Physiology & Biochemistry · patient case question
Injury to which nerve during her thyroidectomy best explains the persistent hoarseness?
Patient case: Family History and a Preoperative Workup
Patient: 26-year-old female
Chief Complaint: “My wisdom teeth need to come out and I want to make sure everything is safe first.”
Background: Multiple sclerosis diagnosed 2 years ago, currently in remission. Total thyroidectomy 6 months ago for papillary thyroid carcinoma, with persistent hoarseness since surgery. Her mother is a known carrier of Duchenne muscular dystrophy. Her brother has hemophilia A. She is planning a pregnancy within the next year.
Medications: Levothyroxine · Glatiramer acetate
Vital Signs: BP 114/70 mmHg · HR 76 bpm · RR 16 · T 98.4°F
Findings: Persistently breathy, hoarse voice. Well-healed anterior neck incision. Four impacted third molars planned for removal. Ibuprofen is planned for postoperative analgesia.
Show answer and explanation
Correct answer: B. Recurrent laryngeal nerve
- A. Incorrect. The hypoglossal nerve supplies the intrinsic and most extrinsic tongue muscles. Injury causes tongue deviation toward the affected side, not hoarseness.
- B. Correct. The recurrent laryngeal nerve supplies all intrinsic laryngeal muscles except the cricothyroid, and it runs in the tracheoesophageal groove immediately adjacent to the thyroid gland. Unilateral injury paralyzes a vocal cord and produces the breathy hoarseness described; bilateral injury threatens the airway.
- C. Incorrect. The glossopharyngeal nerve carries sensation and taste from the posterior third of the tongue and motor supply to the stylopharyngeus. Injury affects swallowing and the gag reflex.
- D. Incorrect. The external branch of the superior laryngeal nerve supplies the cricothyroid and is also at risk in thyroid surgery, but injury produces loss of vocal pitch range and voice fatigue rather than frank hoarseness.
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