Paroxysmal Nocturnal Dyspnea

Paroxysmal nocturnal dyspnea (PND) is a severe shortness of breath that starts abruptly during sleep and forces the patient to sit or stand to breathe. Unlike orthopnea (dyspnea when lying flat), PND typically appears 1–3 hours after falling asleep and resolves in 15–30 minutes after assuming an upright position.

The main mechanism is increased venous return from the lower limbs in the supine position and diminished respiratory drive during sleep, both of which raise pulmonary venous pressure. It occurs most often in heart failure, especially with left ventricular systolic dysfunction.

PND is a highly specific clinical sign of heart failure and warrants urgent cardiac evaluation. Diagnosis is clinical and supported by echocardiography, BNP/NT-proBNP and chest radiography. Treatment focuses on optimizing underlying heart failure therapy with diuretics, ACE/ARB/ARNI, beta-blockers and sleep position adjustment.