Which statement correctly distinguishes central cyanosis from peripheral cyanosis in chest disease?

Which statement correctly distinguishes central cyanosis from peripheral cyanosis in chest disease?

• A. Peripheral cyanosis shows on lips and tongue.
• B. Cyanosis is not related to oxygen saturation.
• C. Central cyanosis reflects increased deoxyhemoglobin; lips and tongue, while peripheral cyanosis affects extremities.
• D. Central cyanosis is due to polycythemia.

Answer: (C)

Central cyanosis appears when arterial blood is markedly deoxygenated, so there is more deoxyhemoglobin circulating and the blue color shows up in central tissues such as the lips and tongue. Peripheral cyanosis, by contrast, results from reduced blood flow to the extremities, so the blue tint shows first in fingers, toes, and nail beds, often with normal overall oxygen levels. In chest disease this distinction matters because central cyanosis signals systemic hypoxemia, whereas peripheral cyanosis can occur with localized vasoconstriction or slowed peripheral circulation even if arterial oxygen isn’t severely low. The statement matches this physiology by noting that central cyanosis reflects increased deoxyhemoglobin with involvement of the lips and tongue, while peripheral cyanosis affects the extremities.

Central cyanosis appears when arterial blood is markedly deoxygenated, so there is more deoxyhemoglobin circulating and the blue color shows up in central tissues such as the lips and tongue. Peripheral cyanosis, by contrast, results from reduced blood flow to the extremities, so the blue tint shows first in fingers, toes, and nail beds, often with normal overall oxygen levels. In chest disease this distinction matters because central cyanosis signals systemic hypoxemia, whereas peripheral cyanosis can occur with localized vasoconstriction or slowed peripheral circulation even if arterial oxygen isn’t severely low. The statement matches this physiology by noting that central cyanosis reflects increased deoxyhemoglobin with involvement of the lips and tongue, while peripheral cyanosis affects the extremities.