Ten days after transection of a peripheral nerve, light microscopy of the corresponding neuronal cell body in the dorsal root ganglion shows eccentric nucleus, dispersal of Nissl granules to the periphery, and cellular swelling. What is this change called and what does it signify?

• A Neuronophagia, reflecting viral destruction of the neuron
• B Neurofibrillary tangle formation, reflecting tau hyperphosphorylation
• C Axonal spheroid formation, reflecting impaired axonal transport
• D Chromatolysis, reflecting increased protein synthesis for axonal repair ✓

Explanation

Chromatolysis is the classical reaction of a neuronal soma to axonal injury, first described by Nissl. The rough endoplasmic reticulum breaks up and Nissl substance disperses because the perikaryon switches to manufacturing structural proteins and membranes needed to regenerate the cut axon. Neurofibrillary tangles occur in Alzheimer disease, axonal spheroids reflect distal transport blockage, and neuronophagia describes microglial clustering around dead neurons in viral encephalitis.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.