Kussmaul breathing is a form of hyperventilation. It is characterized by deep, gasp-like breathing that is also described as air hunger. This symptom was named after Adolph Kussmaul, a 19th century German physician who first recognized and described this type of labored breathing. Kussmaul breathing differs from the rapid, shallow breathing of hyperventilation syndromes that are related to anxiety and panic attacks.

Kussmaul breathing is a symptom of metabolic acidosis (a type of acid imbalance in the body). Acidosis simply means that the body is in an acidic (high acid) state. Normally, the body continuously regulates its acid-base (pH) balance. Acids are those substances that increase acidity, and bases are those that neutralize acids and reduce acidity. However, imbalances in pH levels may occur due to illness or disease. There are many causes of metabolic acidosis, including diabetes, kidney disease and diarrhea.

Among people with diabetes, Kussmaul breathing occurs most commonly during diabetic ketoacidosis (DKA). During DKA, the body lacks insulin to break down glucose (blood sugar) in the bloodstream for energy. Instead, it begins to break down fats, which produces acidic waste products in the blood called ketones.

Kussmaul breathing occurs during metabolic acidosis as a way to alter blood chemistry, helping to temporarily stabilize acid levels in the body. When the blood becomes too acidic, it is unable to effectively carry oxygen and nutrients to the cells of the body. Kussmaul breathing forces increased amounts of oxygen into the lungs, which also increases the amount of carbon dioxide that is exhaled. This decrease in carbon dioxide in the body helps to temporarily lower blood acid levels.

Initially, Kussmaul breathing may be fast, deep and labored, becoming slower and deeper as conditions in the body change. Kussmaul breathing that is severe or prolonged may be life-threatening and should be considered an emergency. Patients experiencing any type of breathing difficulty should seek immediate medical attention.

Kussmaul breathing usually occurs during DKA with type 1 diabetes. In some cases, the diabetes is diagnosed because of DKA with Kussmaul breathing. In other cases, Kussmaul breathing occurs when insulin dosage is missed or otherwise out of control due to pregnancy, infection or trauma.