Amiloidosis primaria sistémica: reporte de un caso y revisión de la literatura / Primary systemic amyloidosis: a case report and literature review

La amiloidosis primaria es una gammapatía monoclonal caracterizada por la formación y depósito de fibrillas insolubles de amiloide en los espacios extracelulares de diversos órganos. El plegamiento y ensamblaje anormal de esta proteína, afecta predominantemente hígado, riñon, bazo y nervios periféricos. Estos pacientes presentan una población monoclonal de células plasmáticas en médula ósea que produce constantemente pequeños fragmentos de cadenas ligeras lambda, kappa, o inmunoglobulinas, que son procesadas de manera anómala. Su infrecuencia y múltiples manifestaciones hacen del diagnóstico un reto para el clínico, quien ante su sospecha, deberá diferenciarla de otras discrasias de células plasmáticas, por lo cual el examen físico minucioso e incisivo juega un papel fundamental en el proceso diagnóstico. En este caso presentamos a un paciente masculino de 54 años cuyo cuadro clínico es caracterizado por edema y máculas hiperpigmentadas circunscritas y descamativas en cabeza y miembros superiores, y laboratorios que revelan anemia, trombocitopenia, hipoalbuminemia, hiperglobulinemia y proteinuria. Ante la sospecha clínica de amiloidosis primaria sistémica se realiza biopsia de grasa periumbilical, donde se visualizan depósitos amiloides en tinción con rojo Congo. Posterior a tratamiento con prednisona, dexametasona y talidomida presenta respuesta hematológica por lo que recibe alta médica al alcanzar mejoría clínica satisfactoria. La ausencia de reporte de casos y revisiones de literatura en nuestra población obliga a presentar este reporte y revisión como referencia diagnóstica y terapéutica.

Primary systemic amyloidosis is a monoclonal gammopathy characterized by the synthesis and extracellular deposition of an insoluble fibrillar protein, the amyloid protein, in a variety of tissues and organs. Its three dimensional beta pleated sheet configuration and abnormal assembly mostly affects liver, kidneys, spleen and peripheral nerves. Patients show free light lambda, kappa and immnoglobulin chains that are abnormally produced by monoclonal plasmatic cell population. Its infrequency and multiple manifestations make its diagnosis a challenge for the physician, who will need to be able to differentiate it from other plasma cell dyscrasias, thus, sharp physical examination plays a key role in diagnostic process. In this case we present a 54 years old male patient consulting for edema and upper limbs descamative and well defined hyperpigmented skin lesions, revaaling anemia, thrombocytopenia, hypoalbuminemia, hyperglobulinemia and proteinuria by laboratory test. In clinical suspect of primary systemic amyloidosis, periumbilical fat biopsy was performed detecting, by Congo red staining, amyloid deposits. Then, after prednisone, dexametasone and thalidomide chemotherapy was stablished, hematologic response and medical discharge was successfully archived. Because no autochthonous case reports have been published, we feel the need to present this one, and its revision, as a diagnostic and therapeutic primary systemic amyloidosis guideline.

Role of the oblique ligament in the integrity of the medial collateral ligament of the canine elbow joint

It was studied the arrangement of the collagen fibrils of the medial collateral ligament of the canine elbow joint and evaluated its diameter, when it was isolated or associated to the oblique ligament and loaded in tension until failure. Eighteen joints were divided in three groups. The first group had the medial collateral ligament collected and not loaded, the second group had the medial collateral ligament tested separately and the third group had both ligaments associately tested. Medial collateral ligament not submitted to strain presented a wavy and reticular pattern of the collagen fibers, which was not totally destroyed when it was loaded associated to the oblique ligament, and totally loses the reticular pattern when stretched separately. When the medial collateral ligament was loaded in tension separately, the mean collagen fibrils diameter increased in relation to the group not submitted to the tensile strain. Associated to the oblique ligament, the mean collagen fibrils diameter was the largest in the insertion area and the smallest in the mid-substance, in relation to the other groups. It was concluded that the oblique ligament could favor the integrity of the medial collateral ligament insertion area, facilitating its reconstruction after lesion with larger efficiency.

Foram estudados o arranjo e o diâmetro médio das fibrilas colágenas do ligamento colateral medial da articulação do cotovelo do cão, isolado ou associado ao ligamento oblíquo e tracionado até a ruptura. Dezoito articulações foram divididas em três grupos. O primeiro grupo teve o ligamento colateral medial coletado, mas não tracionado; o segundo grupo teve o ligamento colateral medial tracionado isoladamente; o terceiro grupo teve os ligamentos colateral medial e oblíquo tracionados associadamente. O ligamento colateral medial não submetido ao ensaio de tração apresentou um padrão ondulado das fibras colágenas, o qual não foi totalmente destruído quando foi tracionado, associado ao ligamento oblíquo, e perdeu totalmente o padrão reticular das fibras colágenas quando testado isoladamente. Quando o ligamento colateral medial foi submetido à tensão isoladamente, o diâmetro médio das fibrilas colágenas aumentou em relação ao grupo não submetido à tensão. Associado ao ligamento oblíquo, o diâmetro médio das fibrilas colágenas foi o maior na região de inserção e o menor na região média, em relação aos outros grupos. Concluiu-se que o ligamento oblíquo pode favorecer a integridade da região de inserção do ligamento colateral medial, aumentando a eficácia de sua reconstrução após a lesão.