Thyroid disease Flashcards
What are the thyroid hormones and which is the most active?
T3 and T4
T4 is converted peripherally to T3 which is the most active form is T3
what is the role of thyroid hormones?
They increase cell metabolism so are essential for growth
What is the useful form of thyroid hormone to measure?
Free thyroid levels because total thyroid hormone is affected by the level of throxine binding globulin
In hyperthyroidism which hormones will be raised?
T4 will be raised and TSH should be decreased
In 1% of cases T3 will be raised without T4
In hypothyroidism which hormones should be requested?
Only T4 and TSH because T3 does not add any extra information
What is sick euthyroidism?
This TFTs becoming deranged that may occur in any systemic illness
Which antibodies may be increased in autoimmune thyroid disease e.g. graves or hashimotos?
Antithyroid peroxidase (TPO) antithyroglobulin antibodies
What disease may have a raised TSH receptor antibody?
Graves disease
What is ultrasound useful for in thyroid disease?
Distinguishing between cycstic and from solid (possibly malignant) nodules
What are isotope scans used for?
These are useful for determining the cause of hyperthyroidism and to detect retrosternal goitre
What are the symptoms of thyrotoxicosis?
Diarrhoea Sweating Decreased weight Increased appetite Heat intolerance Palpatation tremor Irritability
What tests should be done for thyrotoxis?
TSH will be supressed and will be increased T3
Check thyroid autoantibodies
What are the causes of thyrotoxicosis?
Graves disease
Toxic multinodular goitre - iron deficient and elderly
Toxic adenoma - hot nodule on isotope scan
Ectopic thyroid tissue e.g. metastatic thyroid cancer
Exogenous - iodine excess, levothyroxine
What is the treatment of hyperthyroidism?
Drugs:
-beta blockers - rapid symptom control
-Anti-thyroid:
-Titrate up carbimazole 20-40mg depending on TFTs
OR
-Give carbimazole and levothyroixne simultaneously
Radioiodine treatment - risk of thyroid storm
Thyroidectomy - damage to recurrent laryngeal
What are the side effects of carbimazole?
Agranulocytosis so need to watch for infection
Sore throat/mouth ulcers
What are the signs and symptoms of hypothyroidism?
Tiredness, sleepy, lethargic, low mood, increased weight, constipation Signs: Bradycardic reflexes relax slowly ataxia dry thin hair/skin yawning cold hands ascites round face defeated demenour immobile CCF Proximal myopathy - raised ck Weight gain Bradycardia - due to reduce beta adrenergic receptors
What tests should be done for hypothyroid?
Will have low TSH and T4 or High LSH and low T4 in rare secondary hypothyroid
What are the causes of hypothyroid?
Primary atrophic hypothyroidism - most common cause, lymphocytic infiltration of the thyroid causing atrophy - no goitre
Harshimotos thyroiditis - goitre
Iodine deficiency is cheif cause worldwide
What is the treatment of hypothyroidism?
Healthy and young - levothyroxine (T4)
Heart disease - levothyroxine prescribed with caution as may cause MI
What is the treatment of tyrotoxic storm?
A-E IV tube, fluids
Take blood for T3 T4 and TSH, cultures if infection suspects
Give beta blocker (propanolol IV) caution in CHD
May give digoxin to slow heart with cardiac monitoring
Antithyroid drugs carbimazole 15-25mg
Hydrocortisone to prevent peripheral t4 conversion to t3
