[Thrombotic thrombocytopenic purpura - a rare cause of thrombocytopenia in systemic lupus erythematosus].

History and Admission Findings: An 18-year old woman with a systemic lupus erythematosus was referred to our hospital with anaemia, thrombocytopenia and neurological symptoms. Skin haemorrhages had occurred some weeks before. The patient also noticed cardiac palpitations. After the primary care doctor had increased the dosage of prednisolone from 7.5 mg per day to 20 mg per day the symptoms didn't substantially change and that the patient was referred to hospital. An acute lupus flare was assumed.
Investigations: Laboratory examinations showed a Coombs-negative haemolytic anaemia with schistocytes. Von Willebrand factor(vWF)-cleaving protease was decreased. The presence of an inhibitor of the enzyme was proved. Further test results as anti-ds-DNA, anti-Sm, C 3, ESR, CRP were normal. C 4 was slightly decreased. Cerebral MRI, cerebral SPECT and Duplex sonography of the extracranial arteries didn't show any pathologic findings. The performed MRI of the heart revealed signs of myocardial damage.
Diagnosis, Treatment and Course: As cause of the recent symptoms a thrombotic-thrombocytopenic purpura (TTP) was diagnosed. This obviously was due to an auto-antibody against the vWF-cleaving protease. After intensive immunosuppressive therapy with prednisolone and cyclosporin the clinical and laboratory findings normalised. An acute therapy with fresh frozen plasma and plasmapheresis was not necessary, as the symptoms were moderate. Because of the transient cerebral deficits for a short time we administered a low dose of aspirin. The MRI signs of myocardial affection didn't change after 3 months of immunosuppressive treatment so that we started an ACE inhibitor treatment.
Conclusion: Thrombocytopenia in systemic lupus erythematosus demands an individual differential diagnosis. Rare causes as TTP have to be excluded. This disorder has to be diagnosed quickly and the adequate therapy has to be started early.