Thyroid Disease Flashcards
What are the physiological effects of thyroid hormone?
- Increased HR and CO
- increased bone turnover and resorption
- Maintains normal hypoxic and hypercapnic drive in respiratory system
- Increases RBC 2,3-BPG facilitating oxygen release to tissues
- Increases speed of muscle contraction and relaxation and muscle protein turnover
- increases hepatic gluconeogenesis/glycolysis and intestinal glucose absorption
- Increases lipolyisis and cholesterol synthesis and degradation
- Increases catecholamine sensitivity and B-adrenergic receptor numbers in heart, skeletal muscle, adipose cells and lymphocytes
- Decreases cardiac a-adrenergic receptors.
What is hyperthyroidism?
Occurs when there is too much circulating thyroid hormone in the body.
What are the 3 main causes of hyperthyroidism?
- Grave’s disease
- Toxic multinodular goitre and toxic solitary nodule goitre
- De Quervain’s thyroiditis
What is Grave’s disease?
- Most common cause of hyperthyroidism
- Autoimmune
- specific features = ocular changes e.g. exopthalmos, and other signs e.g. pretibial myxoedema.
- Associated with other autoimmune conditions such as pernicious anaemia.
What is toxic multinodular goitre?
- second most common cause of hyperthyroidism
- risk increases with age
- more common in females
- a single nodule is suggestive of thyroid neoplasia
What is De Quervain’s thyroiditis?
- Transient hyperthyroidism that develops after a viral infection
- Goitre is often painful
- A period of hypothyroidsim may follow.
What are the signs and symptoms of hyperthyroidism?
WHAT PMS, Fhx
- Weight loss
- warm skin
- increased appetite
- heat intolerance
- palpitations
- diarrhoea
Expopthalmos (Graves disease), lid lag, anxiety, tremor, goitre +/- bruits, brisk reflexes
What are the complications of hyperthyroidism?
- AF
- High output heart failure
- Cardiomyopathy
- Osteoporosis
What is the conservative treatment of hyperthyroidism?
Conservative: Patient education, smoking cessation.
What is the medical treatment for hyperthyroidism?
- symptomatic control = beta blockers for the tremor and palpitations and eyedrops for lubrication of eyes.
- Anti thyroid medication - carbimazole, propylthiouracil - side effects: agranulocytosis.. therefore monitor bloods carefully.
- Radioactive iodine ablation - definitive treatment; patients must be euthyroid before commencing treatment.
what is the surgical treatment of hyperthyroidsim?
subtotal thyroidectomy: patients must be euthyroid before the procedure. give the patient potassium iodide before surgery since it decreases gland vascularity.
What are the investigation for hyperthyroidism?
- TFTs (decreased TSH, increased T3, and increased T4).
- Ultrasound scan of nodules.
- Fine needle aspiration of solitary nodules to exclude malignancy
- isotope scan to assess hot and cold thyroid nodules.
Thyrotoxicosis
- Hyperthyroid crisis - TOOO MUCH thyroid hormone circulation
- F:M = 4.1
- Signs: AF/Palpitations, tachycardia, agitation, D&V, goitre, heart failure
- Usually following recent infection, thyroid surgery, MI, trauma
- Treatment: Rx systemic effects of thyroid hormone (symptomatic Rx), inhibit hormone synthesis (e.g. carbimazole), give hydrocortisone to prevent peripheral conversion of T4 -> T3. Treat any precipitating causes (e.g. infection w ABX)
Myxoedema coma
The ultimate hypothyroid state before death
- Inability of the brain to function as a result of severe, longstanding low levels of thyroid hormone in the blood.
Severe hypothyroidsim resulting in a decompensated metabolic state and mental status change
Signs: Signs of thyroid surgery, “myxoedema madness” (psychosis) prior to coma, hypothermia, hypo-reflexia, low glucose, bradycardia, poor appetite.
Treatment: correct electrolyte imbalance, give T3 (Liothyronine), hydrocortisone treat symptoms (e.g. hypothermia)
