Thyroid Flashcards
Increased TSH and low T4?
Hypothyroidism :
Atrophic
Hashimoto’s
De Quervains
Post partum
Riedel thyroiditis
Increased TSH and normal T4?
Treated hypothyroidism or subclinical hypothyroidism
High TSH and high T4?
TSH secreting tumour or thyroid hormone resistance
Low TSH and increased t4?
Hyperthyroidism:
Grave’s disease
Toxic multinodular goitre
toxic adenoma
drugs
ectopic
Low TSH and normal T3?
Subclinical hyperthyroidism
This can progress to primary hypothyroidism
Increasing then decreasing TSH, low T3?
Sick euthyroidism
Low TSH and Low t4?
Secondary hypothyroidism
Symptom relief for hyperthyroid?
Beta blockers
Topical steroids for dermopathy
Eye drops for patients with eye disease
Which antithyroid medications are used for medical management of hyperthyroidism?
Carbimazole
- titrate to normal T3 or block and replace
Carbimazole side effects?
Agranulocytosis
Rashes
When is radio-iodine used?
Sometimes after medical therapy has failed, can use for hyperthyroidism
Risk of permanent hypothyroidism
Contraindicated in pregnancy and lactating women
Indications for surgical thyroidectomy?
- Women intending to become pregnant in the next 6 months
- Local compression due to goitre
- Cosmetic
- Suspected cancer
- Co-existing hyperparathyroidism
- Refractory to medical therapy
How to prepare patients for thyroidectomy?
Patient must be euthyroid prior to surgery
How does a thyroid storm present?
Shock
Pyrexia
Confusion
Vomiting
Radio iodine uptake in Graves disease?
High diffuse uptake
painless goitre
anti-TSH receptor antibodies
isotope scan uptake in toxic multinodular goitre?
High uptake hot nodules
painless nodules
(also called plummers)
isotope uptake in toxic adenoma?
solitary ‘hot nodule’ = 1 area of uptakr
Which types of thyroidneoplasia are there? (5)
Papillary
Follicular
Medullary
Anaplastic
Lymphoma
What isotope uptake is seen in postpartum thyroiditis?
Low uptake
What is the most common cause of hypothyroidism in the UK?
Primary atrophic hypothyroid
- diffuse lymphocytic infiltration causing atrophy
No goitre, no known antibodies
Associated with perniceous anaemia, vitiligo
What is hashimotos thyroiditis?
Plasma cell infiltration and goitre
- hypothyroidism
Seen in elderly females
++ auto antibody tites (anti TPO/TTG)
What is the most common cause worldwide of hypothyroidism?
Iodine deficiency
Which drugs can cause hypothyroidism?
Amiodarone
Antithyroid drugs
Lithium
What is Riedel’s thyroiditis
dense fibrosis replacing normal parenchyma
stony hard
- hypothyroid
Who gets Papillary thyroid carcinoma?
20-40 female
Associated with irradiation
Very good prognosis
Most common thyroidneoplasia
How does papillary thyroid carcinoma spread?
Lymph nodes and lung
What is seen on histology for papillary thyroid carcinoma?
Psammoma bodies (calcification)
Orphan annie eyes (empty appearing nuclei)
How to investigate and manage papillary thyroid carcinoma?
Tumour marker: thyroglobulin
Mx : Surgery +/- radioiodine, thyroxine to lower TSH
What is the most common thyroidneoplasia?
Papillary
How does follicular thyroid cancer spread?
Though the blood -> lungs + liver, breast, adrenals
What is Follicular thyroid cancer like on histology?
Uniform cells forming small follicles, looks almost like normal thyroid
What cells are medullary neoplasms derived from?
Parafollicular C cells
What tumour marker is expected in medullary thyroid cancer?
Secrete calcitonin tumour marker : CEA + calcitonin
What does medullary thyroid cancer look like on histology?
Sheets of dark cells, amyloid deposition within tumor (amyloid is broken down calcitonin)
Who gets medullary tumour cancer?
80% is sporadic
20% is linked to familial MEN2 gene AND SO need to screen for phaechromocytoma
Which thyroid cancer is aggressive and rare?
Anaplastic - most patients due within 1 year
- pleomorphic giant cells
- spindle cells with sarcomatous appearance
Which autosomal dominant inherited disorders cause a predisposition to developing cancers of endocrine system?
MEN1 (pituitary, pancreatic, parathyroid)
MEN2a (parathyroid, phaeochromocytoma, medullary thyroid)
MEN2b (phaeochromocytoma, medullary thyroidm mucocutaenous neuromas)
Which cancers occur if someone has MEN1 gene?
3Ps
(pituitary, pancreatic, parathyroid)
Which cancers occur if someone has MEN2a gene?
2Ps and 1M
MEN2a (parathyroid, phaeochromocytoma, medullary thyroid)
Which cancers occur if someone has MEN2b gene?
1P and 2M
(phaeochromocytoma, medullary thyroidm mucocutaenous neuromas)
