Causes and Types of Disseminated Infections

A disseminated infection is one in which a localized infection spreads (disseminates) from one area of the body to other organ systems.

While there are systemic infections that can affect the entire body at once, doctors will reserve the term for those infections that are normally constrained to a specific site. Dissemination is used to describe a serious progression of a disease wherein the ability to contain the infection is far more difficult.

Disseminated infections are different from disseminated neoplastic diseases. While both can spread from a primary site to a secondary site, neoplastic diseases are those that involve the growth of abnormal cells (neoplasia).

Cancer is a prime example. In this instance, the primary tumor can disseminate to other parts of the body, a process we refer to as metastasis. A disseminated infection, by contrast, involves the invasion of a foreign pathogen (such as a virus, bacteria, fungus, or parasite) which causes damage to cells and tissues of the body.

Examples of Disseminated Infection

Disseminated infections are most often associated with the worsening of symptoms and the deterioration of a person's condition. Some of the more common examples include:

• Sexually transmitted infections (STIs) can readily disseminate from the primary site (such as the genitals, anus, or mouth) to other parts of the body if left untreated. Some of the most serious forms include disseminated syphilis and gonorrhea. While the primary infection will typically resolve on its own without treatment, the failure to treat can affect other organs (including the brain, bones, and joints) during the secondary and tertiary stages of infection.
• Disseminated tuberculosis (TB) occurs when the contagious bacterium spreads from the lungs to other organs through the bloodstream or lymphatic system. Around 90 percent of cases involve multiple organs and have a nearly 100 percent risk of death if left untreated.
• Disseminated shingles, involving the herpes zoster virus, is an uncommon condition more often seen in people with severely compromised immune systems (such as those with advanced HIV). In cases like these, the shingles outbreak will not be constrained to a single nerve string, known as a dermatome, but involve two or more areas of skin that are either adjacent or non-adjacent. Besides the skin, other organs (such as the eyes, liver, or brain) may also be affected.
• Disseminated candidiasis involves the spread of the same fungus seen in yeast infections and oral thrush to other parts of the body. It is, again, seen primarily in immune compromised individuals and is associated with an increased risk of death.
• Disseminated herpes simplex, the same virus that causes cold sores and genital herpes, can disseminate after the initial adult or neonatal infection. It most typically involves the brain and spinal cord and can cause a condition known as acute disseminated encephalomyelitis (ADEM) in which the protective coating around nerve cells, called the myelin sheath, is damaged.

Disseminated infections can be prevented by treating the pathogen early when the infection is still localized and/or by treating the underlying cause of the immune disorder.