What is the best course of treatment for a patient with symptoms of bloating, fatigue, hair loss, palpitations, and weight gain, potentially indicative of hypothyroidism?

Treatment of Hypothyroidism with Bloating, Fatigue, Hair Loss, Palpitations, and Weight Gain

Initiate levothyroxine immediately at 1.6 mcg/kg/day for patients under 70 years without cardiac disease, or 25-50 mcg/day for elderly patients or those with cardiac risk factors, after confirming the diagnosis with TSH and free T4 measurement. 1, 2

Diagnostic Confirmation Before Treatment

Measure TSH and free T4 to confirm overt hypothyroidism (elevated TSH with low free T4) versus subclinical hypothyroidism (elevated TSH with normal free T4). 1, 2 The constellation of fatigue (68-83% of hypothyroid patients), weight gain (24-59%), hair loss, cold intolerance, and constipation are classic hypothyroid symptoms that warrant immediate testing. 3, 2, 4

Check anti-TPO antibodies to confirm autoimmune etiology (Hashimoto's thyroiditis), which accounts for up to 85% of hypothyroidism cases in iodine-sufficient areas and predicts higher progression risk (4.3% per year versus 2.6% in antibody-negative individuals). 1, 2, 5

Repeat TSH after 3-6 weeks if initially elevated, as 30-60% of elevated TSH levels normalize spontaneously, avoiding unnecessary lifelong treatment. 1, 5

Critical Safety Assessment Before Starting Levothyroxine

Rule out concurrent adrenal insufficiency before initiating thyroid hormone, particularly in patients with suspected central hypothyroidism or hypophysitis, as starting levothyroxine before corticosteroids can precipitate life-threatening adrenal crisis. 3, 1, 6 Check morning cortisol and ACTH if central hypothyroidism is suspected (low free T4 with inappropriately normal or low TSH). 3, 6

In patients with both adrenal insufficiency and hypothyroidism, always start physiologic dose steroids at least 1 week before thyroid hormone replacement. 3, 1

Levothyroxine Dosing Algorithm

For Patients Under 70 Years Without Cardiac Disease:

• Start levothyroxine at full replacement dose of 1.6 mcg/kg/day to rapidly normalize thyroid function and prevent cardiovascular dysfunction, adverse lipid profiles, and quality of life deterioration. 1, 2, 5

For Patients Over 70 Years or With Cardiac Disease:

• Start at 25-50 mcg/day and titrate gradually to avoid unmasking cardiac ischemia, precipitating arrhythmias, or triggering heart failure decompensation. 1, 2, 5
• Rapid normalization of thyroid hormone can unmask or worsen cardiac ischemia in patients with coronary artery disease, making conservative dosing essential. 1

Special Consideration for Palpitations:

The palpitations mentioned may represent either hypothyroid-related cardiac dysfunction (delayed relaxation, abnormal cardiac output) or unrelated cardiac disease. 1 Obtain baseline ECG before starting levothyroxine to screen for atrial fibrillation or other arrhythmias, particularly if the patient is over 60 years. 1

Monitoring Protocol

Recheck TSH and free T4 in 6-8 weeks after initiating therapy or any dose adjustment, as this represents the time needed to reach steady state. 1, 2, 5 Target TSH within the reference range of 0.5-4.5 mIU/L with normal free T4 levels. 1, 5

Adjust levothyroxine dose by 12.5-25 mcg increments based on TSH results, using smaller increments (12.5 mcg) for elderly patients or those with cardiac disease. 1

Once TSH is at goal, monitor annually or sooner if symptoms change. 1, 2, 5

Expected Symptom Resolution Timeline

• Fatigue and weight should stabilize within 6-8 weeks of adequate levothyroxine replacement. 1
• Hair loss should improve within 3-4 months of adequate treatment, as extensive hair loss is a cardinal symptom of hypothyroidism. 1
• Palpitations related to hypothyroid cardiac dysfunction should resolve as thyroid function normalizes, though this may take several months. 1

Critical Pitfalls to Avoid

Never treat based on a single elevated TSH value without confirmation, as transient elevations are common and 30-60% normalize spontaneously. 1, 5

Never start thyroid hormone before ruling out adrenal insufficiency in patients with suspected central hypothyroidism, as this can precipitate adrenal crisis. 3, 1, 6

Avoid overtreatment, which occurs in 14-21% of treated patients and increases risk for atrial fibrillation (3-5 fold), osteoporosis, fractures, and cardiovascular mortality, particularly in patients over 60 years. 1 Approximately 25% of patients on levothyroxine are unintentionally maintained on doses sufficient to fully suppress TSH. 1, 2

Do not assume hypothyroidism is permanent without reassessment—consider transient thyroiditis, especially in recovery phase, where TSH can be elevated temporarily. 1

Treatment Outcomes and Quality of Life

Levothyroxine therapy significantly improves quality of life by resolving hypothyroid symptoms including fatigue, cognitive impairment, weight gain, and menstrual irregularities. 1 Treatment prevents progression of cardiac dysfunction, reduces LDL cholesterol, and decreases cardiovascular event risk. 1, 2 Untreated hypothyroidism can progress to severe complications including heart failure, myxedema coma (mortality rate up to 30%), infertility, and increased miscarriage risk. 2, 4, 5