What are the symptoms and treatment of hypothyroidism?

Symptoms and Treatment of Hypothyroidism

The most common symptoms of hypothyroidism include fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss, mental slowness, muscle cramps, and menstrual irregularities, and treatment consists primarily of synthetic levothyroxine replacement therapy to normalize TSH levels. 1

Common Symptoms of Hypothyroidism

Hypothyroidism presents with a constellation of symptoms related to metabolic slowing:

• Fatigue and lethargy (occurring in 68-83% of patients) 2
• Weight gain (affecting 24-59% of patients) 2
• Cold intolerance due to decreased heat production 1, 3
• Constipation from decreased intestinal motility 1, 3
• Dry skin (xeroderma) and hair loss 1, 4
• Mental slowness, memory loss, and difficulty concentrating (45-48% of patients) 1, 2
• Voice changes, often presenting as hoarseness 1, 5
• Menstrual irregularities such as oligomenorrhea and menorrhagia (approximately 23% of patients) 2, 5
• Muscle cramps and myalgias 1, 5

Additional Clinical Manifestations

• Edema and puffy appearance, particularly around the eyes 5
• Bradycardia due to decreased cardiac output 5
• Hyperlipidemia as a metabolic consequence 5
• Depression and mood changes 2, 5

Complications of Untreated Hypothyroidism

If left untreated, hypothyroidism can lead to serious complications:

• Cardiovascular complications including heart failure and increased risk of cardiovascular events 2
• Reproductive issues including disrupted ovulation, infertility, and increased miscarriage risk 2, 5
• Myxedema coma - a severe life-threatening complication with hypothermia, hypotension, and altered mental status requiring intensive care and carrying up to 30% mortality rate 1, 2
• Insulin resistance and hyperglycemia in patients with diabetes 2
• Developmental issues in infants (if maternal hypothyroidism during pregnancy) 2, 3

Diagnosis

Diagnosis of hypothyroidism is primarily biochemical:

• TSH testing is the initial screening test for hypothyroidism 1
• Elevated TSH with low free T4 confirms overt hypothyroidism 1, 2
• Subclinical hypothyroidism is defined as elevated TSH with normal T4 levels 1, 2
• Additional testing for thyroid antibodies (TPO) may identify autoimmune causes 1

Treatment Approach

First-Line Treatment

• Synthetic levothyroxine (T4) is the standard first-line treatment for hypothyroidism 6, 2
• The goal of treatment is to normalize TSH levels and alleviate symptoms 2
• Initial dosing should be tailored to patient-specific factors 2:
  • Standard starting dose is typically 1.6 μg/kg/day for most adults 7
  • Lower starting doses should be used for elderly patients and those with cardiovascular disease 2

Monitoring and Dose Adjustment

• TSH monitoring should be performed 6-8 weeks after initiating treatment or changing dose 2
• Once stable, annual TSH monitoring is recommended to avoid overtreatment or undertreatment 2
• Dose adjustments may be necessary during pregnancy as requirements often increase 6

Special Considerations

• Liothyronine (T3) may be used in patients allergic to components in levothyroxine preparations 8
• Treatment is typically lifelong for most forms of hypothyroidism 3, 5
• Despite biochemical normalization with treatment, approximately one-third of patients may still experience persistent symptoms 7

Treatment Pitfalls to Avoid

• Undertreatment can lead to persistent symptoms and complications 2
• Overtreatment can cause iatrogenic hyperthyroidism with symptoms of thyrotoxicosis 1
• In elderly patients, overtreatment increases risk of atrial arrhythmias, particularly atrial fibrillation 6
• Failure to adjust dosage during pregnancy can negatively impact maternal and fetal outcomes 6
• Inconsistent timing of medication administration or taking with interfering substances can affect absorption 2

Remember that hypothyroidism is a common endocrine disorder affecting 4-10% of women and increasing with age 5. With proper diagnosis and treatment, most patients can lead normal, healthy lives 3.