Case presentation
A 72-year-old female presented with a two-day history of bloody diarrhoea, lower abdominal pain, vomiting, reduced appetite and fatigue. Her past medical history included hypertension, transitional cell carcinoma of the bladder and perianal fissure. On examination, she was apyrexial with a pulse rate of 105 beats per minute and blood pressure 140/95mmHg. There was generalised abdominal tenderness and soft stool in the rectum with fresh blood on per-rectal examination. Initial laboratory investigations revealed the following: white cell count 13.5×109/l (4–10×109/l), haemoglobin 158 g/l (120–150 g/l), platelets 263×109/l (150–410×109/l), C-reactive protein (CRP) 103 mg/l (0–10mg/l), serum creatinine 83µmol/l (45-84), alanine aminotransferase (ALT) 12 IU/l (5-65), alkaline phosphatase 80 IU/l (30–130) and total bilirubin 10µmol/l (<20). The initial clinical impression was that of diverticulitis and she was managed with intravenous antibiotics, analgesia and antiemetics. A computed tomography (CT) scan of the abdomen and pelvis was performed which showed no evidence of acute diverticulitis. However, wall thickening was noted in the distal ileum with perienteric fat stranding and perienteric fluid collections (Figure 1).

Figure 1 CT scan showing wall thickening of the distal ileum (white arrows) with evidence of perienteric fat stranding and fluid collection (red arrows).
Furthermore, there was associated congestion of the small bowel mesentery with sub-centimetre mesenteric lymphadenopathy. The radiologist concluded that overall, the appearance was suggestive of acute inflammation in the ileum with differentials of Crohn’s disease or infectious ileitis. The patient made good clinical progress with conservative management. A few days after discharge, she developed a purpuric rash on her lower limbs. She was investigated further by her general practitioner (GP) with a series of urine dipstick and urine protein-creatinine Ratio (PCR) tests. This revealed consistent haematuria and sub-nephrotic range proteinuria with a urine PCR of
201mg/mmol (<15 mg/mmol). Additional immunology screening showed normal antinuclear antibodies (ANA), antineutrophil cytoplasmic antibodies (ANCA) and myeloma screen. She was reviewed by the nephrologist who started her on 2mg perindopril once daily. She also underwent an elective renal biopsy which revealed mesangial proliferation with strong mesangial IgA deposition, in keeping with IgA vasculitis (Figure 2). She was treated with a tapering course of oral prednisolone over six months, which induced remission with a decrease in her urine protein/creatinine ratio (PCR) to
75mg/mmol and complete resolution of her symptoms.

