A purple rash

Abstract

In July, 2010, a 60-year-old white woman with uncontrolled type 2 diabetes mellitus presented with pain and swelling of the hands, wrists, and feet, and a purpuric rash on both heels. She had a 10-year history of diabetes, hypertension, and hyperlipidaemia. Before admission, her baseline creatinine concentration was 126 μmol/L (normal <88 μmol/L for women), GFR was 40 mL/min, 2+ urine protein (1·0 g/L ), and haemoglobin A11c (HbA1c ) was 68 mmol/mol. Her medications included: atorvastatin, metoprolol, bena zepril, furosemide, glargine, and glipizide. While our patient was in the emergency department, a petechial rash developed on her forearms and feet, and a vasculitic rash with tender purpuric lesions on her inner thighs. She also reported new-onset “cokecoloured” urine. There was marked symmetrical polyarticular synovitis in both hands, and oedema with tenderness to palpation in both feet. Initial laboratory tests showed a creatinine concentration of 178 μmol/L, GFR of 30 mL/min, ESR of 62 mm/h (normal <30 mm/h), C-reactive protein of 22·9 mg/L (normal <10 mg/L), and HbA1c of 112 mmol/mol (normal <42 mmol/mol). Urinalysis showed copious red and white blood cells. A vasculitic aetiology was high on our diff erential diagnosis list. We suspected Henoch-Schonlein purpura when her rash progressed to a confl uent, purpuric appearance and spread to the buttocks. Extensive autoimmune and infectious disease investi gations showed a raised titre of anti-streptolysin O. Biopsy samples of the inner thigh lesions showed leukocytoclastic vasculitis with focal deposits of IgG, IgA, IgM, and C3. A renal biopsy sample showed diabetic glomerulosclerosis, IgA nephropathy, arteriolar nephro sclerosis, mild intimal fi brosis, basement membrane thickening, and podocyte eff acement. On the basis of these fi ndings, our patient was treated with methylprednisolone, but with little improvement of her rash and joint swelling. On hospital day 5, mycophenolate mofetil and intravenous immunoglobulin were added and the rash and joint swelling resolved, but her creatinine concentration was 394 μmol/L and GFR was 16 mL/min. Despite high-dose triple therapy, her renal function worsened and haemodialysis was started. After discharge, she had haemo dialysis three times per week. At last follow-up, in May, 2011, her condition was stable. 50–80% of adults with Henoch-Schonlein purpura develop nephritis, of whom 30% progress to chronic renal insuffi ciency. To our knowledge, this is the fi rst described case of refractory Henoch-Schonlein purpura nephritis in an elderly diabetic patient treated with a novel triple combination therapy of methylprednisolone, myco phenolate mofetil, and immunoglobulin therapy chosen because our patient’s renal function was deteriorating rapidly. Studies have shown eff ective treatment of steroid-resistant Henoch-Schonlein purpura with cyclophos phamide, myco phenolate mofetil, or plasmapheresis. In a case series, myco phenolate mofetil (an immuno suppres sant used in renal transplantation), showed promise in treating refractory Henoch-Schonlein purpura. No large studies have demonstrated an eff ective treatment for the prevention of renal failure in patients with this disorder. Despite combination treatment, our patient is likely to have had underlying diabetic nephropathy compounding the renal injury from IgA deposition. Whether she would have benefi ted from plasmapheresis is unclear, but it might be considered for similar cases. Cutaneous and joint manifestations seem to respond well to steroid and immunosuppressant therapy but prevention of renal insuffi ciency remains diffi cult. In adult HenochSchonlein purpura, practitioners should be aware of the high incidence of renal involvement and its devastating outcomes if not managed aggressively.