Hypo/Hyperthyroidism and Thyroiditis Flashcards
define primary thyroid disease
disease affecting the thyroid gland itself
define secondary thyroid disease
hypothalamic or pituitary disease - no thyroid pathology
where is TSH secreted and in response to what?
TSH secreted from anterior pituitary in response to TRH from hypothalamus
what is 99% of T3 and T4 bound to?
TBG, albumin and pre-albumin
primary hypothyroidism - low or high:
(a) free T3/4
(b) TSH
primary hypothyroidism - low or high:
(a) free T3/4 - LOW
(b) TSH - HIGH
primary hyperthyroidism - low or high:
(a) free T3/4
(b) TSH
primary hyperthyroidism - low or high:
(a) free T3/4 - HIGH
(b) TSH - LOW
secondary hypothyroidism - low or high:
(a) free T3/4
(b) TSH
secondary hypothyroidism - low or high:
(a) free T3/4 - LOW
(b) TSH - LOW/NORMAL
secondary hyperthyroidism - low or high:
(a) free T3/4
(b) TSH
secondary hyperthyroidism - low or high:
(a) free T3/4 - HIGH
(b) TSH - HIGH/NORMAL
any disorder that results in insufficient secretion of thyroid hormones from the thyroid gland defines what?
hypothyroidism
define myxoedema
severe hypothyroidism and is a medical emergency
define oretibiyal myxoedema
a rare clinical sign of Graves’ disease, an autoimmune thyroid disease which results in hyperthyroidism!
name the 3 types of primary hypothyroidism
goitrous
non-goitrous
self-limiting
goitrous, non-goitrous or self-limiting:
Chronic thyroiditis (Hashimoto’s thyroiditis)
Iodine deficiency
Drug-induced (e.g. amiodarone, lithium)
Maternally transmitted (e.g. antithyroid drugs)
Hereditary biosynthetic defects
goitrous
goitrous, non-goitrous or self-limiting:
Atrophic thyroiditis
Post-ablative therapy (e.g. radioiodine, surgery)
Post-radiotherapy (e.g. for lymphoma treatment)
Congenital developmental defect
non-goitrous
goitrous, non-goitrous or self-limiting:
Following withdrawal of antithyroid drugs
Subacute thyroiditis with transient hypothyroidism
Post-partum thyroiditis
self-limiting
name the most common cause of autoimmune hypothyroidism
hashimoto’s thyrioditis
what is hashimoto’s thyroiditis characterised by the presence of?
antibodies against thyroid peroxidase (TPO)
T-cell infiltrate and inflammation microscopically
hypothyroidism clinical features:
hair and skin -
thermogenesis -
fluid retention -
hair and skin -
coarse, sparse hair dull, expressionless face pale, cool, dougy skin vitiligo hypercarotenaemia
thermogenesis -
cold intolerance
fluid retention -
pitting oedema
hypothyroidism clinical features:
cardiac -
metabolic -
cardiac -
reduced HR
cardiac dilatation
pericardial effusion
worsening of heart failure
metabolic -
hyperlipidaemia
decreased appetite
weight gain
hypothyroidism clinical features:
GI -
respiratory -
neurological -
GI -
constipation
megacolon
ascites
respiratory -
deep hoarse voice
macroglossia - large tongue
obstructive sleep apnoea
neurological -
decreased intelligence
hypothyroidism clinical features:
gynae/reproductive -
hypothyroidism clinical features:
gynae/reproductive -
menorrhagia
later oligo- or amenorrhoea
hyperprolactinaemia
laboratory investigations of primary hypothyroidism - increased or decreased:
TSH
fT3/4
CK
LDL
TSH INCREASED
fT3/4 DECREASED
CK INCREASED
LDL INCREASED
hypothyroidism in younger patients management?
levothyroxine 50-100μg
hypothyroidism in elderly with IHD patients management?
levothyroxine 25-50μg
what should you check every 2 months after any dose change in hypothyroidism?
TSH
once stabilised on levothyroxine, what should be checked every 12-18 months?
TSH
levothyroxine is T3/T4
levothyroxine is T4
when should levothyroxine be taken?
before breakfast
in what situation is levothyroxine dose increased by 25-50%?
pregnancy as TBG increases
typically affects elderly women with long standing but frequently unrecognized or untreated hypothyroidism
mortality up to 60% despite early diagnosis and treatment
ECG: bradycardia, low voltage complexes, varying degrees of heart block, T wave inversion, prolongation of the QT interval
Type 2 respiratory failure: hypoxia, hypercarbia, respiratory acidosis
Co-existing adrenal failure is present in 10% of patients
diagnosis
myxoedema coma
myxoedema coma treatment?
ABCDE
passively rewarm
the clinical, physiological and biochemical state arising when the tissues are exposed to excess thyroid hormone defines what?
thyrotoxicosis
conditions in which overactivity of the thyroid gland leads to thyrotoxicosis defines what?
hyperthyroidism
thyrotoxicosis symptoms and signs?
CVS sympathetic CNS GI vision hair and skin reproduction muscles metabolism thermogenesis
palpitations, AF, tremor, sweating, anxiety, nervousness, irritability, sleep disturbance, frequent loose bowels, lid retraction, double vision, proptosis, brittle thin hair, rapid fingernail growth, lighter and less frequent periods, muscle weakness, weight loss and increased appetite, heat intolerance
name the most common condition associated with hyperthyroidism
graves disease
also hashitoxicosis, thyrotopinoma, cancer etc
name the 2 different types of thyroid nodule
toxic solitary nodule
toxic multinodular goitre
is thyroiditis like subacute thyroiditis, post-arum thyroiditis and amiodarone induced thyroiditis associated with hyperthyroidism?
no
is smoking important in graves disease?
yes
graves is inflammatory disease so smoking doesn’t help
in graves disease, increased or decreased:
TSH fT4/3 ALP calcium WBC
TSH - DECREASED fT4/3 - INCREASED ALP - INCREASED calcium - INCREASED WBC - DECREASED
what bone disease is graves associated with?
osteoporosis
name the antibody found in graves disease
TRAb
name the condition of the legs seen in graves disease
pretibial myxoedema
fingernail condition associated with graves?
thyroid acropachy
large goitres in graves can result in a thyroid _____
large goitres in graves can result in a thyroid BRUIT
name the main clinical finding of graves seen on the face
thyroid eye disease - TED
graves ophthalmopathy - GO
associated with smoking
TRAb driven
treated topically and with steroids in severe
is TRAb positive or negative in nodular thyroid disease?
negative
fT3/4 and TSH in nodular thyroid disease?
fT3/4 INCREASED
TSH DECREASED
state the medical emergency associated with severe hyperthyroidism
thyroid storm
resp and cardio collapse
hyperthermia
who is thyroid storm seen in?
hyperthyroid patients with an acute infection/illness or recent thyroid surgery
thyroid storm treatment?
Lugol’s Iodine glucocorticoids PTU β-blockers fluids monitoring
drug treatment of hyperthyroidism?
antithyroid drugs - ATDs
carbimazole - once daily
betablockers - propranolol for immediate symptomatic relief
caution in asthma so CCB instead
radioiodine - relapsed graves and nodular thyroid disease, contraindicated in pregnancy and high risk of hypothyroidism when used in graves
drug treatment of hyperthyroidism in 1st trimester of pregnancy?
propylthiouracil
twice daily
side effects of ATDs?
agranulocytosis - ATDs cannot be used again
rash, urticaria, jaundice, hepatic failure
treatment of hyperthyroidism when radio iodine is contraindicated?
thyroidectomy
what is subacute thyroiditis usually triggered by?
viral infection
findings in subacute thyroiditis on scintigraphy scan?
low uptake throughout
TSH is __________ and normal fT3/4 in ___________ hypothyroidism
TSH is __________ and normal fT3/4 in ___________ hyperthyroidism
TSH is INCREASED and normal fT3/4 in SUBCLINICAL hypothyroidism
TSH is DECREASED and normal fT3/4 in SUBCLINICAL hyperthyroidism
68 year old female tired weight gain slow goitre
diagnosis?
primary hypothyroidism
68 year old female FHx of thyroid disease tired goitre TSH high T4 normal TPO high
diagnosis?
subclinical hypothyroidism
52 year old male headache visual field defect dizzy and weak TSH low T4 low
diagnosis?
pituitary tumour causing secondary hypothyroidism
