Criteria of Mendell for Chronic Inflammatory Demyelinating Polyradiculoneuropathy

 

Parameters:

(1) mandatory clinical features

(2) major laboratory features

(3) mandatory exclusion criteria

Clinical	Laboratory	Exclusion	Diagnosis
2 of 2	3 of 2	4 of 4	definite
2 of 2	2 of 3	4 of 4	probable
2 of 2	1 of 3	4 of 4	possible

 

Mandatory clinical features:

(1) progression of muscle weakness in distal and proximal muscles of the upper and lower extremities for >= 2 months (8 weeks)

(2) hypo- or a-reflexia

 

Major laboratory features:

(1) electrophysiologic findings - 3 or 4 of the following:

(1a) reduction of nerve conduction velocity in 2 or more motor nerves

(1b) partial conduction block or temporal dispersion in 1 or more motor nerves

(1c) prolonged distal latencies in 2 or more nerves

(1d) absent or prolonged F wave latencies in at least 2 motor nerves

(2) CSF showing elevated protein (> 55 mg/dL) and white blood cell count < 10 per µL.

(3) demyelination as the primary finding in a nerve biopsy

 

Electrophysiology	Description
nerve conduction	< 80% of lower limit of normal (LLN) if amplitude > 80% of LLN; < 70% of LLN if amplitude < 80% of LLN
partial conduction block (CB)	> 20% drop in negative peak (-p) area or peak-to-peak (p-p) amplitude between proximal and distal sites of nerve stimulation with < 15% change in -p duration
temporal dispersion (TD)	> 20% drop in negative peak (-p) area or peak-to-peak (p-p) amplitude; -p duration exceeds 15%
distal latencies	> 125% of the upper limit of normal (ULN) if amplitude > 80% LLN; > 150% of ULN if amplitude < 80% LLN
F wave latency	> 125% of the upper limit of normal (ULN) if amplitude > 80% LLN; > 150% of ULN if amplitude < 80% LLN

 

All of these must be absent (exclusions):

(1) clinical findings: pure sensory neuropathy, mutilation of hands or feet, retinitis pigmentosa, ichthyosis, orange tonsils, history of exposure to toxins or drugs causing peripheral neuropathy

(2) laboratory findings: low serum cholesterol concentration, evidence of porphyria, hypothyroidism, heavy metal poisoning, CSF WBC cell count > 50 per µL, low serum vitamin B12 concentration, diabetes mellitus (fasting glucose >= 7.7 mmol/L)

(3) nerve biopsy: vasculitis, neurofilamentous swollen axons, intramyelinic blebs, amyloid deposits, deposits in Schwann cells consistent with Fabry's disease, adrenal leukodystrophy, metachromatic leukodystrophy, globoid cell leukodystrophy, Refsum disease

(4) electrodiagnostic features: neuromuscular transmission defect, myopathy, anterior horn disease