- Pneumonia is an infection of the lower respiratory tract affecting either a part (lobe) of the lung or multiple lobes.
- Pneumonia generally presents with cough (yellow/green sputum), fever, shortness of breath and chest pain (on coughing or breathing).
- The diagnosis is made on history and examination, and can be confirmed by a chest X-ray.
- Sputum can be examined under the microscope and cultured in the laboratory to identify organisms and determine appropriate antibiotic treatment.
- Bacterial, atypical and fungal pneumonia can be treated with antibiotics, but in viral pneumonia antibiotics are of no help.
- Pneumonia can be rapidly fatal if not treated early.
What is pneumonia?
Pneumonia is an acute infection of the lung tissue. The infection can be confined to a single lobe or segment of the lung or may involve several areas – generally the more affected areas, the sicker the person will be. Pneumonia does not always require treatment in hospital. Depending on how sick the person is, their age and if they have other medical conditions, the attending doctor will decide if antibiotics are required (either oral or intravenous) and whether hospitalisation is required for administration of intravenous antibiotics and oxygen. In severe cases admission to the intensive care unit may be required with ventilatory support.
What causes pneumonia?
A cause for pneumonia can only be found in 50 to 75% of cases. Several different organisms can cause pneumonia. These include bacteria, viruses or parasites in addition to several other ‘atypical organisms’. It is not uncommon for a bacterial pneumonia to occur as a complication of a viral illness, such as influenza, measles, rubella or chicken pox.
The most common causes of pneumonia vary from country to country, and by age, living conditions etc. In adults Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Chlamydia pneumoniae, are frequent causative agents. Mycoplasma pneumoniae is a particularly common cause in older children and young adults. In elderly people living in old age homes or institutions other organisms such as Legionella may cause outbreaks. It is particularly important to be aware of any recent antibiotic usage or stays in hospitals preceding the onset of the pneumonia. In these situations “hospital- associated organisms” or resistant organisms such as klebsiella or acinetobacter may be the primary causative organism.
In younger children, pneumonias are usually caused by viruses such as respiratory syncytial virus, adenovirus, parainfluenza, influenza A and B, varicella, measles and rubella. These agents can also cause pneumonia in adults, but the only potentially serious ones are influenza A and sometimes B, which can be life-threatening.
Other less common agents include fungi (Histoplasma, Cryptococcus, Pneumocystis etc.) or parasites (Toxoplasma gondii, etc). These organisms usually only infect people with very low immunity – advanced HIV, cancer patients on treatment or organ/ bone marrow transplant patients.
Who gets pneumonia?
About 300 000 to 500 000 people are struck by pneumonia each year in South Africa, and about 5% to 10% of them die. It is the most lethal hospital-acquired infection. In South Africa the death rates are still quite high compared to more developed countries.
Pneumonias develop when the infective organisms are breathed in, or may spread from the blood stream in Staphylococcus infection. For bacterial pneumonias, the origin of the organism is usually from your own body (nose/mouth). In viral pneumonias (“bird” flu/”Swine” flu) they are spread from person to person by sneezing or coughing. Pneumonia can secondarily spread into the bloodstream, which results in a potentially very serious condition called septicaemia.
Aspiration (breathing in) of acid from the stomach results in a very severe pneumonia. This may occur following vomiting in people with reduced consciousness (after an epileptic seizure, severe alcohol intoxication and even during an anaesthetic.) Elderly people who suffer a stroke, are confused or bed ridden frequently aspirate which may lead to pneumonia.
What are the risk factors for pneumonia?
People below 1 year or over 65 years of age are more likely to develop pneumonia.
Many underlying health problems increase the chance for pneumonia:
- Cigarette smoking
- Alcohol or drug abuse
- Viral respiratory tract infections (often influenza or parainfluenza type)
- Chronic obstructive pulmonary disease or bronchiectasis
- Cancer or cancer related treatment.
- Institutionalisation in hospitals or old-age homes, or following a stroke
What are the symptoms of pneumonia?
Bacterial pneumonia can start very swiftly over just a few hours and make you very sick. Often respiratory tract infections precede the episode and the following signs develop:
- Sore throat
- Running or blocked nose
- Dry cough, which changes to a cough with sputum production
Common symptoms of pneumonia are:
- Fever of 38.5°C or more with chills or shaking
- Cough, which often produces sputum from the airways. The colour of the phlegm may be green or rusty, occasionally with blood specks. However, sometimes no sputum is produced.
- Night sweats
- Shallow, rapid breathing and rapid heart rate
- Chest pain, which is worsened on inhalation or coughing. This may be only on one side and felt deep in the chest.
- Tiredness, body weakness (general malaise), confusion (particularly in the elderly)
These symptoms depend on age and other underlying health problems. In elderly people these symptoms may be much less obvious. Shortness of breath is not easy to spot but may be suspected when talking becomes interrupted and difficult.
How is pneumonia diagnosed?
The medical history alone might lead your doctor to strongly suspect pneumonia. He or she will confirm this by careful examination, which will include measurement of temperature, pulse, breathing rate and blood pressure. X-rays of the chest are often the next step to confirm clinical findings and can be very helpful in determining the full extent and severity of the disease.
Your doctor may also take samples for a number of laboratory investigations:
- A full blood count (FBC) can suggest the presence of an infection, if the white cell count is high.
- Investigations called C-reactive protein and erythrocyte sedimentation rate can suggest an infection and indicate its seriousness, but are not specific for a particular type of infection.
- Looking at the sputum under the microscope and culturing it in the laboratory can indicate the type of organism causing the infection and the appropriate antibiotics to use. Samples may show the presence of bacteria, viruses (such as the respiratory syncytial virus in young children), parasites or fungi. This is not always done, as the tests do not always give positive results.
- Blood or urine tests for pneumococcus, Mycoplasma and Legionella antibodies may be necessary, or mouth swabs for viral pneumonias. Blood cultures should be taken if septicaemia is suspected.
- It may also be advisable to have an HIV test if your status is unknown, as being HIV positive predisposes you to a wider range of infections that your doctor should be on the lookout for.
Depending on the severity of the condition, further tests may be required. If the patient is to be hospitalised, further investigations may be required:
- Measurement of blood oxygen levels using a finger probe (pulse oximetry) or arterial blood gas.
- Bronchoscopy – direct visual observation of trachea and bronchi with a thin camera tube. Samples of fluid and tissue can then be examined and cultured to determine the cause of the infection.
- Thoracentesis – drainage of fluid from between lungs and ribcage (if present). This is done by inserting a needle. The fluid can be sent for microscopy and culture.
Computerised axial tomography (CAT) scan – may be required to determine the extent of the disease or other possible causes.
Can pneumonia be prevented?
A vaccine exists that may protect against many types of pneumococcal bacteria that commonly cause pneumonia. It does not protect against pneumonia caused by other forms of bacteria, viruses or fungi, however. The vaccine is recommended for those who are older than 65 years or at higher risk due to various underlying medical conditions (ask your doctor for advice if you think you are at high risk – e.g. cancer, leukemia). In addition the yearly influenza vaccine is also advisable, as this will reduce your risk of flu and subsequent pneumonia.
People with impaired immune systems may be predisposed to complications if they contract pneumonia. Immunosuppressed patients should avoid contact with people who have respiratory tract infections. If they have not had measles or chickenpox, they should avoid contact with those illnesses, as pneumonia is a possible complication. Vaccination for those illnesses is probably advisable. If you are HIV positive, you should be on co-trimoxazole (Bactrimâ) to prevent both PCP and reduce your risk of other bacterial infections.
How is pneumonia treated?
Antibiotics form the backbone of treatment of bacterial pneumonia. In most cases, especially in young, healthy patients, hospitalisation is not required if the patient is able to take the drugs and drink extra fluids. Symptoms usually improve in two to three days. If the patient responds well, antibiotics are usually prescribed for up to 10 days, but usually 7 days is sufficient. It is important to take all the doses that are given to you. Rest and intake of enough fluid are important to aid recovery. If the response to treatment is inadequate, resistant organisms or TB might be the cause and further tests and treatment will be required. Elderly people generally take longer to recover then young healthy individuals.
The decision for hospitalisation is made by the attending doctor and is based on several factors. These include: severity of the pneumonia, age of patient, other medical conditions present and support/care available at home. If you require intravenous antibiotics, oxygen or ventilatory support, admission is inevitable.
A wide range of antibiotics is available for the treatment of bacterial pneumonia. There are national guidelines on the best antibiotics to use in given situations, which will help the doctor decide which one to give. If you are allergic to a specific antibiotic, several other equally good options are usually available. Paracetamol and non-steroidal anti-inflammatory drugs are often required for fever and pain relief.
When there has not been noticeable improvement in three to seven days, another antibiotic may be required. The sputum might need to be cultured to test for sensitivity, so that the appropriate antibiotic can be given. In certain situations such as severe pneumonia, where resistant organisms are present, or with underlying lung diseases (bronchiectasis or cystic fibrosis), prolonged treatment may be needed.
When to see your doctor
It is important to treat pneumonia as soon as it starts, as this will improve the outlook and avoid complications, especially in very young or old people. Unnecessary treatment of viral illness with antibiotics, on the other hand, should be avoided. Urgent attention in an emergency department should be sought if:
- Breathing difficulties occur. Laboured, rapid and shallow breathing with wheezing may indicate a severe episode.
- Chest pains develop that are crushing or burning, increase in intensity and are associated with sweating and nausea.
A doctor should be consulted urgently if:
- A cough producing yellow or green sputum has been present for more than two days, associated with fever of more than 38.5°C.
- Cough productive of rust-coloured sputum occurs, or blood is coughed up.
- Cough persists for more than seven to 10 days.
Preparation for consultation:
- In young patients or elderly patients with memory difficulties, it is useful for the caregiver to accompany them to the doctor to help supply an accurate history of all the symptoms. The history is very important in assessing the seriousness of the situation. Think carefully about all the events that led to this episode of pneumonia. All underlying health problems must be mentioned.
- All drugs taken (for this and other problems) should be known by name and dosage.
- Previous X-rays of the chest and possibly peak flow measurements are useful, and should be taken along.
It is very important to mentioned if the patient has been in contact with someone who has tuberculosis.
Written by Prof J.R. Joubert, MSc, MBChB (Stell), FCP (SA), MMed (Int. Med), MD (Stell)
Revised by Richard van Zyl-Smit, MBCHB, MRCP(UK), DIP HIV Man (SA), FCP(SA) Cert Pulm (SA), Specialist Physician and Pulmonologist, Division of Pulmonology and UCT Lung Institute, Department of Medicine, University of Cape Town, (October 2010)