Wheeze in the time of COVID-19: overcoming obstacles to an unusual diagnosis.

This case is an example of a rare cause of a common clinical presentation (persistent lobar collapse with wheeze). We describe patient management from primary care through to a national thoracic referral centre. We highlight the importance of objective testing to support an asthma diagnosis and the need to consider alternative or additional diagnoses if a patient does not respond to treatment or the clinical course is unexpected. We highlight the importance of follow-up X-ray to determine whether atelectasis has resolved, which was significantly delayed in this case due to COVID-19 restrictions. Though rare, an endobronchial tumour should be considered if atelectasis persists and when planning endoscopy for a presumed foreign body, especially if the clinical history and patient factors make a foreign body less likely. Greater awareness of this as a differential may expedite diagnoses for patients in future. We show how virtual, multicentre, multidisciplinary meetings can aid rapid diagnosis, surgical planning and coordination of follow-up across centres.

Paediatric pulmonary Langerhans cell histiocytosis.

Paediatric pulmonary Langerhans cell histiocytosis (pPLCH) is a rare diffuse cystic lung disease. Unlike pulmonary Langerhans cell histiocytosis (LCH) in adults, which is often seen as an isolated condition with smoking being a major risk factor, isolated pPLCH is vanishingly rare in children and it is most often a component of multisystem LCH. Diagnosis should be based on histological and immunophenotypic examination of affected tissue in addition to clinical and radiological features. It should be considered an important differential for diffuse cystic lung disease in paediatric patients. Recent progress in the biological understanding of the disease supports the classification of LCH as an inflammatory myeloid neoplasia. Chemotherapy and specific management of respiratory complications are the mainstays of treatment. The lungs are no longer considered a "risk organ" in LCH as pulmonary involvement is not associated with a worse prognosis than the involvement of other organs. Multidisciplinary treatment approaches are needed. Prognosis can be good but is adversely influenced by multisystem involvement, and complications such as pneumothoraces and respiratory failure can be life threatening. This review aims to give an overview of this condition, with a focus on the diagnosis, monitoring and management of complications such as pneumothoraces and respiratory failure, which can be challenging for the paediatric respiratory specialist. EDUCATIONAL AIMS: To give an overview of paediatric pulmonary LCH.To discuss the differential diagnosis of paediatric cystic lung disease.

Management of severe pulmonary Langerhans cell histiocytosis in children.

Patients with pulmonary Langerhans cell histiocytosis (LCH) typically have a benign course but may have extensive cystic lung disease with rare life-threatening complications including multiple and recurrent pneumothoraces and respiratory failure. We report seven severely affected pediatric patients treated with chemotherapy, aggressive chest tube management, and pleurodesis of whom five survived. Patients with extraordinary amounts of pulmonary cystic disease and multiple pneumothoraces due to LCH can have remarkable, curative outcomes with early recognition, optimal LCH-directed therapy, and supportive care.