BronchoPneumonia

What is Bronchopneumonia?

Pneumonia is a commonly seen inflammation of the lungs, mostly a complication to upper airway infection and other conditions, like CHARGE syndrome. The lung parenchyma gets infected, causing consolidation and filling of the alveolar spaces with exudate, fibrin and inflammatory cells. From the anatomical/radiological point of view, pneumonia can be divided in three types:

Lobar pneumonia- also known as focal or non-segmental pneumonia
Multifocal/lobular pneumonia- known as bronchopneumonia
Interstitial pneumonia- focal diffuse ^[1].

In case of bronchopneumonia, there is usually a puss-forming peribronchiolar inflammation and on X-ray it is seen as patchy consolidation of secondary lung lobules ^[2].

Causes

Bronchopneumonia is mostly caused by inhalation of the pathogen which causes an inflammation. In rare cases, bronchopneumonia can be caused by pathogen which is spread through blood, for example, if bacteremia occurs in Steven-Johnson Syndrome.

Inhalation of the pathogenic organism leads to peribronchiolar inflammation, which can spread through small communications between alveoli, and create a consolidation of pulmonary lobule. The most common pathogens causing bronchopneumonia are:

Staphylococcus aureus
Klebsiella pneumoniae
Haemophilus influenza
Pseudomonas aeruginosa
Escherichia coli
Anaerobic organisms, like the Proteus species ^[2].

Bronchopneumonia can also be caused by viruses, fungi, chemical and physical factors. It is also commonly seen in disabled patients or those, who are confined to the bed. It is also seen in patients after surgery and due to secondary immunodeficiency ^[5].

Risk factors

There are several groups of people, who are at a higher risk for developing pneumonia. The risk factors are:

Smoking
Recent viral infection, like the common cold or influenza
Difficulty swallowing due to neurological conditions, like stroke, Parkinson’s disease or Guillain-Barre syndrome, which can cause aspiration pneumonia
Chronic lung conditions, like cystic fibrosis, COPD
Cerebral palsy
Heart disease
Liver cirrhosis
Diabetes
Living in a nursing facility or long hospital stay
Recent trauma or surgery
Secondary immune deficiency ^[4]

Symptoms

Bronchopneumonia usually affects acini, lobuli and segments of the lungs. The condition usually develops after the patient has had bronchitis or bronchiolitis, since the low drainage from the bronchi leads to bacteria penetrating respiratory parts of the lung.

Bronchopneumonia usually has a gradual onset, with symptoms worsening over the course of days. Most commonly seen symptoms are:

Fever, accompanied by sweating and chills
Cough with mucus, eventually it can lead to hemoptysis
Shortness of breath, rapid breathing
Chest pain
Headache
Muscle aches
Fatigue, loss of appetite, weight loss
In elderly confusion and delirium is often seen ^[3].

The symptoms can also vary depending on the cause of pneumonia. In bacterial pneumonia, the body temperature can rise to 105 degrees Fahrenheit (or 40 degrees Celsius), the sweating is often profuse.

Breathing and pulse rate is highly increased. Due to lack of oxygen, nail beds and lips can appear bluish. Viral pneumonia usually starts out similar to influenza, with fever, dry cough, headaches and muscle pain. Within 1-2 days, the symptoms get worse and the patient feels breathless, cough becomes productive, but with small amount of mucus ^[4].

Diagnosis

Primary workup

Diagnostic process for bronchopneumonia usually begins with obtaining patient history and physical examination. The doctor usually listens to lung sounds and evaluates the patient history and current signs.

Blood tests are usually performed. Increased white blood cell count usually signifies a bacterial infection. If the white blood cell count is normal or slightly elevated, it can mean that the infection is viral. Microscopic investigation of mucus can also be ordered to test for the exact causative agent. Other tests include pulse oximetry, to determine the oxygen level in the blood and in some cases, bronchoscopy is necessary ^[3].

Morphological features

Histologically, there are multiple small inflammation patches. In the affected areas, there is dilation of blood vessels and extensive congestion. The inflamed areas are separated by areas of normal lung tissue. The morphological features can be quite different depending on the causative agent:

Streptococcus infection is usually mixed with viral infection. It is often seen in patients with diabetes. Streptococcus infection mostly affects lower parts of the lungs, and produce a sero-purulent exudate. In some cases, abscesses and bronchiectasis form.
Pneumococcus bronchopneumonia exudate usually contains fibrin and polymorphonuclear leucocytes.
Staphylococcus aureus pneumonia usually develops after influenza and other viral respiratory infections. It is also commonly seen in people who are prone to aspiration and stay in the hospital for long period of time. Staphylococcus aureus pneumonia is characterized by development of abscess, which can rupture into the pleural cavity, causing tension pneumothorax and pleural effusion.
Pseudomonas pneumonia is usually seen in immunocompromised patients. It can cause infectious vasculitis, where large number of the pathogen infects blood vessel walls. It usually results in lung infarction.
Fungal bronchopneumonia is most often caused by Candida. Often, proliferative inflammation, granuloma formation and necrosis is seen in the lung tissue. In the exudate, there are fungal elements.
Viral bronchopneumonia is usually seen in children. It is characterized by serous, fibrinous or hemorrhagic exudate and hyaline membrane formation in alveoli ^[5].

Imaging studies

For diagnosing bronchopneumonia, the first-choice imaging study is X-ray of the lungs. In the X-ray, multiple small opacities are seen, which appear patchy and confluent. The inflammation patches are separated by normal lung tissue. The distribution is usually bilateral and asymmetric.

In some cases, CT scanning is also used. In CT the exact location of the inflammation can be evaluated. The lobular pattern is seen in multiple foci. The tree-in-bud appearance can often be seen ^[2].

Treatment

The treatment of bronchopneumonia depends on the causative agent, as well as the age of the patient and several other factors.

Antibiotics

Antibiotics are usually started as soon as the doctor makes the clinical diagnosis of pneumonia based on patient history and physical examination. The doctor will prescribe antibiotics for the most commonly seen types of pneumonia. Usually, the condition of the patient gets better within 3 days. In one week, the fever should resolve. The antibiotics are usually given for 7 to 10 days, but it can also be longer, depending on the condition of the patient. If the condition does not get better after 72 hours of starting antibiotics, the regime is usually changed. Most people can treat pneumonia at home, but patients in risk group, like the ones who are not able to take medication themselves or have other serious conditions, should be hospitalized.

Other medication

Pain medication, such as paracetamol and ibuprofen can help to lower chest pain.

Cough medications are usually avoided, since preventing cough reflex might worsen the condition. It is recommended to take a lot of fluids and rest. In hospitalized patients, medications might be given intravenously.^[6].

References

General information for health care specialists: http://emedicine.medscape.com/article/300157-overview#a2
Causes and imaging studies: https://radiopaedia.org/articles/bronchopneumonia
Symptoms and information for patients: http://www.healthline.com/health/bronchopneumonia#Symptoms4
Symptoms and risk factors: http://www.lung.org/lung-health-and-diseases/lung-disease-lookup/pneumonia/symptoms-causes-and-risk.html?referrer=https://www.google.de/
Morphological features: https://www.bsmu.by/downloads/kafedri/k_pat_anatom/2014-2/lung.pdf
Treatment: http://www.nhs.uk/Conditions/Pneumonia/Pages/Treatment.aspx