Be familiar with the interactive activities throughout course modules. You could see
variations of those same questions on your exams.
Week 5
Thyroid
o Diagnosis & Evaluation
What labs are used to diagnose?
- Serum TSH levels = most sensitive for detecting hypothyroidism
- TSH level > 6 is indicative of hypothyroidism
- 0.3-6 is normal TSH level
- Measuring total or free T4 (free T4 is preferred)
Timeframe for re-check of labs after starting levothyroxine
- Need to recheck TSH levels 6-8 weeks after initiating therapy AND
at any dosage change
- Need to monitor therapeutic effects and takes 1 month to establish
plasma levels
Signs and symptoms of hypo and hyperthyroidism
- HYPOTHYROIDISM
- Can be caused by sx removal of thyroid
- Insufficient iodine in diet
- Autoimmune – Hashimoto’s dx
- Tx is lifelong
- T3 and T4 levels going to be low and TSH will be high
o Puffy and pale face
o Cold/dry skin
o Brittle hair
o Hair loss
o HR and temp lowered (bradycardia)
o Lethargy and fatigue
o Intolerance to cold
o Weight gain
o Constipation
o Depression
- HYPERTHRYOIDISM
o Graves’ disease or toxic nodular goiter (plummer dz)
Overactive thyroid
Excessive thyroid secretion due to autoimmune
process attacking thyroid
o TSH levels going to be low and T3/T4 going to be high
o Rapid/ strong HR
o Increased risk of dysrhythmias
o Nervousness
,NR565 Final Study Guide
o Insomnia
o Rapid speech
o Weakened muscles/atrophy
o Increase body temp
o Intolerance to heat
o Increased appetite
o Diarrhea
o Exomphalos can occur = bulging eyes
Dry eye can occur
o Treatment
Treatment of thyroid storm – excessive levels of thyroid hormone
- Pt. experiences:
o Hyperthermia
o Severe tachycardia
o Restlessness / agitation
o Tremors
** can lead to coma and death AND hypotension which can lead to heart failure
- Can occur when undergoing surgery or with major illness
- Pt. is given high dose of potassium iodide to suppress TH release
- Methimazole (tapazole) given to suppress TH synthesis
- BB given to reduce HR
- May also initiative IV fluids, cooling, sedation, corticosteroids
Result of not treating hypothyroidism during pregnancy
- May cause permanent neuropsychological deficits
- Can reduce child IQ
- Dose of thyroid medication needs to be increased by about 50%
especially in 1st trimester
Medication to treat symptoms of hyperthyroidism (notice this is
treating symptoms and not the hyperthyroidism itself)
- Methimazole = first line drug for tx of the disease
o Block TH synthesis
o Prevents oxidation of iodide
o Toxicity = agranulocytosis (sore throat and fever)
Need to monitor CBC for WBC count for infection
Need LFT for hepatic function
o Not indicated for pregnancy. Would use PTU instead
o Tx will last 1-2 years
- Surgery to remove thyroid
- Radioactive iodine
- BB to reduce HR
Drug/Food/Supplement interactions with levothyroxine
** these medications reduce the absorption of levothyroxine
, NR565 Final Study Guide
- Histamine 2 receptor blockers
- PPI
- Sucralfate
- Cholestyramine
- Colestipol
- Aluminum containing antacids
- Calcium supplements
- Iron supplements
- Magnesium salts
- Orlistat
** these medications accelerate levothyroxine metabolism
- Phenytoin
- Carbamazepine
- Sertraline
- Rifampin
- Catecholamines
- ** insulin digoxin, and warfarin may need to be increased if pt.
takes these
Synthroid dose
o 100 – 125 mcg in adults
o 25- 50 mcg in older adults because of slower metabolism by liver
Elderly can experience palpitations with Synthroid
o Medication should be taken on an empty stomach, 30 minutes before a meal and
in the morning
Taking at nighttime can keep patients awake
o May develop thyroid toxicosis from Synthroid
Tachycardia
Angina
Tremors
Nervousness
Insomnia
Sweating
Heat intolerance
Diabetes
o How to confirm a diagnosis prior to beginning treatment
- Fasting plasma glucose > or equal to 126
- Random plasma glucose > or equal to 200 PLUS symptoms of
diabetes
- Oral glucose tolerance test: 2-h plasma glucose > or equal to 200
** patient must be tested on two separate days and a combo of
either test can confirm diagnosis if they are BOTH positive
- A1C 6.5% or higher
- Pre-diabetes is 5.7% - 6.4%