For the last 5 days I’ve struggled with what I suspect may be a mild case of influenza. I got my influenza vaccine in late September, and I suspect it along with the annual immunizations I routinely receive has kept me from being even sicker. Alternatively I could have some other viral crud that I tell patients is an “influenza-like illness.” I say mild because most of the time I can manage to get out of bed, get myself something to drink, and get back to bed safely. Without a doubt for me the fever and chills has been the most annoying part of this illness.
Today I started to feel enough better that I went out on a sunny cold afternoon with Kay to scope some birds on Commencement Bay, have a quick lunch and lay low in a movie theatre, covering my mouth with tissues and not touching anything. By the walk back to the car the shaking chills, also called rigors, had returned. Cabin fever got the better of my judgement. This prompted me to make some attempt at productivity with a review of the biological basis of fever and chills. I’ll preface this with noting that treatment of fever and chills with medications like acetaminophen or ibuprofen is not proven to help, and some experts argue they may hinder, the body’s ability to fight an illness. They sure can help me feel better, and I’m all over feeling better at this point. I’m writing this in part to pass the early evening until I can go to sleep with some hope of staying asleep until morning.
In most infections fever is produced when substances called pyrogens enter the blood stream. They can be on the surface of bacteria or viruses, as well as less common pathogens like trophozoites (malaria), parasites, and various other much less common pathogens in the developed world. When white blood cells called phagocytes attack the organisms with these pyrogens a substance called cytokines are released into the bloodstream, which stimulate receptors in the hypothalamus and change the thermo-regulatory set point to a higher setting. This leads to the a cascade of events, complex enough to bore me so I won’t bore you, but the end result is causing the muscles of the body to contract rapidly in what is commonly called shivering. When this happens we feel very chilled, and if the chills are severe enough to cause violent shaking we call them rigors. In the hospital or tge ofice we note whether the bed rails are rattling from the shivering. If so we call this rigors.
The end product of this febrile cascade is prostaglandin E2(PGE2), and the most common treatment for fever is the use of medications that block the effect of PGE2. The NSAIDS like ibuprofen and naproxen, as well as acetaminophen are examples of drugs used to lower fever by this mechanism.
So what should you do? First get your flu shot this year and every year. Arguments against influenza vaccination are simply not based on solid facts. Although a long way from universally effective the overall benefit of getting an annual influenza vaccine far outweighs the minimal if any risks. People especially at risk to become very ill or die from influenza include especially pregnant women, the very young, and the chronically ill. Dr Paul Offit is a strong and eloquent proponent of vaccines, and you can see a list of his recommended reliable information resources here.