What is the recommended management for hypothyroidism?

Management of Hypothyroidism

Levothyroxine therapy is the first-line treatment for hypothyroidism, with dosing based on patient-specific factors including age, cardiac status, and severity of hypothyroidism. 1

Diagnosis and Initial Assessment

• Diagnosis is based on biochemical testing:
  • Elevated TSH with low free T4 indicates overt primary hypothyroidism
  • Both TSH and free T4 should be measured simultaneously for accurate diagnosis 1
  • Multiple tests over 3-6 months are recommended to confirm abnormal findings

Treatment Algorithm

When to Initiate Treatment

• Definite treatment indications:

  • TSH >10 mIU/L (overt hypothyroidism) 1
  • Pregnant women or those planning pregnancy with subclinical hypothyroidism 1, 2
  • Symptomatic patients with subclinical hypothyroidism 1

• Consider monitoring without immediate treatment:

  • TSH between 4.5-10 mIU/L with minimal symptoms (monitor for 3-6 months) 1

Levothyroxine Dosing

Population	Starting Dose	Target TSH Range
Adults <70 years without cardiac disease	1.6 mcg/kg/day	0.5-2.0 mIU/L
Elderly patients (≥70) or with cardiac conditions	25-50 mcg/day	1.0-4.0 mIU/L
Pregnant women	Adjusted to restore TSH to reference range	0.5-2.0 mIU/L
Thyroid cancer patients (low-risk)	Individualized	0.5-2.0 mIU/L
Thyroid cancer patients (intermediate to high-risk)	Individualized	0.1-0.5 mIU/L
Thyroid cancer patients (persistent disease)	Individualized	<0.1 mIU/L

Monitoring and Dose Adjustment

• Check TSH and free T4 6-8 weeks after initiating treatment or changing dose 1
• Once stable, monitor annually
• For pregnant women, monitor TSH every 6-8 weeks during pregnancy 1, 2
• Return to pre-pregnancy dose immediately after delivery 2

Special Populations

Elderly Patients

• Use lower starting doses (25-50 mcg/day) 1, 3
• Target higher TSH (1.0-4.0 mIU/L) 1
• Monitor closely for cardiac effects, particularly atrial fibrillation 3

Pregnant Women

• Promptly treat hypothyroidism diagnosed during pregnancy 2
• Maintain TSH in reference range (0.5-2.0 mIU/L) 1, 2
• Untreated maternal hypothyroidism increases risk of complications (spontaneous abortion, gestational hypertension, pre-eclampsia, stillbirth, premature delivery) 2
• May need dose adjustments during pregnancy as requirements often increase 2

Pediatric Patients

• Rapid restoration of normal T4 levels is essential to prevent adverse effects on cognitive development 3
• Initiate therapy immediately upon diagnosis 3
• Monitor closely during first 2 weeks for cardiac overload and arrhythmias 3
• Consider screening for other autoimmune conditions, particularly celiac disease 1

Patients with Diabetes

• Monitor for unexplained hypoglycemia and deterioration in glycemic control 1
• Thyroid dysfunction can affect diabetes management 1, 4

Complications and Risks to Monitor

• Undertreatment risks:

  • Persistent symptoms (fatigue, weight gain, cognitive issues, menstrual irregularities) 4
  • Cardiovascular complications 1, 4
  • Reproductive health issues (disrupted ovulation, infertility, miscarriage) 4
  • Progression to myxedema coma (severe hypothyroidism with decompensation) 4

• Overtreatment risks:

  • Atrial fibrillation (3-fold increased risk with TSH ≤0.1 mIU/L in adults ≥60 years) 1
  • Osteoporosis 1
  • Development of low TSH suggests overtreatment 1

Common Pitfalls to Avoid

1. Ignoring medication interactions:

   • Many medications and supplements can interfere with levothyroxine absorption
   • Advise taking levothyroxine on an empty stomach, 30-60 minutes before breakfast

2. Relying on a single abnormal laboratory value:

   • Confirm abnormal findings with repeat testing 1
   • Consider the clinical context alongside laboratory values

3. Overlooking subclinical hypothyroidism in high-risk groups:

   • Pregnant women or those planning pregnancy 1, 2
   • Patients with positive thyroid antibodies 1

4. Inadequate monitoring:

   • Regular TSH monitoring is essential to adjust dosing and avoid under/overtreatment 1
   • Nearly one-third of treated patients still exhibit symptoms 5

5. Inappropriate combination therapy:

   • Levothyroxine alone remains the treatment of choice 6
   • Combined levothyroxine plus liothyronine therapy has limited evidence for benefit and potential for adverse effects 6