What are the symptoms and treatment options for hyperthyroidism?

Hyperthyroidism: Symptoms and Treatment

Clinical Presentation

Hyperthyroidism presents with a characteristic constellation of cardiovascular, neurological, and metabolic symptoms that reflect thyroid hormone excess affecting multiple organ systems. 1

Cardiovascular Symptoms

• Tachycardia and palpitations are hallmark features, occurring due to increased cardiac output and decreased systemic vascular resistance 1, 2
• Hypertension develops from the cardiovascular effects of excess thyroid hormone 1
• Atrial fibrillation is more common in hyperthyroid patients and represents a serious complication requiring urgent evaluation 1
• In severe, long-standing cases, heart failure can develop despite typically increased cardiac contractility, particularly with persistent tachycardia or rapid atrial fibrillation 1, 2
• Pulmonary artery hypertension with right ventricular dilatation may occur 1

Neurological and Psychiatric Symptoms

• Tremors (fine tremor of the hands) are a classic finding 1, 2
• Nervousness, anxiety, and hyperactivity reflect central nervous system stimulation 1, 2
• Insomnia is commonly reported 1, 2

Metabolic and Dermatological Symptoms

• Excessive sweating and heat intolerance occur from increased metabolic rate 1, 2
• Unintentional weight loss despite normal or increased appetite 3, 4
• Hair loss may be present 2
• Diarrhea can occur from increased gastrointestinal motility 3

Physical Examination Findings

• Goiter (enlarged thyroid gland) is frequently palpable 1, 2
• Muscle weakness particularly affecting proximal muscles 4
• In Graves' disease specifically, patients may exhibit thyroid eye disease (stare or exophthalmos), which is pathognomonic for this condition 3, 4

Life-Threatening Complications

• Thyroid storm is a rare but life-threatening emergency characterized by exaggerated hyperthyroid symptoms plus altered mental status, requiring immediate recognition and treatment 1, 2
• Cardiovascular complications are the chief cause of death after treatment, especially in patients over 50 years 1

Treatment Approach

Immediate Symptomatic Management

Beta-blockers should be initiated promptly as first-line therapy to control cardiovascular symptoms and reduce peripheral manifestations of hyperthyroidism. 1, 2

• Atenolol or propranolol are the preferred agents 1, 2
• The goal is to lower heart rate to nearly normal, which improves tachycardia-mediated ventricular dysfunction 1
• Beta-blockers effectively control tremors, reduce palpitations, and mitigate cardiovascular complications 1, 2

Definitive Treatment Options

Treatment selection depends on the underlying cause (Graves' disease vs. toxic nodular goiter vs. thyroiditis):

Antithyroid Medications

• Methimazole is the preferred antithyroid drug for most patients 4, 5
• Propylthiouracil is reserved for specific situations: patients intolerant to methimazole, first trimester of pregnancy, or preparation for surgery/radioactive iodine when methimazole cannot be used 6
• Critical warning: Propylthiouracil carries a black box warning for severe hepatotoxicity, including liver failure requiring transplantation or resulting in death, particularly in children and pregnant women 6
• Patients on propylthiouracil must be counseled to immediately report symptoms of liver dysfunction (anorexia, pruritus, jaundice, dark urine, right upper quadrant pain) 6
• Antithyroid drugs typically require 12-18 months of treatment, with approximately 50% recurrence rate after discontinuation 5

Radioactive Iodine Therapy

• Resolves hyperthyroidism in more than 90% of patients with Graves' disease and toxic multinodular goiter 4
• Most patients develop hypothyroidism within 1 year after treatment, requiring lifelong thyroid hormone replacement 4

Surgical Thyroidectomy

• Treatment of choice for patients with compressive symptoms from obstructive goiter (dysphagia, orthopnea, voice changes) 3, 4
• Also appropriate when other treatments are contraindicated or unsuccessful 4

Special Population Considerations

Pregnancy

• Hyperthyroidism increases risk of severe preeclampsia, preterm delivery, heart failure, spontaneous abortion, stillbirth, and fetal/neonatal hyperthyroidism 1, 2, 6
• Propylthiouracil may be preferred during the first trimester due to potential fetal abnormalities with methimazole 6
• Consider switching to methimazole for second and third trimesters given maternal hepatotoxicity risk with propylthiouracil 6
• Requires careful monitoring throughout pregnancy 2

Monitoring and Follow-up

• Thyroid function tests should be monitored periodically during therapy 6
• For patients on propylthiouracil, monitor liver function (bilirubin, alkaline phosphatase, ALT/AST) particularly in the first 6 months 6
• White blood cell counts should be checked if signs of infection develop, as agranulocytosis can occur (usually within first 3 months) 6
• Prothrombin time monitoring should be considered, especially before surgical procedures 6

Common Pitfalls to Avoid

• Do not delay beta-blocker initiation while awaiting definitive diagnosis or treatment 1
• Do not use propylthiouracil as first-line therapy except in specific circumstances (first trimester pregnancy, methimazole intolerance) due to hepatotoxicity risk 6
• Do not miss thyroid storm, which requires immediate aggressive treatment to prevent cardiovascular collapse and death 1, 2
• Screen high-risk populations including elderly patients, postpartum women, patients with radiation exposure >20 mGy, and patients with Down syndrome 1
• Recognize that subclinical hyperthyroidism (low TSH with normal FT4/T3) is more common than overt disease in primary care and requires treatment in patients over 65 years or with persistent TSH <0.1 mIU/L 1, 5