Cause of central cyanosis include all of the following, Except-
Ans. is 'c' i.e., Congestive heart failure o Congestive Heart Failure is a cause for Peripheral cyanosis and not central cyanosis.o Cyanosis refers to bluish discoloration of skin or mucous membrane.o It is caused by the presence of deoxygenated or an altered hemoglobin in sufficient concentration in the blood,o Presence of at least Sgm % of deoxygenated hemoglobin in the capillary blood is required to produce cyanosis.o This is related to the fact that colour of deoxygenated Hb is bluish or purple.Central cyanosisPeripheral cyanosiso Central cyanosis is caused by in adequate oxygenation of systemic arterial blood due to decreased arterial oxygen saturation or Hemoglobin abnormalitieso Peripheral cyanosis is caused by slowing of blood flow and increased extraction of oxygen from normally saturated bloodo It results from cardiac shunting, pulmonary diseases or hematological disorders (Hb abnormalities)o It results from vasoconstriction or decreased peripheral blood flow, reduced cardiac output or vascular occlusiono Central cyanosis is characterized by cyanosis affecting both mucous membranes and skino Peripheral cyanosis is characterized by cyanosis of skin alone and sparing of mucous membranes Causes of Cyanosis||Central cyanosisDecreased arterial oxvgen saturationPeripheral cvanosiso Vascular occlusiono Decreased atmosphric pressure - high altitudeo Impaired pulmonary function# Arterial obstruction# Venous obstruction# Alveolar hyoventilation# Uneven relationships between pulmonary ventilation and perfusion (perfusion of hypoventilated alveoli)# Impaired oxygen diffusiono Reduced cardiac outputo Cold exposureo Redistribution of blood flow from extremitieso Anatomic shunts# Certain types of congenital hart disease# Pulmonary arteriovenous fistulas# Multiple small intrapulmonary shuntso Hemoglobin with low affinity' for oxygenHemoglobin abnormalitieso Methemoglobinemia - hereditary, acquiredo Sulfhemoglobinema - acquiredo Carboxvhemoglobinemai (not true cyanosis)
Chronic Asthma
Congenital Pulmonary stenosis
Congestive heart failure
Alveolar hypoventilation
General