Influenza is a highly contagious respiratory illness caused by one of hundreds of strains of a virus that causes high fevers, cold sweats or chills, head and joint aches, fatigue, and gastrointestinal symptoms, including nausea, vomiting and diarrhea. According to the National Institutes of Health (NIH), 5 to 20 percent of Americans will become ill with the flu each year, resulting in 200,000 hospitalizations and up to 49,000 deaths.
For about 75 percent of sufferers, symptoms can range from mildly uncomfortable to leaving them bedridden but able to recover at home with home remedies that include chicken soup, rest and over-the-counter (OTC) medications. The remaining 25 percent will suffer from life-threatening complications.
If the thought of spending a week with the common symptoms of the flu isn’t enough to get you to your doctor for an annual seasonal flu vaccine, consider the following five frightening flu complications:
Pneumonia
Pneumonia is one of the most common and serious flu complications. This condition can occur from direct involvement of the flu virus in the lung or when a bacterial infection develops during the flu. Whether the cause is viral or bacterial, pneumonia is a serious condition that requires medical attention and possibly hospitalization.
With pneumonia, patients develop chills, fever, chest pains, cough with green or bloody mucus, increased heart rate, and bluish-colored lips because of a lack of oxygen in the blood. Shortness of breath or sharp pains when inhaling are also common. When the cause is a bacterial infection, often the symptoms of the flu will improve initially, only to return with higher fevers, worsened coughing and the telltale discolored phlegm. Antibiotics can be used to treat bacterial pneumonia but cannot be used to help with viral pneumonia.
This condition, when treated promptly, typically lasts about two weeks (though it can last even longer in young children, the elderly and those who have compromised immune systems). For those in high-risk categories, you can ask your doctor about the pneumococcal vaccines -- for children or adults -- that provide immunity against the 23 types of bacteria that commonly cause pneumonia.
Myocarditis
This complication is far rarer than pneumonia but can result from the flu in otherwise healthy children and adults and is characterized by the inflammation or destruction of the myocardium (middle layer of the heart wall) and can lead to rapid heart failure or blood clot formation resulting in a stroke or heart attack.
Patients who develop myocarditis typically experience difficulty breathing, edema (fluid buildup) around the ankles or calves, sharp, shooting pain when breathing, and irregular heart rhythms. Prompt medical attention can result in treatment including antivirals (if a virus caused the condition) as well as steroids. Prompt medical attention is imperative -- for some, a full recovery is possible, while others will be forced to be on cardiac medications for life or even require a heart transplant.
Guillain-Barre Syndrome
This complication only strikes one or two cases per 100,000 people each year, developing as a result of a cold or flu (or a number of other illnesses). This autoimmune disorder progressively affects muscle strength. Patients typically develop varying degrees of weakness or tingling in the legs, which spreads to the arms and upper body. These symptoms increase in severity until some muscles cannot be used at all. In severe cases - which are life-threatening, a person may be almost totally paralyzed, with the condition affecting the ability to breathe. In these cases, patients are placed on ventilators.
Diagnosis of this condition can be a challenge because it involves ruling out other causes of weakness that are more common. While there is no cure, treatment for this condition includes supportive care, antibody treatments and plasma exchange. While recovery is possible, it is typically a slow process, with about two-thirds of patients taking a month or more to see an improvement in their condition.
Sudden Sensorineural Hearing Loss
Muffled hearing and even ear infections are common complications from the flu virus, but for some patients, this hearing loss can become more serious. Sudden sensorineural hearing loss (SSNHL) is a complication associated with influenza, in which the body becomes unable to convert vibrations in the inner ear into nerve signals the brain can translate. SSNHL seems to occur frequently in people who have cold or flu viruses, with as many as 40 percent of patients with this condition reporting the flu or other upper respiratory illness preceding the onset of SSNHL.
Patients who develop this form of hearing loss may experience swelling, congestion and pressure in the ears with hearing loss. Some people may recover on their own as their flu symptoms improve; however, any hearing loss is a red flag to seek medical attention to avoid permanent damage. Treatment for this condition may consist of oral steroids.
Reye's Syndrome
This rare complication from flu is a condition that causes both the brain and the liver to become inflamed, triggered by a combination of aspirin and viral illness. This condition can result from other viruses, like chicken pox, and develops most often in children and teenagers who are recovering from these viral illnesses.
People who have developed Reye's syndrome may experience vomiting, confusion, seizures, lethargy and mental changes. There is no set treatment plan for this condition, and the outcome varies dramatically, with some patients making a full recovery and about 20 percent dying from the condition. Early diagnosis and medical attention can be key to saving a child’s life, so emergency medical attention should be sought as quickly as possible.
Caregivers have been advised against giving children and teenagers medications containing aspirin when they have developed a cold, flu, chicken pox, fever or other potentially viral illness because of the medication’s link to this condition.