Goiter

Definition

• Costanzo Physiology 7th Edition, p. 431

Classification

Epidemiology

• The most common anatomic disease of the thyroid worldwide, with iodine deficiency as the global leading cause.
• In iodine-sufficient countries (like the US), goiter independent of Graves disease is typically associated with Hashimoto's autoimmune thyroiditis as it progresses toward a hypothyroid state.
• Strong genetic component when it occurs in areas of adequate iodine intake.
• More common in women; frequency increases with age.
• Textbook of Family Medicine 9e, p. 1024

Pathogenesis

Causes and TSH Status

Nontoxic Multinodular Goiter - Specific Pathogenesis

• Solid nodules and colloid cysts
• Areas of fibrosis
• Functional heterogeneity within the gland

• Current Surgical Therapy 14e, p. 880

Clinical Features

Symptoms

• Most goiters are asymptomatic and discovered incidentally
• Compressive symptoms arise with enlargement:
  • Dyspnea / stridor - tracheal compression/deviation (crowing inspiration)
  • Dysphagia - esophageal compression
  • Hoarseness - direct laryngeal pressure or, less commonly, recurrent laryngeal nerve (RLN) stretch/compression (RLN palsy from a benign goiter is uncommon; malignant invasion is the more common cause)
  • Neck pressure / choking sensation, especially with certain movements
  • Venous congestion with certain head positions

Key Examination Signs

• Thyroid moves on swallowing - attached to the larynx via pretracheal fascia (distinguishes from other neck masses)
• Tracheal deviation - asymmetric enlargement pushes trachea contralaterally
• Pemberton's sign - raising both arms above the head produces facial plethora and redness from venous obstruction (indicates significant substernal extension)
• Nodularity, irregular ("knobby") surface in multinodular goiter

Rapid Enlargement - Red Flags

• Hemorrhage into a benign nodule
• Anaplastic thyroid carcinoma
• Thyroid lymphoma

Diagnosis

Workup Algorithm

• TSH, free T4, free T3
• Identifies subclinical/overt thyrotoxicosis, hypothyroidism, or euthyroid state

• Ultrasound - first-line; evaluates nodule characteristics
  • Features raising malignancy risk: hypoechogenicity, microcalcifications, hypervascularity, solid components within cystic nodules, regional lymphadenopathy
• CT (non-contrast preferred) - most sensitive for airway compromise, substernal extension, mediastinal involvement. Avoid iodinated contrast in Graves disease or toxic nodular goiter - iodine load can precipitate acute hyperthyroidism
• MRI - alternative to CT for soft-tissue detail

• Thyroid scan (radioiodine): if TSH is suppressed, to assess hot vs cold nodules. Hot (autonomous) nodules are almost never malignant.

• For any suspicious nodule (cold on scan, or TSH-normal + nodule ≥1 cm, or with suspicious ultrasound features)
• Ultrasound-guided preferred
• Results: Benign, Suspicious, Malignant → guide further management

• Pulmonary function tests / flow-volume loop - detect fixed upper airway obstruction
• Fiber-optic laryngoscopy - mandatory if voice changes or prior neck surgery (assess vocal cord mobility)
• Barium swallow - if dysphagia is prominent (less commonly needed in modern practice)
• Goldman-Cecil Medicine, p. 3278; Sabiston Textbook of Surgery

Graves Disease - The Five Hallmarks

1. Thyrotoxicosis
2. Goiter (present in nearly 100% of patients)
3. Ophthalmopathy (exophthalmos)
4. Pretibial (local) myxedema
5. Acropachy (clubbing of fingers and toes)

Treatment

Treatment Principles

Indications for Active Treatment of Nontoxic Goiter

• Local discomfort, choking, or tightness (especially with movement)
• Mechanical partial obstruction of the aerodigestive tract
• Substantial substernal extension (even without symptoms - relative indication, as future operation may be more disruptive)
• Cosmesis is rarely an isolated indication

Treatment Modalities

• Has little to no role in established multinodular goiter management
• Prospective trials show no benefit
• Side effects (bone loss, atrial arrhythmias) particularly significant in elderly patients

• Can reduce goiter size by 40-60% within 2 years
• Decreases compressive symptoms
• Complications: radiation thyroiditis, hypothyroidism, transient gland enlargement (potentially dangerous in large goiters with airway compromise)
• Can be combined with exogenous TSH (recombinant TSH) to boost radioiodine uptake in goiters with limited iodine uptake
• Useful in patients with comorbidities who are poor surgical candidates

• Definitive treatment for large or symptomatic goiters
• Options: total thyroidectomy or subtotal thyroidectomy
• Substernal goiter may require manubriotomy/median sternotomy for mediastinal component
• Preoperative vocal cord assessment mandatory (fiber-optic laryngoscopy if any voice changes or prior neck surgery)

• Hypoparathyroidism / hypocalcemia - from trauma or inadvertent removal of parathyroid glands; manifests as tingling in hands, feet, and perioral region, carpopedal spasm, and tetany
• RLN injury - hoarseness, voice change
• Hypothyroidism (requiring lifelong levothyroxine)
• Current Surgical Therapy 14e, p. 880-881; Goldman-Cecil Medicine

Special Situations

Endemic Goiter

Substernal (Intrathoracic) Goiter

• Extension below the thoracic inlet
• Can compress the trachea, SVC (superior vena cava syndrome), or esophagus
• Pemberton's sign positive
• CT chest (non-contrast) is critical for surgical planning
• Surgical resection generally via cervical incision; mediastinal extension may require manubriotomy

Pregnancy

Summary Table