flu

Updated on

Ricarda Schwarz studied medicine in Würzburg, where she also completed her doctorate. After a wide range of tasks in practical medical training (PJ) in Flensburg, Hamburg and New Zealand, she is now working in neuroradiology and radiology at the Tübingen University Hospital.

More about the experts All content is checked by medical journalists.

The flu (influenza) is a serious respiratory illness caused by viruses. Many people get it, especially in the winter months - flu is very contagious! However, a simple cold is often misunderstood as the flu, although the differences are very large. Read here which symptoms are typical of the flu and how you can protect yourself!

ICD codes for this disease: ICD codes are internationally recognized codes for medical diagnoses. They can be found, for example, in doctor's letters or on certificates of incapacity for work. J10J11

Brief overview

• Symptoms: sudden onset of fever with chills, muscle and joint pain, dry cough, sore throat, headache, sometimes gastrointestinal complaints (especially in babies and small children), tiredness, feeling very sick
• Contagion: via the finest droplets in the air we breathe, touching contaminated objects and surfaces
• Pathogen: mostly influenza A viruses, more rarely other infuenza viruses
• Prevention: vaccination (for risk groups), avoid contact with infected people, regular hand washing
• Treatment: symptomatically with pain relievers and fever medication (ibuprofen, paracetamol), bed rest, drinking a lot, home remedies; possibly anti-virus medication
• Possible complications: e.g. pneumonia, sinusitis, otitis media, myocarditis, meningitis

Flu: symptoms

Anyone who lies in bed with a cough, runny nose and fever often wonders whether they are plagued by the flu or a cold (flu-like infection). The most important differentiation criterion: While you are slowly getting worse with a cold, the flu attacks you suddenly.

Flu or cold? The main differences

flu	"Cold" (flu-like infection)
Sudden fever of at least 38.5 ° C to 40 ° C	slowly rising fever or no fever at all
Fever usually lasts more than three days	Fever often only briefly
severe feeling of illness	mild to moderate malaise
often nausea, vomiting, diarrhea	no gastrointestinal problems or mild nausea
thereafter often persistent inefficiency	afterwards productive again quickly

The most common signs of flu are high fever, chills, and feeling very sick. A dry, irritating cough often occurs in sick people. Here you will find an overview of all possible flu symptoms:

• high fever
• chills
• Exhaustion
• dry, irritating cough
• seldom cough with tough, sometimes bloody expectoration
• sniffles
• Sore throat
• Sore throat
• Conjunctivitis
• Gastrointestinal complaints such as nausea, vomiting, diarrhea
• headache
• Sensitivity to bright light (photophobia)
• puffy face
• Pain in the limbs and muscles

• "It's best to go to bed!"

  Three questions for

  

  Dr. med. Markus Frühwein,
  Specialist in General Medicine

• 1

  Should I always see a doctor if I suspect flu?

  

  Dr. med. Markus Frühwein

  If there is a suspicion of a real flu, i.e. if there is a high fever and a strong feeling of illness, then yes. The main concern then is to rule out other diseases as the cause of the complaints and to identify risk patients. So that the flu does not take a severe turn. The best way to protect yourself against this is to have the annual flu vaccination. This generally reduces your risk of getting infected.

• 2

  What else will protect me from infection?

  

  Dr. med. Markus Frühwein

  Influenza is transmitted by droplet infection, e.g. by sneezing, coughing, kissing or shaking hands. This means: Basic hygiene measures such as hand washing or hand disinfection are advisable. Also, avoid contact with sick people. A mouthguard would also help - but that is difficult to implement. Basically, a healthy lifestyle with a balanced diet and exercise strengthens the immune system and protects against illness.

• 3

  How can I speed my recovery?

  

  Dr. med. Markus Frühwein

  Influenza is caused by a virus. Because of this, drug therapy is difficult. There are active ingredients, but they have to be taken very early and only shorten the duration of the illness to a limited extent. If you have the flu, go to bed and lower your fever if necessary, either with medication or with measures such as leg wraps.

• 

  Dr. med. Markus Frühwein,
  Specialist in General Medicine

  Dr. med. Markus Frühwein is a specialist in general medicine, tropical medicine, travel medicine and nutritional medicine and owner of the Dr. Frühwein & Partner in Munich.

Influenza: special courses

Influenza viruses do not cause typical symptoms in everyone. Although they can spread and multiply quickly, they often only cause minor discomfort. Then, for example, flu headaches are interpreted as migraines or illness-related exhaustion as work-related exhaustion.

In children, the flu is often accompanied by otitis media with ear pain. Small children can develop a so-called croup: an inflammation of the larynx below the glottis causes a barking cough.

After the flu has healed, many people feel weak and tired for a long time, suffer from circulatory problems and headaches. Even if someone with the flu has not taken good care of himself, the illness can last longer. Coughing and fatigue can then persist for weeks, for example. In this case one speaks of a "carried flu".

Flu: complications

People with weak immune systems are at risk of the flu taking a complicated course. These include children, pregnant women, the elderly, the chronically ill (e.g. asthma patients) and people who take drugs to inhibit the immune system (immunosuppressants) - for example after an organ transplant.

If the immune system is running at full speed due to the flu virus infection, the body is also more susceptible to other diseases - for example bacterial infections. Such an additional infection is called a superinfection. The first signs of this are a renewed rise in fever and weakness or a cough that worsens again. The following complications can arise from bacterial superinfection:

Inflammation of the airways

Sinusitis is often caused by the flu as a bacterial superinfection.

It is not uncommon for people with asthma or COPD to develop pneumonia caused by bacteria during the flu. It is even more common than the pneumonia caused by the influenza virus itself. Bacterial pneumonia is a life-threatening complication and the most common cause of fatal flu.

Otitis media

Children in particular often get a bacterial otitis media in addition to the flu. Signs of this are sudden, severe earache. Often the patients also report a knocking or throbbing in the ear as well as hearing impairment or dizziness.

Inflammation of the heart

The flu can also affect the heart. The heart muscle can become inflamed (myocarditis) - a dangerous complication that often only manifests itself as a few symptoms. Occasionally, there is a fever, chest pain and noticeable irregular heartbeat. If people who have unwittingly developed myocarditis try too hard, the risk of sudden cardiac death increases.

Inflammation of the pericardium (pericarditis) is also possible during the course of the flu. It is usually less dramatic than myocarditis and heals on its own after a while.

For both peri- and myocarditis, hospitalization and bed rest are necessary to reduce the risk of further complications.

Meningitis

In rare cases, the flu can develop meningitis. In addition to a fever, severe headache and neck pain as well as "neck stiffness" usually occur. If confusion, sleepiness or a seizure is added to these symptoms, it is very likely that not only the meninges but also the brain have become inflamed (encephalitis).

Influenza: protection against infection

When a flu patient sneezes or coughs, the viruses fly through the air - enclosed in fine droplets of secretion. If another person inhales the droplets, they can also get flu (droplet infection). Infection is also possible if you touch surfaces contaminated with influenza viruses (e.g. door handles, PC keyboards, handrails in the bus) or shake hands with a flu patient and then touch your face.

You can reduce your risk of infection by

• wash your hands regularly

• do not touch the face, especially the eyes, with your hands

• refrain from shaking hands

• avoid large crowds
• keep the room air moist (dry heating air removes moisture from the airways and makes it easier for pathogens to penetrate there)

As with any infectious disease, people who come into frequent contact with the pathogen are particularly at risk. Therefore, there is an increased risk of infection for people who work in medical facilities such as hospitals, medical practices, old people's or nursing homes. But the flu viruses can also spread faster in schools, kindergartens and day-care centers.

Preventing the flu: vaccination

The best way to protect yourself from flu infection is to have a vaccination. The Standing Vaccination Commission (STIKO) recommends that people with a weak immune system get vaccinated.

The best time to get a flu shot is in autumn. However, because the flu viruses change very quickly, the vaccination must be repeated every year to be effective. More recent studies show that vaccination repeated every year can improve protection against influenza even further.

What you need to consider when vaccinating and further information about the flu vaccination can be found here: Flu vaccination

Influenza: treatment

The cause of the flu can only be treated to a limited extent. However, the symptoms can be significantly alleviated by various means.

Flu Treatment: Medication

There are special drugs that block the protein neuraminidase against influenza viruses. These so-called neuraminidase inhibitors (antivirals) prevent the flu viruses from multiplying further. As a result, the disease is usually much milder and shorter. However, neuraminidase inhibitors only work in the first two days after the onset of symptoms. In addition, they are not effective against all influenza viruses and have some side effects.

This is how neuraminidase inhibitors work

Influenza viruses are encased in the enzyme neuraminidase, which enables them to detach themselves from the infected cell after they have reproduced. The neuraminidase inhibitor group of drugs prevents detachment, so that the newly formed viruses adhere to the cell membrane and cannot spread further in the body.

If the flu takes a complicated course, bacteria often cause symptoms of illness in addition to the influenza viruses. Such a bacterial superinfection can be treated with antibiotics. These kill the bacteria, but do not work against the flu viruses.

Symptom relief

Various medications can reduce the symptoms of the flu and make the illness more bearable. Antipyretic pain relievers such as ibuprofen, acetylsalicylic acid or paracetamol help relieve pain (such as headaches) and high fever.

Children should not take acetylsalicylic acid if they have the flu! The active ingredient can trigger the potentially life-threatening Reye's syndrome in minors in connection with certain viral infections.

In addition, cough syrups or decongestant nasal drops can be useful if the symptoms are relevant.

Flu Treatment: Home Remedies

Calf compresses, inhale, gargle - home remedies are often used in conjunction with drug therapy to relieve flu symptoms and support the healing process.

You can read about the home remedies for flu in the article Home remedies for colds and flu.

Influenza: disease course and prognosis

The first symptoms appear an average of one to two days after being infected with the influenza virus (incubation period). Infected people, however, are often contagious before the onset of symptoms (for about a week).

The flu can take very different courses. With normal flu, the fever goes away in five to seven days. Symptoms such as coughing, runny nose or a feeling of weakness can persist for one to two weeks longer.

Flu often lasts longer in people with a weakened immune system such as children, the elderly, pregnant women or patients with chronic illnesses (especially respiratory diseases). Complications can then also occur, which in rare cases can even be fatal.

Because the flu virus is constantly developing new subtypes as a result of changing gene segments, you can catch the flu several times in your life. In contrast to other infectious diseases, which you only get once because the immune system has developed effective protective mechanisms against the pathogen, you do not become permanently immune to flu.

This is true at least for the more common influenza A virus. However, there are different types of flu viruses. Type B changes much more slowly, so that you usually only catch the flu from influenza B viruses once in your life, often in childhood. The disease is usually mild.

How does a summer flu work?

The so-called summer flu, which is actually not a "real flu" at all, is also mostly mild. Because it is not triggered by influenza viruses, but by enteroviruses. As the name suggests, it usually occurs in summer and is similar to a cold.

How to distinguish summer flu from flu and information on treating summer flu can be found in the article Summer flu.

Flu: examinations and diagnosis

Anyone who suspects they may have been infected with the flu virus should see a doctor. In particular, people with an increased risk, such as the elderly and the chronically ill, should consult their family doctor as soon as the first signs of flu appear.

In many cases, the doctor can use the medical history (anamnesis) and a physical examination to determine whether there is actually a flu (influenza) or just a flu-like infection (cold). However, if the person concerned is doing very badly or if there is a risk that the disease will take a severe course, a virus detection makes sense. If this is positive, anti-virus treatment can be started immediately.

Influenza Virus Detection

The rapid influenza test is an important indicator of whether the virus is actually a flu virus. For this test, secretion from the nose or throat is wiped off with a cotton swab and placed on a test strip. If it becomes discolored, influenza infection is very likely.

Sometimes, however, the sample material has to be sent to a laboratory, where the virus can be identified one hundred percent through a genetic analysis.

Reporting requirement

If flu viruses have been detected in a patient, the doctor must report this to the health department. This allows precautionary measures to be taken to prevent the disease from spreading further. In the hospital, for example, sick people are isolated in a single room. Visitors and medical personnel must wear protective clothing when entering the hospital room. Regular hand washing also prevents the virus from being passed on to other people.

Influenza: the influenza virus

The flu is caused by viruses that are scientifically known as influenza viruses. There are three different types of flu virus: A, B and C. Only influenza A viruses can be really dangerous to humans. In contrast to the B viruses, which usually only provoke milder disease processes, and the C viruses, which occur only very sporadically, A viruses are responsible for the severe flu epidemics. They are very versatile and are divided into a number of subgroups (subtypes).

These subtypes are named after the proteins on their surface, with the help of which they can penetrate the host cells and then free themselves from them again. H stands for hemagglutinin, N for neuraminidase. Well-known flu virus subtypes are H1N1 and H3N2.

If the flu occurs frequently and locally, it is called an epidemic. If the wave of disease crosses countries or even continents, this is called a pandemic. Influenza waves occur almost every year in winter. A flu pandemic occurs every ten to 40 years, but the severity of the flu can vary. For example, 18,000 people around the world died of "swine flu" in 2009.

Tags:  laboratory values alcohol drugs pregnancy