Myasthenia gravis

Diagnostic criteria and categories for myasthenia gravis[4]Jaretzki A 3rd, Barohn RJ, Ernstoff RM, et al. Myasthenia gravis: recommendations for clinical research standards. Task Force of the Medical Scientific Advisory Board of the Myasthenia Gravis Foundation of America. Ann Thorac Surg. 2000 Jul;70(1):327-34. http://www.ncbi.nlm.nih.gov/pubmed/10921745?tool=bestpractice.com

Mild: Class I and II

Class I: Any eye muscle weakness; possible ptosis; all other muscle strength is normal

Class II: Mild weakness of other muscles; may have eye muscle weakness of any severity

• IIa: Predominantly limb or axial muscles or both

• IIb: Predominantly oropharyngeal or respiratory muscles or both

Moderate: Class III

Class III: Moderate weakness of other muscles; may have eye muscle weakness of any severity

• IIIa: Predominantly limb or axial muscles or both

• IIIb: Predominantly oropharyngeal or respiratory muscles or both

Severe: Class IV and V

Class IV: Severe weakness of other muscles; may have eye muscle weakness of any severity

• IVa: Predominantly limb or axial muscles or both

• IVb: Predominantly oropharyngeal or respiratory muscles or both; use of feeding tube without intubation

Class V: Intubation needed to maintain airway