This paper describes the utility of flexible bronchoscopy in a sick child diagnosed with dermatomyositis, celiac disease. Mucus plug is a common medical cause of lung atelectasis. Due to deteriorated respiratory condition, the child was highly febrile, cyanotic, liver 6-7 cm, palpable under the right rib arch. We described a child with dermatomyositis and lung atelectasis. Atelectasis causes difficulty breathing and decreased oxygen saturation, so the child was intubated and put on a complete mechanical ventilation.Before intubation, the number of respirations exceeded 40/min, O2 saturation on the pulse oximeter fell under 73%. Pulse rate was 173/min, blood pressure 94/37 mmHg. Before intubation, the gas analysis of blood showed: Ph below 7.30 and pCO2 9 kPa, pO2 in the blood below 4.9 kPa. After flexible bronchoscopy was performed, therapeutic and diagnostic, lung re-expansion was enabled. After performed bronchoalveolar lavage with 0.9% NaCL 1 ml per kg TT, twice repeated, corticosteroids were introduced at the site of the changed mucus membrane. Mechanical ventilation parameters: Fio2, number of respirations and inspiratory pressure decreased. Values of gas analysis: ph improvement above 7.30 Pco2 3.6kPa, pO2 in the blood 11. O2 saturation 95%, pulse rate 120/min. The five-year-old child patient was extubated five days after bronchoscopy and was transferred to the standard Pulmonology Ward. Blood derivatives were obtained on several occasions. The condition improved, methotrexat therapy was introduced, with corticosteroids once a week, 3x40 mg i.v., on other week days Pronison 5 mg 4x1.