Please enable JavaScript.
Coggle requires JavaScript to display documents.
Thyroid - Coggle Diagram
Thyroid
Goitre
enlargement of thyroid gland
hyperplasia
colloid storage
in conditions assoc. with
abnormal production of thyroid hormones
aetiology
^TSH -> ^ thyroid size
causes
iodine deficiency
dietary goitrogens
inherited enzyme(defect) in hormone synthesis
types
diffuse non-toxic goitre
often leads to multinodular goitre
toxic goitre
4 types of inherited enzyme defects
General
functional unit
thyroid follicle
follicular epi cells
surround lumen filled with colloid
C-cell
secretes calcitonin
Developmental anomalies
can give rise to
cysts
thyroglossal duct cyst
sinuses
fistulae
ectopic thyroid tissue
occurs due to
developmental disorder
teratoma
struma ovarii
function
hypothalamus releases TRH
anterior pituitary releases TSH
thyroid produces and secretes T3&4
T3&4
low
hypothyroidism
myxoedema
high
hyperthyroidism
thyrotoxicosis
Thyroiditis
Acute
rare
bacterial, viral, fungal
subacute
de Quervain's thyroiditis
also called granulomatous, giant cell, struma granulomatous
age
20-50
predominantly females
can cause hyper, hypo or normal thyroidism
granulomatous thyroiditis
macroscopically
gland adherent to
trachea
adjacent strap muscles
intact capsule
moderate enlargement
microscopically
neutrophils
aggregations of macrophages
giant cells around pools of colloid
fibrosis later
chronic
Hashimoto's thyroiditis
most common
chronic thyroiditis
thyroiditis causing hypothyroidism
primary autoimmune
dx
anti-microsomal antibody/peroxidase
females more than males
age
30-50
rarely in chilldren
genetic predisposition
familial occurence
assoc. with HLA-DR3
features
diffusely enlarged thyroid
4-5 times normal size
smooth/finely nodular surface
firm to hard consistency
lymphoid follicles with germinal centres
Hurthle cell metaplasia
plasma cells
fibrosis
Grave's disease
autoimmune
IgG antibody against TSH receptor
diffuse symmetrical enlargement
weight 100g (normal=18)
microscopy
hyperplastic follicles with papillary infoldings
colloid with peripheral scalloping
vascular stroma
Hyperthyroidism
causes
diffuse toxic hyperplasia (Graves)
toxic multinodular goitre
toxic adenoma
thyroiditis
thyroid carcinoma
TSH secreting pituitary adenoma
struma ovarii/teratoma
not really assoc. with hyperthyroidism
iatrogenic(uncommon)
exophthalmos/proptosis
Teprotumumab has reduced
Hypothyroidism
causes
insufficient thyroid parenchyma
congenital
radiation injury
surgical ablation
Hashimoto's thyroiditis
interference with hormone synthesis
heritable biosynthetic defects
iodine deficiency
drugs
lithium
supra-thyroidal
pituitary lesion reducing TSH secretion
hypothalamic lesions reducing TRH
Myxoedema
Neoplasia
Benign
adenoma
usually <4 cm
foetal
embryonal
simple
colloid
Hurthle cell
follicular
complete fibrous encapsulation
clear distinction between architecture inside and out of capsule
compression of surrounding thyroid parenchyma
lack of multinodularity in adjacent gland
Carcinomas
Papillary
75-80%
variants
microcarcinoma
encapsulated
follicular
solid and cribiform
diffuse sclerosing
tall
columnar cell
usual type
lymphatic invasion common
cervical node metastases (33%)
blood vessel invasion
7%
low grade
excellent prognosis