thyroid diseases Flashcards
what are the two categories of thyroid diseases
primary
secondary
what is a primary thyroid disease
a disease affecting the thyroid disease
what is a secondary thyroid disease, how is it defined
hypothalamic or pituitary disease
no thyroid gland pathology
what is primary thyroid disease split into
goitre or non-goitrous
what is hypothyroidism
any disorder which causes insufficient secretion of thyroid hormones from the thyroid gland
what are the primary goitres causes of hypothyroidism
chronic thyroiditis (most common) iodine deficiency drug-induced
what would be a cause of chronic thyroiditis
Hashimoto’s thyroiditis
what drugs cause hypothyroidism
amidarone
lithium (anti-psychotics)
what are the primary non-goitrous causes of hypothyroidism
atrophic thyroiditis
post cancer treatment
congenital developmental defect
what are the primary self-limiting causes of hypothyroidism
withdrawal of anti-thyroid drugs
subacute thyroiditis
post-partum thyroiditis
what are the common symptoms of hypothyroidism
peri-orbital puffiness pale, cool skin pitting oedema vitiligo cold intolerance hyperlipidaemia (causing many cardiac issues) low HR decreased appetite weight gain hyperprolactinaemia
what thyroid hormone levels would you expect in PRIMARY hypothyroidism
high TSH
low T3 &T4
what thyroid hormone levels would you expect in SECONDARY hypothyroidism
Low or normal TSH
low T3 & T4
(all low)
what auto antibodies are associated with hypothyroidism, what condition do they suggest
anti-TPO = autoimmune hypothyroidism
what is the treatment of hypothyroidism
levothyroxine
young = 50-100 micrograms daily
old = 25-50 micrograms daily
why are elderly patients started on a lower dose of levothryoxine
due to the risk of cardiac ischaemia
what is myxoedema
severe hypothyroidism
who is typically affected by myxoedema
elderly women with long-standing but unrecognised/untreated hypothyroidism
what are the ECG symptoms of myxoedema
heart block
t wave inversion
prolonged QT interval
what are the symptoms of myxoedema
unusual ECG
bradycardia
type 2 resp failure
co-existing adrenal failure (10%)
what is the treatment of myxoedema
passively rewarm cardiac monitoring monitor fluid balance broad spectrum antibiotics give thyroxine cautiously give hydrocortisone until adrenal failure has been ruled out
what is autoimmune hypothyroidism also known as
hashimoto’s thyroiditis
what is the most common cause of hypothyroidism in the western world
hashimoto’s thyroiditis
what is hashimoto’s thyroiditis
gradual failure of thyroid function due to autoimmune destruction of the thyroid gland resulting in reduced thyroid hormone production
what is diagnostic of hashimoto’s thyroiditis
positive TPO autoantibodies
when would you treat subclinical hypothyroidism
if pregnant
if TSH >10
what is hyperthyroidism
overactivity of the thyroid gland which leads to thyrotoxicosis
what is thyrotoxicosis
clinical, physiological, and biochemical state arising when the tissues are exposed to excess thyroid hormone
what diseases cause excess thyroid stimulation which leads to hyperthyroidism
graves disease
thryoid cancer (rare)
thyroid nodules
what causes thyrotoxicosis without hyperthyroidism
thyroiditis
over-treatment with levothyroxine
what are the symptoms of hyperthyroidism
palpitations/ AF tremor sweating anxiety/irritable frequent, loose stools eye problems = graves weight loss increased appetite intolerance to heat
what thyroid hormone levels would you expect in PRIMARY hyperthyroidism
low TSH
high T3 & T4
what thyroid hormone levels would you expect in SECONDARY hyperthyroidism
high or normal TSH
high T3 & T4
(all high)
what is the treatment of hyperthyroidism
beta-blocker (propanol)
thyroid suppressant drug
radioiodine
surgery s
what is the first line drug treatment of hyperthyroidism
carbimazole
what are the contraindications of carbimazole
pregnancy
what is the 2nd line drug treatment of hyperthyroidism
propylthiouracil
when is surgery indicated in hyperthyroidism
if pressure symptoms are present:
dysphagia, stridor, hoarseness
what are the risk with surgery in the treatment of hyperthyroidism
recurrent laryngeal nerve palsy
hypothyroidism
hypoparathyroidism
what is thyroiditis
inflammation of the thyroid
what are the common causes of thyroiditis
hashimotos post-partum drug-induced acute suppurative thyroiditis de Quervain's
what is acute suppurative thyroiditis
thyroiditis caused by bacteria
what is De Quervain’s thyroiditis
thyroiditis caused by a virus
what are the investigations of acute suppurative thyroiditis, what would it show
sctintigraphy scan = low uptake though-out
what are the symptoms of acute suppurative thyroiditis
neck tenderness
fever
other viral symptoms
what is the treatment of acute suppurative thyroiditis
self-limiting
when is subclinical hyperthyroidism often seen
multinodular goitre
what is subclinical hyperthyroidism associated with
AF
osteoporosis
when would you treat subclinical hyperthyroidism
if TSH <0.1
if there is co-existing fracture, AF or osteoporosis
what is graves disease
autoimmune disease causing hyperthyroidism
what age range is affected by graves disease
20-50
what are the SPECIFIC symptoms of graves disease
pre-tibial myxoedema
diffuse goitre
thyroid bruits (if goitre is large)
graves eye disease
what is the treatment of graves eye disease
lubricants, steroids, radiotherapy, surgery (depends on severity)
what thyroid hormone levels would you expect in graves disease
low TSH
high T3 & T4
what other investigations would you do in graves disease
hypercalcaemia
high all phos
TSH receptor antibody (TRAb) present
imaging
when is imaging unnecessary in graves disease
if TRAb is present
what is the treatment of graves disease
carbimazole
radioiodine
surgery
what is the 1st line treatment in relapse of graves disease
radioiodine
when is radioiodine contraindicated
pregnancy
active graves eye disease
what is thyroid storm/crisis
severe hyperthyroidism
who does thyroid crisis usually affect
hyperthyroid patients with an acute infection/illness or recent thyroid surgery
what are the symptoms of thyroid crisis
exaggerated reflexes
hyperthermia
respiratory and cardiac collapse
what is the treatment of thyroid crisis
Lugol’s iodine Glucocorticoids PTU Beta-blockers Fluids Monitoring
what are the types if congenital thyroid disease
primary
secondary
give examples of primary congenital thyroid disease
dysplastic gland +/- abnormal site
error in thyroid hormone metabolism
give examples of secondary congenital thyroid disease
congenital pituitary disease
hypopituitarism
what are the symptoms of congenital thyroid disease
delayed jaundice
poor feeding but normal wight
hypotonia
- umbilical hernia
- constipationwhat are the investigations of congenital thyroid disease
guthrie test
TSH levels
T4 level
what can a delay in treatment of congenital thyroid disease cause
cretinism
why does amidarone cause abnormal thyroid function hormone levels
it inhibits DIO1 which increases free T4, decreased T3 and leave TSH at normal levels
what does amidarone cause
hypothyroidism in iodine rich areas
Hyperthyroidism in iodine deficient areas
what is a goitre
any enlargement of the thyroid gland
what causes a goitre
lack of dietary iodine
reduced T3 & T4
what are the investigations of a goitre
TSH levels
Ultrasound guided FNA
when would you do an isotope scan in goitre
if TSH is suppressed
what does a midline goitre suggest
thyroid
thyroglossal cyst
dermoid cyst
what are the types of goitres
diffuse/solitary
multi-nodular
what is the cause of a multi-nodular goitre
evolution from a long-standing, simple goitre
variation of response of follicular cells to external stimuli
what is the treatment of a goitre
nothing = asymptomatic radioiodine = significant hyperthyroid issues surgery = causing structural problems
what would make you suspect a thyroglossal cyst
moves when tongue is stuck out
describe a dermoid cyst
soft and non-fluctuant
what is the cause of a brachial cyst
which arises in the upper part of the anterior triangle.
where does a brachial cyst arise
upper part of the anterior triangle
what is the investigation for brachial cyst
FNA for cholesterol crystals
what is the description of a brachial cyst
half-filled hot water bottle
what is the description of cystic hygroma
lymph filled and so are Transilluminate
what is follicular adenoma
discrete solitary mass composed of neoplastic thyroid follicles and encapsulated by a surrounding collagen cuff.
what causes thyroid adenoma
mutations of TSHR signalling pathway
mutant RAS or PIK3CA
what is the most common thyroid malignancy
papillary carcinoma
how does papillary carcinoma present
solitary nodule within the thyroid, may be cackled by psammoma bodies
what is the treatment of papillary carcinoma
thyroidectomy
what is the follow up after treatment of papillary carcinoma
TSH 0.4-4 (lower levels of normal are preferred)
check Thyroglobulin
TSH/Tg measured every 6 months for 1st 5 years and then annually for the next 5 years
what is the 2nd most common thyroid cancer
Follicular Carcinoma
at what age does Follicular Carcinoma occur
40-50s (later than papillary carcinoma)
at what age does papillary cancer arise
30-40
what is the treatment of Follicular Carcinoma
minimally invasive = thyroid lobectomy
significant invasion = total thyroidectomy
what is thyroglobulin
precursor of T4/T3 made by follicular epithelial cell
what is the follow up after the treatment of Follicular Carcinoma
TSH 0.4-4 (lower levels of normal are preferred)
check Thyroglobulin
TSH/Tg measured every 6 months for 1st 5 years and then annually for the next 5 years
what is the cause of Follicular Carcinoma
iodine deficiency
mutation in PI3K (RAS family)
what is the cause of papillary carcinoma
ionising radiation
activation of MAP kinase pathway
what does cells does Medullary Thyroid Carcinoma arise from
C cells aka parafollicular cells
what cells does follicular carcinoma arise from
follicular cells
what cells does papillary carcinoma arise from
follicular cells
what causes Medullary Thyroid Carcinoma in young people
MEN2
what causes Medullary Thyroid Carcinoma on adults
sporadic mutation = solitary nodule
familial medullary carcinoma = bilateral/multi-centric nodule
what can be secreted in Medullary Thyroid Carcinoma
calcitonin
what can secretion of calcitonin in Medullary Thyroid Carcinoma cause
amyloid deposition
what are the investigations of Medullary Thyroid Carcinoma
FNA = amyloid and high calcitonin
24hr urinary metanephrines = MEN2
how does hCG impact thyroid hormones
causes an increases thyroxine with surpasses TSH
what thyroid condition does hCG cause thyroid hormones to mimic
hyperthyroidism
why is hypothyroidism common in pregnancy
plasma protein binding increases causing an increased demand in thyroid hormones
what should you do with a pregnant patient who has pre-existing hypothyroidism
increased thyroxine dose by 25mcg
check thyroid function test monthly, then twice monthly after 20 weeks
what TSH level should be aimed for in a pregnant patient who has pre-existing hypothyroidism
TSH <3
how can you tell the difference between hyperthyroidism in pregnancy and hyperemesis
TRAb antibody is present in 3rd trimester in hyperthyroidism
what is the treatment for a pregnant patient who has pre-existing hyperthyroidism
treat symptoms if they are on going by 20 weeks
low-dose antithyroid drugs
what antithyroid drugs are used to treat a pregnant patient who has pre-existing hyperthyroidism
1st trimester = propylthiouracil
2nd/3rd trimester = carbimazole
what is postpartum thyroiditis
For 1-4 months postpartum, women may become transiently thyrotoxic before experiencing hypothyroidism
