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Charcot-Marie-Tooth disease (CMT) is a common hereditary peripheral polyneuropathy encompassing distinct monogenetic disorders. Pathogenic mutations in mitofusin 2 (MFN2) are the most frequent cause of its axonal type, CMT type 2A, with diverse phenotypes. We herein report a Japanese patient with a novel heterozygous MFN2 pathogenic variant (c.740 G>C, p.R247P) and severe CMT phenotypes, including progressive muscle weakness, optic atrophy, urinary inconsistency, and restrictive pulmonary dysfunction with eventration of the diaphragm that developed over her 60-year disease course. Our case expands the clinico-genetic features of MFN2-related CMT and highlights the need to evaluate infrequent manifestations during long-term care of CMT patients.

Background Weaning from prolonged mechanical ventilation is extremely difficult in tracheostomized patients with restrictive pulmonary dysfunction. High-flow oxygen via tracheostomy supplies heated and humidified oxygen gas at > 10 L/minute. However, little has been reported on the use of high-flow oxygen via tracheostomy during weaning from ventilators in patients with restrictive pulmonary dysfunction. We report successful weaning from ventilators in patients with restrictive pulmonary dysfunction using high-flow oxygen via tracheostomy. Case presentation The first patient is a 78-year-old Japanese man with severe pneumococcal pneumonia who was mechanically ventilated for more than 1 month after esophagectomy for esophageal cancer. After he underwent tracheostomy because of prolonged mechanical ventilation, restrictive pulmonary dysfunction appeared: tidal volume 230–240 mL and static compliance 14–15 mL/cmH2O with 10 cmH2O pressure support ventilation. He was weaned from the ventilator under inspiratory support with high-flow oxygen via tracheostomy over a period of 16 days (flow at 40 L/minute and fraction of inspired oxygen of 0.25). The second patient is a 69-year-old Japanese man who developed aspiration pneumonia after esophagectomy and received prolonged mechanical ventilation via tracheostomy. He developed restrictive pulmonary dysfunction. High-flow oxygen via tracheostomy (flow at 40 L/minute with fraction of inspired oxygen of 0.25) was administered with measurement of the airway pressure and at the entrance of the tracheostomy tube. The measured values were as follows: 0.21–0.3 cmH2O, 0.21–0.56 cmH2O, 0.54–0.91 cmH2O, 0.76–2.01 cmH2O, 1.17–2.01 cmH2O, and 1.76–2.01 cmH2O at 10 L/minute, 20 L/minute, 30 L/minute, 40 L/minute, 50 L/minute, and 60 L/minute, respectively. The airway pressures were continuously positive and did not become negative even during inspiration, suggesting that high-flow oxygen via tracheostomy reduces inspiratory effort. He was weaned from the ventilator under inspiratory support with high-flow oxygen via tracheostomy over a period of 12 days. Conclusions High-flow oxygen via tracheostomy may reduce the inspiratory effort and enhance tidal volume by delivering high-flow oxygen and facilitate weaning from prolonged mechanical ventilation in patients with restrictive pulmonary dysfunction.

Avaliou-se a função respiratória de 40 parkinsonianos (P), entre 50 e 80 anos, nos estágio I a III da Escala de Hoehn e Yahr e de 40 não parkinsonianos (NP), com características semelhantes. A amplitude torácica de 1,8±0,8 cm nos P foi menor que 4,3±1,0 cm nos NP (p=0,00001), assim como os percentuais das capacidades vital e vital forçada de 66,8±20,3% e 69,6±22,2% nos P e de 82,3±15,7% e 82,7±16,6% nos NP (p=0,00001 e p=0,0023). Apresentaram-se equivalentes as pressões inspiratória e expiratória máximas, de 33,5±12,7 cmH2O e 36, 3±17,8 cmH2O nos P e de 37,0±12,2 cmH2O e 43,1±16,6 cmH2O nos NP (p=0,1753 e 0,0398), o volume do 1º segundo da curva expiratória forçada de 71,3±25,6% nos P e 80,6±23,6% nos NP (p=0,0899) e o percentual da capacidade vital forçada expirada em um segundo, de 104,5±19,9% nos P e 97,4±22,8% nos NP (p=0,1234). Os parkinsonianos evidenciaram restrição respiratória e diminuição de amplitude torácica, sem alteração da força muscular respiratória.We studied 40 parkinsonian patients (P), mean age 50-80 years, with Hoehn and Yahr stages I-III and 40 no parkinsonian patients (NP), with similar characteristics. The results of the thoracic amplitude was 1,8±0,8cm of P that showed a reduction to 4,3±1,0 cm of NP (p=0,00001), the vital capacity and forced vital capacity, 66,8±20,3% and 69,6±22,2% of P was decreased that 82,3±15,7% and 82,7±16,6% of NP (p=0,00001 and p=0,0023). There was not difference among the maximal inspiratory and expiratory mouth pressures, 33,5±12,7 cmH2O and 36,3±17,8 cmH2O of P and 37,0±12,2 cmH2O and 43,1±16,6 cmH2O of NP (p=0,1753 and p=0,0398), the forced expiratory volume in 1 second, 71,3±25,6% of P and 80,6±23,6% of NP (p=0,0899), and the forced expiratory volume in 1 second/ forced vital capacity, 104,5±19,9% of P and 97,4±22,8% of NP (p=0,1234). The parkinsonian patients present restrictive pulmonary dysfunction, low chest wall compliance and the respiratory muscle strenght do not decreased.