carcinoma and TMNG
what can goitre cause
compression of local structures - difficulties breathing and swallowing
DeQuervain’s thyroiditis
- transient (self-limiting) hyperthryoidism from an acute inflammatory process (probably viral in origin)
- there is usually fever, malaise and pain in the neck with tachycardia and local thyroid tenderness
outline the 4 phases of De Quervain’s thyroiditis
- (3-6 weeks): hyperthyroidism, painful goitre, raised ESR
- (1-3 weeks): euthyroid
- (weeks-months): hypothyroidism
- Thyroid structure and function returns to normal
treatment of DeQuervain’s thyroiditis
acute phase - aspirin
short term prednisolone in severely symptomatic cases
other causes of thyroiditis
(which drugs +)
post partum
drug induced eg amiodarone
other causes of thyrotoxicosis not associated with hyperthyroidism
exogenous thyroid hormones: over treatment with levothyroxine or thyrotoxicosis factiita (self/deliberate poisoning)
rarely, ectopic thyroid tissue:
- metastatic thyroid carcinoma
- struma ovarii - ovarian teratoma containing thyroid tissue
what drugs can the production of thyroid hormones be inhibited by
carbimazole and proplythiouracil (PTU)
work by inhibiting the attachment of iodine to tyrosine residues on thryoglobulin to from MIT and DIT
how are CBZ and PTU started
intitially at a high dose and then gradually reduced over the course of 12-18 months
side effects of CBZ
risk of agranulocytosis (dramatically lowered neutrophils, can lead to dangerous sepsis)
- if the patient develops a dry cough/sore throat the medication must be stopped immediately
- risk is highest within the first 6 weeks of being on the drug
what medication is given to treat the heart problems associated
atrial fibrillation and tachycardia
- ß blockers eg propanolol
radio iodine
use of radioactive iodine 131 can suppress excretion of exces hormone
one off oral dose to destroy cells within the thyroid gland
what often happens post radio iodine treatment
become hypothyroid - managed with medication
can also precipitate a thyroid storm
what is the usually cause of a painful neck swelling and hyperthyroidism
thyroidits
