Neonatal pulmonary interstitial glycogen accumulation disorder

An additional clinicohistopathological observation of neonatal pulmonary interstitial glycogenosis is described, confirming the findings in the original description by Canakis and coworkers [1]. The most striking finding is the presence of glycogen-laden cells within the interstitium of the lung. The outcome is favourable relative to other chronic interstitial lung diseases. We propose an alternative term as ‘‘glycogenosis’’ refers to a group of inborn errors of metabolism that are not related to this disease. A few hours after birth, a term infant developed signs of respiratory distress and was transferred with supplemental oxygen. Congenital heart disease was ruled out. In the hours after admission, the respiratory condition deteriorated and the baby was intubated and treated with surfactant, high frequency oscillation and nitric oxide inhalation for 12 days. Tracheal aspirate showed normal surfactant protein C and B. Chest X-ray films showed progressive hyperinflation and evolution to a mixed interstitial and alveolar pattern. Owing to chronic oxygen dependency and obvious tachypnoea, a high resolution CT scan of the chest was performed on day 55 demonstrating distortion of the lung architecture with the presence of linear opacities, mixed with areas of overinflation/emphysema and ground glass opacity. In the further work-up, cystic fibrosis was excluded and serum alpha-1-antitrypsin was normal. An infectious cause including Chlamydia, adenovirus, coxsackievirus, influenza, parainfluenza, Epstein-Barr virus, cytomegalovirus and Mycoplasma could not be demonstrated. Bacterial cultures remained sterile. A Mantoux test was negative. On day 68, an open lung biopsy was performed. Haematoxylin and eosin stained sections revealed diffuse thickening of the alveolar septae (Fig. 1A,B), while frozen sections showed the presence of abundant glycogen in the cytoplasm of the interstitial cells (Fig. 1C,D). Ultrastructural analysis of lead-contrasted ultrathin sections showed interstitial cells containing intracytoplasmic pools of high contrast granular material compatible with monoparticulate glycogen. Methylprednisolone pulse therapy was initiated at 10 mg/kg per day once daily for 3 days every month. There was no effect on oxygen need after 4 monthly treatments. The child was discharged home on supplemental oxygen at the age of 6 months and steroid therapy was continued monthly. Oxygen requirement decreased gradually and could be stopped at the age of 10 months, as was steroid therapy. He remained well except for a brief hospitalisation at the age of 1 year for a viral respiratory infection and 10 days hospitalisation at the age of 19 months because of bronchiolitis due to respiratory syncytial virus. Canakis and coworkers described seven cases of chronic interstitial lung disease (ILD) presenting with an atypical respiratory disorder during the neonatal period [1]. Most patients were symptomatic within 24 h after birth. Infectious or inflammatory causes of respiratory insufficiency were ruled out. All patients showed uniform histological features: thickened interstitium with immature interstitial cells containing abundant cytoplasmic glycogen. Although cytoplasm of occasional type 2 cells may contain residual aggregates of K. Smets (&) AE P. Vanhaesebrouck Neonatal Intensive Care Unit 1 B1, Ghent University Hospital, De Pintelaan 185, 9000 Ghent, Belgium E-mail: koenraad.smets@ugent.be Tel.: +32-9-2403535 Fax: +32-9-2406105