Hypothyroidism Flashcards
Define hypothyroidism
it is a common condition
it is the deficiency of T4 and T3
Epidemiology of hypothyroidism
6F:1M
If treated prognosis is excellent, if not disastorous
you and your patient must be wary changes might be subtle so be careful with >40yr and female
Causes of hypothyroidism
Many
Autoimmune disease - Hashimoto’s thyroiditis
Thyroid failure after radioiodine therapy or surgical subtotal thyroidectomy account for 90% of causes in regions without iodine deficiency
Other causes
2ndry hypothyroidism
pituitary adenoma
carbimazole
Symptoms of hypothyroidism
common
Weight gain Cold intolerance - cold disliking Fatigue, somnolence (sleeplissness) Dry skin Dry hair Menorrhagia
Less common
Constipation
Alopecia
Depression
Signs of hypothyroidism
Weight gain
cold skin
dry skin
thinning of hair - loss of lateral eyebrow
bradycardia
delayed reflexes
Investigating hypothyroidism
TSH is high
T4 is low, T3 not sensitive shldnt be measured
Thyroid peroxidase antibodies
lipid profile - raised
FBC: anaemia and increased MCV
ECG: sinus bradycardia
What is subclinical hypothyroidism
When TSH is high but T4 is normal
2ndy hypothyroidism TFT results
TSH low
T4 low
and clinical picture will be vague
this can happen with no thyroid disease, Pts on steroids and anticonvulsants
Medical management of hypothyroidism
Most patients will require lifelong therapy with Levothyroxine
Start small and titrate up
Problems with levothyroxine
40% angina patients cant take it - risk of MI and death
Pregnancy - need increased dose
What is a myxoedema coma
very rare
4 Hys
hypothermia
hypotensive
hypoxia
hypercapnia - raised CO2
HF
