25. Hypothyroidism. Myxoedema. Flashcards
(10 cards)
What is hypothyroidism?
Hypothyroidism is when the thyroid gland is underactive, resulting in a deficiency of the thyroid hormones triiodothyronine (T3) and thyroxine (T4).
What are the congenital causes of hypothyroidism?
Congenital causes include sporadic thyroid hypoplasia (85%) and hereditary defects in hormone synthesis or peripheral resistance to hormones.
What are the acquired causes of hypothyroidism?
Acquired causes include primary insufficient hormone production (e.g., Hashimoto thyroiditis, postpartum thyroiditis, iatrogenic causes, nutritional deficiencies) and secondary pituitary disorders leading to TSH deficiency.
What are common symptoms of hypothyroidism?
Common symptoms include fatigue, bradykinesia, hair loss, dry skin, cold intolerance, weight gain, constipation, myalgia, stiffness, cramps, delayed tendon reflex relaxation, and entrapment syndromes.
What are symptoms related to generalized myxedema?
Symptoms include puffy appearance, myxedematous heart disease, myxoedema coma, hoarse voice, pretibial and periorbital oedema, symptoms of hyperprolactinemia, and goiter or atrophic thyroid.
What is the most sensitive indicator of primary hypothyroidism?
A high TSH level is the most sensitive indicator of primary hypothyroidism.
What laboratory findings are associated with hypothyroidism?
Findings include low free T4 level, increased antimicrosomal antibodies in Hashimoto thyroiditis, bradycardia, low-amplitude QRS complexes, flattened or inverted T waves on ECG, high LDL, and low HDL levels.
What is the treatment for hypothyroidism?
Treatment includes addressing the underlying illness and administering 50–100 μg of levothyroxine (T4) daily, with lower doses for elderly or heart disease patients.
How is myxedema coma treated?
Myxedema coma is treated with a single IV bolus of levothyroxine (500 micrograms) followed by daily treatment with levothyroxine (50–100 micrograms per day) and hydrocortisone (50 mg every 6 hours).
What considerations are there for pregnant patients with hypothyroidism?
Pregnancy affects TSH levels; monitoring is essential as maternal hypothyroidism may affect neural fetal development.
