Hyperthyroidism

Background

• Hyperthyroidism: Excess circulating hormone resulting from thyroid gland hyperfunction
• Thyrotoxicosis: Excess circulating thyroid hormone originating from any cause

Causes

Primary Hyperthyroidism

• Graves disease (toxic diffuse goiter)
  • Most common cause (85% of cases)
  • Associated with diffuse goiter, ophthalmopathy, local dermopathy
• Toxic multinodular goiter
  • 2nd most common cause
• Toxic nodular (adenoma) goiter
  • Enlarged thyroid gland with small nodules that overproduce thyroid hormone

Secondary Hyperthyroidism

• Thyrotropin-secreting pituitary adenoma
• Thyroiditis
• Hashimoto thyroiditis
  • Initially gland is overactive (hyperthyroidism state) followed by hypothyroidism
• Subacute painful thyroiditis (de Quervain thyroiditis)
• Subacute painless thyroiditis
• Radiation thyroiditis

Other causes:

• Apathetic thyrotoxicosis (elderly, masking comorbidities)
• Metastatic thyroid cancer
• Iodine-induced thyrotoxicosis
• Amiodarone (contains iodine)
• Molar pregnancy

Clinical Features

Constitutional signs:

• Lethargy
• Diaphoresis
• Weakness
• Fever
• Heat intolerance
• Weight loss

Neuropsychiatric:

• Emotional lability
• Fine tremor
• Anxiety
• Muscle wasting
• Confusion
• Hyperreflexia
• Coma
• Periodic paralysis
• Psychosis

Ophthalmologic:

• Diplopia
• Lid lag
• Eye irritation
• Exophthalmos
• Ophthalmoplegia

Endocrine:

• Neck fullness/tenderness (thyroid gland)

Cardiorespiratory:

• Dyspnea
• Widened pulse pressure
• Palpitations
• Systolic hypertension
• Chest pain
• Sinus tachycardia
• A-fib/flutter
• CHF

GI:

• Diarrhea
• Hyperactive bowel sounds

Reproductive:

• Oligomenorrhea
• Gynecomastia
• Telangiectasia

Gynecologic:

• Menorrhagia
• Sparse pubic hair

Hematologic:

• Anemia
• Leukocytosis

Dermatologic:

• Hair loss
• Pretibial myxedema
• Warm, moist skin
• Palmar erythema
• Onycholysis

Apathetic hyperthyroidism: (elderly patients)

• Placid apaethetic facies
• Depression
• Lethargy
• Muscular weakness and wasting
• Excessive weight loss
• Cardiac dysrrhythmias
• Absent or small goiter
• Absence of ocular symptoms
• Agitation and confusion

Differential Diagnosis (Tachycardia)

• Anemia
• Dehydration
• Fever
• Drug intoxication
• Drug withdrawal
• Pain
• Infection
• Anion gap acidosis
• Sepsis
• Hyperthyroid
• Psych (anger, fear)
• Arrhythmia
• PE
• CHF
• Tamponade
• Myocardial contusion
• Cardiac valvular disease
• Hyper/hypoglycemia
• AMI
• Toxicity
  • ASA
  • TCA
  • Anticholinergic
  • Theophylline

Evaluation

Workup

• TSH (↓)
• Free T4 (↑)
• Free T3 (↑)

Management

• If asymptomatic or mild symptoms, no treatment required in ED
• If symptomatic, consider Thyroid storm

Disposition

• If asymptomatic or no thyroid storm, discharge with outpatient follow-up.
• Admit for significant symptoms or thyroid storm.

See Also

• Thyroid storm
• Thyroid (Main)

References

Authors

Ross Donaldson