Toxic nodular goiter Flashcards
is TNG the most common cause of hyperthyroidism?
no, -it is 15-30% of hyperthyroid in US (2nd to grave’s)
`
In poor iodine diet areas, TNG is responsible for what percentage of hyperthyroidism
58%
What is the most common cause of hyperthyroidism in elderly and low dietary iodine
Toxic Nodular Goiter
is TNG more common in males or females?
females
F>M F5-7%, M1-2%
usual age of TNG diagnosis
Most >50 years old- lot of time has to do with mutation rate. You can have benign nodules and then overtime they can mutate and become functional- so in older age it can happen
Thyrotoxicosis occurs often after longstanding asymptomatic goiter once nodules become autonomous- peaks in what age?
50’s and 60’s
Symptoms of TNG
Can be Asymptomatic
- Hyperthyroid related: Heat intolerance, palpitations, tremor, weight loss, ↑ amount of bowel movements
- Compressive effects: dyspnea, hoarseness, dysphagia, (SVC syndrome- pt will have head edema)
Physical Exam of TNG
- Tachycardia
- Hyperkinesis
- Moist skin
- Tremor
- Proximal muscle weakness- over time can have motor end plate damage which can result in muscle weakness and myopothy
- increased DTRs (deep tendon reflexes)
- Variable size of thyroid gland/nodules- size doesn’t translate with increase in symptoms
- +/-hoarseness, +/-tracheal deviation
- No ophthalmopathy, acropachy, pretibial myxedema! These are only in grave’s.
if there is ophthalmopathy, acropachy, pretibial myxedema, could the patient have Toxic Nodular Goiter?
- No ophthalmopathy, acropachy, pretibial myxedema! These are only in grave’s.
Toxic Nodular Goiter etiology
- Related to iodine insufficiency- especially multinodular goiters, single adenomas tend to be due to mutations.
- Deficiency → low T4- because thyroid needs iodine to produce T4, inducing hyperplasia to compensate
- ↑cell replication increases risk of somatic mutations of TSH receptors, cell clone replication causing nodules
Toxic Nodular Goiter Imaging
Nuclear scintigraphy (iodine uptake imaging)
- Grave’s: homogenous diffuse uptake
- Tyroiditis: low uptake
- TNG: usually patchy uptake
- Can also show substernal extension of the thyroid gland- with uptake imaging you can pick this up
If compressive symptoms: CT, don’t put this off- do this quickly especially if airway compression
would Cold nodules or hot nodules on Nuclear scintigraphy be concerning?
cold nodules
Toxic Nodular Goiter will look like what in Nuclear scintigraphy?
very patchy because nodules in different places
Why are cold nodules on Nuclear scintigraphy concerning?
sign of malignancy
would you do fine needle aspiration on a hot nodule?
FNA not usually needed for “HOT” nodule (autonomously functioning nodule)- risk is low malignancy
would you do fine needle aspiration on a cold nodule?
yes
TNG treatment
Surgery or Radioactive iodine-requires definitive treatment
if pt has compressive symptoms then need to do _______.
surgery
Complications from Radioactive Iodine
- Less occurrence of Hypothyroidism than Grave’s: only 10-20%
- Could get radiation induced thyroiditis (rare)
- Thyroid storm, very rare (from rapidly enlarging goiter)- pretreat with antithyroids
- Role of anti-thyroids/BB: short courses to get patient euthyroid before radiation/surgery, after radiation while thyrotoxic until full response from radiation
- not as immediate of a response as surgery, takes a little time
Indications for surgery in toxic nodular goiter
o Young o Large nodules o Compressive symptoms o Non-functioning/suspicious nodules o Pregnant o Radiation failure - Total or near total cure 90% (rapid relief) - Recurrence less likely than in subtotal- total thyroidectomy will have less recurrence rate than subtotal.
Surgery Complications in toxic nodular goiter
- Hypothyroid
- Vocal cord paralysis
- Hypoparathyroidism
- Post op bleed- every surgery has this risk
- Infection- every surgery has this risk
toxic nodular goiter patient care information
- Radiation may take 10 weeks to achieve clinical response
- Levothyroxine started after thyroidectomy , re-evalaluation after 4-6 weeks. (Subtotal thyroidectomy doesn’t necessarily need it)
- Subclinical hyperthyroid checked biochemically every 6 months- go through ROS to make sure there isn’t any thyroid symptoms
toxic nodular goiter prognosis
- Treated= good
- Untreated=much worse
- Leads to Osteoporosis, dysrhythmias, HF, death
In toxic nodular goiter, autonomously functioning thyroid nodules result in ______.
hyperthyroidism
Toxic Nodular Goiter Labs
TSH low, T4/T3 elevated (similar to graves- but can run autoantibodies to graves and can tell difference between the two)
- If isolated T4 elevation- could be due to medications that reduce conversion of T4 to T3: propranolol, corticosteroids, radiocontrast, amiodarone)- remember T4 is precursor to T3
- Subclinical hyperthyroidism: low TSH, normal T4/T3 levels= pts are typically asymptomatic
what is a toxic nodular goiter?
a single hyper functioning nodule (toxic adenoma) within a multi nodular thyroid to multiple areas of hyperfunctiom
when is a TNG toxic?
if It is hyperfunctioning
autonomously functioning thyroid nodules result in ____.
hyperthyroidism
when does tang CAUSE THYROTOXICOSIS?
TSH receptors mutate and become hyperactive and thus cause thyrotoxicosis
