Thyroid Flashcards
TSH receptor antibodies are found in most patients with which disease?
Graves’ disease (form of autoimmune hyperthyroidism)
What is primary hypothyroidism and what are the causes?
Autoimmune - hashimotos thyroiditis
Thyroid atrophy
Iodine deficiency (developing world)
Drugs (amiodarone, lithium, iodine)
What is secondary hypothyroidism?
Usually due to a disorder of the pituitary gland or a lesion compressing the pituitary gland - much rarer.
What is Hashimoto’s thyroiditis?
A type of primary hypothyroidism, due to autoimmune attack of the thyroid, that is associated with T1DM, Addison’s or Pernicious anaemia. It may cause transient thyrotoxicosis in the acute phase.
It often presents as a goitre in women aged 60-70 years old.
What are the symptoms of hypothyroidism?
- Fatigue
- Menorrhagia
- Weight gain
- Decreased mood
- Intolerance to cold
- Constipation
- Weakness
- Dry skin/nails/hair
- Facial oedema
How is hypothyroidism diagnosed?
Decreased T3/4 and increased TSH
What hormones does the anterior pituitary produced?
- Thyroid stimulating hormone
- ACTH
- FSH and LH
- Growth hormone
- Prolactin
- Endorphs
What are the symptoms of hyperthyroidism?
- Fatigue
- Sweating
- Irritability/anxiety
- Intolerance to heat
- Weight loss
- Diarrhoea
- Tremor
- Tachycardia
- Menstrual irregularity
What are the signs of hyperthyroidism?
Agitation Tachycardia Warm/clammy Brisk reflexes Eye signs - proptosis/liflag Thyroid acropachy (soft tissue swelling of hands and clubbing of fingers) Pretibial myxoedema
What are the signs of hypothyroidism?
Bradycardia Reflexes relax slowly Ataxia (coordination and balance difficulties) Dry thin hair/skin Ascites and non pitting oedema Round puffy face CCF Goitre
What is myxoedema?
Swelling of the skin and underlying tissues, giving a waxy consistency. This is associated with severe hypothyroidism
What are the common causes of hyperthyroidism?
- Graves disease
- Toxic multinodular goitre
- Toxic adenoma
- Drugs (amiodarone/iodine)
How can thyroid problems be investigated?
CLINICAL
BIOCHEMICAL - TSH, T4, T3
IMMUNOLOGY - thyroid peroxidase autoantibodies, TSH receptor antibodies
IMAGING - isotope scans (useful for detecting the cause of hyperthyroidism), USS (looks at nodules specifically)
How is hyperthyroidism diagnosed?
Decreased TSH and increased T3/T4
What drugs can be used to treat hyperthyroidism?
Inhibit fT4 to fT3 - Carbimazole, propylthioruracil
Symptom control - B blockers (propanolol)
Radioiodine (but will lead to hypothyroidism)
What is a thyroid storm and what are the features?
Severe hyperthyroidisim causing tachycardia, fever, encephalopathy, fits, stroke, hypertension, D&V, circulatory collapse and death. It is a medical EMERGENCY.
How is a thyroid storm treated?
Propylthiouracil Iodine Steroids(hydrocortisone) Beta-blockers (propanolol) IV fluids
What drugs can be used to treat hypothyroidism?
- Levo-thyroxine
- Tri-iodothyronine
What is a myxoedema coma?
Severe hypothyroidism causing hypothermia, bradycardia, coma, seizures, cyanosis, decreased BP and heart failure
How is a myxoedema coma treated?
Tri-iodothyronine
Steroids (hydrocortisone)
IV fluids
Active warming for hypothermia
What is thyroid eye disease?
Eye discomfort, grittiness, photophobia, afferent pupillary defect and expothalmous. This is associated commonly with Graves’ disease but can be present in any thyroid disorder.
What is subclinical hyper/hypothyroidism?
When TSH levels are changed but T3/T4 are normal
What is sick euthyroidisim?
This is the derangement of TFTs in any systemic illness - typically everything will be low.
What is the most common cause of hypothyroidism in the developing world?
Iodine deficiency
What is parathyroid hormone?
A hormone released in response to low levels of calcium in the blood which causes:
- Increased osteoclast activity (indirectly)
- Activation of vitamin D to increase absorption of calcium from the small intestine.
What are the symptoms of hyperparathyroidism?
HIGH CALCIUM IN BLOOD - abdo pain, vomiting, polyuria, polydipsia, weight loss, osteoporosis, renal stones
What causes hyperparathyroidism?
Primary - adenoma, hyperplasia, carcinoma (high calcium, high PTH)
Secondary - (secondary to decreased calcium) low vitamin D, chronic renal failure (low calcium, high PTH)
What are the symptoms of hypoparathyroidism?
LOW CALCIUM IN BLOOD - cramps, anxious, seizures, trousseau sign (spasm)
What causes hypoparathyroidism?
Primary - autoimmune gland failure, congenital (di george) (low PTH, low Ca)
Secondary - radiation, surgery
What are some causes of diffuse goitre?
Iodine deficiency
Congenital
Acute thyroiditis
Autoimmune (graves, hashimotos)
What is the most common cause of nodular goitre?
Toxic multinodular goitre (hypperthyroid)
What are the DDs for a single thyroid nodule?
Cyst, adenoma, malignancy
What are the complications for surgery for goitres?
EARLY: Recurrent laryngeal nerve palsy, haemorrhage, thyroid storm
LATE: hypothyroidism
What are the side effects of carbimazole?
Mild: Hair loss, headaches, nausea, itchy
Serious: Sore throat due to bone marrow suppression
What is tetany?
A condition marked by intermittent muscular spasms, caused by hypoparathyroidism and a consequent deficiency of calcium.
