Surgery is tough on the body, and it’s not unusual to have a fever during the first 48 hours after surgery. Any fever that develops in the hours or days after a surgical procedure is considered a postoperative fever.

While it can be alarming to find yourself with a fever after surgery, it’s usually not anything to worry about. However, postoperative fevers can occasionally be a sign of an underlying problem.

While you’ve probably heard that 98.6°F is the optimal body temperature, some people have slightly higher or lower temperatures. Anything in the range from 97°F to 99°F can be considered normal, depending on the person.

For adults who have not just had surgery, a fever under 103°F usually isn’t too concerning. If you have a fever higher than this, regardless of whether or not you’ve recently had surgery, it’s best to call your doctor.

Keep reading to learn more about what causes postoperative fevers and when they indicate something serious, such as an infection.

Many things can cause a postoperative fever. To remember all the potential causes, medical students are taught something called the five Ws, which stand for:

  1. Wind. This refers to respiratory problems, such as pneumonia or atelectasis, a lung condition that’s sometimes caused by anesthesia.
  2. Water. The fever may be caused by a urinary tract infection.
  3. Walking. This refers to venous thromboembolism (VTE), which is a potential complication of surgery.
  4. Wound. This is an infection of the surgical site.
  5. Wonder drugs. Some medications, including certain antibiotics or medications containing sulfur, can cause a fever in some people. A central line site can also become infected and cause a fever.

While many things can cause a fever after surgery, most of the them fall within these categories.

If you’ve had surgery in the last two days and your body temperature is a degree or two higher than it usually is, you can treat your fever with over-the-counter medications. Both acetaminophen (Tylenol) and ibuprofen (Advil, Motrin) can help bring down a high fever and reduce your symptoms.

If your body temperature is higher than usual by more than two degrees, it’s best to contact your doctor right away. You may need additional treatment, including:

  • antibiotics to treat an infection, either near the surgical site or in another part of your body
  • anticoagulants to treat VTE
  • chest physiotherapy, such as postural drainage, for atelectasis

If you develop a fever 5 or more days after surgery (but fewer than 30 days), it’s more likely to be the result of an infection requiring treatment than fevers that happen within a day or two.

While a fever is sometimes your body’s normal response to surgery, it can also be a sign of an underlying problem.

Call your doctor right away if you’ve recently had surgery and have a fever above 101°F. You should also call your doctor about any fevers that don’t start until several days after your procedure.

As you recover, also keep an eye out for any signs of an infection around your surgical site or any areas that received intravenous medication. Common signs of infection include:

  • swelling and redness
  • increasing pain or tenderness
  • drainage of a cloudy fluid
  • warmth
  • pus
  • bad smell
  • bleeding

Other signs that your postoperative fever might be more serious include:

  • unexplained leg pain
  • severe headache
  • trouble breathing
  • painful urination
  • frequent urination
  • nausea or vomiting that won’t stop
  • a tear near the surgical site
  • severe constipation or diarrhea

If you notice any signs of an infection or other problem after surgery, it’s important to get treatment as soon as possible to avoid any lasting complications. If you can’t get a hold of your doctor, ask to speak to a nurse or head to an urgent care facility.

There’s no foolproof way to prevent postoperative fevers. However, doctors and nurses go to extreme lengths to keep hospitals and operating rooms as free of bacteria, viruses, and fungi as possible. If you’re concerned about a hospital-acquired infection, you can also ask your doctor or other hospital staff about their sanitation procedures and guidelines.

To reduce your risk of complications after surgery, there are also a few things you can do on your end.

Before you have surgery:

  • Quit smoking. Smoking increases your risk of infection and blood clots.
  • Don’t shave. Shaving anywhere near your surgery site can introduce bacteria into the skin. If you have a lot of hair around the surgical site, speak with your surgeon first to see if shaving is necessary.
  • Wash your whole body. On the night before and morning of your surgery, you should wash with a surgical soap, like this one.
  • Ask about antibiotics. Ask your doctor if they plan to prescribe antibiotics for you as a preventive measure.

After you have surgery:

  • Know who to call. Before leaving the hospital, make sure you know who to call if you get a fever or have any unusual symptoms.
  • Follow instructions. Your doctor should give you all the information you need about caring for your wound, such as any medications you should take and how often you should change your bandages.
  • Wash your hands. Always wash your hands with soap and warm water before touching your incision for any reason, including scratching an itch. Also make sure anyone helping you change your bandages washes their hands as well.
  • Get the right help. Make sure loved ones and caretakers wash their hands before helping you with wound care or catheters.
  • Protect yourself. Ask visiting friends and family members to thoroughly wash their hands before entering your hospital room.
  • Call for help. Contact your doctor immediately if you have a high fever or any other unusual symptoms.

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