Kussmaul's sign

Not to be confused with Kussmaul breathing.

Kussmaul sign is a paradoxical rise in jugular venous pressure (JVP) on inspiration. It can be seen in some forms of heart disease and is usually indicative of limited right ventricular filling due to right heart failure.

Pathophysiology

Ordinarily the JVP falls with inspiration due to reduced pressure in the expanding thoracic cavity and the increased volume afforded to right ventricular expansion during diastole. Kussmaul sign suggests impaired filling of the right ventricle due to either fluid in the pericardial space or a poorly compliant myocardium or pericardium. This impaired filling causes the increased blood flow to back up into the venous system, causing the jugular vein distension (JVD) and is seen clinically in the external jugular veins becoming more readily visible.

Causes

The differential diagnosis generally associated with Kussmaul sign is constrictive pericarditis, as well as with restrictive cardiomyopathy.

With cardiac tamponade, jugular veins are distended and typically show a prominent x descent and an absent y descent as opposed to patients with constrictive pericarditis (prominent x and y descent), see Beck's triad.

Other possible causes of Kussmaul's sign include:

• Right ventricular infarction - low ventricular compliance
• Right heart failure
• Cardiac tumours
• Tricuspid stenosis
• Restrictive cardiomyopathy
• pulmonary embolism

History

Kussmaul's sign is named after the German doctor who first described it, Adolph Kussmaul (1822-1902). He is also credited with describing Kussmaul breathing.