Diagnosis and Clinical Affects of Pneumonia

Pneumonia is an infection that causes the tissue in either 1 or both lungs to become inflamed, this can be caused by different types of organisms, but is most commonly caused by a bacterial infection in the upper respiratory tract. When pneumonia affects both of the lungs this is known as bilateral lobular pneumonia. This in turn causes a build-up of fluid within the alveoli and the bronchiole of the lungs. This causes a pneumococcal infection which is caused by the streptococcus pneumoniae bacteria, and although bacterial pneumonia is the most common, it can also be present in other forms. Streptococcus pneumoniae is accountable for causing approximately 70-80% of all cases of pneumonia. This is treated with a course of antibiotics which allows for the pneumococcus bacterium to clear up and out of the lungs. Here are some other examples of how pneumonia can appear:

• Viral pneumonia - caused by the respiratory syncytial virus (RSV)
• Aspiration pneumonia - caused by inhaling a foreign substance (e.g. vomit, or harmful substances)
• Ventilator Associated Pneumonia – caused by a colonisation of bacteria which causes an aspiration of the microorganism to enter directly into the lungs e.g. through an ET tube.

When a patient contracts pneumonia they can experience a range of symptoms that can either be present from the start of the infection, or symptoms can develop slowly over a course of several days. There are different risk factor groups that are more susceptible to contracting pneumonia. Some of these groups are:

• Babies/young children – as they have an underdeveloped immune system making them more likely to pick up pathogens.
• People who are immunocompromised e.g. HIV/AIDS / undergoing chemotherapy.
• Patients with pre-existing respiratory disease e.g. chronic bronchitis/bronchiectasis
• Smoking/excessive alcohol users as this increases risk of pneumonia attacks.

Epidemiology

Pneumonia affects people of all ages, and only affects 1% of the population each year. Approximately 50% of all pneumonia cases affect those under the age of 50 years old.

This common disease is more prevalent in the winter months due to the rapid decrease in temperature, as well as in the spring months, again due to the sudden contrast of temperatures. Issues regarding overcrowding also contribute to the spread of bacteria and viruses which becomes responsible for causing pneumonia in the lower socio-economic groups. This is due to the fact that many people are confined to a small space which allows for the pathogens that cause pneumonia to spread very quickly. Also, the ratio of the number of people to the space that they are all living in means that this can allow bacteria to multiply quickly therefore contributing to the growth of bacteria/viruses present that cause pneumonia.

Mortality rates for this disease is 5-10% of all cases, however this is most common in young children and the elderly. Young children are more susceptible due to the fact that they have narrow airways which can become blocked easily by mucus secretions which they are unable to clear. They also have very weak immune systems due to being under developed which means they have not built up the immunity within their white blood cells that is needed to fight off the pathogens that cause pneumonia.

Mechanism and Pathophysiology

Whilst pneumonia can be caused by a range of microorganisms, the most common is a bacteria called streptococcus pneumoniae. However pneumonia can also be caused by virus and uncommonly, fungi. Bacterial pneumonia typically affects just 1 part of the lung, often what is known as ‘a lobe’. This form of pneumonia often occurs in patients who have recently had a viral cold/flu, and this specific form of pneumonia is known as lobular pneumonia.

Some bacteria are able to cause atypical pneumonia, which is a strain that is caused initially by a pathogen that is not commonly associated with the disease. For example the most common bacteria that causes atypical pneumonia is mycoplasma pneumoniae. This is a contagious respiratory infection which in severe cases can cause damage to the vital organs. This form affects people usually under 40 years old, and particularly those who live in crowded living/working conditions. In terms of viral infections relating to pneumonia, the influenza virus is the biggest cause of pneumonia in adults whereas in children the respiratory syncytial virus is the lead cause of viral pneumonia. With viral forms of pneumonia they are typically short lived and don’t tend to cause too much disruption to the bodies ‘normal’ daily functions. However they can be severe and result in a hospital admission for the patient. This is due to the virus invading the lungs and multiplying therefore causing more of an impact and needing a higher response from the body’s immune system to fight the virus. Viral pneumonias can also be made more complex due to a secondary bacterial infection build up in the lungs also, which again puts more strain on the immune response systems resulting in the patient having more prolonged severe symptoms. Fungal pneumonias aren’t common however they can be caused by candida albicans. This form of pneumonia typically affects those with immunological disorders.

DiagnosisIn terms of diagnosing pneumonia (regardless of the microorganism that caused the infection) several tests may be necessary. An initial assessment carried out by a health professional will be the first step to diagnosing pneumonia, and this may be performed by a GP, or a doctor in a hospital setting. This is where the patient will be asked questions relating to the symptoms they may be experiencing, and the patient’s initial observations will be taken – temperature, listening to patients chest for any crackles, blood pressure reading, possible echocardiogram trace, oxygen saturations.

From these readings a clinical decision will be made whether to refer the patient for any diagnostic tests such as a chest x-ray, and alternatively whether they need any immediate treatment such as oxygen or Ventolin nebulisers to help aid the patient with breathing less erratically and to increase oxygen levels. They may also require some blood tests to look at inflammation markers, or possible sputum samples to understand what type of infection a patient may have in order for the appropriate antibiotics to be issued.

Screening and preventionThe majority of pneumonia cases are caused by bacterial infections and are not typically transmitted from one person to the next. However personal hygiene levels of those close to affected person, and the patient themselves, should be kept to a high standard. This is to prevent the microorganisms from spreading, which in turn reduces the chances of a pneumonia outbreak. This is essential in a healthcare setting to ensure that no risks to the public health through outbreaks are created. As smoking and alcohol misuse also increases a person’s chance of developing pneumonia, it should be a conscious decision for those at greater risk to cut down/stop these habits. Alcohol misuse particular weakens the pulmonary systems natural defence against infections, therefore making a person more vulnerable to the infection.

Disease Management

Pneumonia is typically treated with antibiotics as the pneumococcus is very sensitive to these drugs, therefore making the treatment more effective. The antibiotics chosen to treat pneumonia can vary depending on the severity of the case, and in turn this can affect the dose also. The most appropriate antibiotic can be investigated for via blood tests/sputum samples where staff can analyse what microorganism is present. This would in turn affect treatment methods for the patient. However with the use of antibiotics there is always a concern with patients developing antibiotic resistance in relation to superbugs i.e. MRSA. This is why many tests may be carried out to properly identify the pathogen before any long term treatment will be issued.

Often with pneumonia the oxygen saturation levels can drop and can partly be because it causes the efficiency of O2 diffusion from the lungs into the bloodstream to decrease. Therefore oxygen can be issued as part of the treatment plan. With issuing acute oxygen therapy this helps to increase the oxygen levels, however there is potential risk of CO2 retention which could lead to hypercapnic respiratory failure (type II respiratory failure). Therefore people who have acute oxygen therapy may have regular capillary/arterial blood gas samples taken to assess their levels whilst on treatment.

Also with O2 saturations, they can drop if a person is changing their breathing pattern very rapidly. For example if a patient with pneumonia is finding it difficult to breathe they may start hypo ventilating. This is where the body’s ventilator system becomes inadequate to carry out the gas exchange between O2 and CO2. This process causes an increase in the CO2 levels, which in turn will lower the O2 levels due to the fact that the CO2 is not getting blown off meaning that CO2 gets retained.

Patient outlookAfter an inpatient stay a follow with the GP will be made within 6 weeks of the discharge date, and this is to ensure that any symptoms have relieved. A follow up chest x-ray may be arranged also to check the resolution of any consolidation within the lungs. If after the 6 weeks, the symptoms are still prevalent then further tests will be carried out to check whether the infection is still present.

If the patient has had aspiration pneumonia then it may be necessary to have a bronchoscopy to remove the foreign body that has been inhaled.