Resumen: La vasculitis reumatoidea es una complicación sistémica y poco frecuente de la Artritis Reumatoidea. Si bien su incidencia ha descendido en los últimos años con el advenimiento de las nuevas terapias inmunosupresoras y biológicas, continua teniendo una alta morbimortalidad. Predomina en el sexo masculino, en pacientes seropositivos y con un largo período de la enfermedad establecida. Requiere de alta presunción diagnostica, siendo el compromiso cutáneo y nervioso periférico el más frecuente. La biopsia de nervio o piel es requerida habitualmente para su diagnóstico. El tratamiento se basa en corticoides e inmunosupresores. Presentamos tres casos clínicos y realizamos una revisión de la literatura.

Abstract: Rheumatoid vasculitis is a rare systemic complication of rheumatoid arthritis. Although its incidence has decreased in recent years with the advent of new immunosuppressive and biological therapies, it continues to have a high morbidity and mortality. It predominates in males, in seropositive patients and with a long period of established disease. It requires high diagnostic presumption, with skin and peripheral nervous involvement being the most affected. Nerve or skin biopsy is usually required for diagnosis. Treatment is based on corticosteroids and immunosuppressants. We present three clinical cases and carry out a review of the literature.

Resumo: A vasculite reumatóide é uma complicação sistêmica rara da artrite reumatóide. Embora sua incidência tenha diminuído nos últimos anos com o advento de novas terapias imunossupressoras e biológicas, continua apresentando elevada morbidade e mortalidade. Predomina no sexo masculino, em pacientes soropositivos e com longo período de doença estabelecida. Exige alta presunção diagnóstica, sendo o envolvimento cutâneo e nervoso periférico os mais afetados. A biópsia de nervo ou pele geralmente é necessária para o diagnóstico. O tratamento é baseado em corticosteroides e imunossupressores. Apresentamos três casos clínicos e realizamos uma revisão da literatura.

In this study, Fourier transform infrared spectroscopy (FT-IR) was employed to investigate the gaseous pyrolysis products of ethylene - propylene - diene rubber (EPDM). The objective was to evaluate the potential of FT-IR analysis of gaseous pyrolyzates (PY-G/FT-IR) for characterization of EPDM additives. Two EPDM formulations, containing additives typically employed in EPDM rubbers, were analyzed. Initially, gaseous pyrolysis products from paraffin oil, stearic acid, 2,2,4-trimethyl-1,2-dihydroquinoline, tetramethylthiuram monosulfide (TMTM), tetramethylthiuram disulfide (TMTD), and 2-mercaptobenzothiazole (MBT) were characterized separately, and their main absorptions were identified. Subsequently, the gaseous pyrolysis products of raw, unvulcanized, and vulcanized EPDM formulations were analyzed. The similarities observed in the FT-IR spectra of unvulcanized and vulcanized EPDM show that the vulcanization process does not interfere with the pyrolysis products. The identification of the functional groups of the studied additives was possible in both unvulcanized and vulcanized EPDM samples, without solvent extraction. Results also demonstrate that the PY-G/FT-IR technique can identify additives containing sulfur in concentrations as low as 1.4 phr (1.26%) in both unvulcanized and vulcanized EPDM. However, the method showed some limitation due to overlapping and to similarities of TMTM and TMTD PY-G/FT-IR spectra, which could not be distinguished from each other. The PY-G/FT-IR technique is a faster and cheaper alternative to the sophisticated techniques usually applied to detection of additives in rubbers.