PMID- 16672291
OWN - NLM
STAT- MEDLINE
DCOM- 20060619
LR  - 20091119
IS  - 1460-2156 (Electronic)
IS  - 0006-8950 (Linking)
VI  - 129
IP  - Pt 6
DP  - 2006 Jun
TI  - MRI and clinical studies of facial and bulbar muscle involvement in MuSK 
      antibody-associated myasthenia gravis.
PG  - 1481-92
AB  - A proportion of patients with myasthenia gravis (MG) without acetylcholine 
      receptor (AChR) antibodies have antibodies to muscle-specific kinase (MuSK). MG 
      with MuSK antibodies (MuSK-MG) is often associated with persistent bulbar 
      involvement, including marked facial weakness and tongue muscle wasting. The 
      extent of muscle wasting in MuSK-MG, and whether it is also found in the few 
      acetylcholine receptor (AChR-MG) patients who have persistent bulbar involvement, 
      is not clear. We studied 12 MuSK-MG patients and recruited 14 AChR-MG patients 
      matched broadly for age, sex ratio, duration of disease and degree of ocular, 
      bulbar and facial weakness. We used coronal and sagittal T1-weighted (T1W) and 
      T2-weighted (T2W) magnetic resonance imaging (MRI) to assess muscle wasting in 
      facial and tongue muscles. Hyperintense signal on T1W MRI and comparison of axial 
      T1W sequences with cUTE sequences were used to assess fibrous/fatty tissue in the 
      tongue. We compared the results with those of four patients with myotonic 
      dystrophy and 12 healthy individuals. We correlated the changes with clinical and 
      treatment histories, and established a new ocular-bulbar-facial-respiratory 
      (OBFR) score. At the time of study, none of the clinical measures, including the 
      OBFR score, differed between the two MG groups. MRI demonstrated thinning of the 
      buccinator, orbicularis oris (O.oris) and orbicularis oculi (O.oculi) muscles in 
      MuSK-MG patients compared with healthy controls, whereas thinning of these 
      muscles was not significant in AChR-MG. Tongue areas with T1W high signal were 
      increased in MuSK-MG patients and the intensity of the signal on axial T1W 
      sequences was greater in MuSK-MG than in controls. To look for possible 
      correlations between imaging and clinical findings, we pooled results from all MG 
      patients. The duration of treatment with prednisolone at >40 mg on alternate days 
      (AD) correlated positively with the percentage of tongue area with high signal (P 
      = 0.006) and negatively with MRI measurements of individual muscles and with the 
      mean muscle dimensions (P = 0.001). The new OBFR score correlated positively with 
      current Myasthenia Gravis Foundation of America grades and with the percentage of 
      high signal (P = 0.004) and negatively with the mean muscle dimensions (P < 
      0.001). The results show that bulbar and facial muscle weakness and wasting are 
      associated with significant muscle atrophy and fatty replacement in MuSK-MG, 
      which was not found in the AChR-MG patients. MuSK antibodies per se may 
      predispose to muscle thinning, but the difficulties in obtaining clinical 
      remission under steroid therapy in some patients, resulting in long duration of 
      treatment with higher doses (>40 mg AD), may be an additional factor.
FAU - Farrugia, Maria Elena
AU  - Farrugia ME
AD  - Department of Clinical Neurology, University of Oxford, Oxford, UK.
FAU - Robson, Matthew D
AU  - Robson MD
FAU - Clover, Linda
AU  - Clover L
FAU - Anslow, Phil
AU  - Anslow P
FAU - Newsom-Davis, John
AU  - Newsom-Davis J
FAU - Kennett, Robin
AU  - Kennett R
FAU - Hilton-Jones, David
AU  - Hilton-Jones D
FAU - Matthews, Paul M
AU  - Matthews PM
FAU - Vincent, Angela
AU  - Vincent A
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20060503
PL  - England
TA  - Brain
JT  - Brain : a journal of neurology
JID - 0372537
RN  - 0 (Autoantibodies)
RN  - 0 (Glucocorticoids)
RN  - 0 (Receptors, Cholinergic)
RN  - EC 2.7.10.1 (MUSK protein, human)
RN  - EC 2.7.10.1 (Receptor Protein-Tyrosine Kinases)
SB  - IM
MH  - Adolescent
MH  - Adult
MH  - Aged
MH  - Autoantibodies/*analysis
MH  - Child
MH  - Child, Preschool
MH  - Drug Administration Schedule
MH  - Facial Muscles/pathology
MH  - Female
MH  - Glucocorticoids/administration & dosage/adverse effects
MH  - Humans
MH  - Magnetic Resonance Imaging/methods
MH  - Male
MH  - Masticatory Muscles/pathology
MH  - Middle Aged
MH  - Muscle, Skeletal/pathology
MH  - Muscular Atrophy/etiology/pathology
MH  - Myasthenia Gravis/complications/*immunology/pathology/therapy
MH  - Receptor Protein-Tyrosine Kinases/*immunology
MH  - Receptors, Cholinergic/*immunology
MH  - Severity of Illness Index
MH  - Tongue/pathology
EDAT- 2006/05/05 09:00
MHDA- 2006/06/20 09:00
CRDT- 2006/05/05 09:00
PHST- 2006/05/05 09:00 [pubmed]
PHST- 2006/06/20 09:00 [medline]
PHST- 2006/05/05 09:00 [entrez]
AID - awl095 [pii]
AID - 10.1093/brain/awl095 [doi]
PST - ppublish
SO  - Brain. 2006 Jun;129(Pt 6):1481-92. doi: 10.1093/brain/awl095. Epub 2006 May 3.