Meningococcemia (cont.)

Children and adolescents 5 to 19 years of age are at highest risk for meningococcemia. Newborns acquire antibodies from their mothers via the placenta, although these antibodies fade after a few weeks or months. Toddlers are not immune, and there have been several exposures in day-care settings. As children age, they gradually gain immunity to meningococcal strains by coming into contact with milder strains of the bacteria. However, because this immunity is imperfect, it is still possible for adults to get meningococcemia.

The immune system is critical in fighting off the bacteria. Patients who have a history of a specific genetic deficiency in the complement system are at high risk for severe disease. The spleen is also needed for an effective immune response, so people are at higher risk for severe disease if they have had their spleens taken out or have spleens that function poorly.

People who have been in close contact with an infected patient are at increased risk to acquire the disease themselves. People who live together in close quarters such as military barracks are at especial risk for disease. One study showed that the attack rate in household contacts was 500 times greater than that of the general population.

In some parts of the world, outbreaks of meningococcal disease occur regularly. This is true of a group of countries in sub-Saharan Africa, which is known as the "meningitis belt." Because travelers from this area visit Saudi Arabia during the Hajj, there have been outbreaks associated with the pilgrimage. Saudi Arabia now requires proof of vaccination before admitting pilgrims.

After an average incubation period of three to seven days (range one to 10 days), infected patients initially experience fatigue, fever, headache, and body aches, similar to those experienced by people with influenza, including swine flu or bird flu. Shaking chills may be present. Rash is common and appears like small red dots (petechiae) associated with low platelet counts or a bleed into the skin (purpura) associated with vasculitis. The rash may appear anywhere on the body, even on the palms or soles or inside the mouth.

In addition to the rash, physical examination reveals a fast heart rate and often a low blood pressure and other signs of shock. Laboratory examination shows increases in white blood cell counts and may show low platelet counts (thrombocytopenia). The bacteria may spread to the heart, causing myocarditis. In severe cases, multiple organ systems may fail, including the kidneys, lungs and airways, liver, or heart. Uncommonly, the bacteria may cause a low-grade bloodstream infection (chronic meningococcemia) with fever, joint pain, and rash that lasts one to three weeks.

Although meningococcemia refers to an infection of the bloodstream, it is important to note that some patients with meningococcemia will develop meningococcal meningitis. Meningococcemia poses a higher risk of shock and death than meningococcal meningitis. Thus, although they are defined differently and have different prognoses, there is significant overlap between meningococcemia and meningococcal meningitis.

Source: MedicineNet.com
http://www.medicinenet.com/meningococcemia/article.htm