010. A CURIOUS CASE OF ABDOMINAL PAIN: IGG4-RELATED PERIAORTITIS

Abstract

Background: A 46 year old gentleman of Bangladeshi origin presented to the Emergency Department with a 3 week history of bilateral Loin pain, worse in the left Loin. Methods: Clinical examination elicited left renal angle tenderness. The abdomen was otherwise soft with no signs of peritonism. The clinical impression initially was that of renal calculi and pyelonephritis; however it was noted that there were atypical features against either diagnosis. He proceeded to have a CT of the abdomen with contrast, which showed a soft tissue density thickening along the left posterolateral margin of the descending aorta. This was radiologically suspected to represent acute left infra-renal Peri-aortitis, which would account for the patient's symptoms. A subsequent PET/CT confirmed increased activity in the aortic soft tissue. The patient had significantly raised ESR and CRP. In addition IgG4 serology was performed and was strongly positive. Upon review by the Rheumatology team the patient was commenced on oral steroids and low dose azathioprine with dramatic improvement in his symptoms within 2-3 days. He was diagnosed with IgG4-related Peri-aortitis. Results: The patient has since been followed up in rheumatology outpatients, with gradual tapering of his immunosuppressants, and regular review of symptoms and clinical condition. Conclusion: IgG4-related disease has recently been documented and acknowledged as a clinical entity since early 2000. Since then further cases of IgG4 disease have been described, however the diagnosis remains rare. IgG4-related disease is an immune-mediated condition characterized by a Lymphoplasmacytic infiltrates enriched in IgG4 plasma cells, affecting various different organs. Clinical features can vary considerably, depending on the organ involved. Commonly IgG4- related disease can cause autoimmune pancreatitis, Retroperitoneal Fibrosis, Aortitis or Peri-aortitis, Thyroid disease, Lung and pleural disease, and IgG4-related sclerosing cholangitis. Peri-aortitis classically presents with dull abdominal and flank pain of insidious onset. Systemic features such as fever, weight loss, malaise and vomiting may also be present. There are limited data on the natural history of the disease. Typically, patients display a fast recovery with immunosuppressants; however relapses are common with discontinuation of therapy. The current recommendations for treatment is prednisolone 40mg/day.