Hypothyroidism
Comprehensive Nursing Notes
Introduction
Hypothyroidism is a clinical condition characterized by insufficient production of thyroid hormones (T3 and T4) by the thyroid gland, resulting in a hypometabolic state affecting multiple body systems.
Hypothyroidism is one of the most common endocrine disorders, affecting approximately 4.6% of the U.S. population, with higher prevalence in women and older adults. As nursing professionals, understanding this condition is vital for providing comprehensive care to affected individuals.
Pathophysiology
Normal Thyroid Function
- The hypothalamus produces Thyrotropin-Releasing Hormone (TRH)
- TRH stimulates the anterior pituitary to release Thyroid-Stimulating Hormone (TSH)
- TSH stimulates the thyroid gland to produce and release the thyroid hormones: triiodothyronine (T3) and thyroxine (T4)
- Thyroid hormones regulate metabolism, growth, development, and body temperature
Disruption in Hypothyroidism
In hypothyroidism, this process is disrupted at one of several possible levels:
| Type | Description | Common Causes |
|---|---|---|
| Primary | Disorder in the thyroid gland itself (most common, ~95% of cases) | Autoimmune thyroiditis (Hashimoto’s), iodine deficiency, post-thyroidectomy, radiation therapy |
| Secondary | Failure of the pituitary gland to produce adequate TSH | Pituitary tumors, pituitary surgery, Sheehan syndrome |
| Tertiary | Failure of the hypothalamus to produce TRH | Hypothalamic disorders, brain injury, tumors affecting the hypothalamus |
Key Pathophysiological Changes
- Decreased metabolic rate and oxygen consumption
- Reduced heat production leading to cold intolerance
- Decreased sympathetic nervous system activity
- Reduced carbohydrate metabolism and glucose utilization
- Decreased protein synthesis and turnover
- Increased deposition of mucopolysaccharides in tissues (myxedema)
Clinical Manifestations
SLOW METABOLISM Mnemonic for Hypothyroidism
S – Slow thinking, speech, and movements
L – Lethargy and fatigue
O – Obesity or weight gain
W – Weakness and muscle cramps
M – Myxedema (facial puffiness)
E – Edema (especially periorbital)
T – Temperature intolerance (cold)
A – Altered menstruation (menorrhagia)
B – Bradycardia
O – Obstipation (constipation)
L – Low reflexes
I – Increased cholesterol
S – Skin changes (dry, coarse, cold)
M – Memory impairment
System-Based Manifestations
Metabolic Effects
- Decreased basal metabolic rate
- Weight gain despite decreased appetite
- Cold intolerance
- Decreased perspiration
Dermatological Changes
- Dry, coarse, pale, cold skin
- Brittle nails
- Coarse, brittle hair with increased hair loss
- Loss of outer third of eyebrows (Queen Anne’s sign)
- Facial puffiness, especially periorbital
Cardiovascular Effects
- Bradycardia
- Decreased cardiac output
- Hyperlipidemia (increased risk of atherosclerosis)
- Hypertension (especially diastolic)
- Pericardial effusion (in severe cases)
Neurological Manifestations
- Lethargy and fatigue
- Memory impairment and poor concentration
- Delayed reflexes (especially Achilles tendon reflex)
- Paresthesias (especially carpal tunnel syndrome)
- Depression
Gastrointestinal Effects
- Constipation
- Decreased appetite
- Abdominal distention
- Reduced gastric acid secretion
Reproductive System Changes
- Females: Menorrhagia, anovulation, decreased libido, infertility
- Males: Decreased libido, erectile dysfunction, reduced sperm count
Warning Sign: Myxedema Coma
A rare but life-threatening complication of severe untreated hypothyroidism characterized by:
- Profound hypothermia
- Altered mental status or coma
- Respiratory depression
- Hypotension
- Hypoglycemia
- Hyponatremia
Note: Myxedema coma is a medical emergency with a high mortality rate requiring immediate intervention.
Diagnostic Evaluation
Laboratory Tests
| Test | Findings in Hypothyroidism | Significance |
|---|---|---|
| TSH (Thyroid Stimulating Hormone) | Elevated (in primary hypothyroidism) | Primary screening test; most sensitive indicator |
| Free T4 (Thyroxine) | Decreased | Confirms diagnosis when TSH is elevated |
| Free T3 (Triiodothyronine) | Normal or decreased | Less reliable; may be normal in early hypothyroidism |
| Anti-thyroid antibodies | Elevated in autoimmune thyroiditis | Anti-TPO and anti-thyroglobulin indicate Hashimoto’s thyroiditis |
| Total cholesterol & LDL | Elevated | Secondary to decreased metabolism of lipids |
| CPK (Creatine Phosphokinase) | May be elevated | Indicates muscle involvement |
| CBC | Normocytic anemia | Common finding in hypothyroidism |
Imaging Studies
- Thyroid Ultrasound: May show decreased vascularity, heterogeneous echo texture in Hashimoto’s thyroiditis
- Radioactive Iodine Uptake (RAIU): Reduced uptake in primary hypothyroidism
- Thyroid Scan: To evaluate nodules or structural abnormalities
Additional Assessments
- ECG: May show bradycardia, low voltage, flattened or inverted T waves
- Basal Body Temperature: Often decreased in hypothyroidism
- Achilles Reflex Testing: Delayed relaxation phase (Woltman’s sign)
Types of Hypothyroidism Based on TSH and T4 Levels
- Overt Primary Hypothyroidism: Elevated TSH, decreased Free T4
- Subclinical Hypothyroidism: Elevated TSH, normal Free T4
- Secondary (Central) Hypothyroidism: Low or inappropriately normal TSH, decreased Free T4
Medical Management
Pharmacological Management
Levothyroxine (T4) Therapy
The cornerstone of hypothyroidism treatment is hormone replacement with synthetic levothyroxine (T4).
- Initial Dosing: Based on weight, age, cardiovascular status, and duration/severity of hypothyroidism
- Standard Starting Dose: 1.6 mcg/kg/day for healthy adults; lower for elderly or those with cardiac disease (25-50 mcg/day)
- Administration: Taken once daily on an empty stomach, 30-60 minutes before breakfast or 4 hours after last food intake
- Monitoring: TSH levels checked 6-8 weeks after initiating therapy or changing dose
- Goal: Normalize TSH levels (typically 0.5-4.5 mIU/L) and resolve symptoms
Factors Affecting Levothyroxine Absorption
- Medications: Calcium supplements, iron supplements, proton pump inhibitors, sucralfate, bile acid sequestrants, phosphate binders
- Foods: Dietary fiber, soy products, coffee
- Medical conditions: Celiac disease, H. pylori infection, atrophic gastritis
Patients should maintain consistent timing between levothyroxine intake and these substances to avoid fluctuations in hormone levels.
Alternative Thyroid Formulations
- Liothyronine (T3): Occasionally used in combination with levothyroxine; has shorter half-life and more rapid onset
- Desiccated Thyroid Extract: Animal-derived product containing both T3 and T4; less predictable and generally not recommended as first-line therapy
Special Considerations
- Pregnancy: Increased levothyroxine requirements (by approximately 30-50%); TSH goal < 2.5 mIU/L in first trimester
- Elderly: Lower initial doses with gradual titration to avoid precipitating cardiac events
- Cardiac Disease: Start with low doses (12.5-25 mcg) and increase slowly every 4-6 weeks
- Myxedema Coma: IV levothyroxine and supportive care in ICU setting
Treatment Monitoring
- Initial Phase: TSH every 6-8 weeks until stable
- Maintenance Phase: TSH annually once stable, or sooner if symptoms return
- Clinical Monitoring: Symptom resolution, vital signs, weight
Nursing Management
Nursing Assessment
Comprehensive Assessment
- Vital Signs: Bradycardia, hypothermia, hypertension
- Weight: Recent weight gain despite normal or decreased appetite
- Skin: Dryness, coarseness, pallor, coldness, edema (especially periorbital)
- Hair and Nails: Brittle hair/nails, hair loss, thinning of outer eyebrows
- Neurological: Delayed deep tendon reflexes, paresthesias, cognitive status
- Cardiovascular: Heart rate, rhythm, signs of heart failure
- Respiratory: Rate, depth, effort (assess for respiratory depression in severe cases)
- Gastrointestinal: Bowel sounds, abdominal distention, constipation
- Musculoskeletal: Muscle strength, cramping, joint pain
- Psychosocial: Energy level, mood, cognition, social functioning
Nursing Diagnoses
Decreased Cardiac Output
Related to: Bradycardia and decreased myocardial contractility secondary to hypothyroidism
Interventions:
- Monitor vital signs, especially heart rate and blood pressure
- Assess for signs of heart failure (dyspnea, edema, fatigue)
- Position patient to maximize cardiac output (semi-Fowler’s)
- Administer thyroid replacement therapy as prescribed
- Monitor response to therapy with daily weight and fluid balance
Hypothermia
Related to: Decreased metabolic rate and heat production
Interventions:
- Monitor body temperature regularly
- Provide additional warmth (blankets, warm room)
- Administer warm fluids and food
- Avoid cold environments
- Encourage layered clothing to maintain warmth
Constipation
Related to: Decreased gastrointestinal motility secondary to hypothyroidism
Interventions:
- Assess bowel patterns and characteristics
- Encourage adequate fluid intake (2-3 liters daily if not contraindicated)
- Promote high-fiber diet as tolerated
- Encourage physical activity as tolerated
- Administer stool softeners or laxatives as prescribed
- Teach abdominal massage techniques
Fatigue
Related to: Decreased metabolic rate and energy production
Interventions:
- Assess energy levels and patterns of fatigue
- Plan care activities to allow for rest periods
- Assist with activities of daily living as needed
- Encourage energy conservation techniques
- Prioritize activities based on patient’s energy levels
- Monitor for improvement in energy levels with thyroid replacement therapy
Impaired Skin Integrity
Related to: Dry skin and decreased tissue perfusion
Interventions:
- Assess skin condition daily
- Implement gentle cleansing with mild soap and tepid water
- Apply moisturizers frequently (avoid alcohol-based products)
- Maintain adequate hydration
- Reposition frequently if mobility is decreased
- Protect skin from pressure, friction, and shear
Deficient Knowledge
Related to: Unfamiliarity with the chronic nature of hypothyroidism and its management
Interventions:
- Assess current knowledge level regarding hypothyroidism
- Provide education about the disease process, treatment, and self-management
- Teach proper medication administration (timing, interactions)
- Explain importance of lifelong therapy and regular follow-up
- Provide written materials to reinforce teaching
- Assess understanding through teach-back method
Medication Management
Nursing Responsibilities for Thyroid Replacement Therapy
- Administration: Ensure levothyroxine is taken on an empty stomach, 30-60 minutes before breakfast or 4 hours after last meal
- Medication Interactions: Educate about spacing with calcium, iron, antacids (at least 4 hours apart)
- Monitoring: Assess vital signs before administration, especially in patients with cardiac disease
- Signs of Overtreatment: Monitor for tachycardia, palpitations, nervousness, insomnia, tremors, weight loss
- Consistency: Emphasize importance of taking medication at the same time each day
- Brand Consistency: Advise patients to stay with the same brand of levothyroxine when possible
Patient Education
Essential Teaching Points
- Medication Adherence: Emphasize lifelong nature of therapy and importance of daily medication
- Monitoring: Teach self-monitoring of pulse and symptoms; when to contact healthcare provider
- Follow-up: Stress importance of regular lab tests and provider visits
- Nutrition: Balanced diet with adequate fiber; consistent iodine intake (if not contraindicated)
- Activity: Gradual increase in physical activity as energy improves with treatment
- Warning Signs: Symptoms that require medical attention
- Medical Alert: Recommend medical identification indicating hypothyroidism
Emergency Management: Myxedema Coma
Critical Nursing Interventions
- Airway Management: Ensure patent airway; assist with intubation if needed
- Thermoregulation: Passive rewarming to avoid vasodilation and hypotension
- Fluid Management: Careful IV fluid administration (risk of hyponatremia)
- Medication Administration: IV levothyroxine and possibly hydrocortisone as prescribed
- Monitoring: Continuous cardiac monitoring, frequent vital signs, neurological assessments
- Laboratory Values: Monitor electrolytes, glucose, thyroid function tests
Note: Myxedema coma has high mortality (30-60%) even with appropriate treatment. Early recognition and intervention are crucial.
Complications of Hypothyroidism
| System | Complications | Preventive Nursing Measures |
|---|---|---|
| Cardiovascular | Atherosclerosis, coronary artery disease, heart failure, pericardial effusion | Monitor lipid levels, encourage heart-healthy lifestyle, administer thyroid replacement as prescribed |
| Respiratory | Sleep apnea, pleural effusion, respiratory failure | Assess respiratory function, elevate head of bed, encourage optimal weight |
| Neurological | Peripheral neuropathy, carpal tunnel syndrome, cognitive impairment | Assess neurological function, provide safety measures, cognitive stimulation |
| Reproductive | Infertility, menstrual disorders, pregnancy complications | Educate about potential impact on fertility, monitor closely during pregnancy |
| Metabolic | Hyperlipidemia, obesity, insulin resistance | Monitor weight, lipid profile, and glucose levels; encourage balanced nutrition |
| Psychiatric | Depression, anxiety, psychosis | Assess mood regularly, provide emotional support, refer for psychological care if needed |
| Emergency | Myxedema coma | Educate about trigger factors (infection, cold exposure, sedatives), ensure medication adherence |
Discharge Planning and Follow-up
Discharge Education Checklist
- Medication Management:
- Take levothyroxine at the same time each day, preferably 30-60 minutes before breakfast
- Do not skip or double doses; if a dose is missed, take it as soon as remembered unless it’s almost time for the next dose
- Store medication away from heat, moisture, and light
- Maintain a consistent brand/manufacturer of levothyroxine when possible
- Symptom Management:
- Understand that symptom improvement may take weeks to months
- Energy levels typically improve first, with other symptoms resolving gradually
- Monitor weight weekly and report significant changes
- Follow-up Care:
- Schedule laboratory testing 6-8 weeks after starting therapy or dose adjustment
- Keep all follow-up appointments with healthcare providers
- Bring medication list to all appointments
- When to Seek Medical Attention:
- Signs of overtreatment: palpitations, excessive sweating, tremors, insomnia, weight loss
- Signs of undertreatment: returning fatigue, cold intolerance, constipation
- New or worsening symptoms despite treatment
Lifestyle Modifications
- Nutrition:
- Balanced diet rich in fiber to combat constipation
- Moderate iodine intake (seafood, iodized salt)
- Limit goitrogenic foods if large goiter present (raw cruciferous vegetables like cabbage, broccoli, cauliflower)
- Maintain adequate calcium and vitamin D intake for bone health
- Physical Activity:
- Begin with low-intensity exercise and gradually increase as tolerated
- Include both cardiovascular exercise and strength training when able
- Monitor heart rate response to exercise
- Environmental Adjustments:
- Maintain warmer home environment
- Layer clothing for temperature regulation
- Use moisturizers regularly for skin dryness
Community Resources
- Support Groups: Local and online thyroid disorder support groups
- Patient Education Materials: From organizations like the American Thyroid Association
- Medication Assistance Programs: For patients with financial constraints
- Nutritional Counseling: Referral to registered dietitian if needed
Application: Nursing Case Study
Patient Scenario
Mrs. Johnson, a 58-year-old female, presents to the primary care clinic with complaints of increasing fatigue, unintentional weight gain of 15 pounds over 6 months, dry skin, hair loss, and constipation. She reports feeling cold all the time, even when others are comfortable. Her vital signs show HR 52 bpm, BP 146/92, Temp 97.0°F. Lab results reveal TSH 18.5 mIU/L (normal 0.5-4.5) and Free T4 0.6 ng/dL (normal 0.8-1.8).
Nursing Process Application
1. Assessment
- Vital signs indicate bradycardia, hypertension, and hypothermia
- Symptoms consistent with hypothyroidism: fatigue, weight gain, cold intolerance, dry skin, hair loss, constipation
- Lab values confirm primary hypothyroidism with elevated TSH and low Free T4
2. Nursing Diagnoses
- Decreased Cardiac Output related to bradycardia secondary to hypothyroidism
- Constipation related to decreased gastrointestinal motility
- Fatigue related to decreased metabolic rate
- Deficient Knowledge related to new diagnosis of hypothyroidism
3. Planning & Interventions
- Administer levothyroxine as prescribed (likely starting at 50-75 mcg daily due to age and cardiac status)
- Provide education about medication administration (empty stomach, consistent timing)
- Teach about proper skin care with moisturizers for dry skin
- Discuss dietary modifications to manage constipation (increased fiber, adequate hydration)
- Explain gradual nature of symptom improvement with treatment
- Provide education about the chronic nature of hypothyroidism and lifelong medication needs
4. Evaluation
- Patient verbalizes understanding of medication regimen and demonstrates correct administration technique
- Patient describes dietary changes to address constipation
- Follow-up appointment scheduled for 6-8 weeks with repeat TSH and Free T4
- Patient demonstrates understanding of hypothyroidism and when to seek medical attention
Review Questions
1. A patient with newly diagnosed hypothyroidism is prescribed levothyroxine. Which nursing instruction regarding medication administration is most appropriate?
A. Take the medication with meals to reduce gastrointestinal upset
B. Take the medication at bedtime to maximize absorption
C. Take the medication 30-60 minutes before breakfast
D. Take the medication with calcium supplements to enhance absorption
Answer: C. Take the medication 30-60 minutes before breakfast
Rationale: Levothyroxine should be taken on an empty stomach, 30-60 minutes before eating, to maximize absorption. Food, especially calcium-rich foods, can interfere with absorption.
2. When assessing a patient with hypothyroidism, which finding would the nurse most likely document?
A. Tachycardia
B. Diarrhea
C. Weight loss
D. Cold intolerance
Answer: D. Cold intolerance
Rationale: Cold intolerance is a classic symptom of hypothyroidism due to decreased metabolic rate and heat production. Tachycardia, diarrhea, and weight loss are more consistent with hyperthyroidism.
3. A nursing diagnosis for a patient with hypothyroidism would be:
A. Risk for Hyperthermia related to increased metabolic rate
B. Diarrhea related to increased gastrointestinal motility
C. Fatigue related to decreased metabolic rate
D. Ineffective Breathing Pattern related to hyperventilation
Answer: C. Fatigue related to decreased metabolic rate
Rationale: Hypothyroidism causes a decreased metabolic rate, resulting in fatigue. The other options describe manifestations more consistent with hyperthyroidism or other conditions.
4. Which laboratory finding would be most consistent with primary hypothyroidism?
A. Decreased TSH, increased T4
B. Increased TSH, decreased T4
C. Decreased TSH, decreased T4
D. Increased TSH, increased T4
Answer: B. Increased TSH, decreased T4
Rationale: In primary hypothyroidism, the thyroid gland fails to produce adequate T4, resulting in low T4 levels. The pituitary gland responds by increasing TSH production in an attempt to stimulate the thyroid gland.
5. What is the most serious complication of severe untreated hypothyroidism that requires emergency intervention?
A. Thyroid storm
B. Myxedema coma
C. Graves’ disease
D. Hashitoxicosis
Answer: B. Myxedema coma
Rationale: Myxedema coma is a life-threatening complication of severe hypothyroidism characterized by altered mental status, hypothermia, bradycardia, hypoventilation, and hypotension. It requires immediate emergency treatment.
References
- American Thyroid Association. (2021). Hypothyroidism booklet. https://www.thyroid.org/hypothyroidism/
- Chaker, L., Bianco, A. C., Jonklaas, J., & Peeters, R. P. (2017). Hypothyroidism. Lancet, 390(10101), 1550-1562.
- Garber, J. R., Cobin, R. H., Gharib, H., Hennessey, J. V., Klein, I., Mechanick, J. I., … & Woeber, K. A. (2012). Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid Association. Thyroid, 22(12), 1200-1235.
- Jonklaas, J., Bianco, A. C., Bauer, A. J., Burman, K. D., Cappola, A. R., Celi, F. S., … & Sawka, A. M. (2014). Guidelines for the treatment of hypothyroidism: prepared by the American Thyroid Association task force on thyroid hormone replacement. Thyroid, 24(12), 1670-1751.
- Ross, D. S., Burch, H. B., Cooper, D. S., Greenlee, M. C., Laurberg, P., Maia, A. L., … & Walter, M. A. (2016). 2016 American Thyroid Association guidelines for diagnosis and management of hyperthyroidism and other causes of thyrotoxicosis. Thyroid, 26(10), 1343-1421.
- Taylor, P. N., Albrecht, D., Scholz, A., Gutierrez-Buey, G., Lazarus, J. H., Dayan, C. M., & Okosieme, O. E. (2018). Global epidemiology of hyperthyroidism and hypothyroidism. Nature Reviews Endocrinology, 14(5), 301-316.