Causes of cyanosis

Question 5.5 from the second paper of 2010 asked for non-cardiac and non-respiratory causes of cyanosis. The following list was concocted using Walker's  chapter ("Cyanosis.") in the third edition of Clinical Methods: The History, Physical, and Laboratory Examinations.

  • Methylene blue or indocyanine gree dye injection
  • Hemosiderosis
  • Excess consumption of colloidal silver
  • Chronic massive doses of amiodarone
  • Chlorpromazine

And, the causes suggested by the college in their model answer:

  • Severe methemoglobinemia (though the blood in these cases is supposed to be chocolate brown)
  • Sulfhemoglobinemia
  • Hemoglobin mutation (eg. Haemoglobin Beth Israel, etc)
  • Polycythaemia
  • Hypothermia
  • High altitude

References

Nagel, Ronald L., et al. "Hemoglobin Beth Israel: A mutant causing clinically apparent cyanosis." New England Journal of Medicine 295.3 (1976): 125-130.

Walker, H. Kenneth, et al. "Cyanosis." in Clinical Methods: The History, Physical, and Laboratory Examinations. 3rd edition (1990).