Endo- thyroid disorders Flashcards
what is hyperthyroidism
refers specifically to the conditions in which overactivity of the thyroid gland lead to thyrotoxicosis
most common cause of hyperthyroidism (85% of cases)
Graves disease
graves disease more common in females/males
females (10:1)
in graves disease, which receptor antibodies stimulate the thyroid
anti-TSH
general symptoms of hyperthyroidism
weight loss despite increased appetite
frequent, loose bowel movements
sweating and heat intolerance
goitre (swelling in neck)- diffuse, toxic
what is a goitre
enlarged palpable thyroid gland, which moves on swallowing
CVS symptoms of hyperthyroidism
increased pulse rate
palpitations, AF
rarely cardiac failure
what is graves eye disease associated with
smoking
what produces the TSH
the pituitary gland (located in the brain)
primary hyperthyroidism thyroid hormone levels
TSH low
T3/T4 high
thyroid autoantibodies in graves disease
TSH receptor antibody (70-100%)
Anti-TPO antibody (70-80%)
Anti-thyroglobulin antibody (30-50%)
1st line medical management in graves disease
carbimazole
what is a thyroid storm
rapid deterioration of hyperthyroidism with:
hyperpyrexia
severe tachycardia
extreme restlessness
cardiac failure
liver dysfunction
immediate symptomatic relief of thyrotoxicosis symptoms
beta blockers
preferred antithyroid medication in first trimester of pregnancy
PTU
what is hypothyroidism
results from any disorder that results in insufficient secretion of thyroid hormones from the thyroid gland
symptoms of hypothyroidism
tiredness/malaise
weight gain, despite < appetite
cold intolerance
< sweating
constipation
bradycardia
primary hypothyroidism hormone levels
TSH high
T4 and T3 low
Thyroid antibodies in autoimmune hypothyroidism
anti-TPO antibody
antithyroglobulin
TSH receptor antibody
when does graves disease usually present
20-40 years
sign of graves disease, associated only with large goitres
thyroid bruit
systemic symptoms associated with hyperthyroidism
double vision
cardiac- palpitations, tachycardia
msk- muscle weakness thighs and upper arms
neuro- increased nervousness, sleep disturbance, depression
hair and skin- thin brittle hair, rapid fingernail growth
reproductive- lighter and less frequent periods
first choice treatment in relapsed graves disease
radioiodine
what treatment is useful for relapsed graves disease when radio iodine is contraindicated eg pregnancy
thyroidectomy
who are thyroid storms typically seen in
hyperthyroid patients with an acute illness/infection or recent thyroid surgery
causes of congenital hypothyroidism
absent or underdeveloped thyroid gland
dyshormonogenesis
iodine deficiency during pregnancy
maternal use of antithyroid drugs
what is the most common cause of primary hypothyroidism in iodine-sufficient regions
hashimoto’s thyroiditis (chronic lymphocytic thyroiditis)
what are the risk factors for hashimotos thyroiditis
middle age women (45-60 years)
family history of autoimmune thyroid disease
associated with HLA-DR3 and DR5
what is the most common type of primary hypothyroidism worldwide
iodine deficiency
what are iatrogenic causes of primary hypothyroidism
post-radioiodine therapy
thyroid surgery
certain drugs (eg lithium, amiodarone)
what causes secondary hypothyroidism
pituitary disorder resulting in TSH deficiency
what causes tertiary hypothyroidism
hypothalamus disorders causing TRH deficiency
what is Hashimoto’s thyroiditis
autoimmune condition causing gradual destruction of the thyroid gland, leading to hypothyroidism
what antibodies are characteristic of hashimotos thyroiditis
anti-thyroglobulin
anti-thyroid peroxidase (TPO antibodies)
how does hashimotos thyroiditis cause thyroid cell destruction
antibody-dependent cell-mediated cytotoxicity
CD8 + T cell mediated destruction
cytokine-mediated apoptosis
what is hashitoxicosis
a transient hyperthyroid phase that may precede the hypothyroid state in hashimotos thyroiditis
what do hurthle cells look like
large, pink (eosinophilic), puffy cells
what are the key histological features in hashimotos thyroiditis
lymphocytes and germinal centre
thyroid follicles atrophy
hurthle cells
may see progressive fibrosis
Symptoms related to generalised myxoedema (severe hypothyroidism)
doughy skin texture, puffy appearance
what heart issues are related to Myxoedema
dilated cardiomyopathy
bradycardia
pericardial effusion
dyspnoea
worsening heart failure
which type of oedema is seen in hypothyroidism
periorbital oedema (around the eyes)
What is pretibial myxoedema?
swelling on the shins
seen in hypothyroidism and graves disease
what is a common entrapment syndrome in myxoedema
carpal tunnel syndrome
what neurological symptoms may occur with myxoedema
peripheral neuropathy
what happens to the tongue in myxoedema
macroglossia- enlarged tongue
how does the voice change in myxoedema
deep, hoarse voice
what severe condition can result from untreated myxoedema
myxoedema coma
goitres can be found in both hyper and hypothyroidism true/false?
true
common abnormalities found in primary hypothyroidism
macrocytosis (>MCV)
elevated creatine kinase
elevated LDL cholesterol
hyponatraemia
hyperprolactinaemia
treatment of primary hypothyroidism in younger patients
start levothyroxine 50-100ug daily and gradually increase
treatment of primary hypothyroidism in elderly patients with history of IHD
start levothyroxine 25-50ug daily, adjusted every 4 weeks
what is the mortality of myxoedema coma
60%
who do myxoedema comas typically affect
elderly women with long standing but frequently unrecognised or untreated hypothyroidism
what is queen annes sign in hashimotos thyroiditis
loss of lateral third of eyebrow
treatment of myxoedema coma
IV hydrocortisone and IV levothyroxine
what is De Quervains thyroiditis
describes the presentation of a viral infection with fever, neck pain and tenderness, dysphagia and features of hyperthyroidism
which ages are most commonly affected by de quervains thyroiditis
20-50
clinical features of de quervains thyroiditis
painful, diffuse, firm goitre
fever and/or malaise may be present
hyperthyroid phase followed by hypothyroid phase
management of de quervains thyroiditis
supportive treatment
drugs that can induce thyroiditis
amiodarone
lithium
what is subclinical thyroid disease
abnormal TSH with normal thyroid hormone
treat subclinical hypothyroidism when TSH is over what?
TSH>10
subclinical hyperthyroidism often seen in what
multi-nodular goitre
what is subclinical hyperthyroidism associated with
osteoporosis
atrial fibrillation
treat subclinical hyperthyroidism when TSH is under what?
<0.1%
solitary thyroid nodules affect what percentage of women
5%
what percentage of solitary thyroid nodules are benign
95%
examples of benign thyroid nodules
cyst
colloid nodule
benign follicular adenoma
hyperplastic nodule
clinical features of solitary thyroid nodules
lump moves on swallowing
majority are painless
signs of malignancy- enlarged lymph nodes, hoarseness
what does a U2 classification on thyroid USS mean
benign nodule
from which USS classification of thyroid is FNA (fine-needle aspiration) recommended
U3 and above (U3=atypical)
what does U4 classification on thyroid USS suggest
probably malignant
what does U5 classification on thyroid USS suggest
malignant
what does Thy1 mean on the FNA Bethesda classification
inadequate sample
what does Thy2 indicate in the Bethesda classification
benign result
what does Thy3 indicate in the Bethesda classification
Atypical (suspicious, but not clearly malignant)
what does Thy4 indicate in the Bethesda classification
Probably malignant
what does Thy5 indicate in the Bethesda classification
malignant
effects of thyroid during pregnancy-
increased demand on thyroid-
enlarged thyroid
increased T4 production
postpartum thyroiditis affects what percentage of post part women
5% (25% in T1DM)
which type of thyroid cancer is associated with hashimotos
papillary carcinoma
what age group of patients usually develop anaplastic carcinomas
elderly
which is more aggressive- medullary/anaplastic carcinomas
anaplastic carcinomas
what test is screened regularly after medullary carcinomas
serum calcitonin
which type of thyroid cancer carries the worst prognosis
anaplastic carcinoma
what is the least common type of thyroid cancer
anaplastic carcinoma
