What are the signs and symptoms of hyperthyroidism and how is it managed?

Signs and Symptoms of Hyperthyroidism and Its Management

Hyperthyroidism presents with distinctive clinical manifestations including tremors, nervousness, insomnia, excessive sweating, heat intolerance, tachycardia, hypertension, and goiter, and is managed primarily with beta-blockers for immediate symptom relief followed by definitive treatment with antithyroid drugs, radioactive iodine, or surgery depending on the underlying cause. 1, 2

Clinical Presentation

Common Signs and Symptoms

• Cardiovascular manifestations:

  • Tachycardia and palpitations
  • Hypertension (often systolic)
  • Atrial fibrillation (especially in older patients)
  • High-output heart failure in severe cases 1

• Neurologic and muscular signs:

  • Fine tremor of outstretched hands
  • Nervousness and anxiety
  • Hyperactivity
  • Insomnia
  • Proximal muscle weakness 2

• Dermatologic manifestations:

  • Warm, moist skin
  • Excessive sweating
  • Hair loss
  • Pretibial myxedema (in Graves' disease) 1, 2

• Ophthalmologic signs (particularly in Graves' disease):

  • Eyelid lag or retraction
  • Exophthalmos
  • Stare 1, 2, 3

• Metabolic effects:

  • Weight loss despite increased appetite
  • Heat intolerance
  • Fatigue
  • Diarrhea 3

Physical Examination Findings

• Goiter (diffusely enlarged in Graves' disease, nodular in toxic nodular goiter)
• Lid lag and stare
• Fine tremor
• Tachycardia
• Warm, moist skin
• Proximal muscle weakness 2

Diagnosis

Laboratory Testing

1. Initial screening:

   • Thyroid-stimulating hormone (TSH) - suppressed (<0.4 mIU/L)
   • Free thyroxine (FT4) - normal or elevated
   • Free triiodothyronine (FT3) - may be elevated 1, 2

2. Confirmatory testing:

   • Radioactive iodine uptake and scan (to determine etiology)
   • TSH receptor antibodies (for Graves' disease diagnosis) 2, 3

Diagnostic Criteria

• Overt hyperthyroidism: Low/undetectable TSH with elevated T4 or T3 levels
• Subclinical hyperthyroidism: Low TSH with normal T4 and T3 levels 1, 4

Management

Immediate Symptomatic Relief

• Beta-blockers (e.g., propranolol):
  • Provides rapid symptom control
  • Reduces heart rate and tremor
  • Alleviates anxiety and palpitations
  • Improves muscle weakness even before achieving euthyroid state 2, 5
  • Dosage should be adjusted to achieve near-normal heart rate 1

Definitive Treatment Options

1. Antithyroid drugs:

   • Methimazole: First-line for most patients (5-30 mg daily)

     • Contraindicated in first trimester of pregnancy due to risk of congenital malformations 6
     • Monitor for agranulocytosis, vasculitis, and liver dysfunction 6

   • Propylthiouracil (PTU):

     • Preferred in first trimester of pregnancy and thyroid storm
     • Higher risk of hepatotoxicity, especially in children
     • Monitor liver function tests and complete blood count 7

   • Treatment duration typically 12-18 months, with 50% recurrence rate

   • Long-term treatment (5-10 years) associated with fewer recurrences (15%) 8

2. Radioactive iodine ablation:

   • Most widely used treatment in the United States
   • Preferred for toxic nodular goiter
   • Contraindicated in pregnancy and breastfeeding
   • May worsen ophthalmopathy in Graves' disease 9, 8

3. Surgical thyroidectomy:

   • Option for large goiters, suspicious nodules, or when other treatments are contraindicated
   • Risks include hypoparathyroidism and recurrent laryngeal nerve damage 9

Special Considerations

1. Pregnancy:

   • PTU preferred in first trimester
   • Switch to methimazole in second and third trimesters
   • Untreated hyperthyroidism increases risk of maternal heart failure, spontaneous abortion, preterm birth, and fetal/neonatal hyperthyroidism 6, 7

2. Thyroid storm:

   • Medical emergency requiring hospitalization
   • Treatment includes high-dose antithyroid drugs, beta-blockers, corticosteroids, and supportive care 1, 4

3. Subclinical hyperthyroidism:

   • Treatment recommended for:
     • Patients ≥65 years with TSH <0.10 mIU/L
     • Symptomatic patients
     • Those with cardiac disease or osteoporosis risk factors 4, 3

4. Cardiac complications:

   • Monitor for atrial fibrillation and heart failure
   • Adjust medications like digitalis and theophylline when becoming euthyroid 6, 7

Complications of Untreated Hyperthyroidism

• Increased all-cause mortality
• Cardiovascular events and atrial fibrillation
• Osteoporosis and fractures
• Heart failure
• Adverse pregnancy outcomes
• Thyroid storm (rare but life-threatening) 4, 3

Monitoring During Treatment

• Regular thyroid function tests (TSH, FT4)
• Complete blood count to monitor for agranulocytosis
• Liver function tests, especially with PTU
• Prothrombin time before surgical procedures 6, 7

Hyperthyroidism requires prompt diagnosis and treatment to prevent serious complications. The choice of therapy should be based on the underlying cause, severity of disease, and patient factors, with beta-blockers providing immediate symptomatic relief while definitive treatment addresses the underlying thyroid dysfunction.