Laboratorio en reumatología / Laboratory in rheumatology

La reumatología es una subespecialidad de la medicina interna que estudia y trata pacientes con problemas músculo esqueléticos, así como también enfermedades autoinmunes que comprometen el mesenquima y diferentes órganos, teniendo en común un rol patogénico del sistema inmune. El laboratorio juega un papel importante en el proceso diagnóstico de estas condiciones. Sin embargo, a pesar del progreso y refinamiento de algunos exámenes, la baja sensibilidad y especificidad que muchos de ellos tienen, hacen que la interpretación sea ocasionalmente muy difícil. En este artículo se revisan algunas características de los exámenes más comúnmente usados en reumatología, así como su sensibilidad y especificidad en el diagnóstico de estas enfermedades. Ya que la correcta interpretación de un examen requiere una compresión de conceptos estadísticos subyacentes, se revisan en forma muy somera algunos aspectos de ellos. Como conclusión, se remarca la necesidad de cuidar la interpretación de estos resultados, para evitar lo más que se pueda el costo económico, el stress psicológico y el problema médico derivado de la mala interpretación de estos exámenes.

Rheumatology is a medical subspecialty that takes care of some non traumatic musculoskeletal problems as well as many autoimmune diseases that involves the integuments and different organs, having as a common issue a pathogenic role of the immune system. Laboratory plays an important role in the diagnosis process of these conditions. However, despite the progress and refinement of some test, lack sensitivity and specificity makes interpretation of them occasionally quite difficult. Some characteristic, disease association as well as sensitivity and specificity are reviewed here for the most common rheumatic test. Since part of a correct interpretation of a test, needs an understanding of statistical principles underneath it, in a very simple way some of them are also considered in this review. As a conclusion, an underscoring of the need to process cautiously the rheumatic test results is made, to avoid as much as it can, unnecessary test and the burden both economically, psychological and medically an incorrect diagnosis, based on a misinterpretation of a test.

Revisión general de compromiso renal en enfermedades autoinmunes / General concepts on renal involvement in rheumatic autoinmune diseases

Las enfermedades autoinmunes reumatológicas son un diverso grupo de patologías, que tienen en un común una patogenia mediada por diversos elementos del sistema inmune. Las manifestaciones clínicas son muy polimorfas, pudiendo comprometer casi cualquier órgano de la economía. Los riñones no son ajenos a esta afección y en las enfermedades autoinmunes encontramos una gran gama de enfermedades renales que involucran a los glomérulos, los túbulos, los vasos, el tejido intersticial, etc. Se revisaran las manifestaciones clínicas y anatomapatologicas más comunes de algunas de las enfermedades autoimunes sistémicas. El tratamiento solo se esboza, ya que una discusión en detalles de este sobrepasa la intención de esta revisión.

The autoinmune diseases are a heterogenous group of disease with a common underlying pathogenic mediators, that is the immune system. The clinical manifestations are highly polymorphic as well as the kidney involvement. Almost any part of the kidney can be affected by this diseases: the glomerulous, tubules, interstitial tissue and vessels. Some of the clinical and pathological manifestation of disease will be reviewed in this article. Treatment is mention only briefly because a full discussion of it is over and above the aim of this article.

Síndrome de anticuerpos antifosfolípidos / Antiphospholipid antibody syndrome

La intención de esta publicación ha sido revisar una patología emergente y de impacto reproductivo como es el síndrome antifosfolípidos. Especialmente nuestro enfoque es hacia su relación con patología obstétrica y su enfrentamiento en el embarazo. Además se revisan sus nuevos criterios diagnósticos y las nuevas estrategias para su estudio y tratamiento los que han logrado modificar en forma considerable el pronóstico y consecuencias de la enfermedad durante la gestación y el puerperio.

Actualización en el diagnóstico y terapéutica en hipertensión pulmonar arterial / Update in the diagnosis and therapy for pulmonary arterial hypertension

Pulmonary Arterial Hypertension includes a heterogeneous group of disorders with a common genetic, pathological and hemodinamyc origin. It is characterized by a high pulmonary artery pressure due to a primary vascular disease, as a consequence of genetic and environmental factors. The common pathway is a vascular imbalance towards vasoconstriction and proliferation inside the small vessels. According to the World Health Organization, 2003, Pulmonary Arterial Hypertension is classified as idiopathic, familiar or associated to connective tissue diseases, HIV, drugs, porto-pulmonary hypertension, congenital intracardiac shunts and others. The diagnosis is based in hemodynamics. Echocardiogram is a non invasive and right ventricular catheterization is an invasive diagnostic tool. Follow up is based on a clinical and functional assessment through functional class classification, dyspnea scores and 6-minute walking test. The prognosis is historically devastating but new therapies are changing the natural history of the disease. New treatments have demonstrated improvement in symptoms, hemodynamic profiles and survival. Intravenous, subcutaneous or inhaled prostanoids such as Epoprostenol, Treprostinil or Iloprost respectively have been approved for Pulmonary Arterial Hypertension treatment as well as oral endothelial receptor blockers. They are all considered first line treatments for arterial pulmonary hypertensive patients with even better benefits than lung transplantation. Phosphodiesterase inhibitors (Sildenafil), have been recently approved for the treatment of pulmonary arterial hypertension.

Caracterización clínica, funcional y hemodinámica de la población con hipertensión pulmonar arterial evaluada en el Instituto Nacional del Tórax / Clinical, functional and hemodynamic features of patients with pulmonary arterial hypertension

Background: Pulmonary Arterial Hypertension is a rare, progressive and devastating disease with severe consequences in quality of life and survival. Aim: A clinical, functional and hemodynamic assessment of patients with pulmonary arterial hypertension and categorization according to severity. Material and methods: Prospective registry of patients with arterial pulmonary hypertension, hemodynamically defined. Clinical evaluation was performed using World Health Organization functional score (I to IV) and Borg dyspnea scale. Six minute walking test, echocardiography and right heart catheterization were used for functional and hemodynamic assessment. Intravenous Adenosine was used to assess vascular reactivity during the hemodynamic evaluation. Results: Twenty nine patients were included (25 women, age range 16-72 years). Pulmonary hypertension was idiopathic in 11, associated to connective tissue disease in seven, associated to congenital heart disease in nine and associated to chronic thromboembolism in two. The mean lapse of symptoms before assessment was 2.9 years and 100% had dyspnea (Borg 5.1). Functional class I, II, III and IV was observed in 0, 5, 21 and 3 patients respectively. Six minutes walking test was 378±113 m. Mean pulmonary pressure was 59.4±12.2 mmHg, cardiac index was 2.57±0.88 and pulmonary vascular resistance index: 1798.4±855 (dyne.sec)/cm5. Nine patients had a mean pulmonary arterial pressure >55 mmHg and a cardiac index <2.1, considered as bad prognosis criteria. Adenosine test was positive in 17%. Conclusions: This group of patients with Pulmonary Arterial Hypertension was mainly conformed by young females, with a moderate to severe disease.

Manifestaciones clínicas de la granulomatosis de Wegener y la poliangeítis microscópica en Santiago-Chile, 1990-2001 / Clinical features of Wegener granulomatosis and microscopic polyangiitis in Chilean patients

Background: Systemic vasculitis are a group of heterogeneous diseases characterized by inflammation and necrosis of blood vessel walls. The etiology is not known, but geographic and environmental factors are implicated. Aim: To describe the clinical features of microscopic polyangiitis (MPA) and Wegener's granulomatosis (WG) in a Chilean cohort of patients. Patients and methods: Retrospective review of the medical records of 123 patients with the diagnosis of systemic vasculitis (65 MPA and 58 WG), seen from 1990 to 2001. The diagnosis were made based on the American College of Rheumatology and Chapel Hill criteria. Results: The mean follow-up for MPA was 15 months (1-120) and for WG, 20 months (1-120). The median age (years) at diagnosis for MPA was 61 (19-82) and WG 50 (20-82). Gender distribution was similar in both groups (male: 68percent and 57percent respectively).The main clinical features in the MPA group were renal involvement (68percent), peripheral nervous system involvement (57percent), pulmonary hemorrhage (28percent), and skin disease (32percent). In the WG group were alveolar hemorrhage (62percent), renal involvement (78percent), paranasal sinus involvement (57percent), and ocular disease (26percent). In both, creatinine levels above 2.0 mg/dl were associated with a higher mortality (p< 0.01). ANCA by immunofluorescence was performed in 56 MPA patients (75percent had pANCA, 4percent had cANCA and 21percent were ANCA negative) and in 55 WG patients (17percent had pANCA, 79percent had cANCA and 4percent were ANCA negative). Global mortality was 18percent and 17percent respectively, and the most common causes of death were infections. Conclusions: The clinical features of our patients are similar to other published data. In our WG and MPA patients the main predictor for death was a serum creatinine above 2 mg/dl.

Síndrome antifosfolípido catastrófico (SAFC): presentación de un caso clínico / Catastrophic antiphospholipid syndrome (CAPS): presentation of a clinical case

El síndrome antifosfolípidos (SAFL) es una trombofilia adquirida auto inmune, caracterizada por la ocurrencia de trombosis arteriales y/o venosas y abortos recurrentes. En raras ocasiones este cuadro puede tener una presentación catastrófica, con compromiso de microangiopatía y un curso grave de muy alta mortalidad. La frecuencia de este cuadro es menor al 1 por ciento de los SAFL, y cuando ocurre el compromiso de tres órganos se denomina síndrome antifosfolípido catastrófico (SAFC). Presentamos el caso de un paciente que debuta con una insuficiencia renal de rápida progresión, asociado a trombocitopenia y accidentes vasculares, en el cual se demuestra la presencia de anticuerpos antifosfolípidos. Se maneja con plasmaféresis, anticoagulación e inmunosupresión con excelente respuesta. Este caso es de interés por presentar un diagnóstico infrecuente de insuficiencia renal, cuyo manejo oportuno y agresivo puede cambiar el pronóstico sombrío publicado en la literatura.

Estudio del polimorfismos de receptores Fcylla en pacientes chilenos con lupus erimatoso sistémico / Polymorphisms of Fcylla receptors in chilean patients with systemic lupus erythematosus

Background: Polymorphisms of Fc receptors for IgG (FcgR) have been proposed as a genetic factor that influences susceptibility for systemic lupus erythematosus (SLE). Human FcgRIIa has 2 codominantly expressed alleles, H131 and R131, which differ at amino acid position 131 in the second extracelular domain (histidine or arginine respectively) and differ substantially in their ability to bind human IgG2. The H131 allele binds IgG2 efficiently, whereas R131 binds it poorly. Because IgG2 is a poor activator of the classical complement pathway, the H131 is essential for the disposal of IgG2 immune complexes. Aim: To determine the distribution of FcgRIIA genes in a cohort of Chilean SLE patients, with or without a history of lupus nephritis. Patients and methods: We studied 52 Chilean SLE patients fulfilling the 1982 American College of Rheumatology (ACR) criteria, 20 of whom had a history of nephritis, and 44 ethnically matched disease-free controls. FcgRIIa allotypes were genotyped by PCR. Results: No significant association was observed between the low affinity FcgRII receptor (FcgRIIa-R131) and the presence of SLE or lupus nephritis. However, genotype frequencies in SLE patients but not in controls, departed from the proportions predicted by the Hardy-Weinberg equilibrium, suggesting this locus might be related to the disease. Conclusions: Our results suggest that in Chilean patients with SLE, as well as in many other populations, the R131 allotype is not a major factor predisposing to the development of SLE or lupus nephritis

Tenosinovitis por ciprofloxacino: caso clínico / Tenosynovitis due to ciprofloxacin use: report of 1 case

We report a 67 years old diabetic female that received ciprofloxacin for an acute pyelonephritis. 12 days after starting this treatment, a hand and forearm tenosynovitis appeared, that subsided after the discontinuation of ciprofloxacin. Literature review disclosed other reports of tenosynovitis associated with the use of this antimicrobial

Aplicación de dos sistemas de evaluación, Apache y Tiss, en pacientes bronquíticos crónicos ingresados a una unidad de cuidados intensivos / Use of 2 evaluation systems, Apache and Tiss, in patients with chronic bronchitis admitted in an intensive care unit

Se analizaron 63 casos clínicos de enfermos bronquíticos crónicos ingresados a la Unidad de Cuidados Intensivos (UCI), del INERyCT, entre junio de 1985 y mayo de 1987, a los cuales se les aplicó el sistema de evaluación de gravedad APACHE y el de evaluación de acciones terapéuticas TISS, con el fin de verificar su utilidad en este tipo de pacientes. El 68% de los pacientes era de sexo masculino con una edad promedio de 66 años, la mortalidad intra-UCI fue de 32%, y aumentó a 48% al realizar un seguimiento de 6 meses. Se demostró que tanto el valor de APACHE como el de TISS fue significativamente mayor en los pacientes que posteriormente fallecieron (p<0.001). Por lo tanto, el uso de estos métodos de evaluación de gravedad, en este tipo de pacientes, permite establecer su pronóstico y evaluación vital a corto y mediano plazo