Thyroid Flashcards
Side effects include: Rash Agranulocytosis Cholestasis Fulminant liver failure
PTU
–> use only in pregnancy d/t liver SE, Methimazole teratogenic effects
Side effects include: Rash Agranulocytosis Cholestasis Teratogenic?
Methimazole
May cause iodine-induced thryoiditis or worsening proptosis
I-131
Diseases leading to excess thyroid hormone state
Graves’ disease (overproduction + oversecretion)
Nodular thyroid disease (overproduction + oversecretion)
Thyroiditis (oversecretion due to inflammation)
Pituitary tumor (overproduction)
Ectopic production (i.e. ovary)
Symptoms of decreased metabolic activity
Fatigue, weakness Cognitive dysfunction Cold intolerance Weight gain Constipation
Increased free T4 may be of these two origins
Pituitary or Thyroid
How do you distinguish?
Check TSH! (high = pituitary, low = thyroid)
What is the disease course of thyroiditis?
Initial hyperthyroid phase
Hypothyroid phase
Spontaneous recovery back to normal
What is the composition of thyroid nodules?
Most are benign
Of malignant, most are well-differentiated cancers (papillary or follicular)
High FT4 + High TSH –>
Pituitary hyperthyroidism
–> most likely tumor
How do you diagnose hypothyroidism?
Check TSH and FT4
Low FT4 + High TSH = thyroid origin (history)
Low FT4 + Low TSH = pituitary origin (–> MRI)
What disease would you suspect in a patient with onycholysis (soft nails), goiter/nodules, thinning hair, hypertension, menstrual irregularity, tremors, anxiety, hyperreflexia, palpitations?
Hyperthyroidism
High FT4 + Low TSH –>
Thyroid origin hyperthyroidism
Follow-up with I-131 uptake
- -> diffuce decreased = thyroiditis (may test ESR)
- -> diffuse increased = Graves (may test TSI abs)
- -> localized increased = nodule (may get scan)
What does the thyroid gland primarily produce?
T4
T4 converted to T3 in target tissues/organs
What mechanism has symptoms like heat intolerance, excessive sweating, weight loss, hyperphagia, hyperdefecation and warm, moist palms?
Increased metabolic activity
–> think Hyperthyroidism
Symptoms of glycosaminoglycan accumulation
dry skin
hoarseness
edema
paresthesia
Low FT4 + Low TSH –>
Secondary hypothyroidism
may be pituitary or hypothalamic
If a thyroid nodule is overactive, it is _____ likely to be malignant.
less likely –> FNA not necessary
How do you medically treat Graves’ and nodular hyperthyroidism?
Methimazole or PTU
- -> inhibit synthesis of thyroid hormone
- -> can cause rash, agranulocytosis, cholestasis
Low FT4 + High TSH –>
Primary hypothyroidism
may be surgical or Hashimoto’s thyroiditis (high TPO)
What do you use to replace thyroid gland hormone?
T4 - levothyroxine
What mechanism has symptoms like palpitations, tremors, anxiety, irritability, sleep disturbance, tachycardia, atrial fibrillation, lid lag, hyperreflexia?
Sympathetic overactivity
–> think Hyperthyroidism
If thyroid nodule + low TSH, how do you follow-up?
Radionuclide scan
Presents with symptoms of increased metabolic activity and sympathetic overactivity
Hyperthyroidism
How do you treat thyroiditis?
Beta blockade
What are all treatments for forms of hyperthyroidism?
Beta blockade (thyroiditis)
Methimazole, PTU
I-131 –> hypothyroidism
Thyroidectomy/lobectomy
What is the goal of treatment for primary (thyroid origin) hypothyroidism?
Normal TSH
How do you test for hyperthyroidism?
Check TSH and FT4
These medications may impair the thyroid gland
lithium, amiodarone, thionamides
Potential causes of decreased thyroid hormone state
Autoimmune thyroid failure (Hashimoto’s, chronic lymphocytic)
Surgical/radiologic destruction
Hypothyroid phase of thyroiditis
Medicinal impairment of thyroid
Pituitary or hypothalamic disease that decreases TSH production (tumor)
What is the goal of treatment in secondary (pituitary origin) hypothyroidism?
Normal FT4 (TSH will always be low in this case)
What are side effects of over-replacement of thyroid hormone?
atrial fibrillation, accelerated bone loss
