Diaphragmatic ultrasound and pulmonary functions evaluation in thyroid patients: a case-control study

Abstract

Abstract Background Dyspnea is a frequent symptom among patients with thyroid disorders. However, its actual causative mechanism is not clear. The diaphragm is the main inspiratory muscle and contraction of the diaphragm is essential for breathing, so any disorder that interferes with contractile muscle function can cause diaphragm dysfunction which is associated with dyspnea. The objective of study is to assess the effect of thyroid disorders on diaphragm excursion and thickness. Results Diaphragmatic excursion during tidal, deep, and sniff respiration were significantly decreased in patients with thyroid disorder in comparison to control and significantly decreased in hypothyroid patients (right tidal 1.42 ± 0.29, right deep respiration 5.07 ± 0.72, and sniff 2.15 ± 0.26 cm) than hyperthyroid patients (right tidal 1.61 ± 0.34, right deep respiration 5.63 ± 0.50, and sniff 2.67 ± 0.27 cm) and than the control group (right tidal 2.17 ± 0.27, right deep respiration 6.63 ± 0.33, right sniff 2.89 ± 0.19 cm). Diaphragmatic thickness at end tidal inspiration was significantly decreased in patients with thyroid disorder in comparison to control (p value < 0.05). There was negative correlation between diaphragmatic excursion and duration of disease. Conclusion Diaphragmatic excursion and thickness are affected in hypothyroidism compared to hyperthyroidism and control groups. There is significant negative correlation between diaphragmatic excursion and duration of disease in patients’ group. Respiratory symptoms are more frequent in hypothyroid patients.