Compared with the normal ultrastructure of axons in a nerve (A), an “onion bulb” (B) is composed of a thinly myelinated axon (arrow) surrounded by multiple concentrically arranged Schwann cells.
■ Inset, Light-microscopic appearance of an onion bulb neuropathy, characterized by “onion bulbs” surrounding axons
● It is due to SEGMENTAL MYELINATION AND DEMYELINATION…
● It is SEEN in–
- CIDP(Chronic Inflammatory Demyelinating polyneuropathy)
- CHARCOT MARIE TOOTH DISEASE
- refsums disease and dejerine sottas syndrome, adreno leukodystrophy
