Thyroid Case Examination in Surgery

1. Anatomy Revision (Know Before You Examine)

• Normal thyroid weighs 20-25 g, lies at the level of C5-T1 vertebrae
• Two lobes connected by an isthmus, often with a pyramidal lobe projecting upward
• Arterial supply: superior thyroid artery (from external carotid) and inferior thyroid artery (from thyrocervical trunk)
• The recurrent laryngeal nerve (RLN) runs in the tracheo-oesophageal groove - injury causes hoarseness. ~2% of right-sided nerves are non-recurrent
• Lymphatics drain to central compartment (Level VI) then to deep cervical nodes (Levels II-V)

2. Classification of Thyroid Swellings (Table 55.3)

3. History Taking

Presenting Complaint

• Duration and progression of neck swelling
• Rapid increase in size (suggests malignancy or haemorrhage into cyst)

Symptoms of Thyroid Dysfunction

Local Pressure Symptoms (important for surgery)

• Dysphagia - oesophageal compression
• Dyspnoea / stridor - tracheal compression (may be positional - worse lying flat)
• Hoarseness - RLN involvement (strongly suggests malignancy)
• Facial flushing/venous distension - SVC compression (retrosternal goitre)

Risk Factors for Malignancy

• Prior head/neck irradiation
• Family history of thyroid cancer or MEN syndrome
• Male sex with solitary nodule
• Rapid growth, pain, voice change

4. Physical Examination - Systematic Approach

General Inspection

• Body habitus (thin/cachexia vs overweight)
• Tremor (hyperthyroidism)
• Skin and hair: warm/moist and fine (hyper) vs dry/coarse (hypo)
• Eye signs: exophthalmos, lid lag, lid retraction, chemosis (Graves')
• Pretibial myxoedema (Graves')

Neck Examination

• Ask patient to sit upright, neck slightly extended
• Look from front and side for any visible swelling
• Ask the patient to swallow a sip of water - thyroid swellings move upward on swallowing (attached to pretracheal fascia)
• Ask patient to protrude the tongue - a thyroglossal cyst will move upward (differentiates it from a thyroid swelling)

• Stand behind the patient
• Use both hands to palpate from behind while patient swallows
• Note:
  • Site: isthmus/lobe/diffuse
  • Size: estimate in cm
  • Shape: diffuse/multinodular/solitary nodule
  • Surface: smooth (Graves', physiological) vs irregular/nodular (multinodular goitre, malignancy)
  • Consistency: soft, firm, hard (hard = malignancy/Riedel's), cystic/fluctuant
  • Tenderness: tender (De Quervain's thyroiditis, haemorrhage into cyst)
  • Fixity: moves on swallowing (normal thyroid); if fixed to surrounding structures = malignancy
  • Lower border: can it be felt below? If not palpable = retrosternal extension
  • Check for tracheal deviation (midline of trachea)
  • Palpate cervical lymph nodes: submandibular, anterior and posterior cervical chains, supraclavicular

• Percuss the manubrium sterni - dullness over the upper sternum suggests retrosternal extension of goitre

• Place the stethoscope bell over each lobe
• A bruit indicates increased vascularity - characteristic of Graves' disease (also feel for a thrill)

5. Special Tests / Signs to Demonstrate

6. Cardiovascular and Neurological Examination

• Pulse: tachycardia/atrial fibrillation (hyper); bradycardia (hypo)
• Blood pressure: wide pulse pressure (hyper)
• Reflexes: brisk/hyperreflexia (hyper); slow-relaxing (hung-up) reflexes (hypo)
• Proximal myopathy: test shoulder abduction, hip flexion (thyrotoxic myopathy)
• Palmar erythema, onycholysis (Plummer's nails in Graves')

7. Investigations to Mention

• Serum TSH - single best screening test; suppressed in hyperthyroidism, elevated in hypothyroidism
• Free T3 and free T4
• Thyroid antibodies: anti-TPO (Hashimoto's), TSH receptor antibodies (Graves'), anti-thyroglobulin
• Serum calcitonin (if medullary carcinoma suspected)
• Serum calcium (to rule out concurrent hyperparathyroidism in MEN)

• Ultrasound neck: first-line for nodule evaluation - size, echogenicity, vascularity, lymph nodes; guides FNAC
• Radioisotope scan (Tc-99m/I-123): identifies hot (autonomous) vs cold (non-functioning) nodules. Cold nodules carry higher malignancy risk
• CT/MRI: assess retrosternal extension, tracheal compression, lymphadenopathy
• CXR: tracheal deviation, retrosternal shadow, calcification

• FNAC (Fine Needle Aspiration Cytology): cornerstone of nodule assessment
  • Thy1: Non-diagnostic
  • Thy2: Non-neoplastic (benign)
  • Thy3: Follicular lesion (indeterminate)
  • Thy4: Suspicious of malignancy
  • Thy5: Malignant

• Pre-operative fibreoptic nasolaryngoscopy to assess vocal cord function - mandatory before thyroid surgery per AAES guidelines

8. How to Summarise Your Findings (in Exam)

9. Red Flags Suggesting Malignancy

• Hard, irregular, fixed swelling
• Hoarseness (RLN invasion)
• Rapid recent growth
• Dysphagia
• Cervical lymphadenopathy
• Prior radiation to neck
• Male with solitary cold nodule
• Pemberton's sign positive (retrosternal extension)