Acute Onset Ptosis with Motor/Sensory Symptoms and Neck Drop: Differential Diagnosis

Primary Diagnostic Considerations

The American Academy of Ophthalmology suggests that myasthenia gravis presenting with neck drop indicates generalized disease involving bulbar, limb, and potentially respiratory muscles, which can lead to life-threatening respiratory failure 1
The American Academy of Ophthalmology recommends assessing for fatigable weakness that worsens with sustained activity and improves with rest, a key clinical feature of myasthenia gravis 2
The American Academy of Ophthalmology notes that variable ptosis that worsens with fatigue and may show Cogan lid-twitch sign is a characteristic feature of myasthenia gravis 3
The American Academy of Ophthalmology states that neck weakness/head drop indicates involvement of large motor groups beyond ocular muscles in myasthenia gravis 1
The Centers for Disease Control and Prevention recommends immediately contacting local/state health department emergency staff for expert consultation and botulinum antitoxin if botulism is suspected 4
The American Society of Clinical Oncology suggests that immune checkpoint inhibitor-related neurologic toxicity can present with fatigable/fluctuating muscle weakness, ptosis, double vision, dysphagia, dysarthria, facial weakness, head drop or neck weakness 5

The Centers for Disease Control and Prevention recommends immediate assessment of respiratory function, including vital capacity and negative inspiratory force, in patients with suspected myasthenia gravis or botulism 4
The American Academy of Ophthalmology suggests using the ice pack test, which involves applying an ice pack over closed eyes for 2 minutes, to diagnose myasthenia gravis 1
The American Academy of Ophthalmology recommends assessing for fatigability with prolonged upgaze and looking for Cogan lid-twitch sign as part of the diagnostic algorithm for myasthenia gravis 3

The American Academy of Ophthalmology emphasizes that the presence of neck drop with ptosis indicates generalized neuromuscular disease requiring ICU-level monitoring for respiratory failure 1