Difficulties associated with differential diagnosis between cystic fibrosis and primary ciliary dyskinesia

Differential diagnosis between some orphan diseases might be challenging for doctors. Cystic fibrosis and primary ciliary dyskinesia share the main pathogenetic feature, which is the accumulation of viscous inflammatory secretion in the lumen of the respiratory tract and impaired mechanisms of its escalation. Clinical manifestations of both diseases are similar. Objective. To demonstrate the difficulties associated with differential diagnosis between cystic fibrosis and primary ciliary dyskinesia on the example of a clinical case. We describe a patient who was initially diagnosed with cystic fibrosis in the Research and Clinical Institute of Childhood, but then was diagnosed with primary ciliary dyskinesia in the Department of Pulmonology, Y.E Veltischev Research and Clinical Institute for Pediatrics, N.I. Pirogov Russian National Research Medical University, Ministry of Health of Russia. This case demonstrates the need for a more careful and thorough examination of children with chronic bronchopulmonary diseases, since some of them may share most of their clinical manifestations, for example cystic fibrosis and primary ciliary dyskinesia. Key words: cystic fibrosis, ciliary dyskinesia, differential diagnosis, light microscopy, sweat test, next-generation sequencing