Myasthenia Gravis Medical Slides

Present a structured ICU approach: (1) secure airway if FVC <1L or NIF worse than -20 cmH2O, (2) hold pyridostigmine (paradoxically worsens secretions in crisis), (3) initiate IVIG 0.4 g/kg/day for 5 days or PLEX 5 exchanges — both equally effective, (4) identify and treat triggers (infection in 40%, medication changes, surgery), (5) avoid MG-exacerbating drugs (aminoglycosides, fluoroquinolones, magnesium, beta-blockers). Emphasize that crisis mortality has decreased from 40% to <5% with modern ICU care.

Create a comparison: AChR-MG (85% of generalized MG, complement-mediated, thymic hyperplasia/thymoma association, responds to cholinesterase inhibitors and thymectomy) vs MuSK-MG (5-8%, IgG4-mediated non-complement-fixing, bulbar-predominant with facial/respiratory weakness, poor response to pyridostigmine, thymectomy not beneficial, rituximab often highly effective). This distinction directly guides treatment strategy and is a frequent board-style teaching point.

Present eculizumab (REGAIN trial, 2017): C5 complement inhibitor approved for AChR+ refractory generalized MG, improved daily activities score. Efgartigimod (ADAPT trial, 2021): FcRn inhibitor that reduces pathogenic IgG by 80%, with 68% responder rate in AChR+ MG. These represent the first targeted therapies for MG and are indicated when conventional immunosuppression fails — frame them as precision medicine applied to neuromuscular disease.