What are the symptoms and treatment options for hyperthyroidism?

Symptoms of Hyperthyroidism

Hyperthyroidism presents with tachycardia, palpitations, anxiety, heat intolerance, unintentional weight loss, excessive sweating, fatigue, and muscle weakness. 1 These symptoms result from the excessive concentration of thyroid hormones in tissues and can significantly impact quality of life, morbidity, and mortality.

Common Clinical Manifestations

• Cardiovascular symptoms:

  • Tachycardia and palpitations
  • Atrial fibrillation (3-5 fold increased risk)
  • High-output heart failure
  • Pulmonary artery hypertension 1

• Neuropsychiatric symptoms:

  • Anxiety
  • Insomnia
  • Tremor
  • Emotional lability 1, 2

• Metabolic symptoms:

  • Unintentional weight loss despite increased appetite
  • Heat intolerance
  • Excessive sweating 1

• Gastrointestinal symptoms:

  • Diarrhea or increased bowel movements
  • Nausea (especially with severe hyperthyroidism) 2

• Musculoskeletal symptoms:

  • Muscle weakness
  • Fatigue
  • Accelerated bone loss and increased fracture risk 1

• Dermatologic manifestations:

  • Warm, moist skin
  • Excessive sweating
  • Hair loss
  • Pretibial myxedema (in Graves' disease) 1

• Ophthalmologic signs (particularly in Graves' disease):

  • Eyelid lag or retraction
  • Exophthalmos (bulging eyes)
  • Stare 1

Special Considerations

Age-Related Differences

Older adults may exhibit more subtle symptoms, often limited to cardiovascular manifestations, known as "apathetic hyperthyroidism." 1 This atypical presentation can make diagnosis challenging in elderly patients.

Pregnancy Considerations

Untreated hyperthyroidism during pregnancy increases the risk of:

• Maternal heart failure
• Spontaneous abortion
• Preterm birth
• Stillbirth
• Fetal or neonatal hyperthyroidism 3

Diagnosis

Diagnosis is confirmed by laboratory testing showing:

• Low or undetectable TSH
• Elevated free T4 and/or T3 levels 1

Initial screening typically involves measuring thyroid-stimulating hormone (TSH) and free thyroxine (FT4) levels, with a suppressed TSH (<0.4 mIU/L) and normal or elevated FT4 indicating potential hyperthyroidism. 1

Treatment Options

First-Line Treatments

1. Antithyroid drugs (e.g., methimazole, propylthiouracil):

   • First-line treatment for most patients
   • Typical treatment duration of 12-18 months
   • 50% recurrence rate 1
   • Propylthiouracil is preferred in the first trimester of pregnancy 3

2. Beta-blockers (e.g., propranolol, atenolol):

   • Provide rapid symptom control
   • Reduce heart rate and tremor
   • Alleviate anxiety and palpitations
   • Improve muscle weakness 1

3. Definitive treatments:

   • Radioactive iodine ablation (most widely used in the US)
   • Thyroidectomy (surgical removal of thyroid gland) 1, 4

Treatment Recommendations Based on Severity

• Overt hyperthyroidism (suppressed TSH with elevated T3/T4): Requires treatment with antithyroid drugs, radioactive iodine, or surgery 2

• Subclinical hyperthyroidism (TSH <0.1 mIU/L): Treatment recommended for:

  • All patients ≥65 years
  • Patients with cardiac disease
  • Patients with osteoporosis risk factors 1

Complications and Monitoring

Untreated hyperthyroidism can lead to:

• Increased all-cause mortality
• Cardiovascular events and atrial fibrillation
• Osteoporosis and fractures
• Heart failure
• Adverse pregnancy outcomes
• Thyroid storm (medical emergency requiring hospitalization) 1

Regular monitoring of thyroid function tests is essential during therapy. Once clinical evidence of hyperthyroidism has resolved, an elevated serum TSH indicates that a lower maintenance dose of antithyroid medication should be employed. 1

Warning Signs Requiring Immediate Medical Attention

• Fever, sore throat, skin eruptions (potential agranulocytosis)
• Symptoms of hepatic dysfunction (anorexia, pruritus, jaundice, right upper quadrant pain)
• Signs of vasculitis (new rash, hematuria, decreased urine output, dyspnea) 3