Thyroid Disease Flashcards
Describe thyroid dysfunction caused by excess in thyroid hormone
- Excess thyroid hormone - hyperthyroidism
- primary: common
- secondary: rare
- thyrotoxicosis can occur without hyperthyroidism
- usually due to weight loss attempts using excess thyroid replacing hormone
Describe thyroid dysfunction caused by a deficiency in thyroid hormone
- Deficiency - hypothyroidism
- primary: common
- secondary: less common
What are causes of hyperthyroidism?
- Graves’ disease - 70-80% of cases
- autoantibodies stimulating TSH receptor: results in excess hormone release - Toxic multi-nodular goitre
- Toxic adenoma
- tumour within the thyroid gland which stimulates unregulated release of thyroid hormone resulting in hyperthyroidism - Pituitary tumour (rare)
- produces excess TSH which makes the thyroid gland produce too much hormone
What are signs of hyperthyroidism?
- Signs
•warm moist skin
- increased metabolism results in more heat generation
•tachycardia and atrial fibrillation
•increased blood pressure and heart failure
•tremor and hyperreflexia
• eyelid retraction and lid lag
- in lid lag the eyeball moves down and exposes white sclera of the eye before the eyelid can catch up
What are symptoms of hyperthyroidism?
- Hot and excess sweating, weight loss, diarrhoea
- Palpitations, muscle weakness
- Irritable, manic, anxious
List some diseases which are often found in the family history of patients with Graves’ disease
- Vitiligo
- Pernicious anaemia
- Type 1 diabetes mellitus
- Coeliac disease
- Myaesthenia gravis
What other clinical features are associated with Graves’ disease?
- Diffuse goitre (enlarged thyroid gland)
- Opthalmopthy
- sceral injection
- proptosis
- periorbital oedema - Conjunctival oedema
- chemosis
Describe primary hypothyroidism
- Autoimmune (hashimoto’s) thyroiditis (90% of cases)
- Idiopathic atrophy
- Radioiodine treatment/thyroidectomy surgery
- excessive thyroid tissue removed results in hypothyroidism
- radioiodine treatments reduce thyroid secretion which can lead to atrophy of the thyroid gland - Iodine deficiency
- Drugs
- carbimazole, amiodarone, lithium - Congenital
Describe Hashimoto’s thyroiditis
- Autoimmune
- antibodies attack the thyroid gland resulting in inflammation which causes gradual fibrosis and destruction of specialised thyroid tissue
Describe secondary hypothyroidism
- Caused by hypothalamic/pituitary disease
What are signs of hypothyroidism?
- Dry coarse skin
- Bradycardia, hyperlipidaemia
- Psychiatric or confusion
- Goitre (hashimoto’s)
- Delayed reflexes
What are symptoms of hypothyroidism?
- Tired
- Cold intolerance, weight gain, constipation
- Hoarse voice, goitre, puffed face and extremities
- Angina
- ‘Slow’, poor memory
- Hair loss
What are causes of hypothyroidism?
1.Hashimoto’s thyroiditis
2. Idiopathic atrophy
3. Iodine deficiency
4.
What group is most susceptible to Hashimoto’s thyroiditis and how does it present + what is it associated with?
- Middle Aged and elderly woman
- Presenting features
- goitre
- hypothyroid features - Associations
- often a family history of autoimmune disease
(Vitiligo, PA, type 1 DM, Addison’s disease)
- Down’s syndrome
Describe the epidemiology of idiopathic atrophy
- Increased incidence with age
- 10x more in females
- Likely autoimmune cause
- lymphocyte infiltrate
- associated with organ specific autoimmune disease
What are the 3 main investigations methods for thyroid disease?
- Blood
- TSH, T3 and T4 - Imaging
- ultrasound scan (cysts)
- radioisotope scans - gland uptake - Tissue
- fine needle aspirate/biopsy (FNA and FNB)
Describe the hormone levels in pituitary and graves or adenoma hyperthyroidism
- Pituitary cause
- raised TSH
- raised T3 - Graves or adenoma
- low TSH
- raised T3
(Due to fact that pituitary is still functional so reduces TSH secretion)
Describe hormone levels with a pituitary caused and gland failure caused hypothyroidism
- Pituitary cause
- low TSH
- low T4 - Gland failure
- high TSH
- low T4
What are drug treatments for hyperthyroidism?
- Carbimazole
- titration
- block and replace - T4 as required - Beta-blockers
- Radioiodine- 131I
- hypothyroid risk with time - review
What other treatments are available for hyperthyroidism?
- Surgery - partial thyroidectomy
- usually follows drug therapy to stabilise - Graves’ opthalmopathy - none/simple measures
What are treatments for hypothyroidism?
- Give T4 tablets (thyroxine)
- slow response - weeks
• increase dose slowly
- IHD
• recheck using TSH as a guide of gland failed
Describe goitre
- Diffuse enlargement of the thyroid gland
- often iodine deficient (mountainous are as of developing countries
- diffuse, nodular
- potentially drug related
What other change apart from goitre can occur in the thyroid?
- Solitary nodule enlargement
- adenoma, carcinoma, cyst formation possible
- low cancer risk, however it is suspicious in children or elderly
What feature is often present in thyroid cancer?
Thyroid swelling
What types of thyroid cancer are associated with young and elderly people?
- Papillary (80%) or folicular in younger
2. Undifferentiated in elderly
Describe thyroid cancer
- ‘Cold’ nodules on radioisotope scans
- Often TSH sensitive - give T4 post surgery
- Generally a good prognosis in young people
- 5% 10 year mortality in papillary
But
- 80% 10 year mortality in folicular
What are dental aspects of thyroid disease?
- Goitre detectable to the dentist
•hyperthyroid
- pain, anxiety and psychiatric problems
- caution for treatment until controlled
• hypothyroid
- avoid use of sedatives if severe
Treated patients are normal
