Module 6 (b) Flashcards
(38 cards)
Hypothyroidism
-Definition
- Hypothyroidism is a condition resulting from the synthesis of thyroid hormone that is INSUFFICIENT to meet the body’s needs
Supply is less than demand
Hypothyroidism
-Stats
- Most common disorder of the thyroid gland
- Chronic autoimmune thyroiditis is the MOST COMMON cause
- SLOWING down of many bodily functions and metabolic processes - 5-8x more prevalent in women than men
- Compromises almost all body functions
Hypothyroidism
-Undiagnosed complications
- Infertility
- Hashimoto encephalopathy
- Myxedema coma
Types & Causes of Hypothyroidism
-Congenital Hypothyroidism
Occurs in Infancy or childhood
1. Developmental abnormality of the thyroid gland
Individuals w/ Congenital hypothyroidism can experience
- Developmental delays
- Mental retardation (Cretinism)
Types & Causes of Hypothyroidism
-Cretinism
A resulting mental retardation that occurs w/ congenital hypothyroidism
Types & Causes of Hypothyroidism
-Central Hypothyroidism
- Secondary Hypothyroidism
- Failure of pituitary gland to secrete adequate amounts of TSH - Tertiary Hypothyroidism
- Inadequate secretion of TRH by the hypothalamus
Types & Causes of Hypothyroidism
-Secondary Hypothyroidism?
- Failure of pituitary gland to secrete adequate amounts of TSH
Types & Causes of Hypothyroidism
-Tertiary Hypothyroidism
- Inadequate secretion of TRH by the hypothalamus
Types & Causes of Hypothyroidism
-Iatrogenic Hypothyroidism
- Occurs after treatment with radioactive iodine or surgery
- Accounts for 30-40% of cases
- Can be caused by following meds:
- Amiodarone, lithium, interferon-a, thalidomide
Types & Causes of Hypothyroidism
-Transient Hypothyroidism
Occurs after treatment w/ radioactive iodine or after surgery for hyperthyroidism
2nd most common cause
- Postpartum thyroiditis
- Subacute thyroiditis (Usually viral)
- Withdrawal of thyroid hormone therapy
Iodine deficiency is the MOST COMMON cause of thyroid disorders worldwide
Primary Cause of Thyroid Dz?
- Autoimmune processes are primary cause of thyroid dz
Types & Causes of Hypothyroidism
-Subclinical Hypothyroidism (SCH)
- Presence of NORMAL serum free T4, with ELEVATED TSH
- Untreated SCH can lead to
- CVD, Dyslipidemia, liver dz, neuropsychiatric symptoms, infertility - Detected through Lab test**
- Most Frequent reported symptoms
- Muscle cramps, tiredness, feeling colder, slowness of thinking, constipation - Repeat testing in 2-3 months prior to treatment **
Treat after Dx is made
Types & Causes of Hypothyroidism
-Subclinical Hypothyroidism Common Reported Symptoms
- Memory impairment (Slowness of thinking)
- Tiredness
- Feeling colder
- Hoarseness
- Constipation
- Dry skin
Types & Causes of Hypothyroidism
-Management of Subclinical Hypothyroidism
Once SCH dx is made, sort pt by age, TSH level, and presence of symptoms
- Treat if patients
- TSH levels >/= 10 mU/L
- TSH levels >/=7 to <9, <70 yrs old, symptomatic - Treatment is Levothyroxine 25-50 mcg daily
- Evaluate serum TSH 6 wks after initiation of therapy
Types & Causes of Hypothyroidism
-Causes of SCH
- Autoimmune disease
- Smoking
- Thyroid injury (radiation therapy)
- Inadequate replacement therapy
- Drugs imparting thyroid function
Types & Causes of Hypothyroidism
-Hashimoto’s Thyroiditis (Chronic Autoimmune Thyroiditis)
- MOST COMMON cause of hypothyroidism in the US
- Autoimmune disorder
- Patho = Genetic susceptibility & Environmental factors
- Middle age women (30-60 yrs) but can occur in all populations
Types & Causes of Hypothyroidism
-Diagnosis of Hashimoto’s Thyroiditis
- Symptoms of hypothyroidism
- Presence of a goiter on PE
- Lab testing
- Elevated TSH
- Low levels of Free T4
Family Hx usually present
Types & Causes of Hypothyroidism
-Symptoms of Hashimoto’s Thyroiditis
No s/s that are unique to Hashimoto’s thyroiditis
-Fatigue, weight gain, sensitivity to cold, dry skin
-Irregular and heavy menses
-Enlarged Thyroid (GOITER) may cause
—Neck discomfort and difficulty swallowing
Types & Causes of Hypothyroidism
-Treatment of Hashimoto’s Thyroiditis
- MILD (slight elevation of TSH)
- No medication and repeat testing in 3-4 months - Overt Hypothyroid (elevated TSH & low thyroid hormone)
- Levothyroxine 50 mcg/daily
- adjust dose until normal TSH level achieved - Test TSH every 6-8 wks after dose adjustment then annually
LIFELONG TREATMENT
Hypothyroidism
-Clinical Presentation
- Fatigue is the MOST COMMON presenting symptom
- Cold Intolerance & weight gain
- Decreased deep tendon reflexes
Hypothyroidism
-Diagnosis
- TSH is the most appropriate first diagnostic test
2. In clinical arena, check both TSH and serum free T4
Hypothyroidism
-Differential Dx
- Chronic autoimmune thyroiditis
- Postpartum Thyroiditis
- Radiation-induced thyroid damage
- Post-infectious thyroiditis
- Med-induced hypothyroidism; post Thyroidectomy dysfunction
- Depression **
- Pituitary tumor
Hypothyroidism
-Management
- Normalize TSH not suppress it **
2. Levothyroxine is drug of choice (A synthetic preparation of T4)
Hypothyroidism
-Primary hypothyroidism treatment algorithm (Levothyroxine)
- Initial Levothyroxine dose influenced by ideal or actual body weight & health status
- May begin status (1.7mcg/kg/d)
- May begin at 50 mcg/day
- Increase dose at 4-6 wk intervals to 100 mcg/day - At euthyroid state, monitor TSH once or twice yearly