[Dermatomyositis associated with anti-MDA5 autoantibody]. / Dermatomiositis asociada al autoanticuerpo anti-MDA5.

Dematomyositis is an idiopathic inflammatory myopathy with a variable clinical spectrum. In recent years, a number of myositis-specific antibodies have been identified including anti-MDA5, which is us eful for diagnosis, prognosis and classification of the diverse clinical forms of the disease. This antibody is associated with cutaneous ulcers, rapidly progressive interstitial lung disease, early mortality and poor prognosis, so the detection of this antibody in a suitable clinical context, raises the need for an aggressive immunosuppressive treatment. We describe a case of dermatomyositis classified as hypomyopathic (i.e. involving mild muscle weakness), presenting specific skin lesions, interstitial lung disease, and presence of anti-MDA5 antibody that had a favorable response to combined treatment with cyclophosphamide, gamma globulin and corticosteroids.

[Clinical manifestations of organizing pneumonia]. / Manifestaciones clínicas de la neumonía en organización.

Organizing pneumonia is a clinical entity asociated with nonspecific symptoms and radiological findings and abnormalities in pulmonary function tests. It is defined by the characteristic histopathological pattern: filling of alveoli and respiratory bronchioles by plugs of granulation tissue. It can be idiopathic (COP) or secondary to other causes (SOP). It is an unusual finding and the clinical and radiographic findings are nonspecific. For specific diagnosis an invasive procedure has to be done, but often empirical treatment is started when there's a clinical suspicion. We describe the clinical characteristics of 13 patients with histological diagnosis of organizing pneumonia. Data was obtained from their medical records. The median age was 76 years and the median time to diagnosis from the onset of symptoms was 31 days. In 10 cases the diagnosis was made by transbronchial biopsy. 8 patients required hospitalization, 4 of them received high doses of steroids and 3 required ventilatory support. One patient died from a cause attributable to this entity and 5 relapsed. Dyspnea, cough and fever were the most frequent symptoms. Most patients had more than one tomographic pattern being the most common ground glass opacities and alveolar consolidation. Nine patients were diagnosed with COP and 4 with SOP. The most frequent underlying cause of SOP was drug toxicity. The clinical characteristics of the reported cases are consistent with previously published series. As an interesting feature, there was a group of patients that needed high doses of steroids and ventilatory support.

[Thymic neuroendocrine carcinoma with Pompe's disease of the adult]. / Carcinoma neuroendocrino de timo con enfermedad de Pompe del adulto.

Pompe disease (glycogenosis type II) is an inherited autosomal recessive lysosomal storage disease caused by a deficiency of acid alpha-glucosidase. Thymic neuroendocrine tumors, are primary thymic neoplasms with neuroendocrine differentiation that generally present as a mass within the anterior mediastinum. Both diseases are considered rare. To our knowledge the co-existence of Pompe disease and thymic neuroendocrine tumor in the same patient has not been previously reported. We could not find biological plausibility between both diseases. Further studies are needed to confirm the finding and to further increase our understanding of this association. Clinical data from epidemiological studies, case reports, case series and small formal open or controlled clinical trials may define both clinical plausibility and causality between the two conditions.

[Intrathoracic schwannoma]. / Schwannoma intratorácico.

The schwannoma (neurilemmoma) is a slow-growing benign tumor originating from Schwann sheath whose location in the chest cavity is exceptional. It is generally asymptomatic and is discovered incidentally but can cause symptoms when the lesion grows or invade underlying structures. Its importance lies in the possibility of confusion with malignant tumors. We present a patient who complains of chest pain caused by a prolonged course schwannoma. The tomographic image is suggestive of extrapulmonary tumor, so the schwannoma in this location should be considered in the differential diagnosis of metastatic or primary pleural tumors such as lipoma, solitary fibrous tumor and mesothelioma.

[Analysis of factors associated with chronic hypercapnia in patients with myotonic dystrophy]. / Análisis de factores relacionados con hipercapnia crónica en la distrofia miotónica.

Myotonic dystrophy (DM) is the most common dystrophy in adults. Several factors may explain the chronic CO2 retention. The selection of patients, different clinical stages and evaluation forms may explain the differing results obtained. Our objectives were to characterize respiratory function and to evaluate factors associated with chronic retention of CO2 in DM. We included 27 consecutive ambulatory and stable patients who were allocated into normocapnic and hypercapnic groups (PaCO2 ≥ 43 mmHg). Forced vital capacity (FVC), maximum static pressure, voluntary apnea time, Epworth scale and arterial blood gases were measured. The CO2 chemosensitivity was assessed using CO2 rebreathing (Read method). The slope ΔP0.1/ΔPCO2 expressed the CO2 chemosensitivity. A 59.3% (16/27) presented hypercapnia. FVC and respiratory muscle strength were normal or showed mild to moderate decrease. No significant differences in these variables were found in both groups. Inadequate response to CO2 (slope ΔP0.1/ΔPCO2 low (< 0.1 cm H2O/mmHg) or flat) was associated with hypercapnia (p < 0.005). Chronic retention of CO2 represented 11.56 times higher risk of inadequate response to CO2. The group with low-flat slope ΔP0.1/ΔPCO2 showed higher PaCO2 (p = 0.0017) and more prolonged voluntary apnea time (p = 0.002). We conclude that in our patients with DM, chronic CO2 retention was associated with the presence of abnormalities of the central control of breathing. Our results allow explaining previous reports describing the striking frequency of postoperative respiratory failure and difficulties in the process of weaning from mechanical ventilation.

[Hamman's syndrome in SARS-CoV-2 pneumonia]. / Síndrome de Hamman en neumonía por SARS-CoV-2.

Hamman's syndrome, or spontaneous pneumomediastinum, is the presence of air in the mediastinum without a history of previous pulmonary pathology, chest trauma or iatrogenesis. It has been described as a rare complication in patients with COVID-19 pneumonia. It is postulated that an increase in airway pressure associated with diffuse alveolar damage caused by the virus produces an air leak into the mediastinum. Chest pain and dyspnea associated with subcutaneous emphysema should make the treating physician suspicious. We introduce a 79-year-old patient who, during hospitalization for pneumonia secondary to COVID-19, suddenly developed dyspnea, chest pain, coughing spells and bronchospasm with the discovery of spontaneous pneumomediastinum on chest tomography. He evolved favorably with bronchodilator treatment and temporary oxygen therapy. Hamman's syndrome is a rare cause of respiratory failure progression in patients with COVID-19 pneumonia. Its recognition is crucial to implement the appropriate treatment.

El síndrome de Hamman, o neumomediastino espontáneo, es la presencia de aire en mediastino en pacientes sin antecedentes de enfermedad pulmonar previa, trauma torácico o iatrogenia. Se ha descrito como una complicación rara en pacientes con neumonía por COVID-19. Se postula que un aumento en la presión de la vía aérea asociado a daño alveolar difuso generado por el virus, producen una fuga de aire hacia el mediastino. El dolor torácico y disnea, asociado a enfisema subcutáneo, deben hacer sospechar al médico tratante. Presentamos un paciente de 79 años que durante su internación por neumonía secundaria al virus SARS-CoV-2 evolucionó súbitamente con disnea, dolor torácico, accesos de tos y broncoespasmo con hallazgo de neumomediastino espontáneo en la tomografía de tórax. Evolucionó favorablemente con tratamiento broncodilatador y oxigenoterapia. El síndrome de Hamman es una causa poco frecuente de progresión de insuficiencia respiratoria en pacientes con neumonía por COVID-19. Su identificación es crucial para implementar el tratamiento adecuado.

Burden and typing of rotavirus group A in Latin America and the Caribbean: systematic review and meta-analysis.

The efficacy of licensed rotavirus vaccines has only been shown against certain rotavirus group A (RV-A) types. It is critical to understand the burden of rotavirus gastroenteritis (RVGE) and its prevalent types to assess the potential impact of these vaccines in Latin America and the Caribbean (LA&C). We performed a systematic review and meta-analyses of all the available evidence reported from 1990 to 2009 on the burden of rotavirus disease and strains circulating in LA&C. Eligible studies--185 country-level reports, 174 951 faecal samples--were selected from MEDLINE, Cochrane Library, EMBASE, LILACS, regional Ministries of Health, PAHO, regional proceedings, doctoral theses, reference lists of included studies and consulting experts. Arc-sine transformations and DerSimonian-Laird random-effects model were used for meta-analyses. The proportion of gastroenteritis cases due to rotavirus was 24.3% (95%CI 22.3-26.4) and the incidence of RVGE was 170 per 1000 children-years (95%CI 130-210). We estimated a global annual mortality for 22 countries of 88.2 (95%CI 79.3-97.1) deaths per 100 000 under 5 years (47 000 deaths).The most common G type detected was G1 (34.2%), followed by G9 (14.6%), and G2 (14.4%). The most common P types detected were P[8] (56.2%), P[4] (22.1%) and P[1] 5.4%, and the most prevalent P-G type associations were P[8]G1 17.9%, P[4]G2 9.1% and P[8]G9 8.8%. In the last 10 years, G9 circulation increased remarkably and G5 almost disappeared. More recently, G12 appeared and P[4]G2 re-emerged. To our knowledge, this is the first meta-analysis of rotavirus infection and burden of disease in LA&C.

[Pulmonary alveolar proteinosis]. / Proteinosis alveolar pulmonar.

Pulmonary alveolar proteinosis (PAP) is a rare, diffuse pulmonary disease due to abnormal surfactant homeostasis. We present the case of a 69-year-old woman who was admitted to the hospital for progressive dyspnea with marked limitation in activity, and non-productive cough, of three months of evolution. Type I respiratory failure was confirmed. Chest tomography findings were interlobular and intralobular septal thickening, ground glass opacities and bilateral consolidation. Histological diagnosis was made and whole-lung lavage was performed with clinical improvement. We highlight the need to keep in mind differential diagnoses of respiratory failure and pulmonary infiltrates during COVID-19 pandemic, even rare entities such as PAP.

La proteinosis alveolar pulmonar (PAP) es una enfermedad pulmonar difusa, infrecuente, secundaria a una alteración en la homeostasis del surfactante. Se presenta el caso de una mujer de 69 años que ingresó a sala de internación por disnea progresiva hasta clase funcional III, de tres meses de evolución, asociada a tos no productiva. Se constató insuficiencia respiratoria tipo I. Como hallazgos en tomografía de tórax se evidenció engrosamiento del intersticio pulmonar intra e interlobulillar, opacidades en vidrio esmerilado y áreas con tendencia a la consolidación bilateral. Se realizó biopsia pulmonar con diagnóstico histológico de PAP y se efectuó tratamiento con lavado pulmonar total, logrando mejoría clínica. Se destaca la necesidad de tener presente diagnósticos diferenciales de insuficiencia respiratoria e infiltrados pulmonares en el contexto de la pandemia por COVID-19, incluidas las entidades muy poco prevalentes como lo es la PAP.

Síndrome de hamman en neumonía por SARS-COV-2 / Hamman's syndrome in SARS-CoV-2 pneumonia

Resumen El síndrome de Hamman, o neumomediastino es pontáneo, es la presencia de aire en mediastino en pacientes sin antecedentes de enfermedad pulmonar previa, trauma torácico o iatrogenia. Se ha descrito como una complicación rara en pacientes con neumo nía por COVID-19. Se postula que un aumento en la presión de la vía aérea asociado a daño alveolar difuso generado por el virus, producen una fuga de aire hacia el mediastino. El dolor torácico y disnea, asociado a enfisema subcutáneo, deben hacer sospechar al médico tratante. Presentamos un paciente de 79 años que du rante su internación por neumonía secundaria al virus SARS-CoV-2 evolucionó súbitamente con disnea, dolor torácico, accesos de tos y broncoespasmo con hallaz go de neumomediastino espontáneo en la tomografía de tórax. Evolucionó favorablemente con tratamiento broncodilatador y oxigenoterapia. El síndrome de Ham man es una causa poco frecuente de progresión de insuficiencia respiratoria en pacientes con neumonía por COVID-19. Su identificación es crucial para imple mentar el tratamiento adecuado.

Abstract Hamman's syndrome, or spontaneous pneumome diastinum, is the presence of air in the mediastinum without a history of previous pulmonary pathology, chest trauma or iatrogenesis. It has been described as a rare complication in patients with COVID-19 pneu monia. It is postulated that an increase in airway pres sure associated with diffuse alveolar damage caused by the virus produces an air leak into the mediastinum. Chest pain and dyspnea associated with subcutaneous emphysema should make the treating physician suspi cious. We introduce a 79-year-old patient who, during hospitalization for pneumonia secondary to COVID-19, suddenly developed dyspnea, chest pain, coughing spells and bronchospasm with the discovery of spontaneous pneumomediastinum on chest tomography. He evolved favorably with bronchodilator treatment and temporary oxygen therapy. Hamman's syndrome is a rare cause of respiratory failure progression in patients with COVID-19 pneumonia. Its recognition is crucial to implement the appropriate treatment.

Blunted Hypercapnic Respiratory Drive Response in Subjects With Late-Onset Pompe Disease.

BACKGROUND: Patients with late-onset Pompe disease develop progressive hypercapnic respiratory failure that can be disproportionate to the respiratory muscle compromise and/or thoracic restriction. Although recent studies have reported the presence of a blunted hypercapnic respiratory response in some subjects with neuromuscular disorders and chronic hypercapnia, no study has evaluated the integrity of the respiratory drive in subjects with late-onset Pompe disease. Thus, we endeavor to determine the CO2 rebreathing response in subjects with late-onset Pompe disease. METHODS: Respiratory muscle strength was assessed by measuring the maximum inspiratory pressure, and the maximum expiratory pressure. The maximum inspiratory pressure reflects the strength of the diaphragm and other inspiratory muscles, whereas the maximum expiratory pressure reflects the strength of the abdominal muscles and other expiratory muscles. We studied the hypercapnic drive response (measured as the ratio of the change in airway-occlusion pressure 0.1 s after the start of inspiration and end-tidal PCO2 in 13 subjects with late-onset Pompe disease and 51 healthy controls. RESULTS: Overall inspiratory muscle strength was within normal limits or slightly diminished in the late-onset Pompe disease group. Five subjects (38.5%) were chronically hypercapnic, and 9 (69.2%) had an increased breath-holding time. Compared with controls, the change in airway-occlusion pressure 0.1 s/change in end-tidal CO2 pressure slope (hypercapnic respiratory drive) was lower in the late-onset Pompe disease group (median 0.050 [interquartile range 0.027-0.118] vs 0.183 [0.153-0.233], P < .001). Nine subjects (69.2%) had a blunted change in airway-occlusion pressure 0.1 s/change in end-tidal carbon dioxide pressure slope. CONCLUSIONS: Subjects with late-onset Pompe disease had an impaired hypercapnic respiratory drive response. The clinical impact of this phenomenon in this subject subset deserves further investigation.

Proteinosis alveolar pulmonar / Pulmonary alveolar proteinosis

Resumen La proteinosis alveolar pulmonar (PAP) es una enfermedad pulmonar difusa, infrecuente, secundaria a una alteración en la homeostasis del surfactante. Se presenta el caso de una mujer de 69 años que ingresó a sala de internación por disnea progresiva hasta clase funcional III, de tres meses de evolución, asociada a tos no productiva. Se constató insuficiencia respiratoria tipo I. Como hallazgos en tomografía de tórax se evidenció engrosamiento del intersticio pulmonar intra e interlobulillar, opacidades en vidrio esmerilado y áreas con tendencia a la consolidación bilateral. Se realizó biopsia pulmonar con diagnóstico histológico de PAP y se efectuó tratamiento con lavado pulmonar total, logrando mejoría clínica. Se destaca la necesidad de tener presente diagnósticos diferenciales de insuficiencia respiratoria e infiltrados pulmonares en el contexto de la pandemia por COVID-19, incluidas las entidades muy poco prevalentes como lo es la PAP.

Abstract Pulmonary alveolar proteinosis (PAP) is a rare, diffuse pulmonary disease due to abnormal surfactant homeostasis. We present the case of a 69-year-old woman who was admitted to the hospital for progressive dyspnea with marked limitation in activity, and non-productive cough, of three months of evolution. Type I respiratory failure was confirmed. Chest tomography findings were interlobular and intralobular septal thickening, ground glass opacities and bilateral consolidation. Histological diagnosis was made and whole-lung lavage was performed with clinical improvement. We highlight the need to keep in mind differential diagnoses of respiratory failure and pulmonary infiltrates during COVID-19 pandemic, even rare entities such as PAP.

[Pneumonia due to Legionella pneumophila. Experience gathered in a University Hospital in Buenos Aires]. / Neumonia por Legionella pneumophila. Experiencia en un Hospital Universitario de Buenos Aires.

Legionnaires' disease is a well recognized cause of community acquired pneumonia (CAP) all around the world. In Latin America its incidence remains unknown. This study analyzed a cohort of 9 patients with CAP due to Legionella pneumophila observed from 1997 to 2001, in the Hospital de Clínicas José de San Martin, University of Buenos Aires. Clinical history included recent illnesses, work exposure, physical exam, prior antibiotic use and severity of illness criteria. None of the 9 patients had a history of recent travels, and 4 of them required admission in intensive care unit (ICU). Seven patients had a cigarette smoking history, four of them also had COPD, and one patient had a non-Hodgkin lymphoma. This study confirms the low specificity of clinical and general laboratory criteria to predict this etiology. Legionella isolation is difficult, and serological testing allows retrospective diagnosis but takes several weeks, while urinary antigen test gives a bed-side diagnosis. When Legionella appears in isolated cases, as happens in Argentina, it should be necessary to have a high index of suspicion to successfully arrive at an etiological diagnosis. Legionella pneumophila is a pathogen causing CAP in our area. A surveillance should be established preferably focused on selected populations including severe CAP, immunocompromised hosts and patients with chronic obstructive pulmonary disease.

Burden of influenza in Latin America and the Caribbean: a systematic review and meta-analysis.

OBJECTIVE: Influenza causes severe morbidity and mortality. This systematic review aimed to assess the incidence, etiology, and resource usage for influenza in Latin America and the Caribbean. DESIGN: Meta-analytic systematic review. Arcsine transformations and DerSimonian Laird random effects model were used for meta-analyses. SETTING: A literature search from 1980 to 2008 in MEDLINE, Cochrane Library, EMBASE, LILACS, Ministries of Health, PAHO, proceedings, reference lists, and consulting experts. SAMPLE: We identified 1092 references, of which 31 were finally included, in addition to influenza surveillance reports. We also used information from the 10 reports from the collaborative group for epidemiological surveillance of influenza and other respiratory virus (GROG), and information retrieved from the WHO global flu database FLUNET. MAIN OUTCOME MEASURES: Incidence, percentage of influenza specimens out of the total received by influenza centers and resource-use outcomes. RESULTS: A total of 483 130 specimens of patients with influenza were analyzed. Meta-analysis showed an annual rate of 36 080 (95%CI 28 550 43 610) influenza-like illness per 100 000 persons-years. The percentage of influenza out of total specimens received by influenza centers ranged between 4.66% and 15.42%, with type A the most prevalent, and A subtype H3 predominating. The mean length of stay at hospital due to influenza ranged between 5.8 12.9 days, total workdays lost due to influenza-like illnesses were 17 150 days, and the mean direct cost of hospitalization was US$575 per laboratory-confirmed influenza case. CONCLUSIONS: Our data show that seasonal influenza imposes a high morbidity and economic burden to the region. However, the vaccine-uptake rate has been low in this region. Population-based cohort studies are required to improve the knowledge about incidence and resource utilization, which would inform healthcare authorities for decision making.

Dermatomiositis asociada al autoanticuerpo anti-MDA5 / Dermatomyositis associated with anti-MDA5 autoantibody

La dematomiositis es una miopatía inflamatoria idiopática con espectro clínico variable. En los últimos años se ha identificado un número de autoanticuerpos específicos de miositis útiles para el diagnóstico, la clasificación y el pronóstico de las diversas formas de la enfermedad, entre los que se encuentra el anti-MDA5. Este anticuerpo se asocia al desarrollo de úlceras cutáneas, enfermedad intersticial pulmonar rápidamente progresiva, mortalidad temprana y mal pronóstico por lo que la detección del mismo, en un contexto clínico adecuado, plantea la necesidad de un tratamiento inmunosupresor agresivo. Describimos un caso de dermatomiositis hipomiopática, (es decir, con afección muscular leve) que presentaba compromiso cutáneo específico, enfermedad pulmonar intersticial y anticuerpo anti-MDA5 que respondió favorablemente al tratamiento combinado con ciclofosfamida, gamaglobulina y corticoides.

Dematomyositis is an idiopathic inflammatory myopathy with a variable clinical spectrum. In recent years, a number of myositis-specific antibodies have been identified including anti-MDA5, which is us eful for diagnosis, prognosis and classification of the diverse clinical forms of the disease. This antibody is associated with cutaneous ulcers, rapidly progressive interstitial lung disease, early mortality and poor prognosis, so the detection of this antibody in a suitable clinical context, raises the need for an aggressive immunosuppressive treatment. We describe a case of dermatomyositis classified as hypomyopathic (i.e. involving mild muscle weakness), presenting specific skin lesions, interstitial lung disease, and presence of anti-MDA5 antibody that had a favorable response to combined treatment with cyclophosphamide, gamma globulin and corticosteroids.

Epidemiology of community-acquired pneumonia in children of Latin America and the Caribbean: a systematic review and meta-analysis.

BACKGROUND: This systematic review evaluated the incidence, etiology, and use of resources in bacterial, non-tuberculosis community-acquired pneumonia (CAP) in immune-competent children aged <5 years. METHODS: Systematic searches (1980-2008) were performed using MEDLINE, Cochrane Library, EMBASE, LILACS, generic, and academic Internet searches. Regional health ministries, the Pan American Health Organization (PAHO), regional proceedings, doctoral theses, and the reference lists of included studies were also searched, and experts were consulted. Arcsine transformations and the DerSimonian-Laird random-effects model were used for proportion meta-analyses. RESULTS: The search yielded 1220 references; 60 were included in the meta-analysis, giving a total 23 854 CAP episodes with an incidence of 919/100 000 child-years in children aged <5 years. Streptococcus pneumoniae was the most frequently isolated agent (11.08%; 95% confidence interval (CI) 7.63-15.08), and pneumococcal serotype 14 was most prevalent (33.00%; 95% CI 25.95-40.45). Other common agents were Haemophilus influenzae and Mycoplasma pneumoniae. Health economics data on CAP in the region were scarce. About one-fourth of CAP patients required hospitalization (median length of stay 11 days, range 5-13.5 days). CONCLUSIONS: The burden of CAP was substantial, with S. pneumoniae, H. influenzae, and M. pneumoniae being the most common pathogens identified. High quality primary studies on disease incidence, use of health resources, and standardized data collection on disease burden and circulating strains are essential to provide baseline data for the future evaluation of vaccine impact.