The flu is a common problem that affects children and adults alike. In most cases, this is a temporary problem that clears up within days and has no lasting impact on our health.

Flu viruses are most common during the fall and in winter. Flu season begins in October and ends in May with the peak period being December to February.

Every year, there are approximately 300,000 flu-related hospitalizations along with 20,000 to 30,000 flu-related deaths in the United States. A large number of these deaths are linked to complications that could have been avoided if they were detected in time, which is why you should be able to recognize the signs of flu complications.

Related article: Cold and Flu 101: What You Need to Know

7 Signs Your Flu Is Way More Serious Than You Think

For most healthy adults, about the flu simply means a few days off from studies or work. However, there are times when even the simple flu can turn deadly as it can cause complications and secondary infections.

People who have chronic medical conditions such as asthma, diabetes, heart disease, obesity or cancer are at a higher risk of developing flu complications. Here are 7 signs that your flu is more serious than you think:

1. Green, yellow or bloody mucus

A dry cough is one of the most common symptoms of the flu but if you start coughing up green, yellow or bloody mucus, it could indicate that you’ve come down with pneumonia. People recovering from the flu have a lower immune function. Therefore, they often suffer from pneumonia as a secondary complication.

Pneumonia is a life-threatening disease that can be caused by bacteria or viruses or both. Studies show that 32% of patients with viral pneumonia develop concomitant bacterial pneumonia. A gram stain test and bacterial and viral sputum cultures can help to determine the type of pathogen before initiating treatment.

2. Thickened mucus

In some cases, flu symptoms start to subside and then seemingly rebound and get much worse. For instance, you might go from a mild cough to suddenly cough up thickened mucus.

This would indicate that you might have come down with bronchitis as a secondary infection. Your doctor is likely to recommend a chest x-ray along with a blood test to rule out pneumonia. Non-steroidal anti-inflammatory drugs (NSAID) can help manage the symptoms of acute bronchitis.

3. Wheezing

Coughing is a common symptom of the flu. However, if you experience wheezing and chest tightness, you could be experiencing an asthma attack. People with asthma have sensitive and swollen airways and the flu increases the inflammation which results in wheezing and difficulty breathing.

The flu can trigger an asthma attack as well as aggravate the symptoms and increase the risk of other acute respiratory diseases. Individuals with asthma are more likely to develop post-flu pneumonia as compared to people who do not have asthma. Some studies indicate that influenza vaccinations can reduce the risk of asthma exacerbation. In fact, one study found that the vaccine could reduce this risk by 22% to 41% in children.

4. Chest Pain

Myocarditis is an inflammation of the middle layer of the heart’s wall (myocardium). Flu viruses can cause myocarditis. The condition often begins with mild symptoms such as fever and fatigue. Then it progresses to chest pain and rapid heart rhythms. 

Babies and seniors are at a higher risk of suffering from myocarditis due to the flu. Studies indicate that the prevalence of myocardial involvement in influenza infections may be as high as 11%. Although influenza myocarditis is not common, it can be fatal. Subtle cardiac anomalies in influenza patients can help doctors make an early diagnosis of myocarditis.

5. Confusion and seizures

Headaches and fatigue are common symptoms of the flu but if you experience confusion and seizures, it could indicate a more serious problem – encephalitis. Encephalitis is the inflammation of the brain tissue. It is more likely to affect children, the elderly and those with a weakened immune system.

Acute influenza-associated encephalitis (IAE) is caused by the influenza virus and can occur during or after your bout of flu. Patients with IAE present a variety of symptoms which poses a diagnostic challenge. Magnetic resonance imaging (MRI) can help in the diagnosis of IAE as researchers found that approximately 62% of patients with the condition present anomalies during MRI tests.

6. Calf pain

Body aches and pains are common during the flu. However, if you experience calf pain and weakness, it could be due to a complication called myositis. Myositis is the term used to describe the inflammation of muscle fibers. Influenza-associated myositis (IAM) is more common in children than adults and boys are at a higher risk than girls.

IAM invariably causes an elevation in blood creatine phosphokinase (CPK) concentration which is why that blood test allows for rapid diagnosis. Rapid diagnosis and treatment are important as 3% of patients experience rhabdomyolysis (the breakdown of muscle tissue) as well as renal failure. 

7. The pressure behind the eyes and the cheeks

When you are down with the flu, you are likely to experience headaches because of your stuffy nose. However, if you notice that a sensation of pressure behind your eyes and cheeks, it is possible that you have come down with sinusitis.

Sinusitis is the inflammation of the sinus spaces around the nasal passages and it can be brought on by the flu. Acute sinusitis can become chronic if it is left untreated.

Related article: Everything You Need to Know About This Year’s Flu Season

The bottom line

 The flu is generally a minor health issue that clears up within less than a week. However, it is important to understand flu symptoms and treatment options to reduce your risk and avoid common flu complications.

Children and older people are more susceptible to the flu. They are also more likely to experience more severe flu symptoms. Similarly, pregnant women and women who have delivered a baby within the last 2 weeks are more likely to get the flu. They are also more likely to develop more severe symptoms.

The flu can be fatal for older people suffering from other health issues. Flu shots help to reduce the risk of infection and are particularly important for adults who are 65 and older.

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