cianie

Cianie, or cyanosis in medical terms, is a bluish or purplish discoloration of the skin and mucous membranes caused by an increased amount of deoxygenated hemoglobin in arterial blood or by abnormal hemoglobins. The color change is most evident in thin areas such as the lips, tongue, and nail beds, and its appearance indicates a mismatch between oxygen supply and demand in the body.

There are two main types: central cyanosis and peripheral cyanosis. Central cyanosis reflects widespread low oxygen levels in arterial blood and suggests a significant cardiopulmonary problem. Peripheral cyanosis results from reduced blood flow to the periphery or increased oxygen extraction in tissues, and may occur with normal arterial oxygen tension.

Common causes of cyanosis include cardiopulmonary disorders that impair oxygenation (such as congenital heart disease with right-to-left shunts, severe pneumonia, pulmonary edema, or advanced lung disease), hypoventilation, and air-blood gas abnormalities. Less typical causes include methemoglobinemia and sulfhemoglobinemia, which alter hemoglobin’s ability to carry oxygen even when the PaO2 is normal.

Diagnosis is clinical, supported by measurements of oxygen saturation and arterial blood gas. Pulse oximetry can detect low oxygen saturation, while co-oximetry or arterial blood gas analysis helps distinguish central cyanosis from peripheral causes and identify abnormal hemoglobins. The underlying condition must be identified and treated.

Treatment focuses on addressing the cause and ensuring adequate oxygen delivery. Oxygen therapy is often used for promptly low oxygenation; specific conditions such as methemoglobinemia may require antidotes like methylene blue. Prognosis depends on the underlying disease rather than cyanosis itself. See also cyanosis and methemoglobinemia.