For General Practitioners

• • Lymphadenitis
  • Skin abscesses
  • Perianal abscesses
  • Pneumonia
  • Liver abscesses
  • Osteomyelitis
  • Septicaemia
  • Diarrhoea
  • Specific symptoms to be aware of that require prompt intervention are:
  • A fever of 38oC or above
  • Hard lumps
  • Persistent diarrhoea
  • Night sweats
  • Loss of appetite
  • Pain or difficulty on urination
  • Warm tender or swollen areas
  • Sores with pus or rashes
  • Persistent cough or chest pain
  • Frequent or persistent headaches
  • Weight loss
  • Difficulty in swallowing
  • Vomiting shortly after eating
  • Symptoms may mask dangerous infection

• CGD is an inherited life-threatening disorder that prevents the immune system working properly to fight off certain bacterial and fungal infections. The exact incidence of the condition is unknown but is thought to affect approximately 4-6 people in every million. People with CGD carry a faulty bone marrow gene, which means that white blood cells, known as phagocytes, do not function correctly. These cells are responsible for killing fungi and bacteria and the defect makes people with CGD more susceptible to fungal and bacterial infections.

  The hallmark of the disorder is early onset of severe recurrent bacterial and fungal infections. Three-quarters of people are diagnosed during the first five years of life but it is likely that the medical profession under-diagnoses CGD throughout the population. Pneumonia can be one of the most common symptoms in addition to infections of the skin, lungs, gastrointestinal tract, lymph nodes, liver, and spleen. Another hallmark of CGD is the development of granulomas (nodules of inflammatory tissue) in the skin, gastrointestinal tract, and urinary tract. At diagnosis, some people present with symptoms related to these granulomas. Bowel problems can be also be characteristic. The wide variety of symptoms, and the fact symptoms can be common to other conditions, mean that misdiagnosis can occur. For example, symptoms can lead to misdiagnoses such as Crohn’s, TB and leukaemia.

  Medication in the form of antibiotics and anti-fungal therapy is necessary. These are taken on a daily basis to keep infection at bay but problems can still arise that can lead to serious illnesses and prolonged periods in hospital. The quality of life of those with the condition may also be severely affected. Bone marrow transplant is an effective treatment for the condition, although this is not without risk. It is becoming possible for a greater number of affected people using related and more recently, unrelated matched donors. There are some people for whom transplant will not be possible.

  Progress is being made in other forms of treatment such as gene replacement therapy.

• If CGD is suspected, patients should be referred with urgency to an immunology specialist. Genetic testing is not required to make a diagnosis of CGD and appropriate treatment can be given in the absence of knowing the precise genetic mutation involved. Diagnosis of CGD can be made using a functional blood test rather than a genetic test. This test, called the nitroblue tetrazolium dye reduction test is based on the ability of patient’s phagoctye cells to produce an oxygen burst. It is this oxygen burst that is important for neutralising bacteria and fungi within cells.

  Increasingly this test is slowly being replaced by a more sophisticated method called dihydrorhodamine (DHR) test. Here phagocytic cells reduce DHR to the strongly fluorescent compound rhodamine, individual fluorescent cells are then counted, and the amount of fluorescence per cell is quantified with a specialised piece of equipment known as a flow cytometer. As CGD is an inheritable condition, a diagnosis of CGD must be followed up by appropriate genetic counseling and predictive gene testing for the whole family. Pinpointing the specific gene mutation is useful to establish the genetic inheritance pattern and to help with family counseling.

  The low incidence of CGD and the large number of unique mutations preclude standardized genetic testing. Therefore individual genetic analysis remains the domain of specialized research laboratories. Samples will be sent to these laboratories by the treating clinician. CGD can result from mutations in one of four of the components responsible for the oxidative burst. These mutations cause either a complete absence of one of the components or affect it so that it does not function properly. The most common form of CGD is called X-linked CGD. Here only boys are affected and it is caused by inheritance of the genetic fault from the mother. The other forms of CGD represent about 40% of cases and are inherited in a different manner and are due to both parents carrying a gene mutation. There are a number of issues surrounding genetic testing particularly in relation to children and as such, many patients may wish to be seen and counselled by a consultant clinical geneticist as early on as possible.

• In the UK, patients have the right to ask for a second opinion via their first specialist or through their GP. They are not, however, entitled to receive that second opinion if the clinicians do not think it necessary. A patient may appeal against any decision via their Integrated Care Boards (ICBs).

• Treatment is by daily use of antibiotics and antifungal drugs. Other medicines may be given to deal with problems associated with CGD such as inflammation. It is extremely important to contact a doctor if an infection is suspected so that prompt action can be given. CGD patients should look out for the signs of infection. Simple steps and changes in life style can be taken to avoid infection. Details can be obtained by contacting the CGD Society. Bone marrow transplant is the best treatment option at the present time. This can be a difficult procedure, requiring a prolonged hospital stay. Research and refinement of gene replacement therapy procedures are currently being explored.

Retired GP Dr Roy Evison was a CGD Society trustee of the charity. Here are his suggestions on how GPs can help patients with CGD:

• Prompt attention and treatment is important for anyone with CGD 
• Put an alert attached to the patient notes, so that CGD is immediately flagged up and visible to all surgery staff 

• Scan in this sheet to the notes with a link to the summary page 

• The first port of contact for patients is usually the surgery receptionist. It would help if you (as their GP) could explain to your reception team that CGD families need help promptly 

• Small and seemingly unimportant symptoms can be the pre-cursor to serious and potentially life-threatening illness 
• Swift contact with you is vital