Aching joints and muscles during the flu? Why?

Taking a step from your home to the street, you prepare yourself for the inevitable onslaught of sniffles and coughs as you try to avoid fevers and chills. Flu season has arrived.

Much of the time, the beginnings of the flu are similar to our old-fashioned common cold, but flu symptoms are often more severe and carry additional ones like fever, chills, and aching joints and muscles.

Most Canadians have a pretty good idea of the usual signs to watch for and some steps to take on the road to recovery, but what exactly is the flu?

The flu

Seasonal influenza is an acute and contagious respiratory disease caused by the influenza virus that affects humans globally, with estimates of one billion cases, 3-5 million of which are severe, and anywhere between 250,000 to 500,000 deaths annually. During the 2015/2016 flu season, there were over 5365 hospitalizations and 270 deaths reported here in Canada.

Much like humans come in all different shapes and sizes, so too can viruses. There are three types of the flu virus, but only the A and B types cause seasonal outbreaks. When our immune system first encounters a foreign body, white blood cells and leukocytes attack the intruder, gobble it up, and keep a piece of the enemy as a trophy known as an antigen. This is known as the innate immune response where the body initially encounters a foreign body and attacks it blindly. However, the cells that kept the antigen of the defeated invader do not get a chance to rest. These cells start to educate their friends to prepare them for the next battle with this intruder, developing antibodies that will attack that particular virus. During the next invasion, the body works much like a military strategist preparing for battle. The pathogen is analyzed to see whether it has any parts that the immune system has encountered before, and if it does, there is an adaptive immune response. The body already has antibodies against this virus, so it can muster the necessary resources quicker, attack stronger, and you recover faster.

So if the body gets smarter when it experiences the flu year after year, why do you get sick again and again?

The insidious nature of the influenza virus is due to a trait known as antigenic drift and shift. As the flu replicates and copies itself, there may be mutations that develop in their genes, and suddenly the body cannot recognize that virus as the one it battled before. Drift is much slower and leaves viruses that are more closely related, while a shift is abrupt and can cause a completely different viral subtype.

Aching joints and flu

As the body battles with the virus, there is a two-fold process that can encourage the symptom of muscle and joint pain. As the white blood cells work to protect you against influenza, they release cytokines into the body. These pro-inflammatory agents often accompany infections and serve a variety of functions such as to increase body temperature, recruit different leukocytes to the site of infection, and increase blood flow. This cytokine storm is normally well controlled, but during the flu, they can spill into the circulation and wind up in joints and muscles. This causes a sensation of achiness as inflammation occurs. In addition, as your muscles and joints work, they create metabolic byproducts that need to be cleaned up so the tissues continue to function. This is normally the work of white blood cells, so if they are recruited to fight off the infection, then there are fewer managing the byproducts, exacerbating the ache. However, as the infection subsides, so too does the soreness in your muscles and joints, though it may take a few days before they feel completely normal. So the best way to treat the flu-associated pain is to treat the bug!

Here are a few tips to help manage this year’s flu season:

• Take those sick days! Influenza particles are transmitted through respiratory droplets that are spread when people sneeze, cough, and even talk! The best way to avoid infecting others is to stay home and avoid contact.
• Clean and wipe down common surfaces. Okay, so you took that sick day, but now your house and all the surfaces you touched could be carrying the virus. Disinfectant wipes or sprays are a great way to keep the loved ones sharing your space safe.
• Symptomatic relief. A topical gel such as Absolüt Arnica can help to alleviate joint and muscle pain. The main active ingredient, Arnica montana, has been shown to improve functionality of joints and alleviate inflammatory symptoms in the region to which its applied. Products such as Echinaforce work internally to decrease the severity of flu symptoms and recovery time by modulating the immune system. The roots contain alkylamides that modulate the release of inflammatory cytokines, thus reducing inflammation experienced in the joints and muscles. More recent research has also suggested that Echinaforce may help to prevent secondary infections such as pneumonia, bronchitis, and sinusitis. For those who want an extra kick, there is also Echinaforce Extra.
• The sunshine vitamin. Vitamin D plays a large role in the production of antimicrobial agents in the body. Recent research out of the Queen Mary University of London and published in the British Medical Journal determined that Vitamin D supplementation could help 1 out of every 33 people avoid an acute respiratory tract infection. Talk to your primary care provider to determine the appropriate amount, and to determine the best treatment options for your flu.

Reference

http://www.bmj.com/content/356/bmj.i6583
https://www.canada.ca/en/public-health/services/diseases/flu-influenza/health-professionals-flu-influenza.html
https://www.cdc.gov/flu/index.htm
https://medlineplus.gov/flu.html
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4711683/
https://www.ncbi.nlm.nih.gov/pubmed/10799783
https://www.ncbi.nlm.nih.gov/pubmed/17131933
https://www.ncbi.nlm.nih.gov/pubmed/28275210
https://www.ncbi.nlm.nih.gov/pubmed/28279802
https://www.ncbi.nlm.nih.gov/pubmed/28293045
http://www.who.int/influenza/gisrs_laboratory/flunet/en/