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