Arterial Occlusion from Anti-Jo1 Antibody-associated Autoimmune Myositis: Arteritis not Compartment Syndrome
Article Outline
We present a case of arterial occlusion secondary to polymyositis associated with anti-Jo1 antibodies. A 44 year old lady presented with thigh pain and myositis associated with anti-Jo1 antibody positivity. She developed critical lower limb ischaemia with normal compartment pressures but occlusive disease on angiography. Management was with steroids and methotrexate with amputation of three digits. This case illustrates adult arteritis in the presence of acute polymyositis and anti-Jo1 antibodies as a rare yet diagnostically challenging cause of arterial ischaemia.
Keywords: Arterial occlusive diseases, Arteritis, Jo-1 antibody, Autoimmune disease, Polymyositis
Report
A 44-year old female non-smoker presented with a three week history of right thigh pain, swelling and local erythema. She was well and took no medication. Her skin was normal, peripheral pulses were present and limb perfusion was normal. The swelling progressed to involve the entire right lower limb. Within three weeks the patient developed rest pain in the right foot, low-grade pyrexia and CRP 163
mg/L. Doppler examination revealed monophasic dorsalis pedis signals but patent arteries on duplex. Venous duplex demonstrated a superficial thrombophlebitis and normal deep veins. CT thorax, abdomen and pelvis demonstrated no abnormality. Magnetic resonance imaging demonstrated subcutaneous oedema and myositis of the right antero-medial thigh compartments.
Creatinine kinase was 9241 (25-145IU/L), LDH 1990 (285–540IU/L), Glucose 9.9mmol/L (3–7.8), plasma viscosity 1.97mPa/sec (1.45–1.72), β2-microglobulin 4.15mg/L (0.7–1.8) and IgG 17.4g/L (6.8–15.6). Other immunoglobulins, serum electrophoresis, rheumatoid factor, complement, lupus anticoagulant, serum ACE, full blood count, urea and electrolytes, liver function and thyroid function were all normal. HIV and lymphoma screens were normal. Antibody screening detected anti-Jo1 antibodies. The screen was negative for ANCA, anti-parietal cell, anti-mitochondria, anti-dsDNS, anti-ssDNS, anti-nuclear, anti-centromere, anti-cardiolipin, anti-Sm, anti-Rnp, anti-Lkm, anti-smooth muscle, anti-La, anti-Scl70, anti-staphylolysins and anti-streptococcal O antibodies. Blood cultures were consistently negative. All blood tests were taken before the commencement of immunosuppression.
The patient developed dysphagia and proximal myopathy. Nerve conduction studies and electromyography suggested inflammatory myopathy. Muscle biopsy demonstrated active necrotising polymyositis. The right foot deteriorated [Fig. 1, left] despite normal compartment pressures (16mmHg). The patient received intravenous heparin, high-dose steroids and methotrexate. The swelling improved with CRP, LDH and CK falling. The right foot pain worsened and an arteriogram was performed [Fig. 2]. This demonstrated normal proximal vasculature but occlusion of small vessels in the ankle and foot. Intravenous prostacyclin and warfarin were added with gradual improvement in symptoms but digital necrosis became established [Fig. 1, right].
Fig. 1
Left: Digital ischaemia and vasculitic skin lesions in the forefoot. Right: Established digital necrosis with demarcation of medial toes. These three toes were subsequently amputated.
Fig. 2
Top: Normal iliac and femoral vessels. Middle: Tapering of popliteal artery and proximal anterior tibial artery origin. Bottom: Crural vessel occlusion with reconstitution of the peroneal and posterior tibial arteries (arrowhead) via small collaterals.
The patient mobilised fully and her CK and CRP normalised. At eight months she underwent amputation of the 1st–3rd digits of the right foot. Uncomplicated recovery ensued with good healing and she remains in remission on prednisolone and methotrexate two years later.
Discussion
To our knowledge this is the first case of lower limb ischaemia secondary to arterial occlusion associated with anti-Jo1 antibodies. These antibodies are found in 20–30% of patients with polymyositis1 (also in dermatomyositis, HIV and malignancy) but are also associated with the anti-synthetase syndrome consisting of myositis with Raynaud's phenomenon, interstitial pulmonary disease and arthritis. Interestingly our patient exhibited myositis without the other features of this syndrome: the digital necrosis was angiographically not Raynaud's vasospasm.2 Myositis has previously been shown to cause compartment syndrome3, 4 but in the present case the patient's ischaemia worsened on treatment despite reduced limb swelling, a falling CK and normal compartment pressures. We believe that vasculitis associated with autoimmune myositis5 accounted for the arterial occlusion in the present case. The absence of cardiac disease, response to immunosuppression and ongoing remission would discount a cardiac, embolic or atheromatous aetiology. An echocardiogram and repeat arteriogram have therefore not been performed.
Polymyositis is an autoimmune condition associated with proximal myopathy, muscle enzyme rises, EMG changes and specific muscle biopsy features. Myositis may be isolated or a feature of overlap syndromes that are associated with arterial insufficiency. Repeated investigations have shown no evidence of dermatomyositis, systemic sclerosis, anti-phospholipid syndrome, polyarteritis nodosa or hypereosinophilic syndrome. Conventional therapy of polymyositis utilises prednisolone but there is minimal evidence guiding polymyositis treatment. This patient was overweight, glucose intolerant and hypertensive therefore a steroid-sparing agent was required. Methotrexate was selected because it has a known spectrum of activity with defined side effects.
In this case the anti-Jo1 antibodies were associated with simultaneous myositis and arterial occlusion, suggesting a common immune basis. T lymphocytes from polymyositis patients proliferate to Jo1 antigen (histadyl-tRNA) in a MHC class II restricted manner. Muscle fibres in polymyositis demonstrate both MHC class I and II expression and MHC class I upregulation stimulates autoimmune myositis in mice. Muscle fibres expressing Jo1 may act as antigen presenting cells resulting in T and B cell responses with consequent cellular and humoral cytotoxicity. The basis of anti-Jo1 arteritis is unknown.
We believe that this patient developed anti-Jo1 polymyositis with an associated arteritis causing vascular insufficiency. Given the small vessel occlusion with established tissue necrosis, we feel it was appropriate to adopt non-surgical measures in this case. Revascularisation would be of doubtful success and there was no place for compartmental decompression. Early, aggressive immunosuppression stopped the immune process and prevented further tissue loss.
Acknowledgements
We wish to thank the patient who gave consent for the publication of her case. The authors wish to thank the Medical Photography Department at Southmead Hospital for the photographs included. We also wish to thank Mr Harvey Chant and Dr Michael Bradley for their advice in the preparation of this report.
No financial assistance was gained in the preparation of this report and there are no conflicts of interest.
References
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- Digital necrosis disclosing antisynthetase syndrome. Ann Dermatol Venereol. 1994;121:493–495
- . Focal myositis – a new presentation. Eur J Vasc Endovasc Surg. 2000;19:90–91
- Acute limb ischemia secondary to myositis-induced compartment syndrome in a patient with human immunodeficiency virus infection. J Vasc Surg. 2003;37:1103–1105
- . Clinical and pathogenetic implications of histopathology in childhood polydermatomyositis. Arthritis Rheum. 1982;25:126–139
PII: S1533-3167(06)00086-0
doi:10.1016/j.ejvsextra.2006.10.004
© 2006 Elsevier Ltd. All rights reserved.
Refers to article:
- Arterial Occlusion from Anti-Jo1 Antibody-Associated Autoimmune Myositis: Arteritis not Compartment Syndrome , 30 December 2006
