Thyroid Pt 3 - Hypothyroid

Question 1

___ T3 T4

___ TSH (primary)

___ free T4

Answer 1

↓

↑

↓

Question 2

A deficiency of thyroid hormone resulting in decreased basal metabolic rate

5x more in women than men; a chronic condition

Question 3

Etiology

• Thyroidectomy
• Drug therapy
• Radiation-induced therapy
• Autoimmune
• Endemic iodine deficiency
• Excessive exposure to iodine
• Thyroid cancer
• Congenital

Question 4

Thyroiditis

• Acute
• Subacute
• Chronic

Question 5

___ Thyroiditis: Bacterial Infection

• Pain, edema, neck
• Fever
• Dysphagia
• Usually resolves w/abx therapy

Answer 5

Acute

Question 6

___ (chronic hypothyroidism condition)

• Autoimmune - viral trigger
• Thyroid tissue destruction
• Painless goiter
• Treated w/thyroid replacement hormone

Answer 6

Hashimoto’s disease

Question 7

___ Thyroiditis: (granulomatous) viral infection

• Usually follows a cold or other viral infection
• Fever, chills, body aches
• Dysphagia
• Pain radiating to ear & jaw

Thyroid fxn: hypothyroidism, hyperthyroidism, normal

Answer 7

Subacute

Question 8

Thyroid Cancer

• Hard, irregular nodule
• “Cold” spot - radioactive uptake
• Needle biopsy - confirm diagnosis
• Radiation
• Chemotherapy
• Thyroidectomy

Answer 8

A hallmark sign of thyroid ca is an elevated serum thyroglobulin (Tg) level

Surgery is the treatment of choice for papillary, follicular, & medullary carcinomas

A total thyroidectomy is usually performed, w/a nodal neck dissection if regional lymph nodes are involved

Question 9

Suppressive doses of thyroid hormone are given for 3 mos >surgery; the pt should then be hypothyroid afterwards & will be treated for hypothyroid

Question 10

Manifestations

• Metabolic
• Skin
• Cardiovascular

Answer 10

• Pulmonary
• GI
  > Anorexia = no appetite
• MSK
• Reproductive

Question 11

• Neurologic
• Psychological/emotional

Answer 11

• Other

Low metabolic rate causes metabolites to build up in the cells which causes mucous & water increases, leading to cellular edema & changes in organ texture

The edema is mucinous (myxedema); non-pitting edema forms everywhere esp around the eyes, hands, feet, & between the shoulder blades; the tongue thickens & edema around the larynx may make the voice husky

General physiological functions decrease

Question 12

Nursing Considerations: Hypothyroidism

• Monitor for decreased CO [edema, hypotension, reduced u/o]
• Monitor for myocardial ischemia or infarction
• Alert for angina

! Caution w/analgesics, sedatives, & CNS depressants = effects are prolonged (for older pts = age-related changes in liver & renal function)

Answer 12

• Keep the pt warm
• Skin care
• Assist w/ADLs - fatigue
• Well-balanced diet; fluids & fiber to prevent constipation
• Pt education (life-long therapy)
• Many meds & supplements, esp minerals, can interfere w/the absorption of levothyroxine; teaching is important to take replacement therapy on an empty stomach @ same time each day w/a full glass of water 30 min <breakfast
• Buy the same brand of rx’s

Question 13

Labs at a Glance

Answer 13

Question 14

SOME drugs that can alter thyroid test results

→ estrogens
→ sulfonylureas
→ corticosteroids
→ iodine
→ propranolol
→ cimetidine (Tagamet)
→ 5-fluorouracil
→ phenytoin (Dilantin)

Answer 14

→ heparin
→ chloral hydrate
→ xray contrast media
→ opioids
→ androgens
→ salicylates
→ lithium
→ amiodarone (antiarrhythmic)
→ Clofibrate (lipid-lowering agent)
→ furosemide (Lasix)
→ diazepam (Valium)
→ Danazol (Danocrine; a synthetic steroid)
→ dopamine antagonists
→ Propylthiouracil (PTU)

Question 15

Drug Therapy

• levothyroxine (SYNTHROID)
• liothyronine (Cytomel) [T3]
• thyroxine (T4)
• thyroglobulin (Proloid)

Question 16

Side Effects → STOP THE MED!

! tachycardia, palpitations, CP, HTN
! dysrhythmias, cardiac arrest

Answer 16

Side Effects

• insomnia, HA
• nausea, diarrhea, cramps, increased appetite
• menstrual irregularities
• sweating, heat intolerance, fever

Question 17

Action

• Obtained from thyroid glands of animals or synthetically manufactured
• Exact MoA unknown → influences the way tissues grow & develop & increases metabolic rate
• Replacement therapy

Answer 17

Uses

• Hypothyroidism
• Prep pt for surgery by reducing gland size, e.g., w/simple endemic goiter

Question 18

Side & Toxic Effects

• R/t hyperthyroidism sx’s = tachycardia, excitability, palps
• Acute effect = CP, dyspnea, nervousness, tremor, insomnia, inc BMR, wt loss

Answer 18

• May inc BG & the effects of digitalis glycosides, anticoag agents & indomethacin
• phenytoin (Dilantin) & TCAs may inc effects of thyroid hormone
• Thyroid hormones may also incr pharm effects of digitalis glycosides, anticoag agents, & indomethacin
• Bone loss & osteoporosis may occur

Question 19

Patient Teaching

• Know sx’s of dz alterations & toxicity
• Usually a lifelong drug need
• Diff drug preparations vary in potency
• If pregnancy occurs, notify MD r/t rx use
• Usually take dose before breakfast, same time each day

Answer 19

• Doses of insulin or oral hypoglycemics may need to be adjusted as metabolism rates change

(*) Doses of anticoag’s may need to be dec

• Pulse rate should be monitored & held if >100

Question 20

(*) It’s been known for several decades that increasing thyroid activity either through increased output of the thyroid gland or by administering thyroid hormones increases the anticoagulant response to warfarin & other oral anticoag’s

Question 21

?

! Hypothermia
! Hypotension
! Hyponatremia; hypoglycemia
! Hyperlipidemia; prolonged QT leading to Torsades de Pointes (a polymorphic v-tach)
! Respiratory drive depressed; hypoventilation
! CO2 retention; narcosis
! Coma, death

Answer 21

Myxedema coma

Question 22

Best Practices - Myxedema Coma

• Maintain airway
• Give levothyroxine IV as ordered
• Replace fluids/hypertonic
• Give IV glucose
• Give corticosteroid(s)
• Aspiration precautions

Answer 22

• Check temp hourly
• Monitor BP hourly
• Monitor BG lvls
• Warm blankets
• Monitor for changes in mental status
• Reposition q2h