Linked to smoking, air pollution, inhalation of dust. Common causative bacteria are Strep. If infection spreads to lungs, it becomes a pneumonia. Corynebacterium diphtheria, if it is lysogenic. Nonlysogenic diphtheroids are common in throat cultures.
Lysogenic bacteria produce toxin when levels of iron in the blood drop.
Organism spread by inhaling droplets and infection begins in the pharynx. Bacteria, damaged cells, fibrin and blood cells combine to form a pseudomembrane which firmly adheres to tissue. This pseudomembrane can block the airway and cause suffocation. Toxin is produced in the low iron levels of the pseudomembrane, gets to other organs and kills cells by inhibiting protein synthesis. Particularly dangerous to heart, nervous system and kidneys.