Correlates of outcome and response to IVIg in 88 patients with multifocal motor neuropathy.
OBJECTIVE
Identification and examination of all patients with multifocal motor neuropathy (MMN) in the Netherlands to document the clinical spectrum and response to IV immunoglobulin (IVIg) and to determine correlates of outcome.


METHODS
A national cross-sectional descriptive study was performed. Ninety-seven patients were identified; 88 participated. Logistic regression analysis was used to study determinants of outcome.


RESULTS
Age at onset was younger in men than in women (38 vs 45 years, p = 0.05). Onset of weakness was in distal arm (61%) or distal leg (34%), and occasionally in the upper arm (5%). Initial diagnosis was motor neuron disease in one-third of patients. Brisk, but not pathologic, reflexes in weakened muscles were found in 8%. Conduction blocks were most frequently detected in the ulnar (80%) and median (77%) nerves, but occasionally only between Erb and axilla (6%), or in the musculocutaneous nerve (1%). Ninety-four percent responded to IVIg therapy: nonresponders had longer disease duration before the first treatment (p = 0.03). Seventy-six percent received IVIg maintenance treatment at the time of this study (median duration 6 years; range 0-17): the median dose increased over the years from 12 to 17 g per week (p < 0.01). Independent determinants of more severe weakness and disability were axon loss (p < 0.001; p < 0.0001) and longer disease duration without IVIg (p = 0.03; p = 0.07).


CONCLUSIONS
The results of this study may help aid recognition the clinical picture of MMN. Early IVIg treatment may help to postpone axonal degeneration and permanent deficits.


METHODS
This study provides Class IV evidence that IVIg improves muscle strength of patients with MMN and disability (defined as an increase of >or=1 Medical Research Council grade in at least 2 muscle groups without decrease in other muscle groups) in 94% (95% confidence interval, 86.8%-97.4%) of patients.
Cats
E A
EA
Department of Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht100, 3584 CX Utrecht, the Netherlands.
van der Pol
W-L
WL
Piepers
S
S
Franssen
H
H
Jacobs
B C
BC
van den Berg-Vos
R M
RM
Kuks
J B
JB
van Doorn
P A
PA
van Engelen
B G
BG
Verschuuren
J J
JJ
Wokke
J H
JH
Veldink
J H
JH
van den Berg
L H
LH
D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000188:drug therapy* / Q000503:physiopathology*; D018763:Muscle Fatigue / Q000187:drug effects / Q000502:physiology; D009431:Neural Conduction / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome
D016756:Immunoglobulins, Intravenous