Increased intracranial pressure
Normally, there is a certain amount of pressure inside the skull. This is called intracranial pressure (ICP). Increased ICP is when pressure inside the skull rises. Increased ICP is a serious condition that needs to be treated right away. It may also be called brain swelling or cerebral edema.
The skull contains the brain, blood and cerebral spinal fluid (CSF). CSF is the fluid in the cavities in and around the brain. Any change to the brain or the volume of blood or CSF can increase pressure in the skull. The body adjusts to these changes to try to return the pressure to normal. If the pressure isn’t kept at a normal level and keeps rising, it can cause very serious problems because the brain can’t work normally.
Increased ICP in people with cancer can develop over days to weeks. When it happens, it is an emergency and needs immediate attention.
Increased ICP can be caused by tumours that start in the brain or cancer that spreads, or metastasizes, to the brain. Cancer that spreads from the lung, breast, kidney or skin (melanoma) is more likely to cause increased ICP.
Increased ICP can also develop if other cancers or their treatments cause:
- a blockage in CSF pathways so CSF can’t flow normally
- infection of the brain or the membranes that cover the brain and spinal cord (called the meninges)
- bleeding in the brain
- swelling in the brain (called cerebral edema)
- a reaction in brain tissue to radiation therapy
Increased ICP from radiation therapy can be acute (occurs right away) or delayed (occurs some time after radiation therapy).
Symptoms of increased ICP can vary depending on their cause. They often depend on where a tumour, a blockage, an injury or swelling is in the brain. Symptoms may be mild at first and become worse as the pressure in the skull increases.
A headache is the most common symptom of increased ICP. It is often worse in the morning or after strenuous activity. Report headaches and the following symptoms to your doctor or healthcare team as soon as possible:
- behaviour changes
- poor memory
- nervous system problems, including weakness, numbness, vision problems, coordination problems, loss of muscle strength, loss of movement (paralysis) or difficulty speaking
- lowered consciousness, including drowsiness, lack of energy, confusion or coma
Later signs develop as ICP increases. The following signs of increased ICP are called Cushing triad.
- high blood pressure with an increasing difference between the top (systolic) and bottom (diastolic) blood pressure readings
- slow pulse rate
- abnormal respirations
Your doctor will try to find the cause of the increased ICP. This includes a physical exam, assessment of your symptoms and a neurological exam. For a neurological exam, your doctor will ask you questions and do tests to check your brain, spinal cord and nerve function. These exams also check mental status and coordination, including how well the muscles, senses and reflexes work.
Tests done if increased ICP is suspected may include:
- CT scan of the head
- MRI of the head
- a lumbar puncture, or spinal tap
A lumbar puncture is done to measure the CSF pressure and get a sample of CSF to check for the presence of cancer cells. It is only done occasionally.
Find out more about these tests and procedures.
Treating increased ICP
If you have increased ICP, your healthcare team will monitor you closely. They may measure ICP by placing a small device into a tiny hole in the skull. Try not to cough, sneeze or bend over because these movements can increase ICP. The head of your bed will be raised to help lower the pressure.
Once the cause of increased ICP is known, your healthcare team can treat it. Treatment options may include the following.
Your healthcare team may prescribe corticosteroids. These drugs can help lower or prevent swelling of the brain, or cerebral edema. Dexamethasone (Decadron, Decasone) is the corticosteroid most commonly used to treat increased ICP.
You will be given antibiotics if an infection is the main cause of increased ICP. These drugs fight infections caused by bacteria and other micro-organisms. You may also be given medicines for pain or anxiety or to control seizures.
If your increased ICP is caused by cancer in the brain, treating the cancer can help lower ICP. You may need to have surgery to remove as much of the tumour as possible (called debulking surgery). You may also have radiation therapy or intrathecal chemotherapy to treat the tumour.
Intrathecal chemotherapy is given by a lumbar puncture or Ommaya reservoir. An Ommaya reservoir is a device surgically implanted beneath the scalp. It is used to deliver chemotherapy drugs directly into the CSF around the brain and spinal cord.
You may need to have a cerebral shunt placed to drain CSF and relieve ICP. A shunt is a passage that allows blood or other fluid to move from one part of the body to another. The extra CSF is drained from the brain to the abdomen.
Any steroid hormone that acts as an anti-inflammatory by reducing swelling and lowering the body’s immune response (the immune system’s reaction to the presence of foreign substances).
Corticosteroids are made by the adrenal gland. They can also be produced in the lab.