Signs and Symptoms of Hyperthyroidism
Hyperthyroidism presents with a constellation of hypermetabolic and cardiovascular symptoms, most commonly including weakness, palpitations, weight loss, heat intolerance, tachycardia, tremor, nervousness, and insomnia. 1, 2
Core Clinical Manifestations
Cardiovascular Signs and Symptoms
- Tachycardia is one of the most common and prominent signs 3, 4, 1
- Palpitations occur frequently and may indicate underlying cardiac complications 1, 2
- Hypertension develops due to increased cardiac output 3, 4
- Atrial fibrillation is more common in hyperthyroid patients, particularly the elderly 4
- Heart failure can occur in severe, long-standing cases despite typically increased cardiac contractility 4, 5
- Decreased systemic vascular resistance with increased cardiac output 4, 5
- Pulmonary artery hypertension may develop 4, 5
Neuropsychiatric Symptoms
- Tremor is a hallmark sign, particularly fine tremor of the hands 3, 4, 1
- Nervousness and anxiety are prominent symptoms 3, 4, 5
- Insomnia occurs commonly 3, 4, 5
- Hyperactivity and restlessness 3, 5
- Muscle weakness, often proximal 1, 2
Metabolic and Constitutional Symptoms
- Unintentional weight loss despite normal or increased appetite 3, 1, 2
- Heat intolerance is characteristic 3, 4, 1, 2
- Excessive sweating 3, 4, 5
- Diarrhea may occur 2
Dermatologic and Other Physical Signs
Graves Disease-Specific Features
When hyperthyroidism is caused by Graves disease (responsible for 95% of hyperthyroidism cases in pregnancy and the most common cause overall), distinctive additional signs appear 3, 1:
- Ophthalmologic signs: eyelid lag, eyelid retraction, stare, or exophthalmos (thyroid eye disease is pathognomonic for Graves disease) 3, 1, 2
- Dermatologic signs: localized or pretibial myxedema 3
- Diffusely enlarged thyroid gland on examination 2
Toxic Nodular Goiter-Specific Features
Patients with toxic multinodular goiter or toxic adenoma may present with 2:
- Compressive symptoms from the enlarged thyroid: dysphagia, orthopnea, or voice changes 2
- These symptoms indicate potential need for surgical intervention 1
Life-Threatening Presentation
Thyroid storm is a rare but critical emergency characterized by 3, 5:
- Severe acute exacerbation of all hyperthyroid signs and symptoms 3
- This is a medical emergency requiring immediate intervention 3, 5
- More common in untreated or inadequately treated hyperthyroidism 5
Important Clinical Considerations
Subclinical vs. Overt Hyperthyroidism
- Overt hyperthyroidism does not require the presence of symptoms and is defined biochemically by low/undetectable TSH with elevated T4 or T3 3
- When symptoms are present, they are often relatively nonspecific 3
- Subclinical hyperthyroidism is by definition asymptomatic with low TSH but normal T4 and T3 levels 3, 4
High-Risk Populations Requiring Vigilance
Be particularly alert for hyperthyroidism symptoms in 4:
- Elderly patients (higher risk of cardiovascular complications and atrial fibrillation) 4
- Post-partum women 4
- Patients with high radiation exposure (>20 mGy) 4
- Patients with Down syndrome (symptoms may overlap with syndrome features) 4
Pregnancy-Specific Concerns
Untreated hyperthyroidism in pregnancy increases risk for 3, 5:
- Severe preeclampsia 3, 5
- Preterm delivery 3, 5
- Heart failure 3, 5
- Miscarriage 3
- Low birth weight in neonates 3
Common Pitfalls to Avoid
- Do not dismiss subtle symptoms: The signs and symptoms are often relatively nonspecific and may be attributed to other conditions 3
- Recognize overlap with other conditions: Severe non-thyroid illness can lead to false positive TSH results 4
- Consider iodine exposure: Patients with nodular thyroid disease may develop overt hyperthyroidism when exposed to excess iodine (e.g., radiographic contrast agents) 4
- Remember cardiovascular mortality: Cardiovascular complications are the chief cause of death after treatment of hyperthyroidism, especially in patients over 50 years 4, 5