Hyperthyroidism Flashcards
What is the action of follicular cells of the thyroid gland ?
It converts thyroglobulin to T3 and T4.
What is the pathophysiology of Grave’s disease ?
It is a type to HSR caused by B cell generated thyroid stimulating immunoglobulin which act like TSH on the follicular cells to produce excess thyroid hormones.
What is the pathophysiology of Grave’s opthalmopathy ?
The TSI antibody stimulates the release of TNF alpha and IFN gamma in eye muscles which increases adipocytes and glycosaminoglycans which causes swelling of ocular muscles leading to graves opthalmopathy.
What is the cause of dermal myxedema in hyperthyroidism ?
TSI mediated dermal fibroblast proliferation.
What are the HLA genes seen in Graves disease ?
HLA DR3 and DR8.
What is the histology of thyroid in graves disease ?
Tall and crowded follicular cells with scalopped colloids.
What is the cause of Toxic multinodular goitre ?
It is the inappropriate activation of TSH receptors due to genetic mutations which appears on histology as focal patches or hyperfunctioning cells with lots of colloid.
What are hot nodules ?
These are nodules that show high activity and increased iodine uptake during radioscan and are rarely malignant.
What is Jod- Basedow phenomenon ?
It is the iodine induced thyrotoxicosis that occurs following iodine IV contrast administration. It affects people with iodine deficiency and goitre, Graves disease, TMN goitre or thyroid adenoma.
What is Woolf-Chikoff effect ?
It is the opposite of Jod-Baedow phenomenon in which there is iodine induced hypothyroidism occurs.
What are the symptoms of hyperthyroidism ?
- Heat intolerance, weight loss, hyperhydrosis.
- Warm skin and friable hair.
- Onycholysis
- Lid lag and retraction
- T3 mediated bone resorption
- Hyperdefication and hyperphagia
*
What is thyrotoxic myopathy ?
Proximal weakness with normal CK due to impaired muscle metabolism.
What are the reproductive findings in hyperthyroidism ?
- Oligomenorhhea or amnorrhea
- Low libido and infertility in females
- Gynecomastia in males.
due to increase in sex-hormone binding globulin which causes an increase in testosterone, DH testosterone and estradiol which impair normal sex hormone function.
What is the cause of menstrual disturbances in hyperthyroidism ?
Thyroid hormones alter GnRH signalling leading abnormal pulses of FSH and LH causing menstrual abnormalities.
What is the cause of neuropsychiatric symptoms in hyperthyroidism ?
Increased beta adrenergic activity.
What are the causes of cardiac symptoms in hyperthyroidism ?
Increase in beta adrenergic activity and increased expression of cardiac sarcolemmal ATpase which increases cardiac contractility. In addition there is also decreased expression of phospholamban which regulates the cardiac calcium pump.
What are the symptoms of thyroid storm ?
Fever
Tachiarrhythmia
Agitation
Delirium
Coma
What is the thyroid hormone profile in primary hyperthyroidism ?
Low TSH and high T3 and T4.
What are the radioactive iodine uptake findings in thyroid scan pathologies ?
Grave’s disease = diffuse uptake
TMN goitre = patchy uptake
Decreased uptake in thyroiditis.
What is the cause of secondary hyperthyroidism ?
Pituitary tumor which is indicated by high TSH with hyperthyroidism symptoms can be confirmed by TRH test.
Why is propranolol used in hyperthyroidism ?
It reduces the sympathetic side effects of thyroid hormones.
What is the action of Prophylthyouracil ?
It inhibits the synthesis of thyroid hormones.
What is the role of prednisolone in hyperthyroidism?
It inhibits the T4 to T3 conversion.
How does potassium iodide also known as Lugole solution help in hyperthyroidism ?
Through Woolf -Chikoff effect and by decreasing thyroid vascularisation.
