Treatment of pneumonia

Structure of the lungs

The human lung (pulmo) consists of two lobes. The right lobe comprises three lobes, whilst the left lobe comprises two. Furthermore, the right lung is divided into ten segments and the left lung into nine segments. Each lung segment is supplied with oxygen and oxygen-rich blood by a segmental bronchus and a segmental artery. The bronchial system of the lung – that is, the entire network of airways within the lung – is highly branched, with the smallest branches of the bronchi (bronchioles) terminating in the alveoli. The alveoli are the area of the lung where, during respiration, gas exchange takes place between the air we breathe and the blood. Every person has between 300 and 400 alveoli; together, they form a gas exchange surface area of over 100 square metres. When breathing, air enters the bronchi (airways) either through the nose or the mouth. These are lined with a special type of epithelium (covering tissue) to remove foreign particles that are inhaled along with the air.

Pneumonia – Causes and Types

Pneumonia is a disease of the lungs in which a specific area of lung tissue becomes inflamed. Whilst the condition can be treated very effectively in many patients, it still frequently leads to death, particularly in older patients, due to its sometimes severe and rapid progression.According to Statistics Austria, 36,138 people were treated in hospital for pneumonia in Austria in 2018, and 3,135 died as a result. There are various forms of the disease; classification is sometimes based on the cause of the disease (the causative pathogen), the affected area of the lung and the site of infection. Pneumonia is broadly divided into primary pneumonia and secondary pneumonia. Primary pneumonia refers to a situation where a healthy person contracts pneumonia. Secondary pneumonia occurs in people who belong to a specific risk group, i.e. those who already have an underlying condition that predisposes them to or causes pneumonia, including cystic fibrosis, COPD (chronic obstructive pulmonary disease), emphysema, diabetes mellitus, HIV infection, cancer or various allergies. The risk of pneumonia is also generally higher in older people and young children than in adolescents and adults, as their immune systems are weaker. In addition, the following factors increase the likelihood of developing pneumonia:

• flu and bronchitis
• Organ transplants
• Spleen removal
• mechanical ventilation
• Exposure to radiation
• Smoking
• Alcohol dependence
• poor, nutrient-deficient diet
• Hospital stays and operations
• Bedridden status (due to impaired shallow breathing)

Primary pneumonia is divided into typical and atypical forms. The difference between the two forms lies in the cause, or rather the pathogens that trigger the disease.

• Typical pneumonia: Around 50 per cent of all cases of pneumonia are caused by infection with the bacterium Streptococcus pneumoniae (pneumococci). Almost 100 different strains of the bacterium are now known, and these are responsible not only for pneumonia but also for other illnesses, such as middle ear infections in children.

Other bacteria, viruses, parasites and fungi can also cause pneumonia. Furthermore, the disease can result from inhaling toxic gases or foreign bodies, as well as from aspiration (aspiration pneumonia). Aspiration pneumonia is a form of pneumonia in which vomit, stomach acid, food residues, water or oil enter the lungs and cause pneumonia due to their inflammatory properties. Possible causes of aspiration pneumonia include shock, loss of consciousness or resuscitation.

• Atypical pneumonia: Between 20 and 30 per cent of all cases of pneumonia are caused by infection with atypical pathogens. The most common atypical pathogens include Legionella, Mycoplasma pneumoniae (mycoplasma) and Chlamydia pneumoniae, trachomatis and psittacii (chlamydia).

Further classifications of pneumonia relate to the affected tissue (classification based on pathological criteria) and to the site of infection. In the former, a distinction is made between alveolar pneumonia and interstitial pneumonia. Whilst in alveolar pneumonia the alveoli are inflamed, interstitial pneumonia involves inflammation of the tissue between the alveoli and the blood vessels. Classification by site of infection distinguishes between community-acquired and hospital-acquired pneumonia. In the case of community-acquired pneumonia, those affected become infected with one of the pathogens outside a hospital or other healthcare facility; in the case of hospital-acquired pneumonia, the pneumonia is attributable to an infection with microorganisms within a hospital. Despite the extremely high standards of hygiene in healthcare facilities, nosocomial infections – i.e. infections diagnosed 72 hours or more after admission to hospital – occur time and again. The risk of such an infection is particularly high among older people, premature babies, patients with large, fresh surgical wounds, and patients who are connected to medical devices or have a catheter, as in these cases the body’s own defences are weakened or the pathogens have additional routes of entry into the body.

Prevalence of pathogens

Infection with the bacteria, viruses and fungi responsible for pneumonia occurs in various ways, depending on their occurrence and spread. Infection with pneumococci occurs via what is known as droplet transmission, meaning that the bacteria are passed from one person to another through sneezing or coughing. Legionella bacteria are found in water and are transmitted via the air and vapours, for example from air conditioning systems or when showering – water that is stored in a water tank at too low a temperature before showering, rather than being heated in a flow-through water heater just before use, is an ideal breeding ground for Legionella. In contrast, infection with mycoplasma and chlamydia typically occurs through unprotected sexual intercourse; furthermore, the pathogens can be transmitted from an infected mother to her child during childbirth.

Symptoms of pneumonia

The symptoms of pneumonia are as varied as its causes and pathogens. Furthermore, the symptoms can differ depending on the type of pneumonia. Typical signs of pneumonia include:

• high fever,
• shortness of breath, which in severe cases of pneumonia subsequently leads to rapid breathing,
• cough (initially dry, later accompanied by phlegm),
• chills,
• chest pain, particularly when breathing in and coughing, and
• cold sores.

Furthermore, in some cases, the illness may be accompanied by general fatigue, headaches, muscle and joint pain, and a mild, rapid heartbeat. The incubation period – that is, the time between infection with the pathogen and the onset of the first symptoms typical of the illness – varies from pathogen to pathogen and can last up to three weeks:

• Pneumococci: 1 to 3 days
• Legionella: 2 to 10 days
• Mycoplasma: 6 to 23 days
• Chlamydia: 10 days or more

Diagnosis by a doctor

Based on the consultation between doctor and patient, various tests are carried out if pneumonia is suspected. As further treatment depends on the type of pathogen, it is very important that the treating doctor can accurately determine the cause of the infection and the inflammation. In addition to listening to the chest and lungs, a chest X-ray can provide further information on the severity of the condition. The doctor will also carry out a lung function test to assess the condition of the bronchi. The lung function test is carried out using a spirometer. This is a medical device into which the patient breathes in and out alternately, as instructed by the doctor. In addition to these examinations, laboratory tests are ordered to measure oxygen saturation, white blood cell count, C-reactive protein (a protein) and other key parameters. Based on all the test results, as well as other factors such as any other medical conditions (in the case of secondary pneumonia) and the patient’s age, the appropriate treatment is then determined. If atypical pneumonia is suspected, specific antigen or antibody tests may be carried out.

Treatment of pneumonia

Depending on the causative agent, different medicines are used to treat pneumonia. Bacterial pneumonia is usually treated with antibiotics, including tetracyclines, macrolides, quinolones, cotrimoxazole and pentamidine. Penicillin is usually used to treat pneumococcal infections. If the pneumonia is caused by fungi, antifungal drugs (antimycotics) are used. In addition, bed rest, avoiding physically strenuous activities and ensuring adequate fluid intake (water, unsweetened tea) are important components of treatment. Measures such as mucolytic drugs (secretolytics) and inhalation therapy, as well as cough-suppressing medication, may also be used as part of the treatment. In cases of severe pneumonia or in patients with a weakened general condition – for example, the elderly – hospital treatment is usually necessary. The course of the illness and the prognosis for pneumonia vary from patient to patient. In a healthy person, treated pneumonia clears up within two to three weeks, although the fever may subside after a week. As the lungs are responsible for supplying oxygen to the entire body, the condition must always be treated, as failure to do so can lead to serious complications. Possible complications of pneumonia include sepsis (blood poisoning), respiratory failure, thrombosis (venous occlusion), pulmonary embolism and inflammatory changes in bones and joints. If the bacterial pathogens spread further through the body via the bloodstream, this can lead to other inflammatory conditions such as middle ear infection, pleurisy, meningitis or inflammation of the heart. 

How to protect your lungs

Although infection with certain pathogens cannot always be avoided, there are still a number of ways to protect your lungs and prevent pneumonia: Pneumococcal vaccination: The pneumococcal vaccine involves the injection of an inactivated vaccine – that is, a vaccine containing non-replicating components of the pathogen – which induces active immunity against pneumococci. If a vaccinated person becomes infected with the bacteria at a later date, the body can fight them off using the antibodies it has already produced, thereby preventing the onset of pneumonia. Antibodies are proteins produced by white blood cells in response to specific foreign substances (antigens). The pneumococcal vaccine is particularly recommended for older people aged 60 and over, infants from three to 24 months of age, and people with a weakened immune system or certain underlying medical conditions. Giving up smoking: Smoking increases the risk of pneumonia. People who give up smoking reduce their risk of pneumonia and other serious lung diseases. People who continue to smoke despite having pneumonia delay the healing process, as the smoke they inhale irritates the bronchi and dries out the mucous membranes. Follow hygiene measures: Talking, coughing, sneezing – pneumococci and many other bacteria spread from one person to another via droplet transmission. You should therefore ensure that you do not get coughed on by others, and you should also keep a safe distance from people around you when you sneeze or cough. Avoid air-conditioning systems: the filters and ducts of air-conditioning systems are also a breeding ground for bacteria (e.g. Legionella) and fungi. You should therefore ensure that your air-conditioning systems at home and in your car are regularly serviced and cleaned, and avoid making extensive use of other people’s air-conditioning systems (e.g. in hotels and hire cars). Prevention: People who frequently change sexual partners can protect themselves against chlamydia infection by using condoms.