Necrotizing pneumonia | |
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Specialty | Infectious disease, respirology |
Necrotizing pneumonia (NP), also known as cavitary pneumonia or cavitatory necrosis, is a rare but severe complication of lung parenchymal infection. [1] [2] [3] In necrotizing pneumonia, there is a substantial liquefaction following death of the lung tissue, which may lead to gangrene formation in the lung. [4] [5] In most cases patients with NP have fever, cough and bad breath, and those with more indolent infections have weight loss. [6] Often patients clinically present with acute respiratory failure. [6] The most common pathogens responsible for NP are Streptococcus pneumoniae , Staphylococcus aureus , Klebsiella pneumoniae . [7] Diagnosis is usually done by chest imaging, e.g. chest X-ray or CT scan. Among these, a CT scan is the most sensitive test, which shows loss of lung architecture and multiple small thin walled cavities. [3] Often cultures from bronchoalveolar lavage and blood may be done for identification of the causative organism(s). [8] It is primarily managed by supportive care along with appropriate antibiotics. [8] However, if a patient develops severe complications like sepsis or fails to medical therapy, surgical resection is a reasonable option for saving life. [6] [8]
NP in adults was first described in the 1940s, whereas in children it was reported later in 1994. [3] Necrotizing pneumonia is an ancient disease which was once a leading cause of death in both adults and children. [9] Its clinical features were presumably first outlined by Hippocrates. [9] Later, in 1826, René Laennec described these features in a more detailed fashion in his seminal work De l’auscultation médiate ou Traité du Diagnostic des Maladies des Poumon et du Coeur (A treatise on the diseases of the chest, and on mediate auscultation). [9] [10] Although availability of appropriate antibiotics had made NP a rare disease, over the last two decades it has emerged as a severe complication of childhood pneumonia. [1]
The most common pathogens responsible for NP are Streptococcus pneumoniae , Staphylococcus aureus and Klebsiella pneumoniae . [7] Other pathogens which are less likely to cause NP are bacteria like Haemophilus influenzae , Streptococcus anginosus group, Pseudomonas aeruginosa , Mycoplasma pneumoniae , Acinetobacter baumannii , Streptococcus pyogenes , and Stenotrophomonas maltophilia ; anaerobes like Fusobacterium nucleatum and Bacteroides fragilis ; fungi like Aspergillus sp. and Histoplasma capsulatum ; and viruses like Orthomyxoviridae and Adenoviridae . [7] [3] [9]
Apart from Streptococcus pneumoniae (also known as pneumococcus), several other organisms have appeared to cause necrotizing pneumonia in children since 2002. [1] Most of the aforementioned organisms have been reported to be associated with childhood NP, except that K. pneumoniae is not a common cause in children. [3] However, pneumococci and S. aureus are frequently responsible for it. [3] Pneumococcal conjugate vaccine (PCV7) covering serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F was introduced in the USA in 2000. [11] [12] Consequently, non-PCV7 serotypes like 3, 5, 7F 19A emerged as new threats. Of this, serotypes 3 and 19A were particularly associated with NP. [3] In 2010 PCV7 was replaced by a 13-valent pneumococcal conjugate vaccine (PCV13). PCV13 includes all PCV7 serotypes plus six additional serotypes (1, 3, 5, 6A, 7F & 19A). [12] Panton–Valentine leukocidin (PVL) producing S. aureus strains are oftentimes responsible for life-threatening necrotizing pneumonia in previously healthy children and young adults. [13] These PVL-producing strains are frequently methicillin-resistant (MRSA). [3] In developing countries with high rates of HIV infection, Mycobacterium tuberculosis is the common cause of NP in children. [7]
Adults are more commonly affected by community-acquired Staphylococcus aureus, S. pneumoniae and K. pneumoniae. Gram-negative organisms like K. pneumoniae and P. aeruginosa are usually associated with pulmonary gangrene. [7]
Necrotizing pneumonia typically occurs in adult males who have coexisting health problems like diabetes mellitus, alcohol use disorder, and corticosteroid therapy. [2] Other risk factors may include smoking, gastrectomy, history of substance use disorder or HIV/AIDS. [7]
On the contrary, in most of the cases children of both sexes are affected equally. [3] Furthermore, it is unlikely that affected children have any underlying co-morbidities, but if any, asthma is the most common chronic disorder followed by recurrent otitis media. [3] [1]
Group A streptococcus such as S. pyogenes, often preceded by varicella infection, may cause severe invasive infections and complicated childhood pneumonia. [2] Influenza virus infection substantially increases the risk of developing necrotizing pneumonia in children mostly by PVL-producing S. aureus followed by S. pneumoniae. [7] In the United States it is observed that NP has increased following influenza owing to the emergence of MRSA strain USA300 infections. [14]
a) Initial plain chest radiograph showing a dense right upper zone airspace opacity and lingula airspace changes, consistent with multi-focal pneumonia. The following images were performed 24 h later. b) Plain chest radiograph with the patient intubated and ventilated revealing cavitation in the right mid to upper zones, pleural effusion and more general airspace changes bilaterally. c) Computed tomography (CT) scan, coronal view, demonstrating non-enhancing area (necrotic) thin-walled cavities within the right upper lobe and lingula. d) Lung ultrasonographic image displaying thin-walled cavities in the lingula region of the left lung. This requires further clarification. [note 1]
Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity of the condition is variable.
Atypical pneumonia, also known as walking pneumonia, is any type of pneumonia not caused by one of the pathogens most commonly associated with the disease. Its clinical presentation contrasts to that of "typical" pneumonia. A variety of microorganisms can cause it. When it develops independently from another disease, it is called primary atypical pneumonia (PAP).
Streptococcus pneumoniae, or pneumococcus, is a Gram-positive, spherical bacteria, alpha-hemolytic member of the genus Streptococcus. S. pneumoniae cells are usually found in pairs (diplococci) and do not form spores and are non motile. As a significant human pathogenic bacterium S. pneumoniae was recognized as a major cause of pneumonia in the late 19th century, and is the subject of many humoral immunity studies.
Pleural empyema is a collection of pus in the pleural cavity caused by microorganisms, usually bacteria. Often it happens in the context of a pneumonia, injury, or chest surgery. It is one of the various kinds of pleural effusion. There are three stages: exudative, when there is an increase in pleural fluid with or without the presence of pus; fibrinopurulent, when fibrous septa form localized pus pockets; and the final organizing stage, when there is scarring of the pleura membranes with possible inability of the lung to expand. Simple pleural effusions occur in up to 40% of bacterial pneumonias. They are usually small and resolve with appropriate antibiotic therapy. If however an empyema develops additional intervention is required.
Haemophilus influenzae is a Gram-negative, non-motile, coccobacillary, facultatively anaerobic, capnophilic pathogenic bacterium of the family Pasteurellaceae. The bacteria are mesophilic and grow best at temperatures between 35 and 37 °C.
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. A routine chest X-ray is not always necessary for people who have symptoms of a lower respiratory tract infection.
Bacterial pneumonia is a type of pneumonia caused by bacterial infection.
The bacterial capsule is a large structure common to many bacteria. It is a polysaccharide layer that lies outside the cell envelope, and is thus deemed part of the outer envelope of a bacterial cell. It is a well-organized layer, not easily washed off, and it can be the cause of various diseases.
Bronchopneumonia is a subtype of pneumonia. It is the acute inflammation of the bronchi, accompanied by inflamed patches in the nearby lobules of the lungs.
Pneumococcal polysaccharide vaccine, sold under the brand name Pneumovax 23, is a pneumococcal vaccine that is used for the prevention of pneumococcal disease caused by the 23 serotypes of Streptococcus pneumoniae contained in the vaccine as capsular polysaccharides. It is given by intramuscular or subcutaneous injection.
Lung abscess is a type of liquefactive necrosis of the lung tissue and formation of cavities containing necrotic debris or fluid caused by microbial infection.
Community-acquired pneumonia (CAP) refers to pneumonia contracted by a person outside of the healthcare system. In contrast, hospital-acquired pneumonia (HAP) is seen in patients who have recently visited a hospital or who live in long-term care facilities. CAP is common, affecting people of all ages, and its symptoms occur as a result of oxygen-absorbing areas of the lung (alveoli) filling with fluid. This inhibits lung function, causing dyspnea, fever, chest pains and cough.
Pneumococcal pneumonia is a type of bacterial pneumonia that is caused by Streptococcus pneumoniae (pneumococcus). It is the most common bacterial pneumonia found in adults, the most common type of community-acquired pneumonia, and one of the common types of pneumococcal infection. The estimated number of Americans with pneumococcal pneumonia is 900,000 annually, with almost 400,000 cases hospitalized and fatalities accounting for 5-7% of these cases.
Pneumococcal conjugate vaccine is a pneumococcal vaccine made with the conjugate vaccine method and used to protect infants, young children, and adults against disease caused by the bacterium Streptococcus pneumoniae (pneumococcus). It contains purified capsular polysaccharide of pneumococcal serotypes conjugated to a carrier protein to improve antibody response compared to the pneumococcal polysaccharide vaccine. The World Health Organization (WHO) recommends the use of the conjugate vaccine in routine immunizations given to children.
Hospital-acquired pneumonia (HAP) or nosocomial pneumonia refers to any pneumonia contracted by a patient in a hospital at least 48–72 hours after being admitted. It is thus distinguished from community-acquired pneumonia. It is usually caused by a bacterial infection, rather than a virus.
Panton–Valentine leukocidin (PVL) is a cytotoxin—one of the β-pore-forming toxins. The presence of PVL is associated with increased virulence of certain strains (isolates) of Staphylococcus aureus. It is present in the majority of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) isolates studied and is the cause of necrotic lesions involving the skin or mucosa, including necrotic hemorrhagic pneumonia. PVL creates pores in the membranes of infected cells. PVL is produced from the genetic material of a bacteriophage that infects Staphylococcus aureus, making it more virulent.
Pneumococcal vaccines are vaccines against the bacterium Streptococcus pneumoniae. Their use can prevent some cases of pneumonia, meningitis, and sepsis. There are two types of pneumococcal vaccines: conjugate vaccines and polysaccharide vaccines. They are given by injection either into a muscle or just under the skin.
Pneumococcal infection is an infection caused by the bacterium Streptococcus pneumoniae.
Pneumonia can be classified in several ways, most commonly by where it was acquired, but may also by the area of lung affected or by the causative organism. There is also a combined clinical classification, which combines factors such as age, risk factors for certain microorganisms, the presence of underlying lung disease or systemic disease and whether the person has recently been hospitalized.
Hermínia de Lencastre is a Portuguese-American geneticist honored by the Portuguese Ministry of Science, Technology, and Higher Education with the Medal of Scientific Merit for her contributions to microbial genetics.