Finding the cause of your fever

It's important to find out what is causing your fever. This helps your doctor choose the right treatment for you.

Questions

Your doctor will want to examine you and ask you a number of questions if you develop a fever. This is so they can find out the exact cause of the fever and treat it in the best way. 

They might ask:

• 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?
• Are you coughing up green phlegm?
• Do you have a painful, throbbing tooth?
• Do you have any lines into your veins, for example, a PICC line or central line?
• Do you have any tubes, drains or catheters?
• Is the fever there all the time, or does it come and go?
• Do you have night sweats?
• Do you have any skin changes, for example, redness, your skin feels hot, swelling, or pain?
• Do you have any wounds that have not completely healed?
• Do you have any other illnesses?
• Have you taken medicines to lower your fever or treat any of your symptoms?

Tests

Your doctor will examine you if they suspect you have an infection. 

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

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

You'll have blood samples taken. This is to check that your blood cell counts are normal. You may have a blood test called a blood culture. This looks for infection in your blood.  

You might also have other tests to check for infection from your:

• urine
• spit (sputum)
• wound sites
• poo (faeces)
• nose and throat

What happens if your team can't find the cause?

It's not always possible for your doctor to find out exactly what is causing your fever. So you’re usually treated with a type of antibiotic that is active against a wide variety of bacteria. This is called a broad spectrum antibiotic.

You might need to have some tests repeated. And you may need your antibiotics changed if tests show up a bacteria that needs to be treated with a specific antibiotic, or if you become more unwell.

It's important that your doctor keeps checking to find the cause, but some infections are very hard to find. You may get better with antibiotics before your doctor can find the cause.