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ZusammenfassungDie Granulomatose mit Polyangiitis (GPA) und die mikroskopische Polyangiitis (MPA) stellen als primäre nekrotisierende Kleingefäßvaskulitiden die häufigsten ANCA-assoziierten Vaskulitiden dar. Bei diesen, früher oft tödlich verlaufenden Erkrankungen kann heute durch eine Stadien-adaptierte Immunsuppression in den meisten Fällen eine Remission erzielt werden. Diese mündet jedoch nicht in eine Heilung oder medikamentenfreie Langzeitremission. Es bedarf deshalb einer remissionserhaltenden Therapie. Aktuelle randomisierte kontrollierte Studien zeigen, dass unter einer remissionserhaltenden Behandlung mit halbjährlich verabreichtem anti-B-Zell-Antikörper Rituximab weniger Rezidive auftreten als unter der bisherigen Standardmedikation mit Azathioprin bei vergleichbarem Nebenwirkungsprofil. Diese Daten führten 2018 zur Zulassung von Rituximab als remissionserhaltende Therapie der GPA und MPA. Unter einer solchen Rituximab-Therapie muss mit einer Immunglobulindepletion sowie späten Zytopenien mit begleitenden Infekten gerechnet werden. Leitlinien und Expertenempfehlungen zu Infektprophylaxen, Impfungen und Immunglobulinsubstitution werden in diesem Beitrag vorgestellt.

To prevent serious complications such as permanent loss of vision and structural vascular damage, treatment must be initiated quickly in patients with giant-cell arteritis (GCA). So far, usually long-term corticosteroids in cumulative high dosages have been the standard therapy option. However, steroids are often insufficient to achieve adequate disease control and are associated with serious adverse events. Therefore, steroid-sparing therapy options are the focus of interest.

The diagnosis of ANCA-associated vasculitides (AAV) consists of clinical symptoms, results of technical procedures and a characteristic histology. The diagnostic workup should focus on the prominent clinical symptoms and should involve an interdisciplinary team of specialists. The therapy is divided into induction and maintenance treatment. Cyclophosphamid remains standard therapy for the induction of remission, whereas azathioprine, methotrexate and leflunomide are often used for maintenance therapy. The introduction of a stage-adapted treatment has contributed to a significant improvement of the long-time prognosis of patients with AAV.

History A 63-year-old man developed a Churg-Strauss syndrome with predominantly motor-sensory polyneuropathy. Initial treatment with cyclophosphamide and steroids achieved complete remission. Subsequent relapse with marked retinal vasculitis at first was refractory to the standard treatment. Renewed remission was obtained with additional infliximab, and was maintained with azathioprine for 12 months before the patient again presented with symmetrical polyarthritis. Investigations Clinical examination revealed a symmetrical polyarthritis involving the joints of the hand and fingers. The acute-phase parameters were raised, the rheumafactor was highly positive. Radiology showed early erosions in the bones of the hand. There were no indices of renewed activity of the Churg-Strauss syndrome. Treatment and course These findings indicated sero-positive rheumatoid arthritis and methotrexate was started, later supplemented with sulfsalazine and hydroxychloroquine because of continuing signs of activity. Infliximab was again given because of further progression, but a severe infusion reaction developed during the second infusion. After changing to etanercept remission of the rheumatoid arthritis was achieved. Conclusion The development of rheumatoid arthritis during remission achieved with azathioprine in Churg-Strauss syndrome of four-year duration is very rare. Repeated dosis of infliximab at long intervals greatly increases the risk of an intolerance.

HISTORY AND ADMISSION FINDINGS A 28-year-old man, known to have abnormal intestinal magnesium absorption, presented with recurrent cerebral seizures. Despite daily intravenous sulphate infusions, magnesium concentration remained inadequate. Physical examination was unremarkable. INVESTIGATIONS Serum magnesium concentration was markedly reduced to 0.48 mmol/l. The parenteral magnesium tolerance test indicated reduced enteric magnesium absorption of < 20%. Absolute magnesium concentration in 24-hour urine was normal at 6.3 mmol/24 h, but high in proportion to the hypomagnesaemia. All other laboratory data were within normal limits. TREATMENT AND COURSE In addition to the known intestinal malabsorption the patient also had isolated renal loss of magnesium. It was only by continuous magnesium infusion with a recently developed portable subcutaneous pump system that normal serum magnesium concentrations were attained and all symptoms disappeared. CONCLUSION This patient has combined magnesium transport defects, which could not be effectively treated by conventional methods, but required continuous magnesium infusion with an indwelling subcutaneous infusion pump. This case serves as an example of the way in which subcutaneous infusion can provide physiological substitution of electrolytes.