Kussmaul's sign, named after the German doctor Adolf Kussmaul, is the enlargement of the jugular veins as a result of increased pressure when a person inhales. This condition can have many different heart-related causes; among the most common are congestive heart failure and constrictive pericarditis, both of which are potentially fatal. The appearance of Kussmaul's sign during a physical exam can alert a medical practitioner to the possible existence of these heart problems.
Kussmaul's sign is named after the German physician Adolf Kussmaul, who first reported the jugular symptoms in patients with constrictive pericarditis and other heart conditions. His name is used in the medical world to describe the enlargement of the jugular veins as well as various other conditions he noted, such as Kussmaul's breathing and Kussmaul's coma. Adolf Kussmaul is also credited with first characterizing a number of other conditions, including a learning disability called dyslexia.
In healthy people, the jugular vein doesn't really appear prominent during inhalation. When one inhales, the pressure in the veins is focused on the right section of the heart, which causes the veins to be less visible during inhalation. In some people, however, the jugular veins become enlarged during inhalation. This occurrence can mark the existence of a heart condition, such as heart failure or constrictive pericarditis, that increases the blood pressure in a person's veins. The pressure is the reason the veins of the jugular stick out during inhalation.
Constrictive pericarditis, which is one of the conditions marked by Kussmaul's sign, is characterized by the inflammation of the heart's outer covering. This causes the covering to harden and stop the chambers of the heart from properly filling with blood. As a result, there is much more pressure on the veins, and they may appear enlarged. This change is usually easiest to detect when a person inhales.
A person with congestive heart failure may also exhibit Kussmaul's sign. In fact, the sign is most commonly associated with this medical condition. When a person inhales, the pressure in the veins is carried to the right section of the heart. Congestive heart failure of the right side can cause the pressure to remain in the jugular veins instead of passing over to the right side of the heart as normal. This buildup of pressure can then make the jugular veins stick out, as normally occurs when a patient develops Kussmaul's sign.