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Pneumonia: Symptoms, diagnosis and treatment

Pneumonia is an infection of our lungs. Bacteria are often the underlying cause, but also viruses and other triggers can lead to this type of infection. Patients suffer from shortness of breath, cough and high fever. In elderly patients, a pneumonia counts to one of the most dangerous infections.

In the following text, please find important information on pneumonia, accompanying signs and symptoms, diagnostic tests and treatment options.

Background Information

What leads to pneumonia?

The lung is divided into two parts, one on the right and one on the left side of our heart. As a construct of a fine framework with countless tiny air sacs, it is responsible for the exchange of oxygen and carbon dioxide. In pneumonia, there is an inflammation of the deep respiratory tract and its tissue. Bacteria, viruses and chemicals can cause this type of irritation. The infection can attack just one part of the lung, or several segments, or even both left and right lobe of the lung.

From bacteria and viruses

Many different bacteria can cause pneumonia. A typical candidate are the so-called pneumococci, which are responsible for about 50% of pneumonias acquired in an outpatient basis. Other bacteria that can affect the lungs are called staphylococci, Klebsiella, Pseudomonas or Moraxella.

Physicians differentiate between hospital- and community-acquired pneumonia. This can be important since the bacterial spectrum causing the infections differs in both types a little bit and may need different antibiotic treatment.

Typical and atypical pneumonias

Physicians furthermore differentiate between typical and atypical pneumonia. Typical pneumonia usually goes along with high fever, chills and breathing pain. In atypical pneumonia, however, symptoms are not as prominent and have a much more insidious onset of the disease with little fever.

Whereas blood tests show increased values of inflammation such as CRP (C-reactive protein) and white blood cell count (leukocytes) as well as a whitened lung-areas on chest X-rays in typical pneumonia, this may be much less pronounced in atypical pneumonia.

Common pathogens of an atypical pneumonia include mycoplasma, chlamydia and legionella. Viruses such as influenza A and B as well as adeno- and cytomegaloviruses can also cause pneumonias.

Hospital admission

Young and otherwise healthy people can often be treated on an outpatient basis. Older people, however, and those with pre-existing conditions and with difficulty breathing should be monitored in hospital. Sometimes, the infection can go along with mental confusion and even low blood pressure. Pneumonia can be very serious in some cases. It is the number one cause of death among all infectious illnesses in the modern world.

What is the difference between bronchitis and pneumonia?

While in bronchitis the small airways inside the lung are inflamed, pneumonia affects the fine alveoli and surrounding tissue. Patients are often seriously ill and must be treated with antibiotics.

Down in the depths of the lungs

In order to better understand the difference between bronchitis and pneumonia, we make a brief excursion into the anatomy of the respiratory tract.

The first passage of breathing involves mouth and throat, followed by the trachea. After about ten to twelve centimetres, it divides into a right and a left branch, called the main bronchi. They divide further into multiple small air passages, called bronchi and bronchioles, and end at delicate alveoli. Their surface is covered with a fine network of vessels, where the exchange of oxygen and carbon dioxide takes place.


A common cold can step down into deeper airways and attack the bronchi. These are covered by special cells, which have some sort of “hairy” extensions on their surfaces that work like little brushes. They catch bacteria and viruses. By coughing up our body can get rid of these intruders. Therefore, bronchitis is regularly accompanied by an agonizing cough.

As bronchitis is often triggered by viruses, it usually does not need to be treated with antibiotics. In rare cases, bacteria or fungi can also lead to an inflammation of the bronchi. However, this usually affects people with underlying lung diseases, repeated infections or immunodeficiency.


Pneumonia, on the other hand, affects the deeper structures of our lungs including the small alveoli and sometimes their surrounding tissue. Unlike in bronchitis, in pneumonia, bacteria typically trigger the infection. But also, viruses and fungi can be a source of it.

People with pneumonia are often "very ill". In addition to coughing, shortness of breath and possibly lack of oxygen also play a role. The fever can rise to values around 40°C, weakness and muscle pain can be very pronounced. The breathing rate can climb to over 30 breaths per minute, blood pressure can drop. Older people even experience a clouding of consciousness, which makes them disoriented and sleepy.

Differences between Pneumonia and Bronchitis on examine

Pneumonia and bronchitis also differ in the physical examination. In a "typical" pneumonia, physicians hear a fine rattling over the affected area when listening to the stethoscope. And, the chest X-ray can confirm the area of pneumonia by showing a whitened area in the lung.

In Bronchitis, however, usually you do not have these typical findings. Of course, there are also mixed pictures and cases in which the diagnosis is not always clear and typical. It is important to take warning signals such as high fever and breathlessness seriously.


What causes a pneumonia?

In pneumonia, bacteria, sometimes viruses and rarely fungi colonise parts of the deep respiratory tract. Particularly affected are the small alveoli and sometimes the surrounding tissue. There is an inflammatory reaction, often with fever, shortness of breath and cough. A weakened immune system favours the outbreak.

Bacteria and other triggers

In addition to bacteria, viruses and fungi, gases, dust and radiation can also strongly irritate the respiratory organ and lead to pneumonia. The most frequent bacterial culprits of pneumonia are the so-called pneumococci. They count for more than 50% of cases. Other bacteria that can also attack the lungs are staphylococci, Klebsiella, mycoplasma, chlamydia or pseudomonas as well as influenza viruses A and B and adenoviruses.

Doctors also differentiate whether the inflammation has occurred outside (i.e. on an outpatient basis) or within a clinic or nursing home.

Weak immune system favours infection

Pneumonia can be transmitted by droplets while shaking hands, sneezing or coughing. And wherever people are, there are pathogens such as bacteria and viruses. A healthy, strong body however, usually gets rid of the troublemaker quickly.

This may change with a weakened lungs or immune system. In COPD, for example, or with other pre-existing conditions such as diabetes mellitus or advanced age, the body becomes more susceptible to pneumonia. Heavy consumption of cigarettes and alcohol also compromise body and respiratory tract.

Also, inpatients are more susceptible to infections in general. Any acute disease weakens the organism and hospital-acquired infections may occur. A pneumonia, which starts within 48 hours after admission, is called a "nosocomial" pneumonia. Its pathogen spectrum differs from that of outpatient infections, which again determines, which antibiotic treatment is the right one.

Is pneumonia contagious?

This question is not easy to answer. The infection is passed by droplets, but a healthy immune system can usually defend itself. People with an immune deficiency, infants and elderly people, on the other hand, can become ill more easily.

Many different pathogens

Many germs can lead to pneumonia, the most typical bacterial pathogen of them being pneumococcus, which accounts for 50% of the cases.

Atypical bacterial pathogens such as mycoplasma, chlamydia or legionella, viruses such as influenza A/B and fungi are also possible culprits. All of them can colonize the fine vesicles of the lungs (alveoli) and trigger severe inflammatory reactions.

A healthy immune system helps against germs

By coughing, sneezing and shaking hands, pathogens can pass from one person to the next by droplet infection. If a germ encounters a healthy, strong person, it is trapped by the ciliated epithelium in the respiratory tract of the lungs (bronchi). The ciliated epithelium consists of special cells with small hairs that transport pathogens back outside by stimulating the cough. Together with strong defences, an intruder then has no chance.

Risk groups must watch out

However, the situation is different for immunocompromised people. Infants, young children, elderly and people with HIV infection or an organ transplant on immunosuppressive drugs can be affected more severely. This risk group should avoid contact with people who have pneumonia or upper respiratory tract infections. In their case, the body's defences are not always strong enough to protect itself from transmission and infection. Simple hygiene measures as regular hand washing can prevent infection.

Does pneumonia occur more frequently during winter?

Pneumonias can occur at any time of year, but some types occur more frequently in the winter months. The underlying type of bacterium or virus plays a role.

Pneumonia slightly more frequent in winter times

A study from Barcelona observed about 4000 people with community-acquired pneumonia that received treatment as inpatients on a seasonal basis. One third of all pneumonia occurred in winter, the other two thirds in spring, summer and autumn. Thus, although there was an accumulation of pneumonia in the cold season, the infection was not uncommon in the remaining months.

They further investigated in a subgroup whether individual bacteria prefer certain periods of the year. The analysis showed that the frequently occurring pneumococci prefer autumn and winter, but also occur during spring and summer. The same was true for the flu virus (influenza), which also prefers cool seasons.

Winter and summer infections

Experts discuss what exactly causes pneumonia to occur more frequently in winter times. Certain pathogens simply survive better in cold temperatures. In addition, people spend more time together indoors in autumn and winter. A vitamin D deficiency and a weakened immune system in the cold season may also be responsible for an increased susceptibility to infections.

Individual bacteria such as Legionella, on the other hand, prefer a warm, humid climate and occur more frequently in the summer months.


What are typical symptoms of pneumonia?

A typical pneumonia goes along with high fever, cough and general malaise. Atypical pneumonias on the other side do not have to show these classic symptoms.

A more detailed list of typical symptoms of pneumonia includes the following:

  • flu infection or bronchitis for days, with a tendency to worsen rather than improve
  • mostly (high) fever
  • very fast and strenuous breathing, often moaning or whistling
  • painful cough, dry or purulent
  • movement of the nostrils with heavy breathing
  • severe feeling of illness or even apathy
  • possible shortness of breath and blue lips

in infants:

  • clearly visible movement of the nostrils
  • retraction of the skin over the clavicles and between the ribs

What is a typical pneumonia?

Typical pneumonia is what we commonly call "pneumonia". Patients are seriously ill, have a high fever with a cough and only antibiotic treatment helps. Very specific bacteria trigger the classic course of a typical pneumonia. Symptoms of atypical pneumonias go along with less tangible symptoms such as general weakness and dry irritable cough.

Sudden onset and high fever

With a typical pneumonia, people often fall ill without any warning. The temperature climbs up to 40°C with chills and severe limb pain. Patients are usually short of breath and breathing can be painful. The cough is "productive" with purulent and yellow-green sputum.

When listening with the stethoscope, the doctor hears classic rattling and crackling noises over a part of the lung. A chest X-ray often confirms the diagnosis of pneumonia. It shows an infiltrate, accumulation of bacteria and cells, in one part of a lung lobe as a white are.

What is an atypical pneumonia?

In comparison to typical pneumonia, atypical pneumonia begins rather insidiously and is accompanied by non-specific complaints like headaches and pain in the limbs, mild fever and dry irritable cough. Virus pneumonia also has a similar clinical course. In contrast to a typical pneumonia, the classic high fever and yellow-green productive cough are missing.

Progression depends on the germ

Depending on the location of the infection and the course of the pneumonia, various germs can trigger the disease. Based on the classification, doctors can decide which antibiotic is most likely to help.

The two forms of lung infection are triggered by different bacteria. While the typical one is often caused by pneumococci, the atypical pathogens such as mycoplasma, chlamydia or legionella are.

Dry cough in atypical pneumonia

Inflammation centres caused by atypical bacterial pathogens can spread diffusely in the lungs. In addition to the alveoli, the surrounding intermediate tissue, the scaffold, can also be affected. The cough is not productive but rather dry, tough and agonizing. The infection itself often begins insidiously; high fever plays a less important role.

When listening, it is not easy for the doctor to tell whether and where there are indications of inflammation. The chest X-ray image also occasionally shows no clear findings.

Since clinical complaints, medical examinations and even imaging are not always ground-breaking, diagnosis is sometimes more difficult and takes longer than in classical pneumonia.


How is pneumonia diagnosed?

People with pneumonia often, but not always, have high fever, shortness of breath and cough. Examinations with the stethoscope, blood samples and chest X-rays findings can confirm the diagnosis.

Clinical symptoms, blood tests and chest X-rays

Pneumonia is an infection of the small alveoli and on occasion the surrounding tissue. Often, bacteria trigger the inflammatory reaction. But also, viruses or more rarely fungi can do so.

Depending on the type of bacterium or pathogen, a lung infection can take a typical or atypical course. Patients with typical pneumonia suffer from have high fever, chills, purulent sputum and limb pain.

Generally, blood test show significantly increased inflammation values like CRP values (C-reactive protein) and white blood cell count (leukocytes). When listening with a stethoscope, physicians hear a rattling and crackling sound over the affected area. A chest X-ray shows a brightened area above the otherwise rather dark, airy lung and confirms the diagnosis.

Further tests

In case of pneumonia, physicians also check basic laboratory tests of the kidneys and electrolytes.

If people become seriously ill, they need further examinations in a clinic. Optimally, blood cultures are taken before antibiotic therapy is started in order to check for the causative bacterium and to tailor down the antibiotic treatment.

In severe cases, if a lung abscess for example is assumed, a computer tomogram (CT) or an ultrasound examination may become necessary.

Atypical pneumonia may be more difficult to diagnose

People with so-called atypical pneumonia often show a rather insidious course. The classic rattle sound may often be missing on clinical examination. Compared to typical pneumonia, diagnostic steps are generally similar, but sometimes it takes longer until the final diagnosis is made.

Can pneumonia always be seen on X-rays?

Generally, in pneumonia, a chest X-ray shows typical changes, but not always. Depending on the type of bacteria and the severity of the inflammation, one or more areas of the lung may be affected. In severe cases, pneumonia affects both lungs.

Light shadows in the dark

Clinical examination including auscultation with a stethoscope as well as the chest X-ray form one column a basic diagnostic testing when physicians suspect a pneumonia. X-rays were already discovered at the end of the 1895s.

Doctors can use chest X-rays to depict the infiltrate of a lung infection. While bone and heart appear bright and white, the air-filled lungs look generally dark. The area affected by bacteria and pus displaces the air and therefore also appears bright rather than dark.

Typical and atypical pneumonia on x-rays

Certain bacterial pathogens like pneumococci classically infect one single area in the lung and trigger a typical course of pneumonia with sudden onset and high fever. In severe cases, several lobes or even both sides of the lung can be affected and appear white. The chest X-ray shows respectively one or more white areas. In atypical pneumonia chest X-ray finding may show rather diffuse changes and not always clear findings.


How is pneumonia (pneumonia) treated?

If pneumonia is caused by a bacterium, antibiotic therapy is essential. Patients also must drink enough, sometimes infusions are necessary. Cough irritation, fever and mucus formation must also be treated.

Various antibiotics

In classical bacterial pneumonia, only antibiotic therapy can help. Which antibiotic you need depends on where you got your lung infection, outside or inside a clinic. There are various germs that can lead to inflammation which react differently to the individual drugs. Not every drug always fits.

Antibiotics usually treat a subgroup of these bacteria, of which countless different types exist. The so-called broad-spectrum antibiotics radically eliminate a big group of pathogens. However, they may only be used on severely ill people. Otherwise, the risk of resistance – when drugs against bacteria are no longer effective – increases.

Choice of medication depends on severity of disease

A young person without previous illnesses who has acquired pneumonia on an outpatient basis (outside a clinic) can usually be treated at home with an oral antibiotic like amoxicillin for example.

If the infection is more severe, a drug with a broader spectrum is usually chosen (e.g. Ampicillin Sulbactam or Ceftriaxone). In those cases, initial therapy is usually started as inpatient in the hospital, as the medication is administered intravenously into the vein.

Severe pneumonia can impair organ functions and be accompanied by kidney failure or even sepsis (blood poisoning). Then, very broadly effective drugs must be administered (e.g. Piperacillin/Tazobactam or Ceftriaxone, in each case together with Clarithromycin).

5 to 7 days are usually sufficient

Physicians usually decide how long an antibiotic must be given. This depends on how quickly a patient's condition and test results improve. According to current guidelines, antibiotic therapy can be stopped after 5 to 7 days, depending on the degree of severity.

In addition to the antibiotic therapy, patients must drink enough, sometimes additional infusions are necessary. Recovery is supported by reducing fever, suppressing coughing and relieving pain. Medications to dissolve mucus and respiratory training also help.

If pneumonia is not caused by bacteria but by a virus, general measures are often cornerstone of the therapy. In individual cases antiviral drugs are used. A fungal infection of the lungs is treated with appropriate antifungal drugs. There are special drugs for individual special cases.

What helps in addition to antibiotics?

In addition to antibiotic therapy, there are a few some measures that may help with pneumonia.

Antibiotic first

Pneumonia is a serious infection. Depending on immune status, age and accompanying diseases, it can be mild to very severe or even fatal.

Since most of the pneumonia is caused by bacteria, the administration of antibiotics is usually cornerstone of the therapy. Sometimes viruses, and more rarely fungi, lead to pneumonia in which cases other appropriate drugs are used.

Fluid household

Despite the antibiotic treatment it is important to take in enough fluids. Patients treated in hospital may also require fluid infusions. Additionally, if you have a high fever as part of pneumonia, you urgently need to take care of your body and stay in bed.

Medications such as ibuprofen and paracetamol can lower the temperature. If you feel better after a few days and the fever is back to normal, early mobilisation is recommended. You should occasionally get out of bed and start slowly exercising with appropriate caution. Not in terms of active sports but in terms of light exertion that can aerates and open various areas of the lungs.

Stay at home

Mucus releasing drugs such as acetylcysteine (ACC®) and inhalation with common salt can also help to relieve dyspnoea and cough. Stronger cough syrups with codeine are used at night to alleviate sleep.

To protect other people physicians recommend staying at home until you have recovered completely. Especially older people, infants and toddlers as well as people with a weaker immune system are susceptible to infections.


Is pneumonia dangerous?

Pneumonia is not entirely harmless. In Western countries, pneumonia is the number one cause of infectious death. The diagnosis should be taken seriously and treated well.

Risk factor age and pre-existing conditions

How severely someone is affected by pneumonia depends on their age and previous illnesses, but also on pathogens and possible complications.

Older people are generally more sensitive. An age above 65 years is already considered a separate risk factor. Pneumonias acquired in clinics or nursing homes are more often caused by persistent germs and can also be more difficult to treat.

Pre-existing conditions such as diabetes mellitus, COPD (chronic pulmonary disease), kidney failure or impaired immune status also increase the risk.

CRB65 score assesses hazard

Physicians estimate the severity and risk of dying from pneumonia with a score called “CRB-65”. Its value also determines who should be treated in a clinic or intensive care unit.

The individual letters and the number 65 stand for the following parameters:

  • C: Confusion (change in mental status due to infection)
  • R: Respiratory rate
  • B: Blood pressure
  • 65: Age > 65 years

Points are added up (0 to 4), and the result determines future treatment recommendations.

The higher the score, the more critical

The letter “C” stands for confusion and describes, if a patient suffers from confusion and change in mental status because of a severe infection and consequent dehydration. The letter “R” describes the patients breathing rate. Whereas 12-15 breath per minute are normal, a breathing rate > 30 breath per minute is a risk factor for a more severe course of the disease.

The letter “B” stands for blood pressure. Normal values lie around 120/80 mmHg. If the first value reaches values lower than 90 mmHg and the second value is below 60mmHg, this is a sign for impairment of the body’s circuit. And finally: anyone over 65 years of age is automatically estimated to be at increased risk.

Patients with a low score of 0 have a good prognosis. The risk of dying from pneumonia is less than 1%. With an age > 65 years, increased respiratory, low blood pressure or impaired consciousness, score and mortality risk increase. (6% for score 1-2, up to 23% for higher scores of 3-4). In these cases pneumonia can be life-threatening.

Two to six weeks re-convalescence

Pneumonia is a common infectious disease. Many people recover from the inflammation. After 2-3 weeks, patients usually feel better. Weakened and elderly people may need up to 6 weeks before they feel almost fit again.

Pneumonia: How long will I be on sick leave?

It is not so easy to answer this question. The recovery time depends on many different factors like the severity of pneumonia, age and concomitant diseases.

Generally, pneumonia can be a rather serious infection. Its clinical spectrum ranges from mild and moderate symptoms to severe problems or even fatal clinical histories.

Two weeks of sick leave may sometimes be enough

A young person with a strong immune system without pre-existing conditions who develops pneumonia as an outpatient (outside a hospital) usually has a good prognosis. If the infection is quickly detected and treated directly with antibiotics it can heal without complications. Often, 5 to 7 days of antibiotic therapy are enough. After 2 to 3 weeks, most of these patients feel well again.

Your duration of sick leave is usually for this period, sometimes also one week longer. Yet, the kind of profession you pursue, whether it is physically demanding or can be done from home, also plays a role how long you may stay at home.

Longer sick leave times with more severe disease

The situation is quite different, for example, in people who develop pneumonia during a hospital stay, which may be caused by a persistent and stubborn germ. If antibiotics do not help and need to be changed several times, or if treatment is necessary on the intensive care unit, the time of recovery is delayed. It can take up to several weeks or even a few months for patients to get well again.

Take your time

Do not strain your body too soon after pneumonia. He must be able to recover from the infection. Tell your doctor how fit you feel and follow his advice on when you can go back to work.

How quickly does pneumonia normally heal in children?

Of course, this cannot be answered in general because the type of pathogen and the individual's immune system also play a role. As a rule, however, the symptoms of pneumonia subside after 2-3 weeks at the latest. An X-ray of the breast can confirm that the infection has been overcome.

If, on the other hand, there is still no improvement even after 3-4 weeks, an underlying, hitherto unidentified cause can be assumed, which must be investigated with further examinations. In the first place, this is a possibility:

  • an undetected disease that weakens the immune system (e.g. diabetes, pulmonary tuberculosis, fungal infection, AIDS)
  • Closure of the air passages (e.g. by foreign bodies)
  • a malignant tumor
  • Cystic fibrosis (in children)


A pneumonia can lead to some complications. These include for example water accumulation between the lung layers or at times accumulation of pus. In severe cases, bacteria can spread into the blood stream and cause sepsis and circulatory failure. Also, respiratory failure (ARDS, acute respiratory distress syndrome) can occurs, which may require ventilation on the intensive care unit.

Pneumonia: What is an empyema?

An empyema is a serious complication of pneumonia. It describes an accumulation of bacteria and pus in the space between lung and chest wall.

Water and bacteria accumulate within the lung layers

Lung and chest wall are both covered with a thin layer, of which one sticks to the lung part and the other to the chest wall. Normally, the space between these two layers is filled with about 5 ml of grease, which enables movement of all layers, lungs and chest wall.

Inflammatory processes in the lung can lead to either fluid accumulation in this space. Doctors call this a pleural effusion. Depending on the course of the disease, risk factors and pathogen type, germs and immune system cells can attack this fluid lead to a purulent pleural effusion, which is then called empyema.

Inflammation levels remain high

Empyema is suspected, for example, if the blood tests show persistent infection and fever does not drop despite appropriate antibiotic therapy. Also, the X-ray may show water in the intermediate gap. In such cases, physicians may need to empty the liquid and, if necessary, drain up to 2 litres of fluid or pus. An empyema must be treated antibiotically and always be drained completely. Some patients may need to be treated in the intensive care unit. Of course, an empyema is a rather rare complication of pneumonia.

Lifestyle and vaccinations help

If you want to protect yourself from pneumonia, a healthy lifestyle without cigarettes and excessive alcohol consumption is recommended. If you already have lung disease or other medical problems, make sure you take all your medication correctly and regularly.

People over the age of 60 with immune deficiency, chronic diseases or known lung changes such as COPD should receive a vaccination against pneumococcus and against influenza. We recommend asking your medical doctor for advice.

Authors: Dr. med. Susanne Endres & Dr. Hubertus Glaser


  • Association of the Scientific Medical Societies e.V. (AWMF): Guideline for the Therapy of Pneumonia, accessed June 2019.
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