Hypercapnia is a medical condition characterized by an excess of carbon dioxide (CO2) in the bloodstream. This usually occurs when the body cannot effectively remove CO2 through breathing. Common causes include respiratory diseases, such as chronic obstructive pulmonary disease (COPD), or conditions that affect the central nervous system. Symptoms of hypercapnia can include headaches, dizziness, confusion, and shortness of breath. In severe cases, it may lead to respiratory failure or loss of consciousness. Treatment often focuses on improving ventilation and addressing the underlying cause to restore normal CO2 levels in the body.