April 15 2020
In the Mortality Bills, pneumonia is an easy second, to tuberculosis; indeed in many cities the death-rate is now higher and it has become, to use the phrase of Bunyan 'the captain of the men of death.' Sir William Osler, “Medicine in the Nineteenth Century” (1904)
Q: What is pneumonia?
A: Pneumonia is an acute inflammarory disease of the pulmonary parenchyma (lung tissue).
Q: What causes pneumonia?
A: Pneumonia may be caused by:
Bacteria
Fungi
Viruses
Q: What is the Community-Acquired Pneumonia (CAP)?
A: Community-acquired pneumonia (CAP) refers to an acute infection of the pulmonary parenchyma acquired outside of the hospital.
Q: What is Nosocomial pneumonia?
A: Nosocomial pneumonia refers to an acute infection of the pulmonary parenchyma acquired in hospital settings and encompasses:
hospital-acquired pneumonia (HAP) - pneumonia acquired ≥48 hours after hospital admission, and
ventilator-associated pneumonia (VAP) - pneumonia acquired ≥48 hours after endotracheal intubation.
Q: What is aspiration pneumonia?
A: Aspiration pneumonia refers to an acute inflammation caused by aspiration of bacteria from oral and pharyngeal areas.
Q: What are the aspiration syndromes?
A: There are the types of aspiration syndromes:
Aspiration of gastric acid causes a chemical pneumonitis which has also been called Mendelson syndrome;
Aspiration of bacteria from oral and pharyngeal areas causes aspiration pneumonia;
Aspiration of oil (eg, mineral oil or vegetable oil) causes exogenous lipoid pneumonia;
Aspiration of a foreign body may cause an acute respiratory emergency and, in some cases, may predispose the patient to bacterial pneumonia.
Q: What is the most common cause of bacterial pneumonia?
A: Streptococcus pneumoniae (pneumococcus) is the most frequently detected pathogen in patients with CAP.
Q: How easy is to identify the cause of pneumonia?
A: In a large proportion of cases (up to 62 percent in some studies performed in hospital settings), no pathogen is detected despite extensive microbiologic evaluation.
Q: Is lung sterile in a healthy person?
A: Historically, the lung has been considered sterile. However, culture-independent techniques (i.e., high throughput 16S rRNA gene sequencing) have identified complex and diverse communities of microbes that reside within the alveoli - lung microbiome.
This finding suggests that resident alveolar microbes play a role in the development of pneumonia, either by modulating the host immune response to infecting pathogens or through direct overgrowth of specific pathogens within the alveolar microbiome.
Q: How common is pneumonia?
A: CAP is one of the most common and morbid conditions encountered in clinical practice:
In the United States, CAP accounts for over 4.5 million outpatient and emergency room visits annually;
CAP is the second most common cause of hospitalization and the most common infectious cause of death. Approximately 650 adults are hospitalized with CAP every year per 100,000 population in the United States, corresponding to 1.5 million unique CAP hospitalizations each year;
Nearly 9 percent of patients hospitalized with CAP will be rehospitalized due to a new episode of CAP during the same year;
Pneumococcal pneumonia alone causes an estimated 150,000 hospitalizations each year in the United States;
Pneumonia is the most common cause of sepsis and septic shock, causing 50% of all episodes;
Q: What is the mortality and morbidity of viral pneumonia?
A: The US census for 2000-2001 listed pneumonia/influenza as the seventh leading cause of death (down from sixth) despite a 7.2% decrease in the mortality rate for these diseases during this period. Severe influenza seasons can result in more than 40,000 excess deaths and more than 200,000 hospitalizations.
Patients aged 65 years or older are at particular risk for death from viral pneumonia as well as from influenza not complicated by pneumonia. Deaths in these patients account for 89% of all pneumonia and/or influenza deaths.
Morbidity, especially in elderly persons, is also high. Up to 10-12% of patients older than 65 years required a higher level of assistance for activities of daily living after hospitalization for acute respiratory illnesses. In one nursing home outbreak, residents with acute influenza illness showed significant functional decline.
Q: How high is the mortality from pneumonia?
A: The death rate from pneumonia in the US has had little improvement since antibiotics became widespread more than half a century ago. It is the 4th most common cause of death in the USA. The mortality rate ranged from:
5.1 percent for combined ambulatory and hospitalized patients, to 13.6 percent in hospitalized patients to 36.5 percent in patients admitted to the intensive care unit (ICU);
Approximately 50,000 US adults die from the disease;
Pneumococcal meningitis and bacteremia killed approximately 3,600 people in the United States in 2017;
Q: Is pneumonia dangerous for children?
A: Pneumonia is the world’s leading cause of death among children under 5 years of age, accounting for 16% of all deaths of children under 5 years old killing approximately 2,400 children a day in 2015.
In the US and the rest of the world, viral pneumonias are the leading cause of hospitalization of infants.
Q: Is Ventilator Associated Pneumonia (VAP) dangerous?
A: Yes, being on a ventilator raises especially high risk for serious pneumonia. Ventilator-associated pneumonia is more likely to be caused by antibiotic-resistant microbes and can require the highest antibiotic use in the critically ill population.
Q: Do we have effective medications to treat pneumonia?
A: YES and NO:
Antibiotics can be effective for many of the bacteria that cause pneumonia;
For viral causes of pneumonia, antibiotics are ineffective and should not be used. There are few or no treatments for most viral causes of pneumonia;
Antibiotic resistance is growing amongst the bacteria that cause pneumonia. This often arises from the overuse and misuse of antibiotics in and out of the hospital. New and more effective antibiotics are urgently needed.
Q: Do we have vaccines to prevent pneumonia?
A: Vaccines are available for some but not many causes of pneumonia. The influenza vaccine is effective for those strains circulating that year, so it should be taken again every year. The pneumococcal pneumonia vaccines are recommended for those in higher risk groups (children, immunocompromised individuals, and seniors).
Q: How long it takes to recover from pneumonia?
A: After developing pneumonia, it often takes 6-8 weeks until a patient returns to their normal level of functioning and wellbeing.
Q: Are there long term consequences of pneumonia?
A: While successful pneumonia treatment often leads to full recovery, it can have longer term consequences. Children who survive pneumonia have increased risk for chronic lung diseases. Adults who survive pneumonia may have worsened exercise ability, cardiovascular disease, cognitive decline, and quality of life for months or years.