Excerpt from Gonococcemia

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Background

Gonococcemia is defined as the presence of Neisseria gonorrhoeae in the bloodstream, which can lead to the development of disseminated gonococcal infection (DGI). Gonorrhea is the second most often reported sexually transmitted disease (STD) in the United States behind chlamydia. About 600,000 people each year in the United States are infected, with only about half being reported.¹ Gonococcemia occurs in about 0.5-3% of patients with gonorrhea.

The clinical manifestations of this process are biphasic, with an early bacteremic phase consisting of tenosynovitis, arthralgias,² and dermatitis, followed by a localized phase consisting of localized septic arthritis. Other potentially severe clinical complications include osteomyelitis, meningitis, endocarditis, adult respiratory distress syndrome (ARDS),^{3, 4} and fatal septic shock.⁵ Polymyositis is also a rare complication of gonococcemia.

Patients who are pregnant or menstruating may be particularly prone to gonococcemia. Other populations that are at risk of infection include women and those with complement deficiencies, HIV, or systemic lupus erythematosus (SLE). DGI is an important, potentially life-threatening, and easily treatable clinical entity that remains the most common cause of acute septic arthritis in young sexually active adults.

Related eMedicine articles include Gonococcal Infections and Gonococcal Arthritis. Additionally, the Medscape CME course Highlights of the 17th ISSTDR: International Society for Sexually Transmitted Diseases Research Annual Meeting may be of interest.

Pathophysiology

N gonorrhoeae organisms are spread from a primary site, such as the endocervix, the urethra, the pharynx, or the rectum, and disseminate to the blood to infect other end organs. Usually, multiple sites, such as the skin and the joints, are infected. Neisserial organisms disseminate to the blood due to a variety of factors. Such predisposing factors include host physiologic changes, virulence factors of the organism itself, and failures of the host's immune defenses.⁶ For example, changes in the vaginal pH that occur during menses and pregnancy and the puerperium period make the vaginal environment more suitable for the growth of the organism and provide increased access to the bloodstream.^{7, 8}

Organismal virulence factors, such as pili, aid in adherence of the organism to mucosal surfaces and impede phagocytosis by host macrophages. Outer membrane proteins (ie, proteins 1, 2, and 3) are also involved in determining the virulence of the strain of organism and are used to type the strain (ie, protein 2 is involved in adhesion to host cells). Lipo-oligosaccharides of the organism's cell membrane have marked endotoxic action and are also believed to be related to resistance to serum bacteriocidal action. Additionally, some strains of Neisseria species that are particularly pathogenic produce immunoglobulin A (IgA) proteases that aid in the survival of the organism in mucosal tissues.

Defects in the host's immune defenses are also involved in the pathophysiology, with certain patients more likely to develop bacteremia. Specifically, patients with deficiency in terminal complement components are less able to combat infection, as complement plays an important role in the killing of neisserial organisms. As many as 13% of patients with DGI have a complement deficiency. A study of 22 patients with DGI revealed that total serum complement activity was greater than 25% below the normal mean. Other causes of immunocompromise (eg, HIV, SLE) also predispose to dissemination of infection.

Frequency

United States

The incidence of DGI naturally parallels the incidence of gonococcal infection. In the United States, the number of gonococcal infections peaked in the 1970s, the era of the sexual revolution. With the onset of the HIV epidemic and the practicing of safe sex techniques, the incidence has dramatically decreased from 468 cases per 100,000 population in 1975 to 100-150 cases per 100,000 population at the turn of the century.

N gonorrhoeae infection, the second most commonly reported notifiable disease in the United States, has incidence rates that have been either declining or stable since 1996. However, in 2005, the national rate (115.6 cases per 100,000 population) increased for the first time since 1999. Further, from 2000-2005, rates in the western United States increased 42%, from 57.2 cases to 81.5 cases per 100,000 population, whereas rates in the 3 other US regions decreased (South, -22%; Northeast, -16%; Midwest, -5%).⁹

International

The incidence in developing countries is much greater than that of the United States and Western Europe, where higher levels of education and better access to health care are available. DGI develops in about 0.5-3% of persons with mucosal infection.

Sex

DGI is more likely to occur in women because of a higher incidence of occult infection (difficulty in diagnosis) and also because of menstruation and pregnancy.

Age

Gonococcemia remains an important disease in the adolescent and young adult population, with a peak incidence in males aged 20-24 years and females aged 15-19 years. Symptoms and/or diagnosis in young children should raise the issue of potential child abuse.¹⁰

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