Dyspnea induced by right lateral decubitus

Specialty: Respiratory.

• right trepopnea
• exclusive intolerance to right lateral decubitus

Why it occurs

• Massive left pleural effusion (when lying on the right side, the weight of the fluid on the left side displaces the mediastinum downward, compressing the healthy right lung and preventing its effective ventilation)
• Unilateral right diaphragmatic paralysis (right recumbency causes the weight of the abdominal viscera to freely ascend the flaccid right diaphragm towards the thorax, limiting basal excursion)
• Intrabronchial pulmonary tumor of the left lung that collapses the airway when gravity changes
• Myxoma of the left atrium with obstruction of the mitral valve dependent on the right lateral position
• Right inferior lobar arteriovenous malformation (the position increases perfusion in the fistula due to gravity, increasing the right-left shunt).

Initial workup

Chest x-ray in two projections; Dynamic diaphragmatic and pleural space ultrasound in bilateral recumbency; Computed tomography (CT) of the chest with contrast; Functional transthoracic Doppler echocardiogram (search for myxomas, thrombi or foramen ovale with dynamic postural flow).

Standard management

• Avoid adopting the right lateral decubitus position as an immediate palliative postural measure
• Furosemide — 20-40 mg orally if the effusion is of cardiogenic origin
• Oxygen therapy with titrated nasal cannula to maintain eupneic saturation.