Posted on 8 months ago by Gerry Kennedy
What is Chronic Granulamatous Disease?
CGD is a disease of the immune system. It is described as a primary immunodeficiencydisorder. “Primary” means it is not caused by some other disease or disorder.1 In people who have CGD, a type of white blood cell called a phagocyte is defective.2 These defective phagocytes cannot generate superoxide, leading to an inability to kill harmful microorganisms such as bacteria and fungi.3 As a result, the immune system is weakened. People with CGD are more likely to have certain problems such as recurrent severe bacterial and fungal infections and chronic inflammatory conditions. These patients are prone to developing masses called granulomas, which can occur repeatedly in organs throughout the body and cause a variety of problems.3
CGD was first identified in the 1950s; since then we have learned much about CGD, converting it from a disease of tragic and early complications to a disease of chronic management and high survival.4
Today with treatment, CGD is known to be a condition that most patients can manage. Studies suggest overall survival has improved over the last decade with more patients living well into adulthood.4 Approximately 1 out of every 200,000 live births in the US has CGD.4
Signs and Symptoms of CGD
An individual may begin to show signs of CGD anytime from infancy to adulthood. However, the vast majority of patients are diagnosed before 5 years of age.1
- The signs and symptoms of CGD may include1
- Slow growth in childhood
- Infections caused by specific types of bacteria or fungi that affect the lungs, lymph nodes, liver, bones, or skin, which are often severe, occur spontaneously, and recur frequently
- The formation of granulomas, particularly in the bladder and gastrointestinal tract
- Colitis (inflammation of the colon)
- Wounds that heal abnormally caused by excessive formation of small particles (granulomas) in the tissue
Testing for CGD
A doctor who suspects a person might have CGD may order a lab test that assesses the activity of phagocytes. There are two such tests available.1
The nitroblue tetrazolium (NBT) test1
This blood test assesses the activity of a patient’s white blood cells (phagocytes) when exposed to the chemical nitroblue tetrazolium (NBT). During this process, normal white blood cells will change the NBT, which is a yellow color, to formazan, which is a blue-black color. This change in color can be observed through a microscope. This means the cells produce the chemical needed to kill harmful microorganisms. If the white blood cells do not change the NBT to formazan, they do not have the ability to kill the microorganisms, which means the patient could have CGD.
The dihydrorhodamine (DHR) test1
Today, the DHR test is the preferred method for diagnosing CGD. In this blood test, white blood cells (phagocytes) are exposed to the chemical dihydrorhodamine (DHR) and measured using a process called flow cytometry. Normal white blood cells will emit a fluorescent light, which means the cells produce the chemical needed to kill harmful microorganisms. If the cells do not emit a fluorescent light, it indicates the cells do not produce, or do not produce enough of, the chemical needed to kill the microorganisms, which means the patient could have CGD.
CGD is a chronic disease; however, its symptoms can be managed through1
- Year-round prophylaxis with doctor-prescribed medications to help prevent recurrent infections
- Careful lifestyle choices to avoid potentially harmful activities and environments
- Regular checkups with a physician to facilitate early intervention as necessary
People who have CGD are highly susceptible to severe recurrent infections, which can often require hospitalization and special disease management.1,3 The most important goal in managing patients with CGD is to prevent infections.