Lower respiratory tract infection
Lower respiratory tract infection (LRTI) is a term often used as a synonym for pneumonia but can also be applied to other types of infection including lung abscess and acute bronchitis. Symptoms include shortness of breath, weakness, fever, coughing and fatigue.[3] A routine chest X-ray is not always necessary for people who have symptoms of a lower respiratory tract infection.[4]
Lower respiratory tract infection
Influenza affects both the upper and lower respiratory tracts.
Antibiotics are the first line treatment for pneumonia; however, they are neither effective nor indicated for parasitic or viral infections. Acute bronchitis typically resolves on its own with time.
In 2015 there were about 291 million cases.[1] These resulted in 2.74 million deaths down from 3.4 million deaths in 1990.[5][2] This was 4.8% of all deaths in 2013.[5]
Typical bacterial Infections:
Atypical bacterial Infections:
Parasitic infections:
Viral infections:
Aspiration pneumonia
Prevention[edit]
Vaccination helps prevent bronchopneumonia, mostly against influenza viruses, adenoviruses, measles, rubella, streptococcus pneumoniae, haemophilus influenzae, diphtheria, bacillus anthracis, chickenpox, and bordetella pertussis.[18] Specifically for the children with low serum retinol or who are suffering from malnutrition, vitamin A supplements are recommended as a preventive measure against acute LRTI.[19]
Treatment[edit]
Antibiotics do not help the many lower respiratory infections which are caused by parasites or viruses. While acute bronchitis often does not require antibiotic therapy, antibiotics can be given to patients with acute exacerbations of chronic bronchitis.[20] The indications for treatment are increased dyspnoea, and an increase in the volume or purulence of the sputum.[21] The treatment of bacterial pneumonia is selected by considering the age of the patient, the severity of the illness and the presence of underlying disease. A systematic review of 32 randomised controlled trials with 6,078 participants with acute respiratory infections compared procalcitonin (a blood marker for bacterial infections) to guide the initiation and duration of antibiotic treatment, against no use of procalcitonin. Among 3,336 people receiving procalcitonin-guided antibiotic therapy, there were 236 deaths, compared to 336 deaths out 3,372 participants who did not. Procalcitonin-guided antibiotic therapy also reduced the antibiotic use duration by 2.4 days, and there were fewer antibiotic side effects. This means that procalcitonin is useful for guiding whether to use antibiotics for acute respiratory infections and the duration of the antibiotic.[22] Amoxicillin and doxycycline are suitable for many of the lower respiratory tract infections seen in general practice.[20] Another cochrane review suggests that new studies are needed to confirm that azithromycin may lead to less treatment failure and lower side effects than amoxycillin.[23] In the other hand, there is no sufficient evidence to consider the antibiotics as a prophylaxis for the high risk children under 12 years.[24]
Oxygen supplementation is often recommended for people with severe lower respiratory tract infections.[25] Oxygen can be provided in a non-invasive manner using nasal prongs, face masks, a head box or hood, a nasal catheter, or a nasopharyngeal catheter.[25] For children younger than 15 years old, nasopharyngel catheters or nasal prongs are recommended over a face mask or head box.[25] A Cochrane review in 2014 presented a summary to identify children complaining of severe LRTI, however; further research is required to determine the effectiveness of supplemental oxygen and the best delivery method.[25]
Epidemiology[edit]
Lower respiratory infectious disease is the fifth-leading cause of death and the combined leading infectious cause of death, being responsible for 2.74 million deaths worldwide.[26] This is generally similar to estimates in the 2010 Global Burden of Disease study.[27] This total only accounts for Streptococcus pneumoniae and Haemophilus influenzae infections and does not account for atypical or nosocomial causes of lower respiratory disease, therefore underestimating total disease burden.