miércoles, 22 de julio de 2015

Chronic Granulomatous Disease (CGD)

Phagocyte (purple) engulfing Staphylococcus aureusbacteria (yellow).
Credit: NIAID

CGD is a genetic disorder in which white blood cells called phagocytes are unable to kill certain bacteria and fungi. People with CGD have increased susceptibility to infections caused by certain types of bacteria and fungi, including the following:

Staphylococcus aureus
Serratia marcescens
Burkholderia cepacia
Nocardia species
Aspergillus species

Causes

CGD is caused by defects in an enzyme called NAPDH oxidase that phagocytes need to kill bacteria and fungi. Mutations in one of five different genes can cause this defect, which leads to frequent and sometimes life-threatening infections of the skin, lungs, liver, and bones, with accumulations of inflammatory cells called abscesses (boils) or granulomas (inflamed masses of tissue).

Signs and Symptoms

CGD may be suspected in children or adults with the following symptoms:

Abscesses that involve the lungs, liver, spleen, bones, or skin
Infections caused by unusual germs, such as fungi or Nocardia
Granulomas (tissue masses that can obstruct the bowel or urinary tract or complicate wounds)

In some people, granulomas can cause inflammatory bowel disease that looks similar to Crohn’s Disease. Furthermore, heart or kidney problems, diabetes, and autoimmune disease may occur in people with CGD. However, the incidence of these issues varies depending on which gene is mutated.

CGD is diagnosed by special blood tests that show how well phagocytes produce hydrogen peroxide, a product of NAPDH oxidase activity.

Treatment

The key to managing CGD is early diagnosis and treatment with appropriate antibiotics. The goal is to prevent infections and complications.

Antibiotics taken throughout life help prevent bacterial infections.
Antifungals taken throughout life help prevent fungal infections.
Injections with interferon gamma, a protein that improves the activity of phagocytes, may also be helpful.
Abscesses need aggressive care, which may include surgery.
Granulomas may require steroid therapy.
Some people have been treated successfully with bone marrow transplantation.