EP05 The wolf finds unusual prey
Authors: Chakravorty Mithun , Sandler Robert , El-Nayal Ayman 
Published: April 2020

Abstract

Background
Systemic lupus erythematosus (SLE) or lupus (Latin for wolf) is a rare multi-system autoimmune disease that has usually presented by the fifth decade, with a seven-fold higher incidence in females, especially of Afro-Caribbean descent. It is a recognised cause of pyrexia of unknown origin (PUO) though infection and malignancy are far commoner causes. Lupus nephritis (LN) can be life-threatening and affects nearly one-third of patients. We highlight a surprising case of late-onset SLE in a 65-year-old Caucasian man that presented with PUO and early LN.

Methods
Our patient was known to have atrial fibrillation, hypertension and previous obstructing renal calculus and presented to the Emergency Department with two weeks of right flank pain and fevers. He required critical care admission due to haemodynamic instability. CT excluded obstructive uropathy but a complex right renal cyst was present with mild inflammatory stranding. Bloods showed new neutrophilia (8.31-9.50 x 109/L), anaemia (haemoglobin 93 g/L), thrombocytopenia (platelets 90 x 109/L) and acute kidney injury (creatinine 128 μmol/l from 90 μmol/l baseline). CRP persisted above 110 mg/L. Liver function and ferritin were normal. Despite escalation of antibiotics he remained febrile, creatinine peaked at 291 μmol/L with raised urine protein:creatinine ratio (PCR) of 384 mg/mmol. Repeated septic screens and blood-borne virus tests were negative. Further CT showed mild ascites and pleural effusions. Transthoracic echocardiogram revealed a small pericardial effusion only, and pleural aspirate was a transudate, without malignant cells.

Results
There was clinical improvement after three weeks despite persistent fevers and he was discharged. However, readmission within three days necessitated inotropic support. After stabilisation, he was transferred under Infectious Diseases in a tertiary hospital. Shortly afterwards, the autoimmune screen showed positive anti-nuclear antibody (ANA), with positive Crithidia luciliae IgG double-stranded DNA (dsDNA) and titres &gt;379 IU/mL. Concurrent hypocomplementaemia (C3 0.22 g/L, C4 0.03 g/L) raised the possibility of LN with SLE and renal biopsy demonstrated class 3 LN. Prompt treatment with intravenous glucocorticoids and mycophenylate mofetil (MMF) resulted in an excellent recovery. Almost a year later, he is taking MMF 1g twice daily with prednisolone 10mg daily. His creatinine is stable at 110 μmol/L, urine PCR around 300 mg/mmol and complements have normalised, despite persistent dsDNA titre of 150 IU/mL. He continues driving taxis and reports a good quality of life.

Conclusion
There was low suspicion of SLE in this case given the absence of typical symptoms and considering his age, gender and ethnicity. A literature review of male patients with SLE suggested tendency for later-onset and a worse prognosis. There appears to be less LN but when present requires prompt immunosuppression as occurred in this case. Currently, the oldest documented male patient with both SLE and biopsy-proven LN at diagnosis was 74 years old.

Disclosures
M. Chakravorty None. R. Sandler None. A. El-Nayal None.