Increased intracranial pressure (ICP)

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 cerebrospinal fluid (CFS). CSF is the fluid in the cavities in and around the brain. Any change to the brain or the amount 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. Melanoma and cancers of the lung, breast and kidney that have spread to the brain are 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 (the meninges)
• bleeding in the brain
• swelling in the brain (cerebral edema)

Increased ICP can also be caused by radiation therapy. The brain tissue swells from the effects of the radiation. Increased ICP from radiation therapy can start right away (called acute increased ICP) or it can start later after radiation therapy has finished (called delayed increased ICP).

Symptoms of increased ICP can depend on where a tumour, a blockage, an injury or swelling is in the brain. Symptoms may be mild at first and get 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:

• nausea
• vomiting
• dizziness
• behaviour changes
• poor memory
• restlessness
• nervous system problems, including:
  • weakness in the arms or legs
  • numbness in fingers or toes
  • vision problems
  • coordination problems
  • loss of muscle strength
  • loss of movement (paralysis)
  • difficulty speaking
• lowered consciousness, including drowsiness, lack of energy, or confusion

Cushing triad is a group of three signs that mean that increased ICP is getting higher:

• high blood pressure with an increasing difference between the top (systolic) and bottom (diastolic) blood pressure readings
• slow pulse rate
• abnormal breathing

Your healthcare team will try to find the cause of the increased ICP. This includes your health history, a physical exam, assessment of your symptoms and a neurological exam. For a neurological exam, your healthcare team 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:

• a CT scan of the head
• an MRI of the head

A lumbar puncture, or spinal tap, may sometimes be done to measure the CSF pressure and get a sample of CSF to check for the presence of cancer cells.

Find out more about these tests and procedures.

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 (called cerebral edema). Dexamethasone is the corticosteroid most commonly used to treat increased ICP.

If an infection is the main cause of increased ICP you will be given antibiotics to treat it. 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 the 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 surgery to put in a cerebral shunt placed to drain CSF and lower 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.