Learn all about Kussmaul sign mechanism, pathophysiology, causes and treatment. Kussmaul sign is a paradoxical rise in jugular venous pressure (JVP) with inspiration. Normally during inspiration, the negative intrathoracic pressure causes a fall in systemic venous pressure and therefore a drop in the jugular venous pressure. However, in patients with constrictive pericarditis, the thickened pericardium causes the transmission of intrathoracic pressure to the chambers of the heart to fail; thus the venous pressure does not decrease. It can be seen in some forms of heart disease and is usually indicative of limited right ventricular filling due to right heart dysfunction.
Kussmaul Breathing can also be explained as a form of hyperventilation which is a condition in which an individual breathes in such a deep pattern that the level of carbon dioxide decreases in the blood, which is seen mostly in metabolic acidosis where the breathing becomes extremely fast and shallow and as the condition worsens the breathing becomes shallow and deep and it looks as if the individual is virtually gasping for breath.
The reduction in pulse volume during inspiration was first described by Lomer in 1669 in constrictive pericarditis. A similar finding was described by Floyer and later by William in 1850 in bronchial asthma. Adolf Kussmaul (Freiberg, Germany) coined the term “pulsus paradoxus” in 1873 in three patients with constrictive pericarditis. The “paradox” was: the discrepancy between the absence of the pulse and present corresponding heart beat and amidst this irregularity, the regularity with which the pulse disappeared during inspiration.
The inspiratory increase in jugular venous pressure amplitude is Kussmaul’s sign. It was first described in 1873 and is clearly evident in the Movie. Although commonly ascribed to pericardial constriction, it is also a marker of intrinsic right ventricular diastolic dysfunction. The fact that Kussmaul’s sign was not demonstrated at the time of cardiac catheterization is a salutary lesson that signs of hemodynamically significant cardiac pathology can be masked by relative hypovolemia.
Increased jugular venous pressure with inspiration is commonly referred to as Kussmaul’s sign; and the disappearance of the radial pulse or a drop in systolic blood pressure of 10 mmHg or greater with inspiration is recognized as pulsus paradoxus. Both Kussmaul’s sign and pulsus paradoxus are commonly attributed to the discoveries of Dr. Adolf Kussmaul. Together these two clinical signs are important assessors of pericardial or mediastinal disease.
What is kussmaul sign
Kussmaul’s sign is a paradoxical increase in the peripheral venous distension and pressure during inspiration. The major mechanism is a change in the shape of the pericardium with a resulting increase in the intrapericardial pressure and obstruction to the venous return to the heart.
Kussmaul sign Mechanism
The process occurs as follows:
- Normally there is inspiratory decrease in intrathoracic pressure
- In the condition mentioned above, the pericardium / myocardium is stiff
- The negative intrathoracic pressure is not transmitted to the heart
- The heart cannot accommodate the increased blood flow that occurs during inspiration
- Hence the jugular venous pressure will be elevated
Kussmaul sign 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 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 internal jugular veins becoming more readily visible.
Kussmaul sign Causes
The following medical conditions are some of the possible causes of Kussmaul’s sign. There are likely to be other possible causes, some possible causes of Kussmaul sign include:
- Right ventricular infarction – low ventricular compliance
- Right heart failure
- Cardiac tumour
- Tricuspid stenosis
- Restrictive cardiomyopathy
- Pulmonary embolism
- Constrictive pericarditis
- Cardiac tamponade
- Pericardial effusion
- Acute myocardial infarction
- Cardiogenic shock
- Bronchial asthma
- Tension pneumothorax
- Anaphylactic shock (during urokinase administration)
- Volvulus of the stomach
- Diaphragmatic hernia
- Superior vena cava obstruction
- Extreme obesity
- Diabetic Ketoacidosis
- Metabolic Acidosis
Kussmaul sign Treatment
Kussmaul sign treatment depends upon the underlying condition which in majority of the cases is uncontrolled diabetes or kidney failure. The underlying cause for the uncontrolled diabetes or renal failure needs to be treated first which may automatically treat Kussmaul Breathing. Some of the treatment options are;
- Diuretics (“water pills”) are commonly prescribed in small doses to help the body remove excess fluid. Analgesics may be needed to control pain.
- Decreased activity may be recommended for some patients.
- A low-sodium diet may also be recommended.
- The definitive treatment is a type of surgery called a pericardiectomy. This involves cutting or removing the scarring and part of the sac-like covering of the heart.