Cyanosis

• Cardiovascular disease
  –Cardiogenic shock (e.g., massive MI)
  –Severe valvular heart disease
  –Cor pulmonale
  –Massive pulmonary embolus
• Abnormal hemoglobin
  –Methemoglobinemia: Usually caused by drugs or chemicals (e.g., sulfa, nitrites, benzene derivatives) or genetic defects
  –Hemoglobin Kansas
  –Sickle cell disease
  • Toxins/poisons (e.g., carbon monoxide, nitroprusside, cyanide)
  
  Peripheral cyanosis (cyanosis of phalanges, earlobes, and nose)
  • Increased resistance to blood flow
    –Raynaud's phenomenon
    –Acrocyanosis
    –Superior vena cava obstruction
    –Venous hypertension
    –Arterial embolism
    –Exposure to cold air or water
  • Decreased cardiac output
    –Shock
    –Congestive heart failure
    –Mitral stenosis
  • Increased blood viscosity
    –Polycythemia vera

  Workup and Diagnosis

  • History and physical examination
    –Clubbing of the fingers or toes may indicate congenital heart disease or chronic pulmonary disease
    –Blood pressure, capillary refill, and heart and lung exam are always indicated
    –Pulses and neurologic function in all involved extremities must be evaluated in peripheral cyanosis
• Initial labs include pulse oximetry, CBC, electrolytes, BUN/creatinine, glucose, arterial blood gas (to assess oxygenation, CO level, and presence of methemoglobin), and ECG
• Chest X-ray and/or CT scan to evaluate for lung pathology and heart size
• Echocardiogram will assess ventricular function and valves, and rule out structural abnormalities
• Pulmonary function tests
• Cardiac enzymes may be indicated to rule out MI
• Hemoglobin electrophoresis may be indicated to evaluate hemoglobin structure
• For peripheral cyanosis isolated to one limb, arterial Doppler studies or angiogram may be indicated to rule out embolus
• Pulmonary angiogram may be indicated to rule out an arteriovenous fistula or massive pulmonary embolism

Treatment

• Administer supplemental oxygen to all patients
  –Cyanosis and hypoxemia due to (most) lung disease and carbon monoxide poisoning will quickly improve upon oxygen administration