Superior Laryngeal Nerve Palsy with Chest Pathology
When a patient presents with superior laryngeal nerve (SLN) palsy, immediately obtain contrast-enhanced CT imaging from the skull base through the aortopulmonary window to identify the underlying chest pathology causing nerve compression, as thoracic malignancies—particularly lung cancer and mediastinal masses—are common culprits requiring urgent diagnosis and treatment. 1
Diagnostic Approach
Immediate Imaging Protocol
Obtain contrast-enhanced CT neck extended through the aortopulmonary window as the initial imaging study, which allows complete visualization of the vagus nerve course from skull base to mid-chest and can identify thoracic pathology compressing the nerve 1
CT chest with contrast is essential because thoracic causes of laryngeal nerve palsy (lung cancer, tuberculosis, thoracic aortic aneurysm, mediastinal masses) are common and require rapid identification 1
MRI orbits, face, and neck with pre- and post-contrast sequences provides superior soft tissue characterization if CT is non-diagnostic, particularly for skull base and posterior fossa lesions 1
Clinical Evaluation Specifics
Perform flexible laryngoscopy immediately to document vocal cord position and cricothyroid muscle function, as SLN injury causes loss of vocal pitch control (cricothyroid denervation) and decreased supraglottic sensation 2, 3
Assess for aspiration risk by evaluating cough reflex and performing swallowing studies, since bilateral internal SLN branch injury eliminates the laryngeal cough reflex and dramatically increases aspiration pneumonia risk 4
Look for associated symptoms including changes in vocal pitch (especially high registers), dysphagia with liquids, and silent aspiration during meals 2, 4
Management Based on Underlying Pathology
Chest Pathology Identification
Lung cancer is the most common thoracic cause requiring immediate oncologic evaluation and staging 1
Mediastinal adenopathy in the aortopulmonary window or paratracheal region may compress the vagus nerve and requires tissue diagnosis 1
Superior sulcus tumors can cause combined nerve palsies (Pancoast syndrome) and require specialized multidisciplinary management 1
Symptomatic Management
Implement aspiration precautions immediately including dietary modifications (thickened liquids, pureed foods) and upright positioning during meals to prevent aspiration pneumonia 4
Refer to speech therapy for swallowing rehabilitation and compensatory techniques, which is critical for preventing respiratory complications 1
Consider neurotrophic medications and steroids in the acute phase to reduce inflammation and support nerve recovery 1
Prognosis and Follow-up
Most unilateral SLN injuries show partial compensation over 1-3 months, though complete recovery of vocal pitch control may not occur 1, 3
Permanent bilateral SLN palsy (particularly internal branch) represents a serious complication requiring long-term aspiration precautions and potential feeding tube placement 4
Serial laryngoscopy at 1,3, and 6 months documents recovery trajectory and guides ongoing management decisions 1, 3
Critical Pitfalls to Avoid
Do not delay chest imaging when SLN palsy is identified, as the window for treating underlying malignancy may be narrow 1
Never assume isolated SLN injury without imaging the entire vagus nerve course, as chest pathology may be the primary etiology requiring urgent intervention 1
Recognize that silent aspiration can occur without obvious coughing or choking, particularly with bilateral internal SLN branch injury, necessitating formal swallowing evaluation 4
Document baseline vocal cord function before any neck or chest surgery to differentiate pre-existing from iatrogenic injury 1