This particular case will always stick in my memory. I was on call over the weekend when a concerned parent called the telephone hotline about her young son who had a skin infection which wasn't healing with standard antibiotics. He had been on several courses of antibiotics, with no improvement.
I questioned his mother further and it turned out he had suffered more than his fair share of infections over the last few weeks. In addition, he was pale and tired, which was unusual for him. The history was classic for acute lymphoblastic leukaemia (ALL), the commonest childhood cancer.
I requested that the child attend the emergency clinic for a blood test. Sadly for the child, my suspicions were correct. By the same evening, he had been transferred from the local general hospital to the John Radcliffe hospital in Oxford for further tests and chemotherapy.
There are many different types of leukaemia, some of fairly rapid onset, which tend to be more aggressive and are broadly referred to as the acute leukaemias. Chronic leukaemias are more indolent in their evolution.
ALL accounts for around one in three paediatric malignancies and is on the increase. It is fairly rare but, nevertheless, should always be borne in mind when faced with an unwell child. Children aged between two and five years of age are most often affected, and it tends to affect boys more than girls. Caucasian children are more at risk than other races. Research has shown that markers for ALL may be detectable in the blood of some children at the time of birth.
A number of causes of ALL have been discovered, although in most cases, the cause isn't known. Genetic conditions such as Fanconi anaemia and Down syndrome may be implicated in a minority of conditions. Radiation exposure, such as in the Chernobyl nuclear reactor disaster, has not been shown to be causative of childhood ALL in scientific studies.
BLAST CELLS
ALL is a malignancy of the cells that fight infection. These so-called 'blast' cells multiply exponentially and eventually 'overtake' the bone marrow, causing marrow failure. In the event of marrow failure, the affected patient cannot make enough red blood cells, white cells or platelets.
A reduced number of red cells will lead to anaemia, making the patient feel tired, dizzy and breathless and look pale. Severe anaemia may lead to cardio-respiratory failure. A reduced number of mature and functioning white blood cells will render the patient vulnerable to infection, whereas reduced platelets will increase the risk of bleeding, such as nosebleeds or easy bruising.
Some children may also present with a fever, weight loss, headaches, enlarged lymph nodes (referred to by many people as 'glands'), bone pain, abnormal nerve function or even an enlarged testicle. Abdominal pain or distension may be a manifestation of an enlarged spleen, liver or both.
While the diagnosis of leukaemia for a child is devastating for all concerned, the cure rate is as high as 80 per cent. Adults who develop ALL have a much lower cure rate of between 20 per cent and 40 per cent.
Treatment is multidisciplinary, requiring the input of doctors, nurses, counsellors and teachers, to name a few. Patients may require blood transfusions, antibiotics and other specialised treatments to stop severe bleeding.
Chemotherapy remains the main therapeutic modality. Drugs, often delivered via a 'Hickman line' (an intravenous catheter), are used to induce remission and then kill off any remaining cancerous cells. But chemotherapy is fraught with complications for the patient, including a high infection risk, high potassium levels which can cause potentially fatal heart rhythm disturbance, gout, kidney failure, hair loss and severe mouth ulcers.
In some cases, the cancer cells may spread to the brain or testis, and it is important to clear these areas of leukaemic cells. Radiotherapy to the brain or chemotherapeutic agents injected through the spinal cavity will aim to reduce nervous system involvement.
Once a child has received treatment, they will require ongoing monitoring in case they relapse. In this case, relapsed cells tend to be more resistant to chemotherapy, so a bone marrow transplant, more accurately known as a stem cell transplant (SCT), is offered.
SCT is not without its risks, particularly infection. As such, children who do relapse have a much worse outcome than those who fully recover after the initial chemotherapy phase.
ALL is a devastating but, for children at least, highly curable disease. It may manifest in a number of guises and requires a number of specialties to manage the condition effectively. We must all be vigilant of the signs and symptoms of leukaemia, and always refer the patient to a doctor when in doubt.
Dr Raj Thakkar BSc(Hons) MBBS MRCGP MRCP(UK) is a full-time GP in Buckinghamshire
