What are the signs and symptoms of hyperthyroidism?

Signs and Symptoms of Hyperthyroidism

Hyperthyroidism presents with multiple systemic manifestations including tachycardia, warm moist skin, heat intolerance, nervousness, tremulousness, insomnia, weight loss, diarrhea, and proximal muscle weakness. 1

Common Clinical Manifestations

Cardiovascular Signs

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

Neuropsychiatric Signs

• Anxiety and nervousness
• Insomnia
• Fine tremor of outstretched hands
• Hyperactivity
• Emotional lability 1

Metabolic and Constitutional Signs

• Unintentional weight loss despite increased appetite
• Heat intolerance
• Excessive sweating
• Fatigue
• Muscle weakness 1, 2

Dermatologic Signs

• Warm, moist skin
• Hair loss
• Pretibial myxedema (specific to Graves' disease) 1

Ophthalmologic Signs (particularly in Graves' disease)

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

Gastrointestinal Signs

• Increased bowel movements or diarrhea
• Nausea and vomiting (less common) 2

Special Presentations

Apathetic Hyperthyroidism

Older adults may present with "apathetic hyperthyroidism" characterized by:

• Predominant cardiovascular manifestations
• Absence of typical hypermetabolic symptoms
• Weight loss may be the only obvious symptom 1

Subclinical Hyperthyroidism

• Low TSH but normal T4 and T3 levels
• Milder or absent symptoms 1

Diagnostic Clues

Laboratory findings that confirm hyperthyroidism include:

• Low or undetectable TSH
• Elevated free T4 and/or T3 levels 1, 2

Complications of Untreated Hyperthyroidism

If left untreated, hyperthyroidism can lead to:

• Cardiac arrhythmias
• Heart failure
• Osteoporosis
• Adverse pregnancy outcomes
• Thyroid storm (medical emergency)
• Increased all-cause mortality 1, 2

Important Clinical Pitfalls

1. Atypical Presentations: Hyperthyroidism can sometimes present with minimal or atypical symptoms, especially in older patients who may not display the classic signs 3

2. Masking Symptoms: Beta-blockers can mask certain clinical signs of hyperthyroidism, and abrupt withdrawal may precipitate thyroid storm 1

3. Differential Diagnosis: It's important to distinguish between true hyperthyroidism and euthyroid hyperthyroxinemic states to avoid unnecessary treatment 3

4. Thyroid Storm Recognition: This is a medical emergency requiring immediate hospitalization, characterized by extreme manifestations of hyperthyroidism including fever, severe tachycardia, and altered mental status 1

5. Unilateral Symptoms: Rarely, hyperthyroidism may present with unusual symptoms like unilateral muscle weakness, which can mislead clinicians toward neurological diagnoses 4

The clinical presentation of hyperthyroidism varies widely depending on age, comorbidities, and the underlying cause. Recognition of these diverse manifestations is crucial for timely diagnosis and appropriate management.