Microglia

  • Ch: derived from macrophages / monocyte (mesodermal origin)
  • Trigger: insult / injury / infection (viral, rickettsia)
  • Fx: migrate into CNS --> proliferation, infiltration --> phagocytosis and antigen presentation --> converge on foci of damage --> form microglial nodules 
  • Cl: bipolar, tripolar, or more extensively branched
  • DDx: closely related to CNS macrophages or “glitter cells”
  • Im: lectin


Microglial Nodules
  • Ch: rod cells, cigar shaped nuclei
  • Im: CD 68+
  • o   “Neurophonagia” – aggregation of microglia and macrophages around dying neuron


Neuronophagia:
  • Microglial nodules + macrophages
Picture
Microglia
Picture
Big arrow: viral inclusion body. Small arrow: microglial nodule