Spontaneous Pneumomediastinum May Be Associated with Both Anorexia Nervosa and Obesity

Abstract

We read with great interest the article by Mondello et al. about spontaneous pneumomediastinum (SPM) which was recently published in Lung [1]. In their study, the authors presented their experience with 18 patients with SPM and discussed their symptomatology, diagnosis, treatment, and follow-up. An interesting finding in this review was that the majority of patients (10 of 18, 55%) were overweight or even obese. As the authors state, this was the first description of a possible association between obesity and SPM. In our opinion, this is a very intriguing association because SPM has also been associated with anorexia nervosa (AN) [2, 3]. In 1997, our group presented the case of a young woman with AN who also had SPM and diffuse soft tissue emphysema [2]. SPM is a rare but well-described complication in AN patients. To our knowledge there are only 21 such cases [3]. In these cases, Body mass index (BMI) ranged from 10.8 to 15 kg/m. Purging behavior such as self-induced vomiting is a prominent symptom in AN patients and may lead to SPM. However, vomiting was the precipitating factor [3] in only three of the 21 AN patients with SPM. The rest did not have a history of vomiting. Thus, it seems that SPM in AN patients has a different pathogenesis. Indeed, there are increasing data showing that malnutrition leads to atrophic changes in connective tissue, such as hypoplasia, thin alveolar walls, large alveoli, reduction or absence of building fat, and gelatinous transformation [4, 5]. Thus, it is believed that even a minimal increase of intra-alveolar pressure, which may occur during common daily activities, can be the cause of repeated air leaks through thin and atrophic alveolar walls in AN patients [2]. Interestingly, Mondello et al. found that the majority of SPM patients were overweight or even obese. Unfortunately, Mondello et al. did not provide data about BMI in these patients. However, it seems possible that SPM could be associated with extreme values of BMI—either extremely low or extremely high, which is the case in obesity and anorexia nervosa, respectively. At present, there are no data on the pathogenesis of SPM in obese people. We believe that more studies are necessary to investigate if obesity and anorexia nervosa share common pathophysiologic features that lead to spontaneous pneumomediastinum.