Hypothyroidism test results
- High TSH, low free T3 and low free T4
- Free T3 usually not necessary
Hyperthyroidism test results
- Low TSH, high free T3 and high free T4
- Someone can have a high TSH when in the hospital or sick, don't test then.
- From thyroid destruction from Hashimotos or sarcoidosis (makes it granulomatous)
- Can also be caused by trx with lithium (for bipolar), interferon alpha
Secondary (central or hypothyrotropic) hypothyroidism
From deficient TSH secretion, generally due to lesions or tumors on pituitary
Signs of hypothyroidism
- slow thinking
- thinning hair/hair loss
- dry skin
- weight gain/low appetite
- cold intolderance
- enlarged thyroid
- slow HR
- menstrual irregularity/infertility/fetal retardation
- **Can also make cholesterol high**
Trx of hypothyroidism
- Thyroid hormone replacement therapy
- 1. levothyroxine (synthroid) - any food/antacid will bind this up. T4 replacement. 1/2 life - 6 days. Can lead to MI. Don't substitute, use brand name.
- 2. Liothyronine (Cytomel) - more potent w. much shorter 1/2 life. Inc. cardiotoxicity.
- 3. T4/T3 preparations (Euthroid) - benefit is questionable, usually feel worse later. Overtreatment with T3 can lead to osteoporosis & Afibb.
- Wait 6 weeks to get more readings, that's how long it takes to even out thyroid levels.
- difficulty sleeping
- frequent bowel movements
- heat intolerance
- **usually starts earlier than hypo**
Single most important test is TSH, if that's abnormal, get a free T4
Grave's disease (toxic diffuse goiter) - Thiourea drugs (methimazole & propylthiouracil)
- MOA: Inhibit peroxidase-catalyzed steps in thyroid synthesis. Short half life & takes 4-8 weeks for therapeutic effects.
- Can induce remission or be used before surgery to help w/ symptoms.
- Can cause severe agranulocytosis, hepatits, lupus-like syndrome. PTU has higher incidence of side-effects
- "quick-fix" for someone in thyroid storm or who is getting surgery
- MOA: treats symptoms (palpitations etc)
- Inhibit release of thyroid hormone from gland
- Can be used as adjunctive trx. for pts in thyroid storm or awaiting surgery.
- Can get skin rashes, hypersensitivity rxn. Give this with methimazole so they don't wind up overly hyperthyroid.
- Helps in some, makes others worse
Radioactive iodine - sodium iodide 131
- Everythin on you is radioactive for a week. Can't be near small children during that time.
- Can precipitate thyroid storm.
- Absolute contraindication in pregnancy
Thyroid nodular disease
Common in population, one of the indications for getting a free T3 as that can be elavated before the T4. If T3 is elavated, could be in indication that pt. is getting Graves disease or toxic nodules. Most nodules are benign, only 5% are malignant.
Can be toxic or nontoxic. Toxic common in elderly. Toxic means that it's producing thyroid hormone & can cause symptomatic hyperthyroidism.
papillary most common - benign & won't move
- Life-threatening condition that results from untreated hyperthyroidism. Usually occurs during times of stress - trauma or infection.
- Signs/symptoms - Tachycardia, shaking, sweating, change in consciousness, HTN, agitation, confusion, diarrhea, fever.
- Leads to CHF and pulmonary edema very quickly.