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Legionnaires' Disease

LD

Legionnaires' disease is a type of pneumonia caused by Legionella pneumophila, which was first identified in July 1976, when an outbreak occurred among people attending the 58th annual convention of the American Legion in Philadelphia.


Presentation

Generally patients with Legionnaires' disease develop fever, chills, and cough that may be dry or produce sputum [6]. In some patients muscle aches, headaches, loss of appetite, diarrhea and tiredness may also be seen.

Legionnaires' disease can also lead to severe pneumonia with dyspnea in some patients. In some cases it may lead to the development of adult respiratory distress syndrome. Bradycardia may also occur as a result of the fever that accompanies this condition.

The presentation for Legionnaire’s pneumonia is not distinctive as it closely relates to what is obtainable with other forms of pneumonia like Chlamydia pneumonia and Mycoplasma pneumonia.

In people with Pontiac fever, a self-limiting influenza-like illness with fever, chills, headache and muscle aches is seen but pneumonia is rare. Individuals affected often recover within 5 days without receiving any treatment.

Fever
  • […] for the long-term health effects of Q-fever.[ncbi.nlm.nih.gov]
  • Pontiac fever is different from Legionnaires’ disease because someone with Pontiac fever does not have pneumonia.[cdc.gov]
  • Bradycardia may also occur as a result of the fever that accompanies this condition.[symptoma.com]
  • Table summarizes key clinical differences between Legionnaires’ disease and Pontiac fever Legionnaires’ disease Pontiac fever Clinical features Fever, myalgia, and cough (according to the CSTE* case definition ) These symptoms are typical but not required[cdc.gov]
  • RESULTS: We included 309 Q-fever patients and 190 patients with Legionnaires' disease in the study.[ncbi.nlm.nih.gov]
Chills
  • People with Legionnaires' disease develop fever, chills and cough as the disease progresses. In its most advanced state, the disease can lead to severe pneumonia and respiratory failure.[symptoma.com]
  • Symptoms for Legionnaires' include fever, cough, chills and muscle aches. "We are concerned about this unusual increase in Legionnaires’ disease cases in the South Bronx," Health Commissioner Mary Bassett said in a statement.[web.archive.org]
  • Symptoms for Legionnaires’ include fever, cough, chills and muscle aches. “We are concerned about this unusual increase in Legionnaires’ disease cases in the South Bronx,” Health Commissioner Mary Bassett said in a statement.[reuters.com]
  • The bacteria don't spread from person to person.symptoms of legionnaires' disease include fever, chills, a cough and sometimes muscle aches and headaches. Other types of pneumonia have similar symptoms.[icd9data.com]
  • Typically, but not uniformly, the first symptoms of Legionnaire disease are general malaise and headache, followed by high fever, often accompanied by chills.[web.archive.org]
High Fever
  • Abstract A 51-year-old woman who had been on steroid therapy for systemic lupus erythematosus (SLE) developed a high fever 3 days after visiting a hot spring resort.[ncbi.nlm.nih.gov]
  • A male neonate was admitted to our hospital with high fever and dyspnea, which had started 5 days after birth, and died due to severe pneumonia at 10 days old.[ncbi.nlm.nih.gov]
  • […] commonly Legionnaire's disease Definition of Le gion naires' disease : pneumonia that is caused by a bacterium ( Legionella pneumophila ), is characterized initially by symptoms resembling influenza (as malaise, headache, and muscular aches) followed by high[merriam-webster.com]
  • fever, malaise, muscle aches, respiratory disorders and headache.[icd9data.com]
  • Typically, but not uniformly, the first symptoms of Legionnaire disease are general malaise and headache, followed by high fever, often accompanied by chills.[web.archive.org]
Malaise
  • Abstract The cases of two elderly patients who complained of general malaise after they had undergone ward transfer (due to rationalisation of the rehabilitation service) are discussed. Both were pyrexial and had signs of pneumonic consolidation.[ncbi.nlm.nih.gov]
  • […] naires' disease \ ˌlē-jə-ˈnerz- \ variants: or less commonly Legionnaire's disease Definition of Le gion naires' disease : pneumonia that is caused by a bacterium ( Legionella pneumophila ), is characterized initially by symptoms resembling influenza (as malaise[merriam-webster.com]
  • 482.84 converts directly to: 2015/16 ICD-10-CM A48.1 Legionnaires' disease Approximate Synonyms Legionnaires disease Legionnaire's disease Clinical Information An acute, sometimes fatal, pneumonia-like bacterial infection characterized by high fever, malaise[icd9data.com]
  • Typically, but not uniformly, the first symptoms of Legionnaire disease are general malaise and headache, followed by high fever, often accompanied by chills.[web.archive.org]
  • .… Typically, but not uniformly, the first symptoms of Legionnaire disease are general malaise and headache, followed by high fever, often accompanied by chills.[britannica.com]
Rigor
  • The investigation revealed ice from an ice-making machine in the hospital as the most probable source of the infection through aspiration, even though the hospital had rigorously adhered to strict assessment and decontamination schedules.[ncbi.nlm.nih.gov]
  • Increased standardization of LD investigation and reporting, and more rigorous follow-up of LD events, would help generate stronger, more comparable evidence on LD sources, contributing factors, and control measure effectiveness. 2015 International Society[ncbi.nlm.nih.gov]
  • Dr Romanes said Victoria had a "rigorous regime" for managing the risk of the legionella in water systems. "We've got one of the toughest regimes in the world, recently picked up by New York," he said.[theage.com.au]
  • Any resident at the home who displays symptoms is tested regularly and rigorously and hospitalized if symptoms continue to progress, MacDonna said.[web.archive.org]
  • […] humidifiers, ice-making machines, and misting systems typically found in grocery-store produce sections.The bacteria may also be transmitted from contaminated aerosols generated in hot tubs if the disinfection and maintenance programs are not followed rigorously[en.wikipedia.org]
Cough
  • Symptoms may include: Chest pain Cough that does not produce much sputum or mucus (dry cough) Coughing up blood Diarrhea, nausea, vomiting, and abdominal pain Fever General discomfort, uneasiness, or ill feeling ( malaise ) Headache Joint pain Loss of[web.archive.org]
  • Symptoms may include: General discomfort, loss of energy, or ill feeling (malaise) Headache Fever, shaking chills Joint pain, muscle aches and stiffness Chest pain, shortness of breath Cough that does not produce much sputum or mucus (dry cough) Coughing[nlm.nih.gov]
  • Table summarizes key clinical differences between Legionnaires’ disease and Pontiac fever Legionnaires’ disease Pontiac fever Clinical features Fever, myalgia, and cough (according to the CSTE* case definition ) These symptoms are typical but not required[cdc.gov]
  • Abstract Two male patients ages 54 and 58 years had persisting pneumonia with dry cough, dyspnea, weight loss, and fever up to 39 degrees C that did not respond to erythromycin treatment.[ncbi.nlm.nih.gov]
Dry Cough
  • Abstract Two male patients ages 54 and 58 years had persisting pneumonia with dry cough, dyspnea, weight loss, and fever up to 39 degrees C that did not respond to erythromycin treatment.[ncbi.nlm.nih.gov]
  • Swine influenza pneumonia presents as an influenza-like illness (ILI) with dry cough, fever 102 degrees F and myalgias.[ncbi.nlm.nih.gov]
  • Symptoms may include: Chest pain Cough that does not produce much sputum or mucus (dry cough) Coughing up blood Diarrhea, nausea, vomiting, and abdominal pain Fever General discomfort, uneasiness, or ill feeling ( malaise ) Headache Joint pain Loss of[web.archive.org]
  • Symptoms may include: General discomfort, loss of energy, or ill feeling (malaise) Headache Fever, shaking chills Joint pain, muscle aches and stiffness Chest pain, shortness of breath Cough that does not produce much sputum or mucus (dry cough) Coughing[nlm.nih.gov]
Pleural Effusion
  • ADA activity in pleural effusions due to LD has not been previously reported. The case of a patient with LD complicated by a pleural effusion with high ADA activity is reported.[ncbi.nlm.nih.gov]
  • Pleural effusion is relatively common in Legionnaires' disease but is usually clinically insignificant.[ncbi.nlm.nih.gov]
  • Pleural effusion and mediastinal adenopathies were apparent only in a minority, whereas no pneumothorax or cavitation was noted.[ncbi.nlm.nih.gov]
  • Four of the six patients presented with pleural effusion and five survived the infection episode. Only two patients had a potential soil contact history prior to LD onset.[ncbi.nlm.nih.gov]
  • effusion Prostatitis Respiratory distress Septic shock Typical, atypical, and severe community-acquired pneumonias Viral pneumonia Q Fever Prognosis The prognosis of patients with Legionnaire's disease depends on patient comorbidity, when the condition[ncbi.nlm.nih.gov]
Dyspnea
  • Abstract Two male patients ages 54 and 58 years had persisting pneumonia with dry cough, dyspnea, weight loss, and fever up to 39 degrees C that did not respond to erythromycin treatment.[ncbi.nlm.nih.gov]
  • A 32-year-old man presented with a five-day history of cough, dyspnea and chest pain. Chest radiography revealed patchy opacities in both lungs suggestive of bilateral pneumonia, and a urinary antigen test for Legionella pneumophila was positive.[ncbi.nlm.nih.gov]
  • A male neonate was admitted to our hospital with high fever and dyspnea, which had started 5 days after birth, and died due to severe pneumonia at 10 days old.[ncbi.nlm.nih.gov]
  • Legionnaires' disease can also lead to severe pneumonia with dyspnea in some patients. In some cases it may lead to the development of adult respiratory distress syndrome.[symptoma.com]
  • Cough - 41 to 92 percent Chills - 42 to 77 percent Fever 38.8 C - 88 to 90 percent 40 C - 20 to 62 percent Dyspnea - 25 to 62 percent Headache - 40 to 48 percent Myalgia/arthralgia - 20 to 40 percent Diarrhea - 21 to 50 percent Nausea/vomiting - 8 to[casesjournal.biomedcentral.com]
Purulent Sputum
  • These are referred to as atypical because the associated symptoms and signs are unlike typical pneumonia (as characterized by Streptococcus pneumonia), which involves spiking high fevers, sudden onset, cough, and purulent sputum and often chest pain and[medicinenet.com]
  • In some patients the absence of purulent sputum production, chest pain and cough may fool clinicians into discarding pneumonia as a possibility.[web.archive.org]
Diarrhea
  • CASE: A 53-year-old Japanese male visited our hospital with symptoms of fever, vomiting, diarrhea, and altered mental status, but not with respiratory manifestations.[ncbi.nlm.nih.gov]
  • Cough Shortness of breath Fever Muscle aches Headaches Legionnaires’ disease can also be associated with other symptoms such as diarrhea, nausea, and confusion.[cdc.gov]
  • […] disease Definition of Le gion naires' disease : pneumonia that is caused by a bacterium ( Legionella pneumophila ), is characterized initially by symptoms resembling influenza (as malaise, headache, and muscular aches) followed by high fever, cough, diarrhea[merriam-webster.com]
  • ., shortness of breath, headache, confusion, nausea, diarrhea) may be present A milder illness without pneumonia (according to the CSTE* case definition ) A flu-like illness, often with fever, chills, headache, myalgia, fatigue, malaise; less often with[cdc.gov]
  • Other symptoms can include diarrhea, myalgia, headaches, confusion/delirium and nausea.[orpha.net]
Vomiting
  • CASE: A 53-year-old Japanese male visited our hospital with symptoms of fever, vomiting, diarrhea, and altered mental status, but not with respiratory manifestations.[ncbi.nlm.nih.gov]
  • Symptoms may include: Chest pain Cough that does not produce much sputum or mucus (dry cough) Coughing up blood Diarrhea, nausea, vomiting, and abdominal pain Fever General discomfort, uneasiness, or ill feeling ( malaise ) Headache Joint pain Loss of[web.archive.org]
  • Other symptoms include feeling nauseous, vomiting, diarrhoea and loss of appetite. Diarrhea is seen in 25–50% of cases and vomiting and nausea in 10–30% of cases. There may be a general weakness.[news-medical.net]
  • […] discomfort, loss of energy, or ill feeling (malaise) Headache Fever, shaking chills Joint pain, muscle aches and stiffness Chest pain, shortness of breath Cough that does not produce much sputum or mucus (dry cough) Coughing up blood (rare) Diarrhea, nausea, vomiting[nlm.nih.gov]
Nausea
  • […] symptoms such as cough or nausea Pneumonia (clinical or radiographic) Yes No Pathogenesis Replication of organism Possibly an inflammatory response to endotoxin Incubation period 2 to 10** days after exposure 24 to 72 hours after exposure Percent of[cdc.gov]
  • Cough Shortness of breath Fever Muscle aches Headaches Legionnaires’ disease can also be associated with other symptoms such as diarrhea, nausea, and confusion.[cdc.gov]
  • Symptoms of the disease closely resemble the flu and include cough, fever, nausea and stomach discomfort. Ben Kallos, the City Councilman who represents the area, was handing out fliers to warn people about the disease.[ny1.com]
  • Other symptoms can include diarrhea, myalgia, headaches, confusion/delirium and nausea.[orpha.net]
  • Symptoms may include: Chest pain Cough that does not produce much sputum or mucus (dry cough) Coughing up blood Diarrhea, nausea, vomiting, and abdominal pain Fever General discomfort, uneasiness, or ill feeling ( malaise ) Headache Joint pain Loss of[web.archive.org]
Chest Pain
  • A 32-year-old man presented with a five-day history of cough, dyspnea and chest pain. Chest radiography revealed patchy opacities in both lungs suggestive of bilateral pneumonia, and a urinary antigen test for Legionella pneumophila was positive.[ncbi.nlm.nih.gov]
  • Symptoms may include: Chest pain Cough that does not produce much sputum or mucus (dry cough) Coughing up blood Diarrhea, nausea, vomiting, and abdominal pain Fever General discomfort, uneasiness, or ill feeling ( malaise ) Headache Joint pain Loss of[web.archive.org]
  • Health officials are telling people to watch for symptoms of pneumonia, such as chest pains when coughing or chills. But officials say there’s no reason to worry if you did visit the store.[kiro7.com]
  • Symptoms may include: General discomfort, loss of energy, or ill feeling (malaise) Headache Fever, shaking chills Joint pain, muscle aches and stiffness Chest pain, shortness of breath Cough that does not produce much sputum or mucus (dry cough) Coughing[nlm.nih.gov]
Tachycardia
  • On admission, he was febrile, toxic looking, dehydrated with hypotension and tachycardia. No clinical signs of respiratory infection were detected on admission.[ncbi.nlm.nih.gov]
  • Physical examination findings that are most common include pulmonary rÉles and other evidence of lung consolidation, tachypnoea and tachycardia. Confusion and memory loss are also relatively common findings.[web.archive.org]
Myalgia
  • Table summarizes key clinical differences between Legionnaires’ disease and Pontiac fever Legionnaires’ disease Pontiac fever Clinical features Fever, myalgia, and cough (according to the CSTE* case definition ) These symptoms are typical but not required[cdc.gov]
  • Presenting clinical features were similar to those reported for community-acquired pneumonia, with headache, myalgia and diarrhoea being common. Elevated C-reactive protein, hyponatraemia and abnormal liver function tests were also common.[ncbi.nlm.nih.gov]
  • Swine influenza pneumonia presents as an influenza-like illness (ILI) with dry cough, fever 102 degrees F and myalgias.[ncbi.nlm.nih.gov]
  • Other symptoms can include diarrhea, myalgia, headaches, confusion/delirium and nausea.[orpha.net]
  • Symptoms and transmission Legionnaires’ disease often presents with initial influenza-like symptoms such as myalgia, headache, fever and cough, and may progress to atypical pneumonia, sometimes with confusion.[www2.health.vic.gov.au]
Hematuria
  • […] levels Highly elevated erythrocyte sedimentation rate (ESR) Highly elevated ferritin levels Increased C-reactive protein (CRP) levels ( 30 mg/L) Hypophosphatemia (specific to Legionnaires' disease excluding other causes of hypophosphatemia) Microscopic hematuria[symptoma.com]
  • Laboratory data may include an abnormal liver function test, low phosphorus in the blood (hypophosphatemia), blood in the urine (hematuria), and low blood sodium (hyponatremia).[rarediseases.org]
  • […] following: Hypophosphatemia Hyponatremia (sodium less than 130 mEq/L) secondary to the syndrome of inappropriate antidiuretic hormone is more common in Legionnaires disease than in most cases of pneumonia that are secondary to other pathogens Microscopic hematuria[ncbi.nlm.nih.gov]
Headache
  • The bacteria don't spread from person to person.symptoms of legionnaires' disease include fever, chills, a cough and sometimes muscle aches and headaches. Other types of pneumonia have similar symptoms.[icd9data.com]
  • Pontiac fever, an influenza-like illness characterized by fever, headache, and muscle pain, represents a milder form of Legionella infection.[web.archive.org]
  • .… Typically, but not uniformly, the first symptoms of Legionnaire disease are general malaise and headache, followed by high fever, often accompanied by chills.[britannica.com]
  • ., shortness of breath, headache, confusion, nausea, diarrhea) may be present A milder illness without pneumonia (according to the CSTE* case definition ) A flu-like illness, often with fever, chills, headache, myalgia, fatigue, malaise; less often with[cdc.gov]
  • He became critically unwell during the hospital admission, with headache, uncontrolled fever, breathlessness, decreasing oxygen saturations and increasing oxygen requirements.[ncbi.nlm.nih.gov]
Confusion
  • Abstract A case of Legionnaires' disease is described in a 63 year old man who presented with pneumonia and confusion. Eleven days after admission he became acutely hypotensive and attempts at resuscitation failed.[ncbi.nlm.nih.gov]
  • Cough Shortness of breath Fever Muscle aches Headaches Legionnaires’ disease can also be associated with other symptoms such as diarrhea, nausea, and confusion.[cdc.gov]
  • […] disease : pneumonia that is caused by a bacterium ( Legionella pneumophila ), is characterized initially by symptoms resembling influenza (as malaise, headache, and muscular aches) followed by high fever, cough, diarrhea, severe pneumonia, and mental confusion[merriam-webster.com]
  • Coughing, shortness of breath, pleurisy -like pain, and abdominal distress are common, and occasionally some mental confusion is present.[web.archive.org]
Lethargy
  • Abdominal pain, diarrhea, neurological signs such as headache, confusion, lethargy or agitation may also be present.[rarediseases.org]
  • Initially, symptoms are fever, loss of appetite, headache, malaise and lethargy. Some patients may also have muscle pain, diarrhoea and confusion. There is also usually an initial mild cough, but as many as 50% of patients can present phlegm.[who.int]
  • Complications See the list below: Decreased pulmonary function Fulminant respiratory failure Dehydration, septic shock Respiratory insufficiency, hypoxic respiratory failure Endocarditis Neurologic symptoms: Including lethargy, headache, altered mental[emedicine.com]
Seizure
  • Microcystins can cause fever, headaches, vomiting, and—in rare cases—seizures.[theatlantic.com]
  • The most common symptoms include: a fever above 104 F chills a cough, with or without mucus or blood Other symptoms may include: shortness of breath headaches muscle aches a loss of appetite chest pain fatigue nausea and vomiting diarrhea confusion seizures[healthline.com]
  • Much less common are frank encephalopathy, focal neurological findings, seizures and meningitis. As the untreated disease progresses, the major findings include fever or hypothermia, dense consolidation of the lung, and often respiratory failure.[web.archive.org]
Altered Mental Status
  • CASE: A 53-year-old Japanese male visited our hospital with symptoms of fever, vomiting, diarrhea, and altered mental status, but not with respiratory manifestations.[ncbi.nlm.nih.gov]
  • Complications See the list below: Decreased pulmonary function Fulminant respiratory failure Dehydration, septic shock Respiratory insufficiency, hypoxic respiratory failure Endocarditis Neurologic symptoms: Including lethargy, headache, altered mental[emedicine.com]

Workup

Diagnostic tests are the backbone of diagnosis as these points out bacteria in sputum, presence of Legionella antigens in urine samples as a result of renal fibrosis and the presence of Legionella antibody levels in blood samples [7]. A urine antigen test is the most successful diagnostic test. This is because it detects Legionella pneumophila serogroup 1 which accounts for 70% of disease.

Other laboratory findings seen in patients with Legionnaires' disease include the following [8]:

Pulmonary Infiltrate
  • Histologic examination of the basal pulmonary infiltrates showed fibrosing alveolitis. Serologic titers indicated that the patients had suffered from Legionella pneumophila infection.[ncbi.nlm.nih.gov]
  • […] liver enzymes Elevated erythrocyte sedimentation rate (greater than 90 mm/h) Elevated ferritin levels (greater than 2X normal) Elevated C-reactive protein levels (greater than 30 mg/L) Severe Disease Expect respiratory failure, bilateral pneumonia, pulmonary[ncbi.nlm.nih.gov]
  • Findings on an initial radiograph of the chest may be normal, but eventually a pulmonary infiltrate will develop [ 2, 3 ].[casesjournal.biomedcentral.com]
Hyponatremia
  • ADH levels as the causal pathway to hyponatremia.[ncbi.nlm.nih.gov]
  • Laboratory data may include an abnormal liver function test, low phosphorus in the blood (hypophosphatemia), blood in the urine (hematuria), and low blood sodium (hyponatremia).[rarediseases.org]
  • Laboratory Findings Expect the following: Hypophosphatemia Hyponatremia (sodium less than 130 mEq/L) secondary to the syndrome of inappropriate antidiuretic hormone is more common in Legionnaires disease than in most cases of pneumonia that are secondary[ncbi.nlm.nih.gov]
Legionella Pneumophila
  • This is because it detects Legionella pneumophila serogroup 1 which accounts for 70% of disease.[symptoma.com]
  • The antibody response indicated that his disease was due to Legionella pneumophila serogroup 2.[ncbi.nlm.nih.gov]
  • Legionella pneumophila serogroup 6 was isolated from faucets in two homes owned by the patient.[ncbi.nlm.nih.gov]
  • Obtaining an early diagnosis of legionella infection is a challenge, especially if a Legionella pneumophila serogroup other than serogroup 1 contains the causative agent.[ncbi.nlm.nih.gov]
  • Chest radiography revealed patchy opacities in both lungs suggestive of bilateral pneumonia, and a urinary antigen test for Legionella pneumophila was positive.[ncbi.nlm.nih.gov]
Pleural Effusion
  • ADA activity in pleural effusions due to LD has not been previously reported. The case of a patient with LD complicated by a pleural effusion with high ADA activity is reported.[ncbi.nlm.nih.gov]
  • Pleural effusion is relatively common in Legionnaires' disease but is usually clinically insignificant.[ncbi.nlm.nih.gov]
  • Pleural effusion and mediastinal adenopathies were apparent only in a minority, whereas no pneumothorax or cavitation was noted.[ncbi.nlm.nih.gov]
  • Four of the six patients presented with pleural effusion and five survived the infection episode. Only two patients had a potential soil contact history prior to LD onset.[ncbi.nlm.nih.gov]
  • effusion Prostatitis Respiratory distress Septic shock Typical, atypical, and severe community-acquired pneumonias Viral pneumonia Q Fever Prognosis The prognosis of patients with Legionnaire's disease depends on patient comorbidity, when the condition[ncbi.nlm.nih.gov]

Treatment

Use of antibiotics and some of the newer macrolides are the current treatment of choice. The antibiotics that are used the most frequently are levofloaxacin and azithromycin [9]. The antibiotics are very effective as they have excellent intracellular penetration in cells that are infected with Legionella pneumophila.

Prognosis

As mentioned above, majority of people that become exposed to Legionella pneumophila do not go beyond the Pontiac fever phase. However, the condition can be life-threatening [5]. The risk of dying is highest in patients who have chronic conditions and those that get infected while on admission in a hospital.

The chief cause of death in patients is progressive respiratory failure. However, mortality rate is dependent on the patient’s comorbid conditions as well as the choice of antibiotics and the amount of time taken to begin treatment.

Etiology

The legionellosis condition is chiefly caused by the bacterium Legionella pneumophila [2]. There are two distinct stages of this disease.

Pontiac fever is a milder illness which develops between a few hours and two days after initial infection. It generally resolves spontaneously.

Legionnaires' disease stage is the main stage of the infection and may involve pneumonia. This form of the disease generally kicks in two to 10 days after initial infection but its onset may be delayed by over two weeks. The disease got its name in 1976 following a pneumonia outbreak that hit individuals attending an American Legion convention of that year.

Epidemiology

Legionnaires' disease is not rare but it is not uncommon either. Over 4% of all community-acquired pneumonia is as a result of it [3]. The number of people that develop Pontiac fever is also unknown as majority of such individuals only develop very mild symptoms.

Individuals likely to develop Legionnaires' disease after a Pontiac fever episode are those aged 50 and above, those that smoke or have chronic lung disease and immunosuppressed individuals.

Sex distribution
Age distribution

Pathophysiology

Legionnaires' disease is generally acquired by inhalation [4]. In some cases, it can be acquired by microaspiration of water that has been contaminated. In the lungs, the causative organism is phagocytosed by macrophages in the alveoli. This leads to the release of virulent factors that makes it possible for them to no just survive but also replicate in the individual. In individuals with this disease, the alveoli are filled with bacteria, neutrophils, microphages as well as erythrocytes.

The pathogenesis for Pontiac fever is not clear but it is equally caused by the inhalation of Legionella pneumophila

Prevention

To prevent outbreaks of Legionnaires' disease, pools, spas and other water systems have to be cleaned meticulously [10].

To further lower risk of infection, it is important for individuals to avoid smoking. Smoking increases chances of developing Legionnaires' disease as soon as the human body is exposed to Legionella pneumophila.

Summary

Legionnaires' disease is a condition also known as legionellosis. It is caused by a bacterium which lives mostly in the mist found typically in air-conditioned spaces [1]. This is why the bacterium has been able to infest entire buildings in many cases.

Another variation of the condition is Pontiac fever but Legionnaires' disease is more severe and if neglected, is ultimately fatal. People with Legionnaires' disease develop fever, chills and cough as the disease progresses. In its most advanced state, the disease can lead to severe pneumonia and respiratory failure. Antibiotics are useful in combating the condition but prevention is the most useful approach.

Patient Information

Legionnaires’ disease is an infection, often accompanied by pneumonia. Pneumonias refer to the inflammation of the lungs and in the case of Legionnaires’ disease it is caused by a bacterium known as Legionella pneumophila.

It is not possible to contact this disease from person-to-person contact. As majority of people get this disease by inhaling the bacteria. Older individuals, smokers and people with weak body defences have the highest risk of contracting the disease.

Another disease caused by the Legionella pneumophila is Pontiac fever. Pontiac fever is a milder illness and can occur separately or in combination with the Legionnaires’ disease in people infected with the bacteria. Pontiac fever often clears up on its own without treatment but Legionnaires' disease left untreated may be fatal.

Prompt treatment with antibiotics often cures the disease but follow up is required in some patients as problems may continue after treatment.

References

Article

  1. Kozak-Muiznieks NA, Lucas CE, Brown E, Pondo T, Taylor TH Jr, Frace M, et al. Prevalence of sequence types among clinical and environmental isolates of Legionella pneumophila serogroup 1 in the United States from 1982 to 2012. J Clin Microbiol. Jan 2014;52(1):201-11. 
  2. Nguyen TM, Ilef D, Jarraud S, Rouil L, Campese C, Che D. A community-wide outbreak of legionnaires disease linked to industrial cooling towers--how far can contaminated aerosols spread?. J Infect Dis. Jan 1 2006;193(1):102-11. 
  3. Woo AH, Goetz A, Yu VL. Transmission of Legionella by respiratory equipment and aerosol generating devices. Chest. Nov 1992;102(5):1586-90.
  4. Brandsema PS, Euser SM, Karagiannis I, DEN Boer JW, VAN DER Hoek W. Summer increase of Legionnaires' disease 2010 in The Netherlands associated with weather conditions and implications for source finding. Epidemiol Infect. Jan 24 2014;1-12. 
  5. Halsby KD, Joseph CA, Lee JV, Wilkinson P. The relationship between meteorological variables and sporadic cases of Legionnaires' disease in residents of England and Wales. Epidemiol Infect. Jan 9 2014;1-8. 
  6. Fang GD, Fine M, Orloff J, et al. New and emerging etiologies for community-acquired pneumonia with implications for therapy. A prospective multicenter study of 359 cases. Medicine (Baltimore) 1990; 69:307.
  7. Stout JE, Yu VL. Legionellosis. N Engl J Med 1997; 337:682.
  8. Yu VL, Greenberg RN, Zadeikis N, et al. Levofloxacin efficacy in the treatment of community-acquired legionellosis. Chest 2004; 125:2135.
  9. Fraser DW, Tsai TR, Orenstein W, et al. Legionnaires' disease: description of an epidemic of pneumonia. N Engl J Med 1977; 297:1189.
  10. Kirby BD, Snyder KM, Meyer RD, Finegold SM. Legionnaires' disease: report of sixty-five nosocomially acquired cases of review of the literature. Medicine (Baltimore) 1980; 59:188.

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Last updated: 2019-07-11 21:10