Muscle function in Juvenile Idiopathic Arthritis

97 Pages·2004·2.18 MB·English

Linköping University Medical Dissertations
No. 847
Muscle function in Juvenile Idiopathic Arthritis
A two-year follow-up
Hans Lindehammar
Department of Neuroscience and Locomotion, Division of Neurophysiology
Faculty of Health Sciences
Linköpings Universitet, SE-581 85 Linköping, Sweden
Linköping 2004
© Hans Lindehammar 2004
Published articles have been reprinted with permission of the copyright holder: Journal of Rheumatology and
Acta Paediatrica
Printed in Sweden by Unitryck, Linköping, Sweden, 2004
ISSN 0345-0082
ISBN 91-7373-819-0
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Imagine no possessions
I wonder if you can
No need for greed or hunger
A brotherhood of man
Imagine all the people
Sharing all the world…
John Lennon
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Abstract
This is a study of muscle function in Juvenile Idiopathic Arthritis (JIA). Rheumatoid arthritis
(RA) is a disease that primarily affects the synovial membrane of joints. Muscle weakness,
atrophy and pain occur in adult RA. This may be a consequence of joint pain, stiffness and
immobility. Muscle inflammation and neuropathy occur as complications in adults. Muscle
function in JIA has been much less studied.
The aim of the study was to examine whether muscle weakness and atrophy also occur in
children with JIA.
This was a longitudinal study over a two-year period, where muscle strength and thickness
were measured repeatedly in a group of 20 children and teenagers with JIA. Muscle strength
was measured using different methods and in several muscle groups. Muscle biopsies were
obtained and nerve conduction velocity studies performed.
The study concludes that, compared to healthy people, children and teenagers with JIA have
as a group reduced muscle strength and muscle thickness. For most of these children and
teenagers, muscle strength is only slightly lower than expected, but a few have marked muscle
weakness. This is most apparent in patients with severe polyarthritis where the weakness
seems to be widespread. Patients with isolated arthritis may also have greatly reduced strength
and thickness of muscles near the inflamed joint.
There is a risk of decreasing strength in patients with polyarthritis and in muscles near an
active arthritis.
Minor changes are common in muscle biopsies, and findings may indicate immunological
activity in the muscles.
Atrophy of type II fibres, as in adult RA, was not found in JIA.
No patient had signs of neuropathy.
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Original publications
This thesis is based on the following papers:
I. Lindehammar H, Bäckman E. Muscle function in Juvenile Chronic Arthritis. Journal
of Rheumatology 1995;22:1159–65
II. Lindehammar H, Sandstedt P. Measurement of Quadriceps Muscle Strength and Bulk
in Juvenile Chronic Arthritis. A Prospective, Longitudinal, 2 Year Survey. Journal of
Rheumatology 1998;25:2240–8
III. Lindehammar H. Hand strength in juvenile chronic arthritis: a two-year follow-up.
Acta Paediatrica 2003;92:1291–6
IV. Lindehammar H, Lindvall B. Muscle involvement in juvenile idiopathic arthritis.
Submitted to Rheumatology 2004
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Contents
ABSTRACT...........................................................................................................................................................5
ORIGINAL PUBLICATIONS.............................................................................................................................7
CONTENTS...........................................................................................................................................................9
INTRODUCTION...............................................................................................................................................11
Rheumatoid arthritis....................................................................................................................................11
Rheumatoid arthritis in childhood...............................................................................................................11
Muscles........................................................................................................................................................12
Muscles during growth................................................................................................................................14
Strength measurement.................................................................................................................................14
Strength measurement in children...............................................................................................................16
Muscle function in joint disorders...............................................................................................................16
Muscle function in rheumatoid arthritis......................................................................................................17
Muscle function in juvenile idiopathic arthritis...........................................................................................17
Immunology and muscle..............................................................................................................................18
AIMS OF THE STUDY......................................................................................................................................19
MATERIAL.........................................................................................................................................................21
PATIENTS..........................................................................................................................................................21
CONTROL AND REFERENCE GROUPS..................................................................................................................24
Reference groups.........................................................................................................................................24
Controls.......................................................................................................................................................24
METHODS..........................................................................................................................................................27
MUSCLE STRENGTH...........................................................................................................................................27
Isometric muscle strength............................................................................................................................27
Isokinetic muscle strength...........................................................................................................................27
Handgrip strength.......................................................................................................................................27
Non-voluntary strength................................................................................................................................28
MUSCLE THICKNESS..........................................................................................................................................29
MUSCLE BIOPSY................................................................................................................................................30
Muscle biopsy..............................................................................................................................................30
Staining........................................................................................................................................................30
Immunohistochemistry.................................................................................................................................30
Fibre types and areas..................................................................................................................................31
NERVE CONDUCTION STUDY.............................................................................................................................31
JOINT EVALUATION...........................................................................................................................................31
DATA ANALYSIS................................................................................................................................................32
STATISTICAL ANALYSIS.....................................................................................................................................32
STUDY DESIGN..................................................................................................................................................32
ETHICAL CONSIDERATION.................................................................................................................................32
RESULTS AND DISCUSSION..........................................................................................................................33
PAPER I.............................................................................................................................................................33
PAPER II............................................................................................................................................................51
PAPER III...........................................................................................................................................................70
PAPER IV..........................................................................................................................................................74
SUMMARY OF RESULTS................................................................................................................................81
GENERAL CONSIDERATIONS......................................................................................................................83
MAIN CONCLUSIONS.....................................................................................................................................87
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ACKNOWLEDGEMENTS................................................................................................................................89
REFERENCES....................................................................................................................................................91
PAPER I
PAPER II
PAPER III
PAPER IV
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