Azathioprine treatment in two children with Henoch–Schönlein purpura nephritis

Case 1

Sixteen year-old boy was hospitalised to our clinic with purpura, arthritis and abdominal pain. We diagnosed the case as Henoch-Schönlein purpura (HSP) based on the typical presentation and supportive therapy with hydration, rest and analgesics were initiated. After one week, his urinalysis revealed significant proteinuria (3.45 g/day). However, his family rejected renal biopsy.

Case 2

Fourteen year-old boy was referred to our clinic by Department of Dermatology due to HSP relelated purpura, arthralgia and abdominal pain. He was hospitalised and supportive therapy was recommended. In a two-week period, significant proteinuia (3.2 g/day) was presented and similarly, renal biopsy was rejected.

For both patients, azathioprine (AZA; 2 mg/day) + corti-costeroid (CS; 1 mg/kg/day at the beginning and tapered down) and angiotensin converting enzyme inhibitors (ACE-I) were started. Abdominal pain and purpura were improved in both patients, but proteinuria persisted. Proteinuria began to decrease after two months and urinalysis was normal at the end of six months. CS was stopped but AZA + ACE-I were continued for one year. After two years follow-up, no relaps was seen in both patients.

HSP is one of the most common vasculitides in children. Although HSP is considered to be self-limiting, approximately 7% of the cases will develop renal involvement [2]. Older children and adults are at increased risk for nephritis [3]. The diagnosis of HSPN is based upon the clinical presentation. The urinalysis reveals hematuria or proteinuria. A kidney biopsy can be done to establish the diagnosis, but this invasive procedure is generally reserved for uncertain diagnosis, proteinuria >1 g/day and/or impaired renal function.

Appropriate treatment desicion may be difficult due to the large proportion of patients with a favorable prognosis. Patients with limited evidence of renal involvement may be followed closely without specific treatment. Current guideline has recommended that children with HSPN with persistent proteinuria should be treated with ACE-I or angiotensin receptor blockers, and those with persistent proteinuria after this regimen should be treated with a 6-month course of CSs [2]. However, due to the possibility of a potentially aggressive glomerular inflammation, CSs and various immunosuppressive agents (cyclophosphamide, azathioprin, calcineurin inhibitors and others), with or without adjuvant therapies may be needed at the beginning and have been used in HSPN [1,2]. In spite of the positive results, these treatments have been found to be effective in small-sample patient studies. Due to the favorable prognosis in most of the patients with HSP, it may be hard to relate these positive results directly to the treatment regimens. In regards to significant renal involvement, we wanted to contribute to the previous data by sharing our two-years follow-up results in two children with HSPN. Well-designed prospective randomized controlled studies are still needed for these cases.