Tumours of the central nervous system

A brain tumour occurs when a change occurs in the normal cells in the brain. This change causes the cells to undergo a series of events, resulting in a growing mass of abnormal cells causing a tumour to form. Brain tumours can occur at any age. Brain tumours that occur in infants and children are very different from adult brain tumours, both in terms of the type of cells and the responsiveness to treatment. A primary brain tumour involves a growth that starts in the brain, rather than spreading to the brain from another part of the body. However, some brain tumours can start in the brain but also spread to the spine or other parts of the body. If this is suspected, further investigations will need to be carried out, such as MRI scans.

 For many children, the cause of primary brain tumours is unknown, although some tumours can be hereditary. When discovered early enough, most brain tumours are usually treatable. Many that are slow-growing are cured with surgery alone. Other types that are faster-growing might need additional treatment with radiation therapy or chemotherapy, or both.

When you get the results of your child’s brain tumour, you will not only learn about what type of tumour they have, but also the grade of the tumour. In the past, we talked about the tumour been either benign or malignant.  However, now when you get the results of your child’s brain tumour, your Paediatric Consultant Neurosurgeon will talk to you about the diagnosis including the type of tumour it is and the prognosis including treatment if it is recommended.

1. Admitted to ICU/ St. Gabriel’s Ward or St. Michaels B
2. Meet the Neurosurgery Team
3. Investigations – including Scans & bloods
4. Theatre – Biopsy +/- Removal of the tumour
5. Recovery on the Neurosurgery ward
6. Linked in with Consultant Oncologist in Crumlin
7. Discharge & Follow up arranged in Crumlin/St. Luke’s Rathgar

The first stage of diagnosis starts when your child is checked out by your GP or local hospital. This is usually because your child has had a specific symptom or some vague ones that need to be investigated. Tumours of the brain are generally first discovered on a brain scan. They are seen as an abnormal mass or lesion. Once a brain tumour is suspected, your child is referred to the paediatric neuro-oncology team based in Dublin. Neurosurgery is an important part of the care of brain tumours in children. The neurosurgeon will often be the first specialist from the neuro-oncology team to meet your family. He or she will discuss with you the symptoms you have noticed in your child and explain what the possible causes of these symptoms are. Further tests will probably need to be completed to confirm the tumour type. 

Tests to diagnose a brain tumour

In addition to a complete medical history and physical examination of your child, examination procedures for a brain tumour may include:

1. Neurological exam

 Your child’s doctor tests reflexes, muscle strength, eye and mouth movement, coordination, and alertness.

2. A Computed tomography scan (also called a CT or CAT scan)

A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs, such as the brain. CT scans are more detailed than general X-rays. The CT scanner is shaped like a large ring and has a table which sits inside the ring shape. Your child will need to lie still on this table. A special dye will usually be injected into their vein to give a clearer picture of their brain. A CT scan usually lasts about 15–20 minutes. For this reason younger children may be sedated or given a general anaesthetic.

3. Magnetic resonance imaging (MRI) 

An MRI scan is a type of X-ray that uses a very strong magnet and radio waves to give more information about the position of the tumour. Your child will need to lie still on a table in a special X-ray tunnel for 30 minutes or longer. You should prepare your child in advance for this scan as the machine is very noisy (hammering sound) and they may find it difficult to lie still in the tunnel. However, usually the children can listen to music or look at DVD to distract them until the scan is completed. Very young children are given a general anaesthetic for this type of scan. Older children who are prepared in advance tend to cope very well, but parents or guardians can also remain in the room with them during the scan. Because the scan uses magnets, all metal objects (jewellery, clips or pins) will have to be removed. If your child wears dental braces, this may make the MRI image less clear. You may be advised to have them temporarily removed for the scan. You will also need to tell staff if your child has had any metal devices implanted in their body in the 6 weeks before the scan. For example, a metal pin for a broken leg. The device may not yet be secure and staff may need to take special safety measures.

What other tests might my child need?

Ophthalmology (eye) and hearing exam 

Various eye and hearing tests may be performed as part of the assessment for certain tumours. 

Lumbar puncture/spinal tap

A special needle is placed into the lower back, into the spinal canal. This is the area around the spinal cord. A small amount of cerebral spinal fluid (CSF) can be removed and sent for testing. CSF is the fluid which bathes the brain and spinal cord.

Bloods tests 

Certain tumours called germ cell tumours release chemicals that can be found in the blood. If a germ cell tumour is suspected, a blood test can be taken to look for these chemicals. It is sometimes possible to diagnose the type of tumour in this way without the need for a biopsy. 

EEG

 An EEG or electroencephalogram is a test that measures the electrical activity in the brain. The test may be done for your child if their tumour is causing seizures or fits. It involves placing small electrodes on their scalp, which transmit and record electrical brain activity onto a graph for the doctors to read. This test does not hurt, although children may complain about the sticky gel in their hair. The gel is used to help keep the electrodes in place. 

Endocrine Tests

The pituitary gland is the master gland of the body and responsible for the release of regulating hormones. Craniopharyngioma and its treatment can sometimes interfere with the normal hormone changes that happen as your child grows. More than likely, your child will need their hormones watched closely during childhood and adolescence. This means that they will need to have blood tests. They will have to attend a follow-up clinic after surgery. Here their vision and hormones (endocrine) will be checked and any issues about their general growth and development.

A brain tumour can cause symptoms by directly pressing on the surrounding parts of the brain that control certain body functions, or by causing a build – up of spinal fluid and pressure throughout the brain (a condition known as hydrocephalus). Signs or symptoms vary depending on a child’s age and the location of the tumour, but may include:

Babies

• Persistent/Recurrent Vomiting
• Enlarged Head Circumference and bulging fontanelle
• Balance/Co-ordination/Walking Problems
• Abnormal Eye movements or suspected loss of vision
• Behaviour Change particularly lethargy
• Fits or seizures ( not with a fever)
• Abnormal Head position such as head tilt or stiff neck

Child

• Persistent/Recurrent Headache
• Persistent/Recurrent Vomiting
• Balance/Co-ordination/Walking Problems
• Abnormal Eye movements or suspected loss of vision/double vision/blurred vision
• Behaviour Change 
• Fits or seizures ( not with a fever)
• Slurred Speech/ Weakness of the face, trunk, arms or legs
• Abnormal Head position such as head tilt or stiff neck

Teen

• Persistent/Recurrent Headache
• Persistent/Recurrent Vomiting
• Balance/Co-ordination/Walking Problems
• Abnormal Eye movements or suspected loss of vision/double vision/blurred vision
• Behaviour Change 
• Fits or seizures ( not with a fever)
• Slurred Speech/Weakness of the face, trunk, arms or legs
• Abnormal Head position such as head tilt or stiff neck
• Delayed Puberty