Abstract
Background. Celiac trunk compression syndrome (Dunbar syndrome) is traditionally regarded as a cause of chronic abdominal ischemia. However, respiratory manifestations, including shortness of breath and exertional dyspnea, are observed in the vast majority of patients with this pathology, often leading to misdiagnosis of bronchial asthma and years of ineffective treatment. The role of the diaphragm in the pathogenesis of these disorders remains insufficiently studied.
Objective. To evaluate the functional state of the diaphragm in patients with Dunbar syndrome and respiratory complaints mimicking asthma.
Materials and methods. We examined 44 patients with verified Dunbar syndrome (mean age 23.4±4.1 years, male-to-female ratio 10:34) presenting with respiratory complaints. All patients underwent clinical examination, spirometry with bronchodilator testing, respiratory muscle strength assessment (PImax, PEmax), duplex scanning of the celiac trunk with measurement of peak systolic velocity (PSV) during inspiration and expiration, and ultrasound evaluation of the diaphragm including dome excursion amplitude and thickening fraction of the muscular part.
Results. The main complaints were shortness of breath and exertional dyspnea (98%), prolonged exercise intolerance (87%), decreased work capacity (68%), and moderate non-productive cough (20%). Bronchial asthma had been previously diagnosed in 76% of patients; however, standard anti-asthmatic therapy was ineffective in 89% of them. Respiratory muscle weakness of varying severity was detected in 64% of patients. The mean diaphragmatic excursion amplitude was 1.4±0.4 cm (normal 1.8±0.3 cm), and the mean thickening fraction was 28±7% (normal 35–50%). Thickening fraction below 30% was observed in 57% of patients. Statistically significant correlations were found between celiac trunk parameters and diaphragmatic kinetics indicators: between celiac trunk orifice diameter and excursion amplitude (r=0.31; p<0.05); orifice diameter and thickening fraction (r=0.33; p<0.05); PSV and excursion amplitude (r=–0.28; p<0.05); PSV and thickening fraction (r=–0.36; p<0.05). The strongest correlation was between peak systolic velocity and diaphragmatic thickening fraction.
Conclusion. In patients with Dunbar syndrome, respiratory complaints are caused by diaphragmatic dysfunction associated with its compression and ischemia. This requires inclusion of the syndrome in the differential diagnosis of «difficult-to-control» asthma.