What is the most likely diagnosis and recommended work‑up for a patient presenting with ptosis, dysphagia, and vocal‑cord (vagal) palsy?

Diagnosis and Work-Up for Ptosis, Dysphagia, and Vocal Cord Palsy

This constellation of symptoms—ptosis, dysphagia, and vocal cord palsy—most likely represents either myasthenia gravis (particularly the laryngeal-type variant) or a brainstem/skull base lesion affecting multiple cranial nerves (CNs III, IX, X), and you should immediately obtain MRI head without and with IV contrast or MRI orbits, face, and neck without and with IV contrast as your initial imaging study.

Diagnostic Approach

Immediate Imaging

The ACR Appropriateness Criteria (2022) provides clear guidance for this presentation involving multiple cranial nerve palsies 1:

• For multiple lower CN palsies (CNs IX-XII): MRI head without and with IV contrast OR MRI orbits, face, and neck without and with IV contrast are usually appropriate as equivalent alternatives
• For isolated vagal palsy (CN X): These same imaging modalities plus CT neck with IV contrast are appropriate options
• The ptosis (CN III involvement) combined with dysphagia and vocal cord palsy (CNs IX-X) represents a multiple cranial neuropathy pattern requiring comprehensive imaging from skull base through neck

Critical Differential Diagnoses

Myasthenia Gravis (Laryngeal-Type)

• Vocal cord paralysis as an initial manifestation of MG is exceedingly rare but potentially life-threatening 2
• In a 2025 case series review, 10 of 13 MG cases with vocal cord palsy presented with VCP initially, and 9 of these required airway management 2
• This subtype is frequently seronegative for anti-AChR antibodies 2
• The combination of ptosis with bulbar symptoms (dysphagia, vocal cord palsy) is highly suggestive

Neurosarcoidosis

• Can present with isolated CN X and XII palsy 3
• CSF markers (elevated ACE and soluble IL-2 receptor) support diagnosis 3
• Requires exclusion of other etiologies before diagnosis

Brainstem/Skull Base Lesions

• Tumors, vascular lesions, or inflammatory processes affecting multiple cranial nerve nuclei or pathways
• Imaging will identify structural causes

Specific Work-Up Algorithm

Step 1: Secure the Airway

• Assess respiratory status immediately - laryngeal-type MG can progress rapidly to respiratory failure requiring intubation and tracheostomy 2
• Perform bedside laryngoscopy to evaluate vocal cord position and movement

Step 2: Obtain Imaging (Within 24 Hours)

• MRI head without and with IV contrast OR MRI orbits, face, and neck without and with IV contrast 1
• These are equivalent alternatives per ACR guidelines; choice depends on institutional protocols
• If MRI contraindicated, CT neck with IV contrast is acceptable for lower CN evaluation 1

Step 3: Myasthenia Gravis Testing

Perform these tests even if imaging is negative:

• Edrophonium (Tensilon) test - positive in seronegative MG 2
• Ice pack test for ptosis - positive in MG 2
• Anti-AChR antibodies (recognize these are often negative in laryngeal-type MG) 2
• Anti-MuSK antibodies
• Repetitive nerve stimulation or single-fiber EMG

Step 4: Additional Laboratory Studies

• CSF analysis if imaging suggests inflammatory/infectious process:
  • CSF-ACE and CSF soluble IL-2 receptor (elevated in neurosarcoidosis) 3
  • Cell count, protein, glucose
  • Infectious workup (syphilis, HIV if risk factors present) 3
• Chest imaging to evaluate for thymoma (if MG suspected) or sarcoidosis

Step 5: EMG/Nerve Conduction Studies

• Laryngeal EMG can demonstrate CN X and XII involvement 3
• Helps differentiate neuropathic from myopathic processes

Critical Pitfalls to Avoid

1. Delaying airway assessment: Laryngeal-type MG can cause rapid respiratory decompensation requiring emergency intubation 2

2. Dismissing MG due to negative antibodies: Laryngeal-type MG is frequently seronegative for anti-AChR antibodies; rely on clinical tests (edrophonium, ice pack) and EMG 2

3. Ordering MRI without contrast: The ACR guidelines specifically recommend with and without IV contrast for cranial neuropathy evaluation to identify enhancement patterns suggesting inflammation, infection, or neoplasm 1

4. Assuming post-viral etiology without excluding serious causes: While post-viral vagal neuropathy exists 4, the combination with ptosis suggests a more serious systemic process requiring thorough investigation

5. Inadequate initial laryngoscopy: Ensure thorough vocal cord visualization during initial endoscopy, as incomplete examination can delay diagnosis 5

Treatment Considerations

If MG is confirmed:

• Initiate pyridostigmine for symptomatic relief
• Plasma exchange or IVIG for acute management 2
• Immunosuppression with corticosteroids plus steroid-sparing agent (tacrolimus, azathioprine, or infliximab) 2, 3
• Monitor closely for respiratory compromise

If neurosarcoidosis is diagnosed:

• Pulse corticosteroids followed by maintenance therapy 3
• Consider steroid-sparing agents (infliximab, methotrexate) for better long-term outcomes with fewer side effects 3

The key is recognizing this as a neurological emergency requiring immediate airway assessment, urgent imaging, and parallel investigation for both structural and neuromuscular causes, with particular attention to seronegative myasthenia gravis given its life-threatening potential.