Thyroid Disorders Flashcards
what is thyrotoxicosis
the clinical, physiological, and biochemical state arising when the tissues are exposed to excess thyroid hormone
what is hyperthyroidism
over-production of the thyroid hormones, triiodothyronine (T3) and thyroxine (T4), by the thyroid gland
what is the most common cause of hyperthyroidism
graves disease
who usually presents with graves disease
females 20-40 yrs
mnemonic for the causes of hyperthyroidism
GIST
graves disease
inflammation (thyroiditis)
solitary toxic thyroid nodule
toxic multinodular goitre
name 4 causes of thyroditis
De Quervain’s thyroiditis
Hashimoto’s thyroiditis
Postpartum thyroiditis
Drug-induced thyroiditis
name a drug that can induce thyroiditis
amiodarone
what is hashitoxicosis
transient hyperthyroidism caused by inflammation associated with Hashimoto’s thyroiditis
pathophysiology of graves disease
anti-TSH receptor antibodies stimulate the thyroid resulting in increased function
state 4 specific signs for graves disease
pretibial myxoedema
graves eye disease
diffuse goitre
acropachy
what does thyroid acropachy look like
hand swelling and finger clubbing
general symptoms of hyperthyroidism
weight loss despite increased appetite
frequent loose bowel movements
sweating and heat intolerance
goitre
hormone levels in primary hyperthyroidism
low TSH
high free T3/T4
primary hyperthyroidism
the thyroid is behaving abnormally and producing excessive thyroid hormone
secondary hyperthyroidism
pituitary gland produces too much thyroid-stimulating hormone, stimulating the thyroid gland to produce excessive thyroid hormones
thyroid hormones in secondary hyperthyroidism
high or normal TSH
high free T3/T4
antibody in graves disease
TSH receptor antibody
when is a scintiscan used in hyperthyroidism
patients who are antibody negative to look for toxic nodular disease
management of hyperthyroidism
carbimazole
difference in treatment of hyperthyroidism in pregnancy
propylthiouracil (PTU) used in the 1st trimester
first line management of thyrotoxic symtoms
propanolol
1st line treatment for relapsed graves and nodular thyroid disease
radioiodine
complication of radioiodine
High risk of hypothyroidism when used in Graves’ disease
when is a thyroidectomy indicated in hyperthyroidism
useful when radioiodine is contraindicated
what is a thyroid storm
Rapid deterioration of hyperthyroidism
who usually presents with a thyroid storm
hyperthyroid patient with an acute infection/illness or recent thyroid surgery
symptoms of a thyroid storm
hyperpyrexia, severe tachycardia, extreme restlessness, cardiac failure and liver dysfunction
management of a thyroid storm
high dose carbimazole
propanolol
potassium iodide
what is subacute thyroiditis
transient patchy inflammation of the thyroid
what can cause De Quervain’s thyroiditis
viral infection
clinical presentation of De Quervain’s thyroiditis
painful diffuse goitre
fever/malaise
3 main phases of De Quervain’s thyroiditis
Thyrotoxicosis
Hypothyroidism
Return to normal
investigations for De Quervain’s thyroiditis
thyroid function tests
may perform scintigraphy to rule out other causes
management of De Quervain’s thyroiditis
NSAIDs for pain and b-blockers for relief
causes of congenital hypothyroidism (4)
absent or underdeveloped thyroid
genetic defect in thyroid hormone synthesis
iodine deficiency during pregnancy
maternal transmission of antithyroid drugs
3 types of acquired hypothyroidism
primary, secondary and tertiary
what causes secondary hypothyroidism
pituitary disorders resulting in TSH deficiency
what causes of tertiary hypothyroidism
hypothalamic disorders resulting in TRH deficiency
causes of goitrous primary hypothyroidism
hashimotos thyroiditis
iodine deficiency
drug induced
causes of non-goitrous primary hypothyroidism
atrophic thyroiditis
post-radiotherapy
congenital defect
what is the most common cause of hypothyroidism
hashimotos thyroiditis
thyroid hormones in primary hypothyroidism
high TSH
low free T3/T4
clinical presentation of hypothyroidism
weight gain
fatigue
dry skin, coarse hair
fluid retention
who is more likely to get hashimotos
females
characteristic signs of hashimotos
anti-TPO antibodies and Tcell infiltrate and inflammation (microscopically)
antibody in hypothyroidism
anti-TPO antibody
other abnormalities seen primary hypothyroidism
- Macrocytosis (↑ MCV)
- ↑ creatinine kinase
- ↑ LDL cholesterol
thyroid hormones in secondary hypothyroidism
low or normal TSH
low free T3/T4
management of hypothyroidism
levothyroxine
name a severe complication of hypothyroidism
myxoedema coma
who does myxoedema coma usually seen in
elderly women with long standing but frequently unrecognised or untreated hypothyroidism
name 2 long term complications of autoimmune hypothyroidism
- Increases risk of developing other auto-immune diseases
- Increased risk of developing B-cell NHL in the affected gland
what is hashimotos thyroiditis
autoimmune destruction of thyroid tissue
genes associated with hashimotos
HLA - DR3 and DR5
what is subclinical thyroid disease
abnormal TSH with normal thyroid hormone
when is treatment of subclinical hypothyroidism indicated
if TSH >10
when is treatment of subclinical hyperthyroidism indicated
TSH <0.1%
what is subclinical hyperthyroidism associated with
osteoporosis and atrial fibrillation
common causes of benign thyroid nodules
cysts
colloid nodule
benign follicular adenoma
hyperplastic nodule
features of a benign thyroid nodule
pain/tenderness
soft, smooth, mobile
family history
what is the most common malignant thyroid nodule
papillary thyroid carcinoma
clinical features of a malignant thyroid nodule
firm, hard, immobile
dysphagia, dysphonia
cervical lymphadenopathy
lesion >4 cm
how do we know if a lump is related to the thyroid
moves on swallowing
investigations of a solitary thyroid nodule
thyroid function tests
USS possibly with FNA
2 classification systems for thyroid nodules
USS classification
FNA Bethesda classification
USS classification of thyroid nodules
U2-U5
U2 is benign, U3+ is abnormal so do FNA
FNA Bethesda classification
Thy1-5
Thy3-5 is abnormal
what is a goitre
any enlargement of the thyroid gland, due to impaired synthesis of thyroid hormone
pathophysiology of goitre
Reduced T3/T4 production causes a rise in TSH, stimulating gland enlargement
name some causes of a diffuse goitre
physiological (puberty, pregnancy)
hashimotos, grave
iodine deficiency
inflammation
multi-nodular goitre
develops from a long-standing simple sporadic goitre
what causes multi-nodular goitre
mutations of the TSH signalling pathway
clinical presentation of multi-nodular goitre
irregular enlarged thyroid due to nodule formation - feels bumpy
investigations for multi-nodular goitre
thyroid function test
US - FNA?
CT scan
thyroid isotope scan
management of toxic multi-nodular goitre
carbimazole. radioactive iodine if really bad
most common cause of hyperthyroidism in pregnancy
graves disease
complications of hyperthyroidism in pregnancy
infertility/amenorrhoea
spontaneous miscarriage
stillbirth
thyroid crisis in labour
when does post-partum thyroiditis commonly occur
around 6 weeks
management of post-partum thyroiditis
treat symptomatic hypothyroid with thyroxine
how long does post-partum hypothyroidism last for
up to 1 year, at which it becomes persistent
