Misdiagnosis of interstitial lung diseases according to the register of Irkutsk

The course of interstitial lung diseases (ILD) is characterized by high variability. The extent and heterogeneity of ILDs inevitably leads to diagnostic difficulties. The aim of the study was to analyze misdiagnosis of ILD in patients included in the Irkutsk register. Methods. 270 patients aged 18 – 88 years with various ILDs were followed in the register. The diagnosis of ILD was based on clinical, laboratory, functional, radiological (high-resolution computed tomography (HRCT)) and, if necessary, histological findings. All diagnoses were discussed by a multidisciplinary team. Results. The time from the first signs of interstitial lesions to the diagnosis of ILD varied from several months to several years (0 – 22 years), with a median of 12 (3; 36) months. Only half of the 155 (57.4%) patients with ILD were diagnosed within one year from the first symptoms. Misdiagnoses in patients with respiratory symptoms and/or HRCT changes prior to ILD verification included various forms of pneumonia (recurrent, prolonged course) in 24.4%, pneumosclerosis in 12.6%, obstructive lung disease in 12.6%, and tuberculosis in 10.7%. The main causes of misdiagnosis were underestimation or misinterpretation of clinical, radiological and functional data. Late diagnosis is one of the factors determining progressive pulmonary fibrosis: time to diagnosis ≥ 12 months – odds ratio (OR) of 4.1 (95% confidence interval (CI) 2.4 – 7.1); p < 0.001. Conclusion. To overcome the misdiagnosis of ILD, it is necessary to inform and alert general practitioners, to maximize the effectiveness of the examination of a patient with suspected ILD, and to immediately refer such a patient to a competent specialist to diagnose ILD and verify the diagnosis with a multidisciplinary team.