Hypothyroidism Flashcards
In general, hypothyroidism is d/t what?
Deficiency of thyroid hormones
What is the MCC worldwide of primary hypothyroidism?
Iodine deficiency
Aside from the MCC, what are some other causes of hypothyroidism?
- Autoimmune Diseases
- Iatrogenic Causes
- Congenital
- Infiltrative Disorders
- Medications
What are the 2 autoimmune diseases that can cause hypothyroidism?
- Hashimoto’s Thyroiditis
- Atrophic Thyroiditis
What are the iatrogenic causes that can cause hypothyroidism?
Tx of Hyperthyroidism
- Iodine Tx, Partial/Total Thyroidectomy
What are the 2 congenital causes that can cause hypothyroidism?
- Absent or Ectopic Thyroid Gland
- TSH-R mutation
What are the 4 infiltrative disorders that can cause hypothyroidism?
- Amyloidosis
- Sarcoidosis
- Hemochromatosis
- Scleroderma
What are the medications that can cause hypothyroidism?
- Iodine Excess
- Lithium
- Antithyroid
- Interferon-a
- Amiodarone
High iodine intake may increase the risk of what?
Autoimmune hypothyroidism by immunologic effects or direct thyroid toxicity
Secondary causes of hypothyroidism is d/t what deficiency?
TSH
What are 4 examples of secondary causes of hypothyroidism?
- Injury to the pituitary gland
- Tumor
- Pituitary surgery
- Irradiation
Tertiary causes of hypothyroidism is d/t what deficiency?
TRH
What are 4 examples of tertiary causes of hypothyroidism?
- Disorders that injure the hypothalamus
- Tumor
- Trauma
- Infiltrative disorders
What are some sxs of hypothyroidism?
MOMS SO TIRED
- Memory loss
- Obesity w/poor appetite
- Menorrhagia
- Slowness (mentally and physically-constipation)
- Skin and hair dryness
- Onset gradual
- Tiredness
- Intolerance to cold
- Raised BP
- Energy levels fall
- Depression/Delayed relaxation of reflexes
What are the primary and secondary lab findings for hypothyroidism?
Primary: ↑TSH, ↓TH (T4 = dx)
Secondary:↓-normal TSH, ↓TH (T4 = dx)
Secondary and tertiary cannot be monitored using what lab study?
TSH
Hypothyroidism can be caused by an autoimmune disease and can possibly be associated with what?
Goiter
What does the term “Goiter” mean?
Enlargement of the thyroid gland
In later stages of the autoimmune disease, minimal residual thyroid tissue is known as what?
Atrophic Thyroiditis
D/t an autoimmune process what occurs to the thyroid function?
Gradual reduction
What occurs during the state called Subclinical Hypothyroidism?
There is a phase of compensation when normal TH levels are maintained by a rise of TSH
What occurs later in the subclinical hypothyroidism phase?
Unbound T4 levels fall and TSH levels rise further
At what stage do sxs become apparent in a pt with hypothyroidism d/t autoimmune disease?
Clinical Hypothyroidism or Overt Hypothyroidism
What thyroid antibodies confirm an autoimmune disease?
TPOAb + and/or TgAb+
What is the tx for hypothyroidism in a <60 yo pt w/o evidence of CAD?
Levothyroxine (T4): 50-100 mg daily
What is the tx for hypothyroidism in an elderly pt or a pt known to have CAD?
Levothyroxine 12.5-25 mg daily
- Should adjust in 12.5-25 mg increments q 6-8 wks.
(based on TSH Level)
What is the tx for hypothyroidism in a pt who is pregnant?
Usually Replacement Dose Increased 30-50% During Pregnancy
