The Science Journal of the American Association for Respiratory Care

2003 OPEN FORUM Abstracts


Jessica L. Dietrich, BS, RRT; Luca M. Bigatello, MD; Dean R. Hess, PhD, RRT, FAARC. Massachusetts General Hospital and Harvard Medical School, Boston MA.

Introduction: EDS is a group of autosomal dominant connective tissue disorders with an incidence of 1/150,000. The classic symptoms are joint hypermobility, hyperelasticity of the skin (soft, thin, and fragile), dystrophic scars, and excessive bleeding manifested by bruises and hematomas. The basic defect is in the synthesis and/or processing of collagen type I and III which leads to low tensile strength of the skin and arterial walls. Three mechanisms are known to occur with EDS: 1) deficiency of the collagen processing enzymes lysylhydroxylase and procollagen N-peptidase, 2) dominant-negative effects of mutant collagen alpha-chains, and 3) haploinsufficiency (mutation in a single allele in which one normal allele is not sufficient for a normal phenotype). The diagnosis is based on clinical findings and family history, DNA analysis for the specific gene defect, and skin fibroblast culture. Treatment is supportive and life expectancy is normal in the majority of cases. In an extensive literature search, we could identify no previously published case of EDS presenting as respiratory failure.

Case Summary: A 20 yr old female was transferred to our tertiary hospital with a history of end-stage pulmonary disease. The etiology was felt to be EDS Type III/IV with widespread bronchiectasis. Prior medical history included asthma at age 8 yrs (details unclear), a family history of EDS type III/IV in her mother and grandmother, anxiety, and use of home oxygen and BiPAP. Pulmonary function testing showed both obstructive and restrictive components. Baseline arterial blood gases revealed a compensated respiratory acidosis (pH 7.35, PaCO2 90 mm Hg). She was intubated secondary to acute respiratory failure. Her chest x-ray showed severe hyperinflation. Mechanical ventilation was complicated by the presence of high airways resistance, low respiratory system compliance, and severe auto-PEEP (often >10 cm H2O). She could not tolerate pressure support ventilation and multiple attempts to discontinue ventilatory support failed. Ventilator settings were tidal volume 250 - 300 mL, rate 20 - 30/min, PEEP 8 - 12 cm H2O (to counterbalance auto-PEEP), and FIO2 0.4 - 0.5. Tracheostomy was performed due to her persistent respiratory failure. Despite her respiratory failure, she was able to feed herself, ambulate with a portable volume ventilator, and navigate the Internet. Due to her ventilator dependence, she was transferred to a rehabilitation hospital, where she is awaiting lung transplantation.

Discussion: There are several lines of evidence linking EDS with this patient's pulmonary function: 1) EDS is a connective tissue disorder affecting collagen and the lungs contain collagen and elastin fibers (collagen represents 15% to 20% of lung dry weight); 2) Type IV EDS is known to produce a biochemical defect of collagen type III, and collagen types I and III are major types of collagen within the matrix of the alveolar septa, airways, and blood vessels. To our knowledge, this is the first reported case of EDS presenting as end-stage respiratory failure.