Flu – Causes, Symptoms, Complications, and ER Treatment


Flu – Causes, Symptoms, Complications, and ER Treatment

Flu is a common respiratory illness caused by the flu virus. It can cause mild to severe illness and usually comes on suddenly, sometimes without warning. Most people experiencing the illness will usually recover in two weeks or less.

Flu is different from the common cold. While a cold is a mild respiratory illness and its symptoms can make you feel bad for a few days, flu is much more serious. It can make you feel ill for a few days to a week or longer, and it can lead to serious health issues like pneumonia.

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Common Flu Symptoms

Flu symptoms can be severe and usually come on suddenly. Most symptoms will gradually improve in two to five days but it is not unusual to feel rundown for a week or longer. Below are a few common symptoms of flu.

  • Sore throat
  • Fever
  • Headache
  • Muscle aches and soreness
  • Congestion
  • Cough
  • Chills
  • Fatigue (tiredness) and weakness
  • Sneezing
  • Runny or stuffy nose
  • Chest discomfort
  • Vomiting and diarrhea (more common in children than adults)

Note: Not everyone with the illness will have a fever

Flu Complications

One common complication is pneumonia, especially in the elderly, young or those with lung or heart problems. Another complication is a fever that returns after it has been gone for a day or two.

Other serious complications include sinus and ear infections, inflammation of the heart, brain, or muscle tissues, and organ failure

Flu infection of the respiratory tract can also lead to sepsis – the body’s response to life-threatening infections.

People at Risk of flu

Anybody can get the virus, including healthy people, and flu related issues can occur at any age but some people are at greater risk of developing flu complications if they get the virus. These people include:

  • People over 65 years old
  • Pregnant women
  • Children younger than 5 years (especially those 2 years and younger)
  • People with certain medical conditions (asthma, diabetes, or heart disease)

Flu Emergency Warning Signs


  • Trouble breathing or fast breathing
  • Fever (especially with rash)
  • Not interacting with other children
  • Not waking up as usual
  • Being irritable and refusing to be held
  • Not drinking enough fluids
  • Returning fever
  • Worsening cough


  • Pressure or pain in the chest
  • Pain or pressure in the abdomen
  • Dizziness (especially sudden dizziness
  • Confusion
  • Severe vomiting
  • Shortness of breath or difficulty breathing
  • Symptoms that improve but return a few days later with a fever and worsening cough

In addition to these emergency signs, take your infant or child to the nearest emergency room immediately if he/she has the following symptoms:

  • Unable to eat
  • Trouble breathing
  • Crying but no tears
  • Fewer wet diapers than normal

SignatureCare Emergency Center has 24-hour emergency rooms throughout Texas including many locations in Houston as well as in Austin, Midland, Odessa, Paris, Texarkana, Killeen, College Station, Stafford and Mission Bend/Sugar Land.