Thyroidism ✔️ Flashcards
Hypo/Hyper
Hypothyroidism is
underproduction & secretion of thyroid hormones.
Hypothyroidism signs and symptoms
fatigue, weight gain, constipation, menstrual irregularities, depression, dry skin, intolerance to the cold, & reduced body + scalp hair
Hypothyroidism complications
dyslipidaemia, coronary heart disease, heart failure, impaired fertility, pregnancy complications, impaired concentration and/or memory, and rarely myxoedema coma (which is a life-threatening medical emergency)
Primary hypothyroidism
thyroid gland + caused by iodine deficiency, autoimmune disease (Hashimoto’s thyroiditis), radiotherapy, surgery or drugs
Secondary hypothyroidism
caused by pituitary or hypothalamic disorder
Overt hypothyroidism
thyroid stimulating hormone (TSH) levels HIGH + free thyroxine (FT4) levels LOW
subclinical hypothyroidism
TSH levels HIGH but FT4 & free tri-iodothyronine (FT3) levels within range
~ In pregnancy, defined as overt based on elevated TSH levels (using trimester-specific reference ranges) regardless of FT4 levels.
Overt hypothyroidism management
~ levothyroxine sodium = 1st-line
~ If symptoms persist, even after achieving normal TSH levels, adjusting dose
~ For patients whose TSH level was very high before starting treatment or who have had a prolonged period of untreated disease, the TSH level can take up to 6 months to return to the reference range.
Consider measuring
Monitoring requirements ~levothyroxine
(Primary hypothyroidism)
TSH levels every 3 months until stable, then yearly thereafter.
~ Monitoring free thyroxine (FT4) symptoms of hypothyroidism persist after starting levothyroxine.
Food and lifestyle & levothyroxine
Food, including dietary fibre, milk, soya products, and coffee, might decrease absorption of levothyroxine
MHRA & Levothyroxine
if patient reports symptoms after changing to different tablet of levothyroxine = thyroid function test
~ if patient persistently symptomatic, whether they are biochemically euthyroid or have evidence of abnormal thyroid function, consistently prescribing a specific levothyroxine tablet known to be well tolerated by patient should be considered
~ If symptoms or poor control of thyroid function persist despite adhering to specific tablet, consider prescribing levothyroxine in oral solution formulation.
Thyroid hormone regulates
~ metabolic rate
~ HR
~ digestive function
~ Muscle control
~ brain development
Hyperthyroidism symptoms
- Heat intolerance
- Weight loss
- Diarrhoea
- Tachycardia
- Excitability
- Tremors
- Angina
- Sweating
- Arrhythmias
Hyperthyroidism labs
High T4, T3
LOW TSH
Hyperthyroidism tx
Carbimazole, Propylthiouracil
Carbimazole SEs
bone marrow suppression (neutropenia, agranulocytosis)
Rash / Itching - antihistamine or switch to propylthiouracil
Propylthiouracil SEs
Alternative to carbimazole
~ Hepatotoxicity … report liver failure (jaundice, N, V, abdo pain, pale stools, malaise, itching, dark urine, raised liver enzymes)
Thyrotoxicosis
~ Increased HR
~ Tachycardia
~ Heat intolerance
~ Diarrhoea
~ Seizures
Thyrotoxicosis management
anti-thyroid drugs, fluids, hydrocortisone, radioactive sodium iodine solution
propranolol for rapid symptom relief
hyperthyroidism in pregnancy
1st trimester = propylthiouracil
2nd trimester = carbimazole
Hypothyroidism symptoms
~ cold intolerance
~ weight gain
~ constipation
~ bradycardia
~ lethargy
~ muscle cramps
~ slow movements
~ slow thoughts
~ depression
~ hair thinning
Hypothyroidism labs
LOW T4, T3
HIGH TSH
Hypothyroidism tx
Levothyroxine / Liothyronine
Levothyroxine
drug of choice for maintenance
~ doses = question if >200mcg
~ how to take = OM, at least 30mins before breakfast, caffeine-containing liquid or other medication
