Chronic Granulomatous Disease (cgd)

Patient Education

What is Chronic Granulomatous Disease (CGD)?

Chronic granulomatous disease, also called CGD, is a primary immunodeficiency state where the body's cells (phagocytes) are unable to kill the germs.

Why are the phagocytes unable to kill the germs?

Patients with CGD have defective phagocytes. These phagocytes are unable to form hydrogen peroxide and other oxidants that are needed to kill germs. They are thus susceptible to infections by certain germs that need hydrogen peroxide to kill it.

What are the symptoms of chronic granulomatous disease?

Symptoms of CGD include recurrent infections due to specific bacteria and fungi especially skin or bone infection with a bacteria called Serratia marcasens; lung infections by a fungus called aspergillus and pneumonia by other organisms such as Burkholderia cepacia, Klebsiella pneumonia, Nocardia. Abscesses due to Staphylococci are also quite common. Masses of cells called granulomas also develop in the bowel or urinary tract[1]. Patients with CGD are healthy at birth and then develop infections in the first few months or years of life. Skin, lungs, lymph nodes, liver, bones, and brain are usual sites of infection.

How is the diagnosis of chronic granulomatous disease made?

Chronic granulomatous disease commonly occurs in boys and about 15% of CGD patients are girls, CGD should be suspected in any patient who has pneumonia due to aspergillus, Nocardia, or Burkholderia cepacia liver abscess due to staphylococcus or bone infections due to Serratia marcescens. The diagnosis of CGD is established by doing the Nibroblue Tetrazolium (NBT) test. NBT test measures the production of hydrogen peroxide by phagocytes. In patients with CGD, the NBT test shows no hydrogen peroxide production by the phagocytes. NBT test is a manual test in which phagocytes producing hydrogen peroxide turn blue when in contact with the chemical called dihydroergotamine. These cells are then counted manually counted using a microscope and thus the NBT test is subject to human error.

What is the treatment of chronic granulomatous disease?

Treatment of CGD consists of prompt and aggressive treatment of infections. In patients with frequent infections, a small daily dose of antibiotics (commonly used antibiotics is cotrimoxazole) can help to prevent infection. Patients with CGD are also treated with gamma-interferons to boost their immunity and decrease the number of infections. Gamma-interferon is a protein produced by the immune system that stimulates the phagocytes to kill the bacteria more efficiently. It is given thrice weekly by subcutaneous injection. It is most effective in children under 10 years of age.However, side effects like fevers, muscle aches and headaches may be seen in a few patients. To decrease the frequency of fungal infections, itraconazole (an antifungal) can be given daily. Abscesses may require surgery for treatment.[1] The curative therapy for CGD is a bone marrow transplant.

What are the precautions required in a patient with chronic granulomatous disease?

Patients with CGD need to take a few precautions. They should avoid swimming in freshwater lakes or seas to prevent exposure to the germs. They should avoid handling garden mulch (shredded moldy tree bark) as it increases the risk of aspergillosis. Patients should also avoid gardening, cleaning dusty or moldy areas.

How is chronic granulomatous disease inherited?

CGD is a genetic disease and can be passed on in families. If passed on through the X-chromosome, it affects boys and this form of transmission is seen in 75% of cases. If passed from other chromosomes, both boys and girls can be affected. There are very few specialised labs that do genetic testing for CGD.