A 58-year-old man presents with progressive hoarseness and dyspnea for 3 weeks. He has a history of hypertension managed with medications. On examination, the voice is breathy and weak. Laryngoscopy reveals the left vocal cord in a paramedian position with incomplete glottic closure. There is no history of intubation, thyroid surgery, or malignancy. What is the most likely etiology of his vocal cord paralysis?

Explanation

## Clinical Diagnosis: Idiopathic Vocal Cord Paralysis ### Presentation Analysis The patient presents with: - Progressive hoarseness and dyspnea - Left vocal cord in **paramedian position** (adducted) - **Incomplete glottic closure** (characteristic of unilateral RLN palsy) - **No prior surgery, intubation, or malignancy history** - Isolated finding without systemic symptoms ### Key Point: **Idiopathic vocal cord paralysis (presumed viral neuritis of the RLN) accounts for 25–50% of unilateral VCP cases** when structural causes are excluded. The paramedian position indicates recurrent laryngeal nerve (RLN) involvement, not superior laryngeal nerve (SLN). ### Differential Diagnosis Table | Etiology | Position | Associated Features | Likelihood Here | | --- | --- | --- | --- | | **Idiopathic (viral)** | Paramedian | None; spontaneous recovery common | **Most likely** | | Thyroid malignancy | Paramedian | Neck mass, dysphagia, weight loss | No mass on exam | | Anterior scalene syndrome | Paramedian | Thoracic outlet symptoms, arm pain | No vascular/neurologic signs | | Guillain-Barré | Bilateral abductor | Ascending paralysis, areflexia, CSF protein | Unilateral; no systemic features | ### High-Yield: **Unilateral RLN palsy with paramedian cord position and no structural lesion = Idiopathic (viral neuritis) until proven otherwise.** The RLN innervates all intrinsic laryngeal muscles except the cricothyroid; paralysis leaves the cord in a paramedian position due to passive positioning. ### Clinical Pearl: Idiopathic VCP often has a **viral prodrome** (URI symptoms 1–4 weeks prior) and may show **spontaneous recovery in 50–70% of cases within 3–6 months** due to axonal regeneration or collateral reinnervation. ### Workup for Unilateral VCP 1. **Exclude structural causes:** CT chest/neck to rule out lung apex mass (Pancoast), thyroid, mediastinal pathology 2. **Exclude iatrogenic:** Detailed surgical history 3. **Exclude systemic:** Lyme serology (endemic areas), syphilis, TB if indicated 4. **EMG/NCS:** If diagnosis unclear or to assess prognosis (denervation patterns) ### Management - **Voice rest** and voice therapy initially - **Injection laryngoplasty** (calcium hydroxylapatite, hyaluronic acid) if persistent dyspnea/aspiration risk - **Medialization thyroplasty** if no recovery after 6–12 months - **Tracheostomy** only if bilateral paralysis with airway compromise [cite:Robbins & Cotran 10e Ch 16; Harrison 21e Ch 29]