Blood clotting normally occurs when there is damage to a blood vessel. Platelets immediately begin to adhere to the cut edges of the vessel and release chemicals to attract even more platelets. A platelet plug is formed, and the external bleeding stops.

Next, small molecules, called clotting factors, cause strands of blood-borne materials, called fibrin, to stick together and seal the inside of the wound. Eventually, the cut blood vessel heals and the blood clot dissolves after a few days.

Meningococcemia is a life-threatening infection that occurs when the meningococcus, Neisseria meningitidis, invades the blood stream. Bleeding into the skin (petechiae and purpura) may occur. The tissue in areas may die (become necrotic or gangrenous). If the person survives, the areas heal with scarring.

Meningococcemia is a life-threatening infection that occurs when the meningococcus, Neisseria meningitidis, invades the blood stream. There is usually bleeding into the skin (petechiae and purpura), and the tissue in these areas may die (become necrotic or gangrenous). If the patient survives, the areas heal with scarring. This picture demonstrates more hemorrhage and little tissue death.

Meningococcemia is a life-threatening infection that occurs when the bacteria, Neisseria meningitidis, invades the blood stream. Bleeding into the skin (petechiae and purpura) typically occurs and the tissue may die (become necrotic or gangrenous). If the patient survives, the areas heal with scarring.

Blood clots (fibrin clots) are the clumps that result when blood coagulates.