OBJECTIVES: Chemical pleurodesis is an important therapeutic tool to control recurrent malignant pleural effusion. Among the various sclerosing agents, iodopovidone is considered effective and safe. However, in a recent study, ocular changes were described after iodopovidone was used in recurrent pneumothorax. The aim of the study was to evaluate the efficacy and morbidity of iodopovidone pleurodesis in an experimental model. METHODS: New Zealand rabbits were submitted to intrapleural injection of iodopovidone at concentrations of 2%, 4% and 10%. Biochemical (lactic dehydrogenase, proteins, triiodothyronine, free thyroxine, urea and creatinine) and immunological (Interleukin-8 [IL-8], VEGF and TGFβ) parameters were measured in the pleural fluid and blood. After 1, 3, 7, 14 and 28 days, groups of animals were euthanized, and macro- (pleura) and microscopic (pleura and retina) analyses were performed. RESULTS: An early pleural inflammatory response with low systemic repercussion was observed without corresponding changes in thyroid or renal function. The higher concentrations (4% and 10%) correlated with greater initial exudation, and maximum pleural thickening was observed after 28 days. No changes were observed in the retinal pigment epithelium of the rabbits. CONCLUSION: Iodopovidone is considered to be an effective and safe sclerosing agent in this animal model. However, its efficacy, tolerance and safety in humans should be further evaluated.

OBJECTIVE: Pleural tuberculosis is the most frequently occurring form of extra pulmonary disease in adults. In up to 40% of cases, the lung parenchyma is concomitantly involved, which can have an epidemiological impact. This study aims to evaluate the pleural and systemic inflammatory response of patients with pleural or pleuropulmonary tuberculosis. METHODS: A prospective study of 39 patients with confirmed pleural tuberculosis. After thoracentesis, a high resolution chest tomography was performed to evaluate the pulmonary involvement. Of the 39 patients, 20 exhibited only pleural effusion, and high resolution chest tomography revealed active associated-pulmonary disease in 19 patients. The total protein, lactic dehydrogenase, adenosine deaminase, vascular endothelial growth factor, interleukin-8, tumor necrosis factor-α, and transforming growth factor-β1 levels were quantified in the patient serum and pleural fluid. RESULTS: All of the effusions were exudates with high levels of adenosine deaminase. The levels of vascular endothelial growth factor and transforming growth factor-β1 were increased in the blood and pleural fluid of all of the patients with pleural tuberculosis, with no differences between the two forms of tuberculosis. The tumor necrosis factor-α levels were significantly higher in the pleural fluid of the patients with the pleuropulmonary form of tuberculosis. The interleukin-8 levels were high in the pleural fluid of all of the patients, without any differences between the forms of tuberculosis. CONCLUSION: Tumor necrosis factor-α was the single cytokine that significantly increased in the pleural fluid of the patients with pulmonary involvement. However, an overlap in the results does not permit us to suggest that cytokine is a biological marker of concomitant parenchymal involvement. Although high resolution chest tomography can be useful in identifying these patients, the investigation of fast acid bacilli and cultures for M. tuberculosis in the sputum is recommended for all patients who are diagnosed with pleural tuberculosis.

INTRODUCTION AND OBJECTIVES: Tuberculosis and cancer are the main causes of pleural effusion. Pleural involvement is associated with migration of immune cells to the pleural cavity. We sought to characterize the immunophenotype of leukocytes in the pleural effusion and peripheral blood of patients with tuberculosis or malignancy. METHODS: Thirty patients with tuberculosis (14) or malignancy (16) were studied. A control group included 20 healthy blood donors. RESULTS: Malignant phycoerythrin pleural effusions showed higher percentages of CD3, CD4, CD3CD45RO, and CD20CD25 lymphocytes and lower percentages of CD3CD25 and CD20HLA-DR when compared to PB lymphocytes. Compared to PB, tuberculous effusions had a higher percentage of lymphocytes that co-expressed CD3, CD4, CD3CD45RO, CD3TCRαβ, CD3CD28, and CD20 and a lower percentage of CD14, CD8 and CD3TCRγδ-positive lymphocytes. Malignant effusions presented higher expression of CD14 whereas tuberculous effusions had higher expression of CD3 and CD3CD95L. Peripheral blood cells from tuberculosis patients showed higher expression of CD14, CD20CD25 and CD3CD95L. Compared with the control cells, tuberculosis and cancer peripheral blood cells presented a lower percentage of CD3CD4 and CD3CD28-positive cells as well as a higher percentage of CD3CD8, CD3CD25 and CD3CD80-positive cells. CONCLUSIONS: Tuberculous and malignant peripheral blood is enriched with lymphocytes with a helper/inducer T cell phenotype, which are mainly of memory cells. CD14-positive cells were more frequently found in malignant effusions, while CD3-positive cells expressing Fas ligand were more frequently found in tuberculous effusions.

Apesar dos relatos sobre pleurodese remontarem ao início do século XX, ainda hoje se busca o agente esclerosante ideal. Diversos agentes foram estudados e utilizados, mas o talco é considerado o mais popular. No entanto, efeitos sistêmicos potencialmente tóxicos tem sido associados à pleurodese pelo talco. Neste artigo discutimos os prováveis mecanismos de inflamação pleural e pleurodese, com ênfase na resposta sistêmica produzida pela instilação intrapleural de talco.

Although reports on pleurodesis date back to the beginning of the 20th century, the search for the ideal sclerosing agent is ongoing. Several agents have been studied and used, but talc continues to be the most popular. However, potentially harmful systemic side effects have been associated with talc pleurodesis. In this article we discuss the likely mechanisms of pleural inflammation and pleurodesis with emphasis on the systemic response due to the instillation of talc into the pleural space.

OBJETIVO: A pleurodese química representa uma ferramenta terapêutica utilizada no tratamento dos processos pleurais recidivantes, principalmente nos derrames neoplásicos. A escolha do melhor esclerosante pleural é ainda motivo de controvérsia, não havendo consenso com relação ao agente considerado ideal. O objetivo deste estudo é avaliar a efetividade dos macrolídeos (azitromicina e claritromicina) e das quinolonas (levofloxacina e gatifloxacina) na indução de pleurodese experimental em coelhos. MÉTODOS: Quarenta animais randomizados em grupos de 10, receberam, em volume total de 2 mL, estas drogas através de injeção intrapleural. RESULTADOS: Após 28 dias, os animais foram sacrificados sendo avaliada a cavidade pleural. A intensidade das aderências macroscópicas assim como da fibrose e da inflamação observadas à microscopia foi discreta tanto no grupo que recebeu macrolídeos quanto naquele que recebeu quinolonas. CONCLUSÃO: Azitromicina, Claritromicina, Levofloxacina e Gatifloxacina quando injetados na cavidade pleural de coelhos, não são eficazes na indução de pleurodese. Novas pesquisas devem ser realizadas com o intuito de identificar agentes esclerosantes capazes de produzir sínfise pleural.

PURPOSE: Chemical pleurodesis is a therapeutic tool for the treatment of recurrent pleural effusions, mainly those of neoplastic etiology. In the past, tetracycline was the sclerosant agent of choice in clinical practice, but presently, there is no consensus about an ideal agent. The aim of this study was to evaluate the effectiveness of macrolides (azithromycin and clarithromycin) or quinolones (levofloxacin and gatifloxacin) in inducing experimental pleurodesis in rabbits. METHOD: Forty New Zealand rabbits randomized into groups of 10 received (at a total volume of 2 mL for each animal) 1 of the 4 drugs by intrapleural injection. After 28 days, the animals were euthanized and the pleural cavity was evaluated macroscopically and microscopically. RESULTS: The intensity of the macroscopic adhesions was mild in all groups. On microscopic analysis, minimal pleural fibrosis and inflammation were observed in all animals. CONCLUSION: The macrolides (azithromycin or clarithromycin) and the quinolones (levofloxacin or gatifloxacin) when injected into the normal pleural space of rabbits are not effective in promoting pleurodesis. Additional research is required to identify sclerosing agents capable of inducing pleurodesis.

O linfoma primário de cavidade é um tipo raro de linfoma não-Hodgkin que acomete principalmente pacientes imunocomprometidos e, mais raramente, pacientes imunocompetentes. Neste relato de caso são apresentados os achados clínicos e laboratoriais de um paciente imunocompetente com derrame pleural diagnosticado como linfoma primário de cavidade pleural.

Primary effusion lymphoma is an unusual non-Hodgkin's lymphoma rarely seen in immunocompetent patients. Herein, we present clinical and biochemical data obtained from an immunocompetent patient diagnosed with primary effusion lymphoma.

O edema pulmonar de reexpansão é uma entidade rara, mas de notável mortalidade. Sua fisiopatologia ainda não é bem esclarecida, porém envolve fatores conhecidos, como a diminuição do surfactante pulmonar, e outros ainda incertos, como o papel dos mediadores inflamatórios na gênese e manutenção do processo. É imperativo o diagnóstico precoce, uma vez que o desfecho depende da agilidade no reconhecimento e tratamento dessa entidade. Tendo em vista a alta mortalidade, as medidas de prevenção ainda são a melhor estratégia no manuseio dos pacientes com doenças que podem levar ao edema pulmonar de reexpansão. Esta revisão discute os principais aspectos relacionados à fisiopatologia, diagnóstico, tratamento e prevenção do edema pulmonar de reexpansão, com recomendações práticas para o reconhecimento e adequada abordagem dessa entidade.

Reexpansion pulmonary edema (RPE) is a rare, but frequently lethal, clinical condition. The precise pathophysiologic abnormalities associated with this disorder are still unknown, though decreased pulmonary surfactant levels and a pro-inflammatory status are putative mechanisms. Early diagnosis is crucial, since prognosis depends on early recognition and prompt treatment. Considering the high mortality rates related to RPE, preventive measures are still the best available strategy for patient handling. This review provides a brief overview of the pathophysiology, diagnosis, treatment, and prevention of RPE, with practical recommendations for adequate intervention.

OBJETIVO DE ESTUDO: Avaliar as alterações pleuropulmonares causadas pela injeção intrapleural de talco ou nitrato de prata em modelo experimental, com o intuito de considerar sua utilização em humanos. MÉTODO: 112 coelhos foram aleatoriamente escolhidos para receber, no espaço pleural, 400mg/kg de talco em 2ml de solução salina ou 2ml de nitrato de prata a 0,5%, sendo oito animais, em cada grupo, sacrificados após um, dois, quatro, seis, oito, 10 ou 12 meses. Em relação à cavidade pleural, foram analisados o grau de pleurodese macroscópica (aderências) e as alterações microscópicas representadas por inflamação e fibrose dos folhetos pleurais. O parênquima foi avaliado quanto ao grau de colapso alveolar, edema dos septos interalveolares e celularidade em escore de 0 a 4. RESULTADOS: A injeção intrapleural de nitrato de prata produziu pleurodese mais precoce e mais intensa do que a injeção de talco. A lesão parenquimatosa foi mais evidente com nitrato de prata, sendo considerada de grau moderado e restrita à primeira avaliação (um mês). A partir do segundo mês, e durante todo o seguimento de um ano, a lesão parenquimatosa foi semelhante com ambas as substâncias, sendo apenas as aderências pleurais mais intensas com nitrato. CONCLUSÕES: O nitrato de prata intrapleural produz melhor e mais duradoura pleurodese do que a injeção intrapleural de talco. As alterações parenquimatosas, apesar de discretas, são mais pronunciadas com o uso de nitrato de prata, sendo, porém, mínimas após dois meses e semelhantes, durante todo o período de observação de um ano, às encontradas com o uso do talco. Esses efeitos sobre o parênquima pulmonar não contra-indicam seu uso em seres humanos. Dessa forma, o uso do nitrato de prata intrapleural, com o intuito de produzir rápida e efetiva pleurodese, pode ser considerado nos pacientes em que se deseja a sínfise da cavidade pleural.

OBJECTIVE: To evaluate the pleuropulmonary alterations caused by intrapleural injection of silver nitrate or talc in an experimental model, in order to consider its use in human beings. METHOD: 112 rabbits were randomly selected to receive intrapleural 0.5% silver nitrate or 400 mg/kg talc slurry in 2 ml saline. Eight rabbits of each group were sacrificed after 1, 2, 4, 6, 8, 10, or 12 months. Regarding the pleural cavity, the degree of macroscopic pleurodesis (adherences) and microscopic alterations, represented by inflammation and pleural fibrosis, were analyzed. The parenchyma was evaluated regarding the degree of alveolar collapse, intra-alveolar septum edema, and cellularity, on a 0 to 4 scale. RESULTS: Intrapleural injection of silver nitrate produced earlier and more intense pleurodesis than talc slurry injection. The parenchymal damage was more evident with silver nitrate, considered as moderate, and limited to the first evaluation (after one month). From the second month on and throughout the entire one-year follow-up, the parenchymal damage was similar with both substances, only the pleural adherences were more intense with silver nitrate. CONCLUSIONS: Intrapleural silver nitrate produces better and longer-lasting than intrapleural talc injection. The parenchymal alterations, although discreet, are more pronounced when silver nitrate is used, but minimal after two months, and similar to those produced by talc injection during the entire one-year observation period. These effects on the pulmonary parenchyma do not contraindicate the use in humans. Thus, the use of intrapleural silver nitrate to produce fast and effective pleurodesis can be considered in patients in which pleural cavity symphysis is desired.

INTRODUÇÃO: O comprometimento pleuro-pulmonar é freqüente após cirurgia de revascularização do miocárdio independente do uso de veia safena ou de artéria mamária interna. A presença de atelectasias e derrame pleural tem sido atribuída ao trauma torácico. OBJETIVOS: Definir a incidência do comprometimento pleuro-pulmonar observado através de tomografia computadorizada, analisando a influência do trauma no desenvolvimento destas complicações. MÉTODOS: Trinta pacientes foram submetidos a cirurgia eletiva de revascularização do miocárdio (8 safena e 22 também mamária com pleurotomia). Foi drenada a cavidade pleural esquerda de todos os pacientes do grupo mamária. Realizada Tomografia Computadorizada do tórax no 2º e 7º dias pós-op, avaliando-se o derrame pleural (0: sem líquido e 4: derrame em mais de 75% do hemitórax) e atelectasias (laminar: 1, segmentar: 3 e lobar: 10 pontos). RESULTADOS: Todos os pacientes apresentaram derrame pleural ou atelectasia. Entre o 2º e o 7º dia, o número de pacientes com derrame ou com atelectasia, no lado direito, diminuiu (p < 0.05). A prevalência de derrames, no 2º dia, no grupo safena, (87.5%) foi maior (p < 0.05) do que no grupo mamária (52.3%). A prevalência de atelectasias no lobo inferior direito diminuiu (p < 0.05) de 86.7% (2º dia) para 26.7% (7º dia). O grau de atelectasias, em ambos os lados, não diferiu no dia 2 (p = 0,42) mas sim no dia 7 (p < 0.0001). Houve diminuição das atelectasias do dia 2 para o 7, à direita (p < 0.001), mas não à esquerda (p = 0.21). Houve correlação (dia 2) entre as atelectasias e os derrames à direita (p = 0.04), mas não à esquerda (p = 0.113). CONCLUSÃO: Este estudo evidencia alta prevalência de derrame pleural e atelectasias após cirurgia de revascularização do miocárdio, que se reduz à direita no 7º dia de pós-operatório. Os fatores envolvidos na persis-tência das alterações à esquerda incluem o maior trauma torácico, ressaltando-se a drenagem e a presença de derrame pericárdico.

INTRODUCTION: Pleuropulmonary changes are common following coronary artery bypass grafting surgery performed with a saphenous vein graft, with or without an internal mammary artery. The presence of atelectasis or pleural effusions reflects the thoracic trauma. PURPOSE: To define the postoperative incidence of changes in the lung and in the pleural space and to evaluate the influence of the trauma. METHODS: Thirty patients underwent elective coronary artery bypass grafting surgery (8 saphenous vein grafts and 22 saphenous vein grafts and internal mammary artery grafts with pleurotomy). Chest tubes in the left pleural space were used in all internal mammary artery patients. On the second (day 2) and seventh (day 7) postoperative day, patients underwent a computed tomography, and pleural effusions were rated as follows: grade 0 = no fluid to grade 4 = fluid in more than 75% of the hemithorax. Atelectasis was rated as follows: laminar = 1, segmental = 3, and lobar = 10 points. RESULTS: All patients had pleural effusion or atelectasis. Between day 2 and day 7, the number of patients with effusions or atelectasis on the right side decreased (P < 0.05). The incidence of effusions on day 2 in the saphenous vein graft group (87.5%) was higher (P < 0.05) than in the internal mammary artery group (52.3%). The incidence of atelectasis in the lower right lobe decreased (P < 0.05) from 86.7% (day 2) to 26.7% (day 7). The degree of atelectasis in both sides did not differ on day 2 (P = 0.42) but did on day 7 (P < 0.0001). There was a decrease in the atelectasis from day 2 to day 7 on the right side (P < 0.001), but not on the left (P = 0.21). On day 2 there was a relationship between atelectasis and effusion on the right (P = 0.04), but not on the left (P = 0.113). CONCLUSION: The present series demonstrates that there is a high incidence of both minimal pleural effusion and atelectasis after coronary artery bypass grafting surgery, which drops on the right side from day 2 to day 7 post surgery. Factors that contribute to the persistence of changes on the left side include the thoracic trauma and the presence of chest tubes and pericardial effusion.

Apesar de estarmos completando praticamente um século desde a realização da primeira pleurodese, a metodologia não está consensualmente definida. A tendência atual de executarmos procedimentos minimamente invasivos estimulou novas pesquisas com o objetivo de reduzir a agressão, incluindo o uso de novas substâncias, a colocação de drenos mais finos e a redução ou abolição da necessidade de internação hospitalar. Dentre as drogas esclerosantes, o talco tem a preferência mundial. Entretanto, o possível desenvolvimento da síndrome da angústia respiratória, por vezes fatal, fez renascer o interesse por outras drogas. Os quimioterápicos não têm evidente efeito esclerosante e originam importantes efeitos colaterais. Os agentes irritantes hidróxido de sódio e nitrato de prata produzem pleurodese efetiva. Ambos podem ser utilizados em seres humanos.

This article addresses the evolution of pleurodesis since the beginning of the 20th century and defines the characteristics of the ideal sclerosing agent. Emphasis is placed on the current tendency towards minimally invasive procedures where insertion of catheters is usually given priority over certain surgical procedures such as placement of drains or thoracoscopy. Among the sclerosing drugs, talc is the one preferred throughout the world. However, the possible appearance of respiratory distress syndrome, which is sometimes fatal, caused the awakening of interest in other drugs. Anti neoplastic drugs do not induce a very efficient pleurodesis and still have the disadvantage of causing important side effects. Sodium hydroxide and silver nitrate produce effective pleurodesis. Both can be used in humans.

Não está ainda definido, qual o agente ideal para a produção de uma pleurodese efetiva. O talco é o agente mais freqüentemente utilizado apesar de suas manifestações colaterais. Outra possibilidade é o nitrato de prata, largamente usado no passado. OBJETIVOS: Determinar a influência da injeção intrapleural de lidocaina na produção de pleurodese com nitrato de prata, definir o efeito da lidocaina na maturação das fibras colágenas e confirmar que a pleurodese produzida pelo nitrato de prata é mais potente que a conseqüente à injeção intrapleural de talco. MÉTODOS: Foram estudados três grupos de 8 coelhos. Dois receberam nitrato de prata a 0,5%; em um deles, foi injetado previamente 0,5 ml de lidocaina a 2%. O terceiro grupo recebeu 2 ml de talco (400 mg/kg). Os animais foram sacrificados após 28 dias da injeção intrapleural e as cavidades pleurais examinadas macroscopicamente, analisando-se a presença de fusão entre os folhetos pleurais e microscopicamente avaliando-se a inflamação e a fibrose. Quantificou-se o total de colágeno na pleura e a distribuição de fibras finas e grossas, utilizando-se a coloração de pricrosirius. RESULTADOS: Nos dois grupos em que se injetou nitrato de prata (s/ lidocaina: 3.5 + 0.3 e com lidocaina: 3.2 + 0.3), a pleurodese macroscópica (scala 0 - 4) foi significantemente (p = 0.001) melhor do que a pleurodese resultante do talco (1.6 + 0.2). A média da fibrose pleural induzida pelo nitrato de prata (3.5 + 0.2) foi significantemente (p = 0.004) mais acentuada do que a produzida por talco (1.9 + 0.1). A instilação prévia de lidocaina determinou tendência a diminuir a quantidade de fibrose (3.1 + 0.4). A média (10³mm²) do colágeno pleural foi significantemente (p = 0.009) maior nos coelhos que receberam nitrato de prata (116.9 + 22.7) do que naqueles que receberam talco (10.7 + 3.4). A injeção de lidocaina reduziu discretamente o colágeno (80.1 + 30.3). A distribuição das fibras colágenas não foi diferente entre os grupos estudados. CONCLUSÃO: Este modelo animal confirma que, o nitrato de prata injetado no espaço pleural mais efetivo do que o talco na produção de pleurodese. A injeção intrapleural de lidocaina determina uma tendência a reduzir a quantidade de colágeno, mas não muda a efetividade da sínfise pleural ou modifica a maturação do colágeno.

The ideal agent for producing pleurodesis has not been identified. Talc, the most commonly used, poses several problems. Another possibility is silver nitrate, which was widely used in the past. PURPOSE: To determine the influence of the intrapleural instillation of lidocaine in producing a pleurodesis with silver nitrate, to define the effect of lidocaine in the maturation of the collagen fibers, and to confirm that the pleurodesis after silver nitrate is stronger than after talc. METHODS: We studied three groups of 8 rabbits. Two groups received 0.5% silver nitrate; in one we had previously injected 0.5 ml of 2% lidocaine. The third group received 400 mg/kg talc (2 ml). The animals were sacrificed 28 days after the injection, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of inflammation and fibrosis. The total amount of pleural collagen and the distribution of thick and thin collagen fibers were quantified. Collagen was identified using picrosirius red stain. RESULTS: In the two groups that received silver nitrate (without lidocaine: 3.5 + 03 and with lidocaine: 3.2 + 0.3), the macroscopic pleurodesis (scale 0 -- 4) was significantly (p = 0.001) better than that resulting from talc (1.6 + 0.2). The mean degree of pleural fibrosis induced by silver nitrate (3.5 + 0.2) was significantly (p = 0.004) higher than that induced by talc (1.9 + 0.1). The previous instillation of lidocaine resulted in a tendency for decreased amounts of fibrosis (3.1 + 0.4). The mean amount (10³mm²) of pleural collagen was significantly (p = 0.009) greater in the rabbits that received silver nitrate (116.9 + 22.7) than in those that received talc (10.7 + 3.4). The injection of lidocaine slightly reduced the collagen (80.1 + 30.3). The distribution of collagen fibers did not differ among the groups. CONCLUSION: This rabbit model clearly confirms that intrapleural silver nitrate is more effective than talc for producing pleurodesis. The previous intrapleural instillation of lidocaine results in a decreasing trend in the amount of collagen, but does not change the effectiveness of the pleural fusion or modify the process of collagen maturation.

OBJETIVO: Analisar o teste de esforço cardiopulmonar (TECP) no diagnóstico de miopatias. MÉTODOS: 27 pacientes com miopatia realizaram TECP (protocolo de bicicleta em rampa, máximo, interrompido por sintoma). RESULTADOS: Pacientes distróficos e pacientes com mitocondriopatias mostraram diferenças significativas em relação aos controles para as variáveis potência do trabalho desenvolvido (watt) e pico do consumo de oxigênio (VO2 máx). Pacientes com mitocondriopatias mostraram diminuição significativa do limiar anaeróbio em relação aos controles, além de elevação dos valores do quociente respiratório (QR) do pico do exercício em relação aos demais grupos. CONCLUSÕES: TECP pode ser útil na avaliação evolutiva do grau de limitação física dos pacientes com miopatia. As variáveis potência do trabalho desenvolvido, VO2 máx, limiar anaeróbio e QR do pico do exercício podem sugerir o diagnóstico de miopatia e seus subtipos, excluindo quadros psicológicos.

PURPOSE: To evaluate the cardiopulmonary exercise testing (CPX) for the diagnosis of myopathies. METHODS: 27 patients with myopathy were submitted to CPX testing (symptom limited bike protocol). RESULTS: Dystrophic patients and patients with mitochondrial disease, compared with controls, showed significant differences for the power of work perfomed (watt) and the maximum oxygen consumption (VO2 max). Patients with mitochondrial disease presented significantly lower values of anaerobic threshold when compared to controls and elevation of exercise peak respiratory exchange ratio (RER) values when compared to the others groups. CONCLUSIONS: CPX testing may be useful in evaluating degree of physical limitation of patients with myopathy at inicial stage as well on follow-up examinations. Power of work performed, VO2 max, anaerobic threshold and RER at exercise peak may suggest the diagnosis of myopathy and its sub-types and therefore exclude psychologic causes of limitation.