Post-surgery fatigue may end quickly, or linger


How long do the fatigue and "brain fog" last after general anesthesia for surgery?

It depends - on your age, the specific drugs used, how long the surgery took and how healthy you were to start with. These days, most general anesthesia is short-acting, which means you wake up quickly and the drugs are mostly out of your system within a few hours, said Dr. Carl Rosow, an anesthesiologist at Massachusetts General Hospital.

But tiny amounts can linger for up to seven days - enough so that you may not feel completely normal, especially if you also have a drink or two.

Moreover, if you are one of the unlucky 20 percent to 40 percent of patients who have nausea and vomiting after general anesthesia, that can add considerably to your recovery time because of dehydration and weakness from not eating, said Dr. John Ulatowski, director and chair of the department of anesthesia and critical care at Johns Hopkins Medical Institutions.

It's actually quite difficult to sort out how much of the fatigue and "cognitive dysfunction," or temporarily decreased intellectual function, that often follow surgery is due to general anesthesia and how much to the surgery itself.

Some post-operative cognitive dysfunction can even occur with regional anesthesia, in which pain is blocked in one part of the body and the patient is sedated, but not rendered fully unconscious. That suggests, said Rosow, that part of post-surgical malaise may be due to the outpouring of stress hormones and inflammatory substances called cytokines.

People also vary widely in their response to general anesthesia drugs. For an older person having lengthy, major surgery, it may take six months to feel normal, though much of that would likely be due to healing from the surgery itself. A younger person having a short, minor operation may feel fine and be back at work the next day.

If a fever is a sign that the body is using its own natural defenses to fight off germs, wouldn't taking fever-reducing medicine like Tylenol mean that it would take longer for your body to fight the intruders?

That is one of the most frequently asked questions in medicine and the experts disagree.

Matthew Kluger, vice president for research at the Medical College of Georgia and a fever physiologist, said that animal studies suggest that fever is beneficial. Fever is so "costly" in metabolic terms in humans (each 2 degrees Fahrenheit of fever raises heart rate by 10 percent) that fever probably never would have evolved in the first place unless it did more good than harm.

In ferrets given influenza, those who were treated with aspirin had more virus in their nasal secretions than those whose fevers were left untreated. Other animal studies suggest that treating fever may even increase the mortality rate. "One can't do [such] studies in humans," Kluger said, "but if you extrapolate this to humans, it suggests that moderate fever is protective."

On the other hand, leaving a fever untreated may make you feel miserable, and treating an illness with Tylenol, aspirin or ibuprofen is likely to prolong it by a few hours at most, Kluger said.

Dr. Michael Shannon, chief of emergency services at Children's Hospital Boston, comes down firmly on the side of treating fever. "Your immune system will keep fighting the infection, whether or not you bring the fever down with medications."

When infection occurs, the immune system pours out chemicals called cytokines, including interleukin 1 and interleukin 6. These natural fever-makers trigger a cascade of other chemicals, including prostaglandins, which act on the brain to raise the body's thermostat, or set point. At the end of an illness, other chemicals called cryogens, or antipyrogens, bring it back to normal.

If you're an adult, call a doctor if your fever is 103 degrees Fahrenheit or higher. With a newborn, call the doctor for any temperature over 100.4. With an older child, call the doctor if the temperature is 102 or higher. As for medications, take them if you want.

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