Enfermedad de células falciformes: un diagnóstico para tener presente / Sickle cell disease: a diagnosis to keep in mind

La enfermedad de células falciformes (ECF) es un trastorno genético autosómico recesivo. Es la hemoglobinopatía estructural más frecuente en todo el mundo y se produce por alteración en los genes de la cadena de globina. En Chile, no hay datos sobre la prevalencia de la ECF ya que es considerada una condición muy rara. La incidencia de esta enfermedad ha venido aumentando debido a la migra ción de personas de áreas con mayor prevalencia de ECF. Por esta razón resulta importante conocer y considerar este diagnóstico en un grupo seleccionado de pacientes con anemia, para prevenir y tratar las diferentes complicaciones de la enfermedad. En este artículo se revisan los nuevos aportes en el conocimiento de la fisiopatología, con especial énfasis en aquellas publicaciones de consenso y guías relacionadas al diagnóstico y manejo de esta entidad.

Sickle cell disease (SCD) is an autosomal recessive genetic disorder. It is the most frequent structural hemoglobinopathy worldwide, and it is produced by an alteration in the globin chain genes. In Chile, there is no data on the prevalence of SCD since it is considered a very rare condition. The incidence of this disease has been increasing due to migration of people from areas with greater presence of SCD. It is important to know and consider this diagnosis in a selected group of patients with anemia, in order to prevent and treat the different complications of this disease. This article reviews the most recent information that shows new concepts in the knowledge of the physiopathology, and especially publications of guidelines and consensus in relation to the diagnosis and management of this con dition.

Cáncer medular de tiroides esporádico de curso agresivo, en un adolescente varón / Madullary thyroid cancer in a 14 years old male: case report

Medullary thyroid cancer can appear sporadically or as part of a multiple endocrine neoplasia type 2A or 2B. In both conditions, it is associated with mutations of proto oncogene RET (rearranged during transfection). We report a 14 years old male presenting with a bone lesion in the skull followed by a hard cevical mass. A CAT scan showed an invasive thyroid nodule with involvement of regional lymph nodes , osteolytic lesions in skull, spine and ribs and liver metastases. Serum calcitonin was markedly elevated (9752 pg/ml, normal below 14 pg/ml). Fine needle biopsy showed a medullary thyroid carcinoma and the patient was subjected to a total thyroidectomy and radical cervical dissection. In the postoperative period the patient required calcium and vitamin D supplementation. Serum calcitonin 15 days after surgery was 11.692 pg/ml. Palliative radiotherapy was indicated for spine pain. A percutaneous gastrostomy was indication for nutritional support. The molecular study did not detect mutations of RET gene between exons 10 and 16.

Infección diseminada por adenovirus de curso fatal en un niño inmunocomprometido / Disseminated and fatal adenovirus infection in an immunocompromised child

Las infecciones graves por adenovirus (ADV) tienen una importancia creciente en pacientes inmuno-comprometidos, en especial en niños sometidos a trasplante de precursores hematopoyéticos (TPH). Se reporta un caso de infección por ADV inicialmente gastrointestinal y luego diseminada, de curso fatal, en un niño de 12 años, post LPH. El diagnóstico se confirmó mediante aislamiento viral y detección de genoma viral en tejidos y sangre. Se revisan los principales aspectos de la infección por ADV, su diagnóstico y las posibilidades terapéuticas. Este caso debe alertar a los médicos clínicos para sospechar y estudiar este agente viral en pacientes de alto riesgo y enfatiza la importancia de disponer en Chile de antivirales para su tratamiento.

Severe adenovirus (ADV) infections have become increasingly important in immunocompromised patients, mainly in pediatric stem cell transplant recipients. We report a case of disseminated ADV infection leading to death in a 12-year-old stem cell transplant recipient. The diagnosis was confirmed by viral isolation and viral genome detection in tissues and blood. Main issues associated with infection, diagnosis and therapeutic alternatives are reviewed. This case should alert clinicians to suspect and study this agent in high risk patients and highlights the importance of having antiviral drugs for ADV available in Chile.

Leucoencefalopatía reversible posterior: cuatro casos clínicos / Reversible posterior leukoencephalopathy syndrome in patients with immunosupressive treatment: Report of four cases

Reversible posterior leukoencephalopathy syndrome (PLS) is characterized by headache, clouding of sensorium, visual disturbances and seizures. It is associated to hypertension, renal disease or immunosuppressive therapy. We report three males, aged 9, 12 and 16 years and one female, aged 5 years wih PLS associated to immunosuppressive therapy. All had seizures and three had headache and clouding of sensorium. One case was associated to an hypertensive emergency, one to liver failure and one to high tacrolimus levels. Magnetic resonance imaging showed lesions in the white matter in two patients and in the gray matter in the other two. The lapse between the start of immunosuppressive treatment and neurological symptoms ranged from 4 days to 6 months. All received antiepileptic drugs and immunosuppresive therapy was changed or decreased, with complete clinical recovery.

Tratamiento de anemia aplásica severa adquirida en pacientes pediátricos con inmunosupresión y trasplante alogénico de precursores hematopoiéticos / Treatment of acquired severe aplastic anemia in pediatric patients with immunosupression and allogeneic stem cell hematopoyetic transplant

Background: Severe acquired aplastic anemia (SAA) is an uncommon disease of childhood. Patients with SAA receive supportive care with transfusions and timely treatment of opportunistic infections, along with specific therapies, which may be allogenic stem cell transplantation (SCT) from a matched sibling or immunosupressive therapy (IT). Aim: To report the experience in the management of SAA. Patients and methods: Twenty five children with acquired SAA were treated from July 1992 to September 2005. Patients with full matched sibling donors received allogenic SCT after conditioning with a cyclophosphamide containing regimen. The other patients received immune suppression with cyclosporine plus methylprednisolone (n= 18) plus ATG (n=17). All received supportive care until recovery of hematopoietic function. Those who had severe opportunistic infections at diagnosis or did not respond to two cycles of ATG were evaluated for unrelated donor SCT. Results: Seven patients received sibling donor SCT and 18 IT, which was repeated in six. Three patients received mismatched related (1) or unrelated (2) SCT. Nineteen patients survived with a median follow up time of 4 years, 14 with full hematologic recovery. Six patients died: four due to infections after IT or SCT, one due to intracranial hemorrhage and one with secondary myelodysplasia 12 years after IT. Conclusions: Most children with SAA can be treated successfully with sibling donor SCT or IT. Patients without a histocompatible sibling who fail to respond to IS have a worse prognosis.

Trasplante alogénico de precursores hematopoyéticos en pacientes con síndrome de Wiskott-Aldrich / Hematopoietic stem cell transplantation for patients with Wiskott-Aldrich syndrome

Background: Wiskott-Aldrich syndrome (WAS) is an X linked congenital disease that presents as eczema, thrombocytopenia and immune deficiency. The only curative procedure for this illness is hematopoietic stem cell transplant (HSCT), preferably from a healthy HLA identical sibling donor. Cord blood is becoming an excellent alternative as stem cell source from unrelated donors. Aim: To report our experience with HSCT in children with WAS. Patients and methods: Six boys with WAS diagnosed at 1 to 6 months of age were transplanted at our institution. All of them developed eczema and thrombocytopenia. Two had episodes of severe bleeding and three had repetitive infections (two with recurrent pulmonary infections and one a recurrent otitis). Three patients had a positive family history. Two received HSCT from sibling donors and four from unrelated cord blood donors at 7 months to 4 years of age. Results: AH 6 patients had full hematopoietic engraftment after transplantation. Three had mild chronic graft-versus- host disease which responded to immune suppressive therapy. One patient died of cytomegalovirus related pneumonia 111 days after grafting. The other 5 patients are alive and healthy 11 to 104 months after transplantation. Conclusions: HSCT is an effective treatment for patients with WAS. The procedure should be done as soon as diagnosis is confirmed and before life threatening infections occur.

Uso de DDAVP en pacientes portadores de enfermedad de von Willebrand sometidos a adenoamigdalectomía / Use of DDAVP in patients with von Willebrand disease undergoing adenotonsillectomy

La enfermedad de von Willebrand (EVW) es la coagulopatía más frecuente en niños. Una de las principales complicaciones de la adenoamigdalectomía es la hemorragia. Debido a su patología de base, representan un gran desafío aquellos pacientes con EVW a quienes se efectúa esta cirugía. Desde hace algunos años, se utiliza desmopresina (DDAVP) para el manejo de esta patología. Se estudiaron restrospectivamente 15 pacientes pediátricos portadores de EVW tipo I, adenoamigdalectomizados en el Hospital Clínico de la Pontificia Universidad Católica de Chile. Todos fueron hospitalizados y, previa medición del Factor VIII plasmático, se les proporcionó DDAVP. Una hora después de iniciada la infusión, se controló este factor. Si se incrementaba en 50 por ciento del valor basal, la cirugía se efectuaba sin aporte de hemoderivados; de lo contrario, se indicaba crioprecipitado. En ambos casos se utilizó ácido tranexámico como coadyuvante.La respuesta a DDAVP fue positiva en 13 pacientes (87 por ciento). En los 2 pacientes en quienes ésta no se observó se les suministró crioprecipitado. Todo el grupo estudiado evolucionó satisfactoriamente. No fue necesario utilizar crioprecipitado de apoyo o cirugías de revisión. Se concluye que DDAVP evita el uso de hemoderivados en la mayoría de los pacientes con EVW tipo I sometidos a adenoamigdalectomía, no posee efectos adversos relevantes y no aumenta los costos de la cirugía.

Leucemia prolinfocítica, descripción de dos casos / Prolymphocytic leukemia, description of 2 cases

We present the clinical and laboratory features of 2 patients with B prolymphocitic leukemia. Both are females of the fith and seventh decade of life. One had the classical clinical picture of massive splenomegaly and a high white cell count, with characteristic prolymphocytes and the other was asymptomatic, with a low white cell count. The cells were positive to B cell lineage reagents with strong surface immunoglobuline (Ig) and unreactive to T cell antibodies. Analysis of Ig genes at the DNA level demonstrated that both cases had heavy-chain gene rearrangements, confirming the B-cell origin. These are the first patients of prolymphocytic leukemia described in Chile