Thyroid Disease Flashcards
Describe excess thyroid dysfunction
Hyperthyroidism
Primary - common
Secondary - rare
Thyrotoxicosis without hyperthyroidism
Describe deficiency thyroid dysfunction
Hypothyroidism (myxoedema)
Primary - common
Secondary - less common
What is thyrotoxicosis
Excess thyroid hormone in circulation regardless of the source
Could be hyperthyroidism or sometimes patients take excess thyroid replacement hormone as the effects promote weight loss
What are the causes of hyperthyroidism
Graves’ disease - 70-80% of cases
Toxic multi-modular goitre
Toxic adenoma
Pituitary tumour - rare
What is Graves’ disease
Autoimmune disease where body produces antibody similar to TSH so antibody binds to TSH receptor on thyroid gland stimulating the gland to make more hormone
What are the signs of hyperthyroidism
Warm moist skin Tachycardia and atrial fibrillation Increased blood pressure and heart failure Tremor and hyperreflexia Eyelid retraction and lid lag
What are the symptoms of hyperthyroidism
Hot and excess sweating Weight loss Diarrhoea Palpitations Muscle weakness Irritable, manic and anxious
What are the causes of primary hypothyroidism
Autoimmune (Hashimoto’s) thyroiditis - 90% of cases
Idiopathic atrophy
Radioiodine treatment/thyroidectomy surgery
Iodine deficiency
Drugs
Congenital
What are the causes of secondary hypothyroidism
Hypothalamic/pituitary disease
What are the signs of hypothyroidism
Dry coarse skin Bradycardia Hyperlipidaemia Psychiatric or confusion Goitre (Hashimoto’s) Delayed reflexes
What are the symptoms of hypothyroidism
Tired Cold intolerant Weight gain Constipation Hoarse voice Puffed face Angina Poor memory Hair loss
Describe hypothyroidism caused by Hashimoto’s thyroiditis
Mostly affects middle aged and elderly women
Will present with goitre
Associated with a family history of autoimmune disease
Describe hypothyroidism caused by idiopathic atrophy
Increased incidence with age
10x more likely in females
Likely autoimmune cause
What investigations are carried out in patients with thyroid disease
Blood tests - TSH, T3 and T4
Imaging - ultrasound scan for cysts and radioisotope scans for gland uptake
Fine needle aspirate/biopsy (FNA and FNB)
Describe TSH and T3 levels in hyperthyroidism caused by the pituitary gland
Raised T3 because the gland is being asked to make more thyroid hormone
TSH released from the pituitary is higher than it should be and therefore the gland is making more T3 than it should
Describe TSH and T3 levels in hyperthyroidism caused by Graves’ or an adenoma
Raised T3 but the pituitary recognising there is too much thyroid hormone is trying to reduce gland stimulation by stopping production of TSH
Describe the TSH and T4 levels in hypothyroidism caused by the pituitary gland
Low T4 paired with a low TSH as the pituitary is not asking the thyroid to make thyroxin
Describe the TSH and T4 levels in hypothyroidism caused by gland failure
Problem with the gland which can’t respond when asked to make thyroid hormone by the pituitary so the pituitary level of TSH is increased but there is still a low T4
What drugs can be used to treat hyperthyroidism
Carbimazole - will block and replace T4 as required
Beta blockers to reduce side effects of anxiety, tremor and palpitations
What are the other treatments for hyperthyroidism
Radioiodine
Surgery - partial thyroidectomy
Graves’ ophthalmopathy has no treatment
What are the treatments for hypothyroidism
T4 tablets (thyroxine) Increase dose slowly and the TSH levels will fall As TSH levels return to normal you know the thyroid level is at the right value
What are the causes of goitre
Diffuse enlargement of the thyroid gland
Often iodine deficiency
Modular
Drug related
What are the causes of solitary nodule enlargement and what should be done
Adenoma
Carcinoma
Cyst formation
Must be investigated by ultrasound or biopsy
Describe thyroid cancer and who it usually affects
Usually with a thyroid swelling
Affects all age ranges but older patients do less well
Cold nodules on radioisotope scans
What are the dental aspects of thyroid disease
Feeling entire neck should be part of the normal examination - detect goitre
Hyperthyroid may cause pain, anxiety and psychiatric problems - caution for treatment until controlled
Hypothyroid - avoid the use of sedatives if severe
Both conditions are completely reversed with treatment
