Studio multi-metodologico di cristalli presenti nel liquido sinoviale patologico: microscopia elettronica, spettroscopia e micro-diffrazione a raggi X

The presence of particles and crystals in synovial fluid, easly recognizable under optical microscope, is a common feature in patients with various types of rheumatic disorders. Some crystals, such as monosodium urate (MSU), calcium pyrophosphate dihydrate (CPPD) and basic calcium phosphate (BCP), are certainly linked to specific disease (as gout, chondrocalcinosis and inflammatory osteoarthritis). In clinical practice, crystals identification is based on synovial fluid analysis made by optical microscopy in transmitted polarized light, which represents an effective outpatient procedure, relatively simple and cheap. The main disadvantages of this technique are the lack of specificity and the presence of other crystals or particles of different nature, that can create difficulties of interpretation. Almost all synovial fluid samples studied during this thesis was extracted from knee joint by arthrocentesis. Then, all samples were diluted and centrifuged in order to obtain a small amounts of crystals from the liquid, that was fixed on a suitable holder. The next step consists in synovial fluid crystals analysis by analytical techniques commonly used by geologists in the mineralogical, petrological and crystallographic fields, in order to understand their specific role in the development of the rheumatic diseases. The samples were analyzed by optical microsopy in transmitted polarized light (OM), scanning electron microscopy (SEM) equipped with EDS (chemical analysis), micro-Raman spectroscopy, X-ray powder diffraction (XRPD) and X-ray micro-diffraction (XRSC). The multi-analytical approach applied during this thesis represents a new analytical tool that will become useful to study in a very specific way crystals involved in rheumatic disorders.