What Is It, Contagiousness, Diagnosis, Treatment, and More
Author: Maria Villarreal, MD
Illustrator: Abbey Richard
What is bronchopneumonia?
Bronchopneumonia is the most common type of pneumonia found in children. Among children under five years of age, it is the leading cause of death. In fact, bronchopneumonia accounts for 85% of all respiratory system diseases in children under two years of age. Incidence is also very high among older adults, especially people over 65 years of age. In general, community acquired pneumonia is the most common cause of death due to an infectious disease.
Bronchopneumonia is mostly caused by a bacterial infection, but it can also be caused by a viral infection or a fungal infection. Some pathogens that can cause bronchopneumonia include: Staphylococcus aureus, Klebsiella pneumoniae, Haemophilus influenzae, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Escherichia coli. Other, less common pneumonia-causing organisms, may include viruses such as SARS-Cov-2, or fungi such as Aspergillus fumigatus.
Bronchopneumonia presents with suppurative inflammation that’s localized in patches around bronchi, and may affect one or more lobes of the lung. In severe cases, bronchopneumonia can lead to the formation of a lung abscess (pus-filled pocket in a focal area). In addition, the infection may spread to the pleural space, filling it with an exudate (pus-like fluid resulting from inflammation), this condition is also known as empyema.
Is bronchopneumonia contagious?
Yes, bronchopneumonia is a contagious infection. The pathogens that can cause bronchopneumonia are usually breathed in by people. Normally, these are transmitted when a person coughs or sneezes, creating tiny droplets that can spread and infect others. After a person inhales these pathogen-containing droplets, they colonize the throat (nasopharynx or oropharynx), and then reach the lung alveoli through aspiration. Infection can result when the inoculum size is sufficient or the host immune system is impaired. Replication of the pathogen and its virulence factors—combined with the host immune system response—ultimately lead to inflammation and damage of the bronchi and lung parenchyma.Risk factors include children under 2 years of age, adults over 65 years of age, recent travel, smoking, prior antibiotic use, underlying respiratory conditions (e.g. cystic fibrosis, etc.), recent infection, HIV infection, and autoimmune disorders. These people should practice precautions to avoid infection, as they are more prone to becoming infected with bronchopneumonia-causing pathogens.
How long is bronchopneumonia contagious?
The exact length of time a person is contagious depends on the pathogen causing the infection. The average incubation period tends to be short, typically between 3–6 days. After the incubation period, symptoms tend to start appearing seven days post-exposure.
How do you diagnose bronchopneumonia?
The clinical presentation of bronchopneumonia varies widely. Factors such as the pathogen, age, and presence of comorbid conditions all play a role in defining the presentation. Common symptoms include productive cough, purulent sputum, dyspnea, rigors, malaise, pleuritic pain and occasionally hemoptysis. Severe cases, however, can be characterized by sepsis and respiratory distress.
Physical exam findings include decreased chest expansion on the affected side, dullness on percussion, bronchial breath sounds, and whispering pectoriloquy, which refers to a loud whispering sound heard on a stethoscope when listening to the patient’s lungs. Occasionally, other physical findings such as crackles/rales in the location of the consolidation, and increased vocal fremitus and resonance can be observed.
Assessing severity is an important component of predicting a patient’s overall outcome. Scoring criteria (such as the PSI or CURB-65 scores) can help health professionals identify whether a patient should be admitted to hospital. Some patients with mild illness and no significant comorbidities may be safely discharged home with oral antibiotics and a follow up appointment with a healthcare provider. However, patients with a high-severity score (on either score) might require hospitalization in addition to treatment with IV antibiotics.
Laboratory findings may be a useful tool for healthcare professionals to distinguish the type of pneumonia that has infected a person. The most remarkable laboratory finding is leukocytosis (in cases of bacterial pneumonia). Additional laboratory findings include leukopenia (in cases of atypical pneumonia), eosinophilia (in cases of eosinophilic pneumonia), anemia, hyponatremia, thrombocytopenia, and elevated BUN.
Other tests that can help identify the microorganism and confirm diagnosis include PCR, sputum and blood cultures (including Gram staining), and urine antigen tests (used to detect the C-polysaccharide antigen of Streptococcus pneumoniae in urine).
On the other hand, CRP (C-reactive protein) and procalcitonin are tests used to differentiate between bacterial and viral pneumonia and gauge disease severity. For example, it has been reported that CRP is elevated (> 100 mg/L) in cases of bacterial pneumonia.
Chest X ray findings
In pediatric patients, bronchopneumonia is characterized by scattered foci of consolidation (pus in many alveoli and adjacent air passages) that may be found in one or more lobes of one or both lungs.
Another notable characteristic of bronchopneumonia are confluent patchy opacities that represent the areas of inflammation in contrast to the normal lung parenchyma.
A characteristic finding of bronchopneumonia is the ”tree-in-bud appearance”, which consists of a lobular pattern of lung consolidation centered at centrilobular bronchioles. Often, these foci can overlap and create a larger area of consolidation, giving a 'patchwork quilt' appearance.
How do you treat bronchopneumonia?
The causal pathogen of bronchopneumonia is oftentimes not known at diagnosis, therefore empiric treatment should be initiated with the most suspected pathogen based on clinical characteristics seen during examination. In most cases, empiric treatment is directed after having a suspected pathogen in mind. Antibiotics used in the treatment of bronchopneumonia include first and third generation cephalosporins, as well as penicillin-based antibiotics. Antibiotic therapy usually lasts between 5–7 days. Supportive therapy includes adequate hydration, rest, and home care.
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Resources for research and reference
Fishman, A. (2015). Fishman's Pulmonary Diseases and Disorders (5 edition). New York: McGraw-Hill.
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