Systemic lupus erythematosus (SLE) is a rare autoimmune disease in elderly [1]. Its occurrence in elderly has been reported with a rate of 10-20% [2] [2]. Several studies suggest that age influences disease expression and disease course [2]. Its onset is often insidious with usually atypical features [2] [2]. Although the involvement of peripheral nervous system is scarce, it may be the presenting feature of the disease [4] [5] [6]. We report a case of a 76 year-old woman with mononeuritis multiplex (MM) revealing a SLE.

[enlarge]

Figure 1. Histological findings of neuromuscular biopsy showed inflammatory infiltrate of muscle tissue.

A 79 year old woman with no medical history was admitted for deterioration of general condition, visual hallucinations and mood trouble associated with paresthesia of upper and lower limbs. She reported that she had moderate headaches and polyarthritis of large joints 2 years prior. Physical examination revealed arthritis of the right wrist, crackles in both lungs, an abolition of tendon reflexes and superficial hypoesthesia of upper and lower limbs. Laboratory tests showed an erythrocyte sedimentation rate (ESR) 100 at the first hour, C-reactive protein (CRP) 30 mg/l and fibrinogen level 8g/l. Blood count, renal and liver tests were within the normal ranges. Screening for antinuclear antibodies (ANA: 1/800), anti-nucleosome antibodies was positive. Antiphospholipid antibodies, both IgG and IgM, were negative. Lumbar puncture showed clear cerebrospinal fluid (CSF) with an elevated albumin level 1.7 g/l. Electroneuromyogram patterns were compatible with severe axonal polyneuropathy predominant on the lower limbs. The neuromuscular biopsy showed features compatible with vasculitis and acute sensory-motor MM (Figure 1).

[enlarge]

Figure 2. Thoracic computed tomography scan showed multiple microkystic lesions and thickened septas compatible with pulmonary fibrosis.

Our patient underwent cerebral MRI and disclosed multiple periventricular hyperintensities on T2 and FLAIR signal. Moreover, chest X ray and computed tomography scan showed bilateral pulmonary fibrosis (Figure 2). Measurement of lung function detected lung volume restriction and low diffusing capacity and echocardiography showed a pericardial effusion. The diagnosis of SLE was established on the basis of 5 American College of Rheumatology criteria. The SLEDAI score at onset was 30. The patient was treated with 3 intravenous methylprednisolone pulses linked with oral corticosteroids (1mg/kg/day), monthly pulses of intravenous cyclophosphamide (14mg/kg/day) and hydroxychloroquine: 400mg/day. Clinical course was marked by a complete recovery of neurological disorders 2 years later.

This is an uncommon case of late-onset SLE presenting with MM at the onset of the disease. Our patient fulfilled the revised criteria of SLE of the American College of Rheumatology [7]. She presented 5 of the 11 criteria with photosensivity, non-erosive arthritis, pericardial effusion, neurological features and positive ANA.

Diagnosis of SLE beyond the 6th decade of life is rather rare [1]. It is delayed with a mean lag time of 5 years in elderly because of the low rate of SLE and atypical clinical features at onset [2] [2]. Data showed that arthralgia, arthritis, renal involvement and skin lesions are less frequent in the late onset SLE [1] [8]. However, there is an increase in the frequency of interstitial pneumonitis, serositis, and cytopenias as well as peripheral neuropathy in late-onset disease. Our case is consistent with the literature.

Peripheral nervous system involvement tends to occur more frequently in the SLE elderly [9] [6] [11]. Its rate is variable according to different studies based on clinical manifestations or electroneurophysiological findings (2-30%) [4] [11]. It usually presents with severe motor and sensory dysfunctions [4] [12] [13]. MM could occur at any time, at the onset of SLE or later during its evolution [1] [6]. Indeed, neurological signs should be interpreted cautiously because several diseases may present with similar symptoms [7] [14]. The serological abnormalities of SLE in the elderly patients are also different [1] [8]. Anti-DNA antibodies and anti-Sm were rarely present [1] [8] [9], but they seem yet helpful to sustain the diagnosis of SLE in elders.

Evidence on the effectiveness of corticosteroids in SLE neuropathies is ascertained. However, it has been reported that in potentially severe motor-sensory axonal neuropathy other immunosuppressive drugs even intravenous immunoglobulins and plasmapheresis could be efficient [12]. Mortality is more common in patients with late-onset lupus; the main causes of death were infectious complications [2] [8]. MM related to SLE has a good prognosis.

This is a rare case of late-onset SLE, initially presented with MM. The atypical clinical features and late onset led to a delay of diagnosis. The immunological profile may be of paramount importance to diagnosis of SLE in elders when the approach of neurological features is tricky.