Viral pneumonia

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Viral pneumonia
Specialty Infectious disease, respirology

Viral pneumonia is a pneumonia caused by a virus. Pneumonia is an infection that causes inflammation in one or both of the lungs. The pulmonary alveoli fill with fluid or pus making it difficult to breathe. [1] Pneumonia can be caused by bacteria, viruses, fungi or parasites. [1] Viruses are the most common cause of pneumonia in children, while in adults bacteria are a more common cause. [2]

Contents

Signs and symptoms

Symptoms of viral pneumonia include fever, productive cough, runny nose, chest pain and systemic symptoms (e.g. myalgia, headache). Different viruses cause different symptoms.

Diagnosis

Diagnosis, like with any infection, relies on the detection of the infectious cause. With viral pneumonia, samples are taken from the upper and/or lower respiratory tracts. [3] The samples can then be run through polymerase chain reaction (PCR), allowing for amplification of the virus as that allows better detection if present in the sample. [4] Other ways for a diagnosis to be obtained is by ordering a chest x-ray, blood tests, pulse oximetry, and a medical/family history to see if there are any known risks or previous exposures to a person with viral pneumonia. [4] If the person is in serious condition and in the hospital there are more invasive studies that can be run to diagnose the person. [4]

Cause

Common causes of viral pneumonia are:

Rarer viruses that commonly result in pneumonia include:

Viruses that primarily cause other diseases, but sometimes cause pneumonia include:

The most commonly identified agents in children are respiratory syncytial virus, rhinovirus , human metapneumovirus, human bocavirus , and parainfluenza viruses. [7]

History

In the pre-antibiotic age, pneumonias had been treated with specific anti-serums of highly variable therapeutic effect and undesirable side-effects (a practice eliminated by the advent of sulfamides in 1936 and the beginning availability of penicillin in the 1940s).

Viral pneumonia was first described by Hobart Reimann in 1984, in an article published by JAMA, An Acute Infection of the Respiratory Tract with Atypical Pneumonia: a disease entity probably caused by a filtrable virus. Reimann, Chairman of the Department of Medicine at Jefferson Medical College, had established the practice of routinely typing the pneumococcal organism in cases where pneumonia presented. Out of this work, the distinction between viral and bacterial strains was noticed. [10]

Pathophysiology

Viruses must invade cells in order to reproduce. Typically, a virus will reach the lungs by traveling in droplets through the mouth and nose with inhalation. There, the virus invades the cells lining the airways and the alveoli. This invasion often leads to cell death either through direct killing by the virus or by self-destruction through apoptosis.

Further damage to the lungs occurs when the immune system responds to the infection. White blood cells, in particular lymphocytes, are responsible for activating a variety of chemicals (cytokines) which cause leaking of fluid into the alveoli. The combination of cellular destruction and fluid-filled alveoli interrupts the transportation of oxygen into the bloodstream.

In addition to the effects on the lungs, many viruses affect other organs and can lead to illness affecting many different bodily functions. Some viruses also make the body more susceptible to bacterial infection; for this reason, bacterial pneumonia often complicates viral pneumonia.

Prevention

The best prevention against viral pneumonia is vaccination against influenza, chickenpox (varicella zoster), herpes zoster, measles, respiratory syncytial virus vaccine (RSV), rubella, and adenovirus vaccine. [11] [12] Besides vaccination there are no other ways to prevent viral pneumonia besides basic hygiene skills like covering the mouth when coughing or sneezing, staying home when sick, and washing your hands frequently.

Treatment

In cases of viral pneumonia where influenza A or B are thought to be causative agents, patients who are seen within 48 hours of symptom onset may benefit from treatment with oseltamivir, or zanamivir, or peramivir. [13] Respiratory syncytial virus (RSV) has no direct acting treatments, but ribavirin is indicated for severe cases. [13] Ribavirin has also been known to be used as a treatment for parainfluenza virus, and adenovirus. [13] Herpes simplex virus and varicella-zoster virus infections are usually treated with acyclovir, whilst ganciclovir is used to treat cytomegalovirus. [13] There is no known efficacious treatment for pneumonia caused by SARS coronavirus, MERS coronavirus, or hantavirus. Other forms of care are largely supportive like oxygen supplementation, treatment of comorbidities, and controlling other symptoms, fever and cough, with medications. [13]

Epidemiology

There are roughly 450 million cases of pneumonia every year. Of those case, viral pneumonia counts for about 200 million cases which includes about 100 million children and 100 million adults. [14] Viral pneumonia is more prevalent in the very young, less than 5 years old, and in the very old, more than 75 years old. [14] Developing countries have a higher rate of incidence when it comes to viral pneumonia. On average, developing countries have an incidence rate five times higher than that of developed countries. [14] Being pregnant can also affect the chances of developing viral pneumonia. [15] As with all infectious diseases, viral pneumonia preys on the immunocompromised as well as individuals with one or more comorbidities especially those with:

Related Research Articles

<span class="mw-page-title-main">Pneumonia</span> Inflammation of the alveoli of the lungs

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.

<span class="mw-page-title-main">Varicella zoster virus</span> Herpes virus that causes chickenpox and shingles

Varicella zoster virus (VZV), also known as human herpesvirus 3 or Human alphaherpesvirus 3 (taxonomically), is one of nine known herpes viruses that can infect humans. It causes chickenpox (varicella) commonly affecting children and young adults, and shingles in adults but rarely in children. VZV infections are species-specific to humans. The virus can survive in external environments for a few hours.

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).

<span class="mw-page-title-main">Respiratory syncytial virus</span> Species of a virus

Respiratory syncytial virus (RSV), also called human respiratory syncytial virus (hRSV) and human orthopneumovirus, is a contagious virus that causes infections of the respiratory tract. It is a negative-sense, single-stranded RNA virus. Its name is derived from the large cells known as syncytia that form when infected cells fuse.

<i>Human metapneumovirus</i> Species of virus

Human metapneumovirus is a negative-sense single-stranded RNA virus of the family Pneumoviridae and is closely related to the Avian metapneumovirus (AMPV) subgroup C. It was isolated for the first time in 2001 in the Netherlands by using the RAP-PCR technique for identification of unknown viruses growing in cultured cells. As of 2016, it was the second most common cause of acute respiratory tract illness in otherwise-healthy children under the age of 5 in large a US outpatient clinic.

<span class="mw-page-title-main">Upper respiratory tract infection</span> Medical condition

An upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the nose, sinuses, pharynx, larynx or trachea. This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold. Most infections are viral in nature, and in other instances, the cause is bacterial. URTIs can also be fungal or helminthic in origin, but these are less common.

Coinfection is the simultaneous infection of a host by multiple pathogen species. In virology, coinfection includes simultaneous infection of a single cell by two or more virus particles. An example is the coinfection of liver cells with hepatitis B virus and hepatitis D virus, which can arise incrementally by initial infection followed by superinfection.

<span class="mw-page-title-main">Lower respiratory tract infection</span> Medical term

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.

<span class="mw-page-title-main">Pneumonitis</span> General inflammation of lung tissue

Pneumonitis describes general inflammation of lung tissue. Possible causative agents include radiation therapy of the chest, exposure to medications used during chemo-therapy, the inhalation of debris, aspiration, herbicides or fluorocarbons and some systemic diseases. If unresolved, continued inflammation can result in irreparable damage such as pulmonary fibrosis.

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.

<span class="mw-page-title-main">Respiratory disease</span> Disease of the respiratory system

Respiratory diseases, or lung diseases, are pathological conditions affecting the organs and tissues that make gas exchange difficult in air-breathing animals. They include conditions of the respiratory tract including the trachea, bronchi, bronchioles, alveoli, pleurae, pleural cavity, the nerves and muscles of respiration. Respiratory diseases range from mild and self-limiting, such as the common cold, influenza, and pharyngitis to life-threatening diseases such as bacterial pneumonia, pulmonary embolism, tuberculosis, acute asthma, lung cancer, and severe acute respiratory syndromes, such as COVID-19. Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.

<span class="mw-page-title-main">Adenovirus infection</span> Medical condition

Adenovirus infection is a contagious viral disease, caused by adenoviruses, commonly resulting in a respiratory tract infection. Typical symptoms range from those of a common cold, such as nasal congestion, coryza and cough, to difficulty breathing as in pneumonia. Other general symptoms include fever, fatigue, muscle aches, headache, abdominal pain and swollen neck glands. Onset is usually two to fourteen days after exposure to the virus. A mild eye infection may occur on its own, combined with a sore throat and fever, or as a more severe adenoviral keratoconjunctivitis with a painful red eye, intolerance to light and discharge. Very young children may just have an earache. Adenovirus infection can present as a gastroenteritis with vomiting, diarrhoea and abdominal pain, with or without respiratory symptoms. However, some people have no symptoms.

<span class="mw-page-title-main">Gregory Prince</span>

Gregory Antone Prince is an American pathology researcher, businessman, author, social critic, and historian of the Latter Day Saint movement.

Viral culture is a laboratory technique in which samples of a virus are placed to different cell lines which the virus being tested for its ability to infect. If the cells show changes, known as cytopathic effects, then the culture is positive.

<span class="mw-page-title-main">Chickenpox</span> Human viral disease

Chickenpox, or chicken pox, also known as varicella, is a highly contagious, vaccine-preventable disease caused by the initial infection with varicella zoster virus (VZV), a member of the herpesvirus family. The disease results in a characteristic skin rash that forms small, itchy blisters, which eventually scab over. It usually starts on the chest, back, and face. It then spreads to the rest of the body. The rash and other symptoms, such as fever, tiredness, and headaches, usually last five to seven days. Complications may occasionally include pneumonia, inflammation of the brain, and bacterial skin infections. The disease is usually more severe in adults than in children.

<span class="mw-page-title-main">Classification of pneumonia</span> Medical condition

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.

<span class="mw-page-title-main">Epidemiology of pneumonia</span>

Pneumonia is a common respiratory infection, affecting approximately 450 million people a year and occurring in all parts of the world. It is a major cause of death among all age groups, resulting in 1.4 million deaths in 2010 and 3.0 million deaths in 2016.

Chronic Mycoplasma pneumonia and Chlamydia pneumonia infections are associated with the onset and exacerbation of asthma. These microbial infections result in chronic lower airway inflammation, impaired mucociliary clearance, an increase in mucous production and eventually asthma. Furthermore, children who experience severe viral respiratory infections early in life have a high possibility of having asthma later in their childhood. These viral respiratory infections are mostly caused by respiratory syncytial virus (RSV) and human rhinovirus (HRV). Although RSV infections increase the risk of asthma in early childhood, the association between asthma and RSV decreases with increasing age. HRV on the other hand is an important cause of bronchiolitis and is strongly associated with asthma development. In children and adults with established asthma, viral upper respiratory tract infections (URIs), especially HRVs infections, can produce acute exacerbations of asthma. Thus, Chlamydia pneumoniae, Mycoplasma pneumoniae and human rhinoviruses are microbes that play a major role in non-atopic asthma.

Bovine respiratory disease (BRD) is the most common and costly disease affecting beef cattle in the world. It is a complex, bacterial or viral infection that causes pneumonia in calves which can be fatal. The infection is usually a sum of three codependent factors: stress, an underlying viral infection, and a new bacterial infection. The diagnosis of the disease is complex since there are multiple possible causes.

Bovine respiratory syncytial virus (BRSV) is pneumovirus closely related to human respiratory syncytial virus (RSV) that is a common cause of respiratory disease in cattle, particularly calves. It is a negative-sense, single-stranded RNA virus that replicates in the cytoplasm of the cell. Similarly to other single-stranded RNA viruses, the genome of BRSV has a high mutation rate, which results in great antigenetic variation. Thus, BRSV can be split into four different subgroups based on antigen expression.

References

  1. 1 2 "Pneumonia | NHLBI, NIH". www.nhlbi.nih.gov. Retrieved 2020-11-30.
  2. ↑ Ruuskanen, Olli; Lahti, Elina; Jennings, Lance C; Murdoch, David R (2011-04-09). "Viral pneumonia". The Lancet. 377 (9773): 1264–1275. doi:10.1016/S0140-6736(10)61459-6. ISSN   0140-6736. PMC   7138033 . PMID   21435708.
  3. ↑ Ruuskanen, Olli; Lahti, Elina; Jennings, Lance C; Murdoch, David R (2011-04-09). "Viral pneumonia". The Lancet. 377 (9773): 1264–1275. doi:10.1016/S0140-6736(10)61459-6. ISSN   0140-6736. PMC   7138033 . PMID   21435708.
  4. 1 2 3 "Pneumonia | NHLBI, NIH". www.nhlbi.nih.gov. Retrieved 2020-11-30.
  5. 1 2 3 4 Table 13-7 in: Mitchell, Richard Sheppard; Kumar, Vinay; Abbas, Abul K.; Fausto, Nelson (2007). Robbins Basic Pathology: With STUDENT CONSULT Online Access. Philadelphia: Saunders. ISBN   978-1-4160-2973-1. 8th edition.
  6. ↑ Huang, Chaolin; Wang, Yeming; Li, Xingwang; Ren, Lili; Zhao, Jianping; Hu, Yi; Zhang, Li; Fan, Guohui; Xu, Jiuyang; Gu, Xiaoying; Cheng, Zhenshun; Yu, Ting; Xia, Jiaan; Wei, Yuan; Wu, Wenjuan; Xie, Xuelei; Yin, Wen; Li, Hui; Liu, Min; Xiao, Yan; Gao, Hong; Guo, Li; Xie, Jungang; Wang, Guangfa; Jiang, Rongmeng; Gao, Zhancheng; Jin, Qi; Wang, Jianwei; Cao, Bin (15 February 2020). "Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China". The Lancet. 395 (10223): 497–506. doi:10.1016/S0140-6736(20)30183-5. PMC   7159299 . PMID   31986264.
  7. 1 2 Ruuskanen, O; Lahti, E; Jennings, LC; Murdoch, DR (2011-04-09). "Viral pneumonia". Lancet. 377 (9773): 1264–75. doi:10.1016/S0140-6736(10)61459-6. PMC   7138033 . PMID   21435708.
  8. ↑ "SARS Basics Fact Sheet". US Centers for Disease Control and Prevention (CDC). 6 December 2017.
  9. ↑ Colby, Thomas V.; Zaki, Sherif R.; Feddersen, Richard M.; Nolte, Kurt B. (October 2000). "Hantavirus Pulmonary Syndrome Is Distinguishable From Acute Interstitial Pneumonia". Archives of Pathology & Laboratory Medicine. 124 (10): 1463–1466. doi:10.5858/2000-124-1463-HPSIDF. PMID   11035576.{{cite journal}}: CS1 maint: date and year (link)
  10. ↑ John H, Hodges MD (1989). Wagner, MD, Frederick B (ed.). "Thomas Jefferson University: Tradition and Heritage". Jefferson Digital Commons. Part III, Chapter 9: Department of Medicine. p. 253.
  11. ↑ Ruuskanen, Olli; Lahti, Elina; Jennings, Lance C; Murdoch, David R (2011-04-09). "Viral pneumonia". The Lancet. 377 (9773): 1264–1275. doi:10.1016/S0140-6736(10)61459-6. ISSN   0140-6736. PMC   7138033 . PMID   21435708.
  12. ↑ Freeman, Andrew M.; Leigh, Jr (2020), "Viral Pneumonia", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   30020658 , retrieved 2020-11-11
  13. 1 2 3 4 5 Freeman, Andrew M.; Leigh, Jr (2020), "Viral Pneumonia", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   30020658 , retrieved 2020-11-11
  14. 1 2 3 Ruuskanen, Olli; Lahti, Elina; Jennings, Lance C; Murdoch, David R (2011-04-09). "Viral pneumonia". The Lancet. 377 (9773): 1264–1275. doi:10.1016/S0140-6736(10)61459-6. ISSN   0140-6736. PMC   7138033 . PMID   21435708.
  15. 1 2 3 4 5 6 7 8 Freeman, Andrew M.; Leigh, Jr (2020), "Viral Pneumonia", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID   30020658 , retrieved 2020-11-11
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