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Finding the cause of your fever

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Questions your doctor may ask

To treat a fever, you need to know what is causing it. If you develop a fever, your doctor will want to examine you and ask you a number of questions. This is so they can find out the exact cause of the fever and treat it in the best way. 

The doctor is likely to ask such things as

  • When did the fever start?
  • What symptoms do you have?
  • What cancer treatments are you having?
  • How long is it since your last treatment?
  • Do you have any difficulty passing urine or opening your bowels?
  • What medications are you taking?
  • Do you have any pain? If so, where?
  • Do you have any lines into your veins (for example a PICC line or central line)?
  • Do you have any tubes or catheters?
  • Is the fever there all the time, or does it come and go?
  • Do you have night sweats?
  • Do you have any wounds that have not completely healed?
  • Do you have any other illnesses?

If your white blood cells are low after cancer treatment and you get a fever, you need to go back to hospital straight away. You should see a healthcare professional with experience in managing infections after cancer treatment, within 24 hours of being in hospital. They will assess your risk of becoming very unwell because of an infection. 


Examinations and tests

Your doctor will examine you if they suspect you have an infection. They will closely examine parts of your body where infection is most likely to occur.

Sometimes your signs and symptoms can give your doctor some idea as to where in your body your infection is. For example, if you have burning and stinging sensations when passing urine, then you may have a bladder infection.

The doctor will also check your breathing and you may have a chest X-ray to rule out lung infection. If you have a drip or central line in place, they will carefully examine the entry site for any signs of infection.

Your doctor will arrange for you to have a blood sample taken. This is to check that your blood cell counts are normal. And to look for infection in your blood. Doctors call this test blood cultures. Your doctor may also take urine and sputum specimens to check for infection. And perhaps a throat swab, or a swab from around a drip site or from any wound you have.


What happens if your doctor can’t find the cause of your fever

It is not always possible for your doctor to find out exactly what is causing your fever. Doctors cannot find the cause of infection in half of those (50%) with cancer who have an infection. But you can still have treatment with a broad spectrum antibiotic. This is a type of antibiotic that is active against a wide variety of bacteria.

You may need to have some tests repeated. And you may need your antibiotics changed if tests show up a bacteria that needs treating with a specific antibiotic, or if you become more unwell. Some infections are very hard to find and it is important that your doctor keeps checking to find the cause.

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Updated: 4 September 2012