Myopathy in CRPS-I: Disuse or neurogenic?

When I wrote the entry entitled Outsourcing a while back, I never thought that I would again be referencing another study based on amputated limbs so... soon.

Since writing Outsourcing, I have developed an ulcer on the top of my right foot, and visit a Wound Care Center every Wednesday, just for fun. The topic -- the thought -- the spectre -- of amputation, it disturbs me. I am, in fact, having nightmares.

That said, there is this to report: Myopathy in a certain cohort of fourteen CRPS Type 1 patients --whose affected limbs were amputated -- turned out not to be related to disuse.

I am not sure what exactly this conclusion elucidates... maybe it elucidates nothing and is just another piece of a puzzle that may or may not one day be assembled in an order that approximates meaning.

Myopathy in CRPS-I: Disuse or neurogenic?
European Journal of Pain
30 October 2008

Natalie M. Hulsman (a) Jan H.B. Geertzena (b) Pieter U. Dijkstraa (b, c) Jan J.A.M. van den Dungen (d) and Wilfred F.A. den Dunnen (e)


a--Centre for Rehabilitation, University Medical Centre Groningen, University of Groningen, P.O. Box 30001, 9700 RB Groningen, The Netherlands
b--Graduate School for Health Research, University Medical Centre Groningen, University of Groningen, The Netherlands
c--Department of Oral and Maxillofacial Surgery, University Medical Centre Groningen, University of Groningen, The Netherlands
d--Department of Surgery, University Medical Centre Groningen, University of Groningen, The Netherlands
e--Department of Pathology and Medical Biology, University Medical Centre Groningen, University of Groningen, The Netherlands

Received 28 January 2008; revised 16 July 2008; accepted 4 September 2008. Available online 31 October 2008.


Abstract

The diagnosis Complex Regional Pain Syndrome type I (CRPS-I) is based on clinical symptoms, including motor symptoms. Histological changes in muscle tissue may be present in the chronic phase of CRPS-I. Aim of this study was to analyze skeletal muscle tissue from amputated limbs of patients with CRPS-I, in order to gain more insight in factors that may play a role in changes in muscles in CRPS-I. These changes may be helpful in clarifying the pathophysiology of CRPS-I. Fourteen patients with therapy resistant and longstanding CRPS-I, underwent an amputation of the affected limb. In all patients histological analysis showed extensive changes in muscle tissue, such as fatty degeneration, fibre atrophy and nuclear clumping, which was not related to duration of CRPS-I prior to amputation. In all muscles affected, both type 1 and type 2 fibre atrophy was found, without selective type 2 fibre atrophy. In four patients, type grouping was observed, indicating a sequence of denervation and reinnervation of muscle tissue. In two patients even large group atrophy was present, suggesting new denervation after reinnervation. Comparison between subgroups in arms and legs showed no difference in the number of changes in muscle tissue. Intrinsic and extrinsic muscles were affected equally. Our findings show that in the chronic phase of CRPS-I extensive changes can be seen in muscle tissue, not related to duration of CRPS-I symptoms. Signs of neurogenic myopathy were present in five patients.

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