Signs and Symptoms of Hyperthyroidism
Hyperthyroidism presents with a constellation of hypermetabolic symptoms including anxiety, insomnia, palpitations, unintentional weight loss, diarrhea, and heat intolerance, with physical examination findings that may include tachycardia, tremor, diffusely enlarged thyroid gland, and in Graves disease specifically, exophthalmos or stare. 1
Cardinal Symptoms of Thyrotoxicosis
The most common presenting symptoms reflect the hypermetabolic state created by excess thyroid hormone:
- Anxiety and insomnia are frequent neuropsychiatric manifestations of thyrotoxicosis 1
- Palpitations and tachycardia occur due to increased cardiac output and heart rate from thyroid hormone excess 1, 2
- Unintentional weight loss despite normal or increased appetite is a hallmark feature 1
- Diarrhea results from increased gastrointestinal motility 1
- Heat intolerance and excessive sweating reflect increased metabolic rate 1
- Tremor is a common finding on physical examination 2
Cardiovascular Manifestations
Cardiovascular symptoms are particularly important to recognize and treat early:
- Hypertension is a common cardiovascular manifestation requiring beta-blocker therapy 2
- Atrial fibrillation can occur, particularly in subclinical hyperthyroidism with suppressed TSH 3
- Early recognition and treatment of cardiovascular manifestations can prevent significant cardiovascular events 2
Physical Examination Findings
Physical findings vary depending on the underlying etiology:
- Diffusely enlarged thyroid gland (goiter) is characteristic of Graves disease 1
- Stare or exophthalmos (bulging eyes) are specific to Graves disease and indicate thyroid eye disease 1, 4
- Edema and erythema of periorbital tissues and conjunctivae may be present in Graves disease 4
- Upper eyelid retraction is a classic sign of thyroid eye disease 4
- Proptosis (forward displacement of the eye) occurs in more severe Graves ophthalmopathy 4
Symptoms from Compressive Effects
Patients with toxic nodular goiter may present with local compression symptoms:
- Dysphagia (difficulty swallowing) from thyroid gland compression 1
- Orthopnea (difficulty breathing when lying flat) 1
- Voice changes from recurrent laryngeal nerve compression 1
Special Considerations for Women with Family History
Women are disproportionately affected by hyperthyroidism:
- Graves disease has a strong female prevalence, affecting 2% of women compared to 0.5% of men globally 1, 3
- Family history of thyroid disorders is a recognized risk factor for developing thyroid eye disease 4, 5
- Women with family history should be particularly vigilant for symptoms given the genetic predisposition 5
Subclinical Hyperthyroidism Manifestations
Even with suppressed TSH and normal thyroid hormone levels, clinical consequences occur:
- Bone loss in postmenopausal women is a significant complication of subclinical hyperthyroidism 3
- Atrial fibrillation can develop even with subclinical disease 3
- Treatment is recommended for those older than 65 years or with persistent TSH less than 0.1 mIU/L due to cardiovascular and bone risks 1
Systemic Effects Across Multiple Organ Systems
Hyperthyroidism impacts numerous body systems:
- Integumentary system: warm, moist skin and hair loss 2
- Musculoskeletal system: muscle weakness and osteoporosis risk 2
- Gastrointestinal system: increased motility and diarrhea 2
- Reproductive system: menstrual irregularities and adverse pregnancy outcomes if untreated 1, 2
Critical Pitfalls to Avoid
- Do not overlook cardiovascular symptoms, as untreated hyperthyroidism can cause cardiac arrhythmias and heart failure 1
- Recognize that cigarette smoking or tobacco smoke exposure increases risk of thyroid eye disease in susceptible individuals 4
- Be aware that thyroid hormone levels may be affected by increased stress levels in patients with family history of thyroid disorders 4
- Understand that thyroid eye disease may precede or follow the onset of hyperthyroidism by many years, not always occurring simultaneously 4