Diabetes and Endocrinology Flashcards
What is meant by primary gland failure?
Dysfunction of the peripheral gland with compensatory hypersecretion of the pituitary hormone
What may be damaged during thyroid surgery?
Recurrent laryngeal nerve - laterally
parathyroid glands - posteriorly
what is the 2 major cell types found in the thyroid?
follicular cells
parafollicular cells / C-cells / neuroendocrine cells
What is colloid and where is it found?
Found in the lumen of spherical follicular cells, surrounded by epithelial follicular cells. Colloid is a substance that contains iodinated thyroglobulin
what is secreted by neuroendocrine cells
calcitonin
Medullary Thyroid Cancer
- physiology
- presentation
- tests
- treatment
Physiology : tumour in the neuroendocrine cells (c-cells) causing elevated calcitonin levels
Presentation : Central neck lump, hoarse voice, hard to breathe. There does not seem to be any direct deleterious effect on the body as a result of having too much calcitonin.
Tests: imaging, biopsy, calcitonin levels, CEA (type of tumor marker found in the blood of those with MTC)
treatment: thyroidectomy
what are the three thyroid hormones?
Bound thyroxine binding globulin
transthyretin
albumin
what are the actions of thyroid hormones?
increase basal metabolic rate
affect growth in children
increase heart rate
What hormones are involved in the pituitary-thyroid axis?
hypothalamus : TRH
Pituitary: TSH
Thyroid : T3 and T4
what might cause hyperthyroidism where TSH isnt suppressed?
TSHoma, thyroid hormone resistance, assay interference
what factors might affect the thyroid function tests results?
medication - lithium and amiodarone
pregnancy
acute illness
Causes of thyrotoxicosis?
Graves disease toxic multinodular goitre toxic adenoma ectopic thyroid tissue (metastatic follicular thyroid cancer, ovarian teratoma with thyroid tissue) Exogenous (iodine excess)
symptoms and signs of thyrotoxicosis?
symptoms: diarrhoea, weight loss, increased appetite, over active, sweats, heat intolerance, palpitations, tremor, irritability, oligomenorrhoea/ infertility, anxiety, insomnia
signs: tachycardia, warm moist skin, tremor, palmar erythema, lid retraction, goitre, lid lag( increased sympathetics - not seen in graves)
what is thyroiditis? what causes it?
inflammation of the thyroid, releasing thyroxine
caused by viral infection, medication, childbirth
what is the most common cause of thyrotoxicosis?
young: graves disease
old : nodular thyroid disease
Graves disease
- presentation
- physiology
- demographics
- associated with
- signs: eye disease, exophthalmos, ophthalmoplegia, pretibila myxoedema, thyroid acropachy. Symptoms: tremor, weight loss, palpitations, increased appetite, sweats, diarrhoea, heat intolerance, insomnia.
- physiology: autoimmune condition. TSH receptor stimulating autoantibodies IgG. autoantibodies bind to thyrotropin receptors, increasing the amount of T3 esp.
- females, 40 to 60 yrs,
- associated with vitiligo, type 1 dm, addisons
what is thyroid acropachy?
Thyroid acropachy is a rare complication of Graves disease. Clinically, it presents as nail clubbing, swelling of digits and toes, almost always in association with thyroid ophthalmopathy and dermopathy.
tests of thyrotoxicosis
low TSH, high T4 and T3
mild normocytic anaemia
mild neutropenia in graves
thyroid autoantibodies (TSH receptor stimulating antibodies and thyroid peroxidase antibodies )
radionuclear scan - iodine uptake isotope
if ophthalmopathy then test visual fields, acuity and eye movements
what is subclinical hyperthyroidism?
where there is normal concentrations of T3 and T4 but TSH is suppressed. Suggests autonomous thyroid activity
thyroid peroxidase antibodies are detected in a patient. What can we assume from this?
TPO is a non-specific markers of autoimmune thyroid disease. Likely indicates Hashimotos
