CIDP: Subacute Onset

Note: Patient features

Nerve: Axon loss, Variable & Myelin loss, Diffuse

Neurofilament stain
Axons (Same nerve as on right )
  Variable loss of large & small axons within & among fascicles
  Large axons:
    Preservation of some large axons without surrounding clear myelin rim

Toluidine blue stain
Myelinated axons
  Apparent nearly complete myelinated axon loss in some fascicles
Subperineurial edema

Differential fascicular involvement: Variable loss of myelinated axons among fascicles

VvG stain

Nerve: Variable loss of large axons

Neurofilament stain

Neurofilament stain
Axon Loss
Some fascicles have more loss of large (thick) axons (Right) than others (Left)
Small axons are moderately reduced in both fascicles

Large axons: Demyelinated & Poorly formed onion bulbs

Toluidine blue stain

Toluidine blue stain
Demyelinated axons
Demyelinated, or thinly myelinated axons, often surrounded by poorly formed oniuon bulbs and Schwann cell nuclei

Subperineurial Edema

H & E stain
Subperineurial Edema: Clear region beneath long area of perineurium

Toluidine blue stain
Subperineurial Edema & Few normally myelinated axons

H & E stain
Region of subperineurial edema:
  Contains amorphous material and small vessels

Toluidine blue stain
Intrafascicular septa:
  Widened & Cellular
  Contains enlarged endoneurial vessel
Myelinated Axons: Few remaining; Small

Endoneurial vessels: Large size; Abnormal endothelial cells with large nuclei

H&E stain
Endoneurial capillaries: Enlarged with large endothelial cells

VvG stain

Gomori trichrome stain

Gomori trichrome stain

H&E stain

Endoneurial capillaries: Alkaline phosphatase stained

Alkaline phosphatase stain

Endoneurial cells: Scattered small & punctate acid phosphatase staining

Acid phosphatase stain

VvG stain

VvG stain

Epineurial vessels: Normal

VvG stain
Smaller epineurial vessels

CIDP Sub-Acute Onset: Muscle

Atrophy: Most muscle fibers
Nuclei: Large
Sarcolemma: Irregular

Internal architecture: Irregular
Fiber sizes: Type 2 often smaller than type 1

Neuromuscular junctions: Patchy; mildly elongated

Return to Neuromuscular Home Page
Return to CIDP, Subacute onset