Case Report
Muscle weakness due to vasculitic neuropathy in a patient with rheumatoid arthritis
https://doi.org/10.21203/rs.3.rs-4724860/v1
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The vasculitic neuropathies are a group of disorders that result from inflammatory destruction of nerve blood vessels and subsequent ischaemic injury. It’s not a common but severe complication in rheumatoid arthritis. It’s difficult to make a diagnosis especially when the patient is under regular treatment. It is imperative that rheumatologists recognize these disorders to initiate treatment promptly and prevent morbidity.
Extra-articular manifestations can developed in 40% of patients with rheumatoid arthritis (RA). Among them rheumatoid vasculitis is a rare but potentially serious complication with a high mortality rate within 5 years [1]. The manifestation of rheumatoid vasculitis can be varied from skin lesions to nerve damage. So, the diagnosis is very challenging. It was also connected to seropositive, severe, and frequently uncontrolled RA.
In this manuscript, we reported a male patient who mainly manifested muscle weakness and myalgia accompanied by hypaesthesia. RA-associated vasculitic neuropathy was confirmed by a nerve biopsy. Our goal is to draw attention to this serious RA complication.
A 47-year-old man was admitted to our ward due to muscle weakness and atrophy in April 2021. He had symmetrical swelling and pain in his proximal interphalangeal joints (PIPs), metacarpophalangeal joints (MCPs), knees, and ankles for ten months. The rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACPA) were positive. The diagnosis of RA was made at a local hospital. Even though methylprednisolone (MP) 8 mg/d and leflunomide (LEF) 20 mg/d were taken, his joint pain remained. Worse still, he felt weakness and muscle pain in both arms and legs three months prior to admission. He also had sensation disorders in his lower limbs. Gradually, he wasn’t able to walk or stand. Furthermore, his lower limb muscles had atrophied. Infliximab was used on this patient by a local physician, but the patient’s symptoms didn’t get better. He had a history of smoking for twenty years. He had no history of drinking or drug abuse. His family history made no contribution.
On admission, swelling and tenderness of the PIPs, atrophy of the muscles of his lower limbs were noted (Fig. 1A). He had a 2/5 strength of lower limbs. A hypaesthesia to touch in both legs was noted. The pain of muscle was 9 evaluated by visual analogue scale (VAS, 0–10).
Laboratory tests revealed a high white blood cell count and a high platelet count, which were 25.1×10^9/L and 416×10^9/L, respectively. He had an elevated erythrocyte sediment rate (120 mm/h) and C-reactive protein (158 mg/L). He had positive RF (1410 U/ml) and ACPA (101 U/ml). An extensive workup revealed normal creatine kinase, thyroxine (T4) and triiodothyronine (T3) hormone, and thyroid-stimulating hormone. Anti-nuclear antibody (ANA), anti-DNA, extractable nuclear antibodies (ENA), antineutrophilic cytoplasmic antibodies (ANCA), and myositis auto-antibodies were negative. A magnetic resonance imaging (MRI) of both legs revealed extensive muscle edema (Fig. 1B).
Electromyographic results indicated muscle damage and motor nerve axonal damage. A muscle biopsy revealed few necrotizing muscle fibers without inflammation of the muscle fiber. A superficial peroneal nerve biopsy was then conducted. The result showed multiple lymphocytes infiltrated around nerves and vessels. Nerve fiber axonal degeneration as well as vessel necrosis can be seen (Fig. 1C). A diagnosis of RA and RA-related vasculitic neuropathy was made.
The patient was treated with cyclophosphamide 0.8g every 4 weeks combined with tofacitinib 5mg twice a day, followed by 1 mg/kg/day of oral prednisone for 1 month. The prednisone was then tapered. His pain reduced significantly, along with an improvement in muscle strength, to 4/5 after three months of treatment.
The vasculitic neuropathies are a diverse group of disorders characterized by the acute-to-subacute onset of painful sensory and motor deficits that result from inflammatory destruction of nerve blood vessels and subsequent ischaemic injury [2]. It can occur as a primary process or a secondary phenomenon related to various disorders, including RA [3]. In patients with RA, vasculitis is usually seen in long-standing, severe seropositive patients. Although rare, rheumatoid vasculitis is associated with significant morbidity and mortality. Vasculitic neuropathy is a consequence of peripheral nerve infarction caused by vasculitis of the vasa nervorum. Its presentations vary based on the distribution and severity of inflammation. It manifests as multiplex mononeuritis, distal symmetric sensory or sensorimotor neuropathy, or mononeuritis. Most patients have sensory and motor neuropathy [4]. The patient we reported was characterized by muscle weakness and myalgia. Exclusion of myositis is important, so both a muscle and a nerve biopsy were conducted in this patient. The result of the muscle biopsy didn’t reveal inflammation, which indicated that the muscle disorders were the “results”, not the “causes”.
Currently, there are no formal recommendations for the treatment of vasculitic neuropathy. Corticosteroids remain a first-line treatment. Most researchers recommend starting oral prednisone at a dose of 1–2 mg/kg per day [5]. Besides, most investigators recommend a cytotoxic drug. Cyclophosphamide seems to be the most effective drug for inducing remission and improving survival in non-viral systemic vasculitides. In this case, the patient got a good response after cyclophosphamide and corticosteroid treatment.
In general, vasculitic neuropathy is a rare but severe complication of RA. Intensive immunosuppression would help in controlling the disease.
RA, rheumatoid arthritis; PIP, proximal interphalangeal joints;
Ethics approval and consent to participate: The report was approved by the ethics committee of Shanghai Sixth People’s Hospital.
Consent for publication: The patient gave written informed consent for his personal or clinical details along with any identifying images to be published in this study.
Availability of data and materials: All data generated or analysed during this study are included in this published article.
Competing Interests: The authors disclosed no conflict of interest.
Funding: None.
Authors' contributions: Qian Wang wrote the main manuscript text. Hua Zhang and Qiang Tong prepared Figure 1. Sheng-Ming Dai formulated an appropriate treatment plan for this patient.
Acknowledgements: Thanks to my baby daughter, Xiao-Yi Xu, for keeping me company while I wrote this paper.
No competing interests reported.
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