- Inflammatory syndrome without any clinical sign, Important inflammatory syndrome: Erythrocyte sedimentation rate ≥ 50 at the first hour, and elevation of at least one another inflammatory parameter (haptoglobin, orosomucoïd, fibrinogen or C-reactive protein), Evolution since more than 3 weeks, No diagnostic orientation after clinical examination and history-taking, No diagnostic clue after 3 days of hospitalisation.