Brain - Infectious/Inflammatory/Demyelinating

Question 1

Inflammatory/Demyelinating - NMO Spectrum

Answer 1

Neuromyelitis optica spectrum disorders (NMOSDs) (AKA Devic disease)
Preferential involvement of optic nerves and spinal cord (typically longitudinally extensive transverse myelitis > 3 vert segments, >50% area of central +/- peripheral cord in axial plane)
• Two types:
–AQP4 antibody (+)
 Spinal cord: More common cervicomedullary junction
 Optic nerves: More posterior involvement of optic nerve, including chiasm, bilateral disease
 Brain lesions:
 Different from MS! Lesions correspond to areas with AQP4 expression
 Anywhere next to the ventricular system (think next to the WATER or the ventricular system)
 Corticospinal tracts (PLIC, cerebral peduncle)
 Large extensive or tumefactive hemispheric lesions
 Cloud-like enhancement (ill defined margins) sometimes seen and relatively specific
 Rarely nodular or leptomeningeal enhancement
 However, most common is nonspecific white matter lesions
 MR Spectroscopy: Metabolites are NORMAL in NORMAL-appearing WM (versus in MS they have decreased NAA and increased Cho)

–AQP4 antibody (-), Myelin oligodendrocyte glycoprotein (MOG) ¬antibody-associated disease (MOG-AAD)
 Spinal cord: More likely thoracolumbar and conus
 Optic nerves: Long, bilateral, anterior optic nerve
 Brain lesions:
 Tend to involve DEEP GREY MATTER (Basal ganglia, thalamus) and infratentorial (brainstem, cerebellar peduncles, around 4th ventricle)
 Not all patients with AQP4 (-) have MOG (+)