Overview
The main symptoms include cough, sputum, fever, dyspnea, etc., which can be caused by viruses, bacteria, fungi and other pathogens, and more comprehensive treatment, anti-infective treatment is the key to some of them can be self-healing, but most of them need timely treatment.
Definition
Two-lung infection, also known as double-lung infection, refers to the invasion of both lungs by pathogens such as bacteria, viruses, fungi, and parasites [1-2].
Two-lung infections are most commonly associated with pneumonia on both sides of the body, but they also include stages in which pathogens invade the body without pneumonia occurring, so two-lung infections are not the same as pneumonia on both sides of the body.
Given the reality that by the time two-lung infections are detected, most patients already have significant imaging abnormalities or clinical symptoms, this article also focuses on the development of two-lung infections after the onset of the disease.
Classification
Two-lung infections can usually be categorized as follows, depending on the pathogen [1].
Bacterial two-lung infections
Bacterial infections such as Streptococcus pneumoniae, Staphylococcus aureus, Streptococcus aureus, Streptococcus haemolyticus, Klebsiella pneumoniae, etc. cause two-lung pneumonia.
Two-lung infections caused by atypical pathogens
Pneumonia of both lungs caused by atypical pathogens such as Legionella, Mycoplasma and Chlamydia.
Viral two-lung infections
Pneumonia of both lungs caused by viruses such as coronaviruses, adenoviruses, respiratory syncytial viruses and influenza viruses.
Pneumonia caused by fungal diseases
Two-lung fungal infections caused by Candida, Aspergillus, Cryptococcus, Pneumocystis, etc.
Other pathogens causing two-lung infections
Rickettsiae, Toxoplasma gondii (e.g. Toxoplasma gondii), parasites (e.g. Pneumocystis carinii, Schistosoma pneumoniae, Schistosoma haematobium, etc.).
Causes
Two-lung infections can be caused by a variety of pathogens that invade the lungs, and have multiple routes of transmission. The onset of the disease is also affected by factors such as susceptibility of the population and triggers.
Causes
Pathogens of two-lung infections
Two-lung infections can be caused by bacteria, viruses, fungi, atypical pathogens, parasites and other pathogens.
Among them, viral infections cause two-lung infections, and in recent years, new coronavirus infections are the most common.
Routes of infection for two-lung infections
The route of infection may not exist alone, sometimes it can be infected through multiple routes.
Respiratory route: This is the most common route of infection for two-lung infections. Pathogens enter the respiratory tract through airborne droplets, aerosols, and direct contact with the patient, and colonizing organisms from the upper respiratory tract can also be mistakenly inhaled into the lungs.
Bloodborne route: Some pathogens can enter both lungs through bloodborne route, which often occurs in immunocompromised people, such as HIV-infected patients, organ transplant recipients, etc., and can also be seen in chronically infected people.
Spread from neighboring sites of infection: from one lung to the other, or from the chest to both lungs, or from the bronchus to the lungs.
Direct contact route: the pathogen can infect both lungs through direct contact, such as surgical or medical device contamination, but this is rare.
Susceptible population
Lung infections can involve one or both lungs, and some groups of people are more susceptible to two-lung infections.
These include the elderly, infants and young children, immunocompromised, smokers, long-term bedridden people, people with underlying diseases (e.g. chronic bronchitis, bronchiectasis, congestive heart failure, etc.), people with intensive care unit length of stay, people with invasive mechanical ventilation, people with invasive operations (e.g. double lung lavage, bronchoscopy, etc.), and people with indwelling gastric tubes.
Predisposing factors
Rain, cold, sudden change of climate, over exertion, etc.
Pathogenesis
Various pathogens will constantly try to invade the respiratory tract and lungs in life, but a sound respiratory system is capable of effective defense and will not easily develop respiratory tract infections and lung infections.
When the invasive ability of pathogens increases significantly, such as invading pathogenic microorganisms in large numbers and with high virulence; or when the body’s defense function decreases, such as impaired respiratory defense function and decreased systemic immune function, respiratory tract infections or lung infections will occur easily.
At the onset of the disease, it is possible that the pathogens invade both lungs directly, causing two-lung infections; it is also possible that one side of the lungs becomes infected first, and as the disease worsens, the infection spreads to both lungs, causing two-lung infections.
Symptoms
Symptoms of a two-lung infection may vary among patients with different conditions and causes. The period of time after infection and before the onset of the disease, in which the patient has no symptoms, is known as the incubation period. In the case of a small number of infections in both lungs, there may also be no noticeable symptoms. The following are some typical symptoms of two-lung infections.
Main Symptoms
Symptoms of two-lung infection are related to the type of pathogen, severity of infection and other factors, with respiratory symptoms being the main ones.
Cough
Sometimes a two-lung infection is characterized by a dry cough. For example, Mycoplasma pneumoniae infection may be characterized by a paroxysmal, irritating dry cough.
Some two-lung infections are often accompanied by coughing up sputum, such as staphylococcal pneumonia and streptococcal pneumonia.
Coughing up sputum
Two-lung infections caused by different pathogens cough up sputum of different appearance.
For example, Streptococcus pneumoniae coughs up rusty sputum, Klebsiella pneumoniae coughs up reddish-brown jelly-like sputum, Staphylococcus pneumonia coughs up yellowish pus sputum, and Candida pneumoniae coughs up white foamy sticky sputum or jelly-like sputum, with a yeasty odor.
Dyspnea
Dyspnea does not usually occur when the infection in both lungs is mild.
When both lungs are extensively infected, it will lead to dyspnea, which may be accompanied by bruising of lips and nails, and may even lead to death. This can be seen in new crown infections, severe pneumonia, etc.
Chest pain
It can be seen in severe streptococcal pneumonia, mycoplasma pneumonia, pulmonary aspergillosis, etc.
Other symptoms
When the infection in both lungs is extensive or lasts for a long time, some systemic symptoms, such as fever, chills, chills, malaise, loss of appetite, muscle aches and pains, etc., may often appear.
Complications
When the infection in both lungs is more serious or not treated timely, it can cause many complications, the following are some of the more common complications.
Pleural effusion
When the infection in both lungs is severe, it can lead to an increase in the permeability of the pleura, producing exudate and forming pleural effusion.
A small amount of pleural effusion may have no obvious symptoms, while a large amount of pleural effusion may cause dyspnea, coughing, chest pain, fever and other symptoms.
Pleurisy
Pleurisy is caused when the infection in both lungs spreads to the pleura on the surface of the lungs.
Symptoms such as chest pain and dyspnea often occur.
Pyothorax
It is mainly caused by pathogens from the infected foci in the lungs entering the chest cavity.
Septic pus chest is mostly caused by drug-resistant Staphylococcus aureus, and tuberculous pus chest is mostly caused by Mycobacterium tuberculosis.
Symptoms such as high fever, chest pain, shortness of breath, dyspnea, and purulent sputum may be present.
Lung necrosis and cavities
Commonly found in tuberculosis caused by Mycobacterium tuberculosis with long course, lung abscess caused by Staphylococcus aureus, and many kinds of fungal diseases, which can destroy the normal structure of the lungs, and necrosis and cavitation can occur.
Clinical symptoms such as cough, sputum, hemoptysis, chest pain and dyspnea may occur.
Infectious shock
Elderly people with severe infections in both lungs have a higher risk of developing infectious shock than others.
It is characterized by loss of consciousness, decreased blood pressure, cold extremities, excessive sweating, tachycardia, and cardiac arrhythmia.
Others
There is also a risk of complications such as bacteremia, sepsis, systemic inflammatory response syndrome, and multiple organ dysfunction syndrome.
Seek medical attention
Infections in both lungs carry a high risk of progressing to serious illness, so it is important to seek medical attention when suspicious symptoms occur. During the consultation, the doctor will ask questions, examine the patient, and perform some necessary medical tests.
Department of Medicine
Respiratory Medicine
Adults with symptoms such as cough, sputum, chest pain, and fever should consult a respiratory physician promptly.
Pediatric Internal Medicine
Children with symptoms such as cough, sputum, chest pain, fever, etc. may first seek medical attention at the Department of Pediatric Internal Medicine.
Emergency Medicine
In case of emergencies such as persistent high fever, difficulty in breathing, severe chest pain, etc., it is recommended to go to the Emergency Department immediately, or call 120 for emergency help.
Preparation for medical treatment
Preparing for your visit: registration, information preparation, common problems
Tips for seeking medical treatment
Before seeking medical treatment, people with high fever can first take physical cooling measures, such as applying cold compresses to the forehead, wiping hands, feet and armpits with warm water, and drinking plenty of fluids as appropriate. If possible, record temperature changes.
Chest X-ray or chest CT is often needed for suspected two-lung infections, so avoid wearing clothes made of metal, and inform your doctor if you are pregnant or preparing for pregnancy.
Preparation Checklist
Symptom checklist
Pay particular attention to the time of onset of symptoms, specific manifestations, etc.
What were the first symptoms? When did they start?
Was there a fever before the visit? What was the highest temperature?
Was there a cough? How long have you been coughing?
Did you cough up sputum? What kind of sputum?
Are there any aggravating or relieving factors?
Are there any other discomforts, such as breathlessness, chest tightness, chest pain, etc.?
List of medical history
Have you recently been exposed to rain, cold, or overexertion?
Any exposure to colds, other fevers prior to onset of illness?
Are there any chronic diseases such as chronic bronchitis, chronic obstructive pulmonary disease?
Have you been taking oral glucocorticoids, immunosuppressants, etc. for a long time?
Have you been bedridden for a long time?
Has treatment been given? Which drugs were used?
Checklist
Test results in the past six months, which can be brought to the doctor’s office
Laboratory tests: blood routine, C-reactive protein, calcitoninogen, blood culture, sputum bacterial culture + drug sensitivity test, influenza + parainfluenza virus nucleic acid, novel coronavirus nucleic acid test, etc.
Imaging examination: chest X-ray, chest CT examination, etc.
Medication list
Medication used in the last 3 months, if there is a box or package of medication, you can bring it with you to the doctor’s office
Antibiotics: e.g. penicillin, cefaclor, ceftazidime, roxithromycin, etc.
Antipyretics and analgesics: e.g., ibuprofen, acetaminophen, etc.
Nasal decongestants: e.g. pseudoephedrine nasal drops.
Phlegm-cleansing drugs: e.g., Ambroxol, etc.
Diagnosis
Clinical diagnosis is usually made on the basis of history, epidemiology, clinical symptoms and signs, combined with laboratory tests, chest X-ray or chest CT, but pathogenetic tests can help to clarify the specific pathogen [4-6].
Diagnosis is based on
history of the disease
The following conditions may be present.
Previous close contact with a person with a confirmed or suspected lung infection.
Long-term use of immunosuppressive drugs and immunodeficiency diseases.
Cold, rain, or excessive fatigue prior to onset of illness.
Have poor health and are bedridden for long periods of time.
Suffering from certain underlying diseases, e.g. chronic obstructive pulmonary disease, chronic bronchitis, etc.
Clinical manifestations
Symptoms
There are respiratory symptoms such as cough, sputum, fever and shortness of breath.
May be accompanied by other symptoms such as fever, chills, chest pain, fatigue and poor appetite.
Physical signs
Severe hypoxia may result in bruising of the lips and mouth.
Wet rales can be heard on both sides of the chest if the infection in both lungs is obvious.
If the infection in both lungs leads to pleural effusion, pleural friction may be felt and heard. In moderate to large amounts of effusion, the affected side of the thorax is full, palpable tremor is weakened, localized percussion is turbid, and respiratory sounds are reduced or absent.
Laboratory Tests
Blood tests
Routine blood tests
The blood tests are mainly used to determine the presence of infection.
Bacterial infections of both lungs may result in elevated white blood cell counts and neutrophil percentages; however, white blood cell counts may not be elevated in the elderly, infirm, alcoholic, or immunocompromised, but neutrophil percentages remain elevated.
Virus-induced infections of both lungs often present with normal, slightly elevated, or low white blood cell counts, and the percentage of lymphocytes is often elevated.
Inflammatory markers
These include C-reactive protein, calcitoninogen, and blood sedimentation, and are often checked along with routine blood tests.
In the case of bacterial infection, C-reactive protein, calcitoninogen is elevated, and blood sedimentation is accelerated.
Blood culture
Blood is drawn for culture, mainly used to identify the presence of pathogens in the blood, commonly used in suspected severe pneumonia, or blood-borne infections.
Serologic examination
Serologic tests are mainly used to assist in the diagnosis of the presence of pathogen infections, including the condensation test, serum IgM, IgG test, etc. The test may be used to determine the presence of pathogens in the blood.
For example, 2 weeks after the onset of mycoplasma infection, a positive condensation set test and serum mycoplasma IgM antibodies ≥1:64 are often seen.
Blood gas analysis
Severe infections in both lungs often have different degrees of oxygen saturation reduction, blood gas analysis can understand the degree of hypoxia, blood acidity and alkalinity changes.
Blood biochemistry
Such as liver function, blood lipid, blood glucose, kidney function, uric acid, lactate dehydrogenase, etc., which helps to understand the patient’s physical condition.
Sputum examination
Sputum smear microscopy and sputum culture are often performed, and drug sensitivity test examination is often performed at the same time as sputum culture.
It is mainly used to detect the presence of pathogenic bacteria, and the results of drug sensitivity test can guide the selection of subsequent drugs.
For example, patients with Streptococcus pneumoniae can show typical positive gram stain with sputum smear, and sputum culture can culture the relevant pathogens.
Pay attention to standardized sampling to prevent sputum specimens from being contaminated.
Pleural effusion examination
If pleural effusion is combined, the effusion should be actively extracted for bacterial culture and drug sensitivity test.
It is mainly used to detect the presence of pathogenic bacteria, and the results of drug sensitivity test can guide the selection of subsequent drugs.
Urine examination
It is mainly used for the diagnosis of Streptococcus pneumoniae and Legionella infections.
When the corresponding antigen is positive, it suggests infection.
Imaging
Different causes and severity of the infection in both lungs may lead to different imaging manifestations, but typical lesions basically show grayish-white or white shadows in both lungs in different degrees and patterns.
Chest X-ray
Chest X-ray is the basic test for detecting infections in both lungs, and it can detect large-scale infections and cavities.
When infection is evident in both lungs, a white or grayish-white patchy shadow in both lungs is often seen on the chest X-ray.
Different pathogens may cause different imaging characteristics of two-lung infections, and CT may be performed if necessary.
CT
CT is often used as a complement to chest radiography to detect smaller lesions and to visualize the internal structures of the lungs more clearly and to help in the differential diagnosis.
Endoscopy
When the cause of an infection in both lungs is unknown, tests such as bronchoscopy may also be performed to help clarify the cause and etiologic diagnosis, and may be used for treatment.
Pathologic examination
Some two-lung infections are difficult to diagnose based on symptoms and imaging tests, and may require pathologic testing to confirm or differentiate the diagnosis.
For example, histopathology is the gold standard for pulmonary aspergillosis.
Other tests
Pulmonary function tests, oxygen saturation monitoring, influenza and parainfluenza virus nucleic acid, and novel coronavirus nucleic acid tests may also be performed.
Diagnostic Criteria
The initial diagnosis of a two-lung infection is based on imaging and blood tests, but the criteria are not the same for the diagnosis of specific diseases, as can be seen in the individual disease entries.
Differential Diagnosis
The symptoms and manifestations of many diseases are similar to those of lung infections, such as two-lung edema and two-lung lung cancer.
Edema of both lungs
Edema of both lungs and infection of both lungs can present with large white or grayish shadows on chest radiographs or CT, and both may present with symptoms such as cough and dyspnea.
In the early stages of pulmonary edema, limited interstitial edema can be detected on high-resolution CT (HRCT), which can help to identify it.
Measurement of alveolar fluid protein to plasma protein ratio, >0.7 suggests hyperpermeable pulmonary edema; <0.6 is simple lung infection or high-pressure pulmonary edema, but high-pressure pulmonary edema does not have the former’s clinical manifestations such as fever and leukocyte elevation.
It should be noted that two-lung edema and two-lung infection can often coexist and be causative of each other.
Lung cancer of both lungs
Lung cancer of both lungs and infection of both lungs may present with mass-like white or grayish shadow on chest radiograph or CT, and both may present with symptoms such as cough, dyspnea and fever.
Lung cancer often occurs in people who have smoked for a long time and are of advanced age; it may also present with chest pain and hemoptysis.
Imaging examination can find nodules, enlarged hilar lymph nodes and other changes; sputum exfoliative cells, histopathological examination and other malignant tumor cells can be found, which can clearly confirm the diagnosis.
It should be noted that lung cancer can also be secondary to infection.
In addition, it needs to be differentiated from various diseases such as respiratory distress syndrome and pneumoconiosis.
Treatment
Aims of treatment: to cure the disease, control or relieve symptoms, and prevent complications.
Treatment principle: two-lung infections need to be treated comprehensively according to the different pathogens, choosing appropriate anti-infective drugs when necessary, and giving symptomatic treatment at the same time [7-10].
Drug treatment
Anti-infective treatment is the key treatment for two-lung infections, which involves a variety of drugs and is complicated for the selection of drugs.
Antimicrobial drugs
Empirical medication
When the type of pathogen is unknown, antimicrobials can be chosen empirically first.
For milder patients who can be treated on an outpatient basis, it is recommended that fluoroquinolones (e.g., levofloxacin, moxifloxacin) be avoided.
For patients with more severe disease and treated in the general ward, it is currently recommended to use β-lactams (e.g., penicillin, ceftriaxone, etc.) alone or quinolones (e.g., levofloxacin, moxifloxacin) alone, and to combine macrolides and β-lactams if necessary.
Combination therapy with early administration of antibiotics should be recommended for those with severe pneumonia with indications for ICU admission, and the antibiotic regimen should preferably include macrolides and β-lactams, both administered intravenously [10].
In patients with two-lung pneumonia, for example, considering that Streptococcus pneumoniae is the most common, penicillin treatment is preferred for non-critical patients until the pathogen is clear. If allergic to penicillin, drugs such as cefotaxime or ceftriaxone can be used instead.
Use of drugs according to the drug sensitivity test
When the pathogen is clearly identified by sputum culture, whether to change the drug can be considered according to the results of drug sensitivity test.
Taking patients with two-lung pneumonia as an example, if the infection is streptococcal but is resistant to penicillin, cefotaxime or ceftriaxone can be used; fluoroquinolones, such as norfloxacin and levofloxacin, can also be used.
In the case of staphylococcal infections, penicillinase-resistant semisynthetic penicillins, such as benzathine sodium, can be used; cephalosporins, such as cefuroxime sodium, can also be used.
In the case of Mycoplasma or Chlamydia infections, they are usually more sensitive to macrolide antibiotics (e.g., erythromycin, roxithromycin, azithromycin, and clarithromycin) and quinolones (e.g., levofloxacin, moxifloxacin).
Antiviral drugs
If the two-lung infection is two-lung viral pneumonia, in principle, antibiotics should not be applied to prevent secondary bacterial infections, and the selection of therapeutic drugs according to different viruses can be considered.
Ribavirin has broad-spectrum antiviral activity and can treat two-lung infections caused by respiratory syncytial virus, adenovirus, parainfluenza virus and influenza virus.
Oseltamivir is a neuraminidase inhibitor that treats two-lung infections caused by influenza A and B viruses.
If a two-lung viral pneumonia develops in a medium-sized patient with a new coronavirus infection, consider using medications such as azulfidine and nematrevir tablets/ritonavir tablets.
Antifungal drugs
Fluconazole and itraconazole are used to treat pulmonary candidiasis, pulmonary aspergillosis, and pulmonary cryptococcosis [7].
Pneumocystis pneumonia can be treated with drugs such as cotrimoxazole and caspofungin.
Other medications
Antipyretics, such as ibuprofen and acetaminophen, can be used for those with persistent fever with a temperature over 38.5°C.
Those with cough and phlegm can use cough and expectorant drugs, such as compound licorice combination, aminoglutethimide and so on.
Glucocorticoids are helpful in controlling the progression of infection in both lungs, but are not routinely used.
Surgery
Thoracentesis to extract pus and closed chest drainage may be considered in the case of two-lung infection combined with pyothorax.
Thoracoscopic surgery is also effective in treating acute pyothorax, as all pus and necrotic pleural tissue can be removed under direct vision.
Commonly used surgical methods for chronic pyothorax include pleural fibrous plate debridement, thoracoplasty, and pleurodesis with total pneumonectomy.
Other treatments
When there is a lot of sputum and you cannot cough up the sputum on your own, you may be suctioned with a sputum aspirator or vibratory expectoration may be performed to keep the airway open.
In cases of low-grade fever, the body temperature may be lowered with warm baths, cold towels, or cold packs.
When the infection in both lungs leads to decreased oxygen saturation and respiratory distress, supportive treatment such as conventional oxygen therapy, transnasal high-flow oxygen therapy, noninvasive ventilation or invasive mechanical ventilation will need to be selected according to the patient’s actual condition.
Those who cannot eat or have persistent poor appetite should be given nutritional support.
Prognosis
The prognosis of patients with two-lung infections varies greatly with different conditions and is also affected by other factors, but treatment can significantly improve the prognosis and reduce the harm to patients.
Cure
Untreated
A small percentage of mild two-lung infections resolve spontaneously. In most cases, it may result in a gradual increase in the extent of the infection, or recurrent infections, prolonging the course of the disease and possibly even causing death.
After treatment
Most patients with two-lung infections can be effectively relieved after prompt and effective treatment.
However, some patients with severe disease, advanced age, underlying disease, and multi-drug resistant bacteria infection may have different complications or poor prognosis even after treatment, and some of them may die.
Prognostic factors
Factors such as alcoholism, smoking, advanced age, and immunosuppressed status can lead to a worse prognosis.
Hazards
Two lung infections may cause symptoms such as cough and fever, which can interfere with work and life.
Two-lung infections may aggravate the patient’s underlying diseases, such as chronic obstructive pulmonary disease and heart failure.
In severe cases, two-lung infections may lead to death.
Two-lung infections caused by certain pathogens are contagious and may result in varying degrees of transmission, such as pneumonia due to neocoronavirus infection.
Daily
Treatment of two-lung infections should not be limited to the aforementioned medical treatments. At the time of consultation, patients and their families should be aware of the daily advice provided by the doctor, which can help to control the disease in a more scientific and efficient way. Reasonable preventive measures can reduce the risk of morbidity.
Daily Management
Life management
People with infectious two-lung infection should avoid close contact with others to prevent transmission.
Stay in bed when you are seriously ill, and change your position regularly if you have been bedridden for a long time. Avoid prolonged bed rest when the condition improves, and do moderate activities.
Ventilate the room regularly and keep it at a suitable temperature.
Dietary management
Avoid intoxication and aspiration.
If the patient is able to eat, the diet should be nutritionally balanced, with more eggs, lean meat, fish, and appropriate vegetables and fruits.
Psychological management
Severe two-lung infection patients, the symptoms are heavy, patients often have tension and anxiety, should strengthen the psychological guidance. When negative emotions are severe, necessary medication should be taken by the doctor.
Disease monitoring
Observe temperature changes when fever develops.
Observe whether symptoms such as coughing are reduced.
When coughing up sputum, observe the color, smell and amount of sputum.
Follow-up
About two weeks after discharge from the hospital, you can review the blood test, chest X-ray or chest CT to know the recovery situation.
For special conditions, follow the doctor’s instructions for rechecking.
If symptoms worsen or new symptoms appear, consult a doctor.
Prevention
The following measures will not eliminate the occurrence of two-lung infections, but will reduce the chance of developing them.
Treat the infected person aggressively
Prompt treatment of an infection that occurs in one lung can prevent exacerbation to a two-lung infection as much as possible.
For patients who are clearly infectious, those who are eligible for isolation should be treated in isolation according to the requirements of the hospital and local policies to prevent transmission to others.
Protecting people susceptible to infection
Avoid getting wet, cold, etc.
Maintain adequate rest and avoid overwork.
During the epidemic of infectious diseases, wear masks correctly, do not have close contact with other confirmed patients, and do not share cups, cutlery, etc.
Turn the bedridden patient appropriately and avoid choking on food. Perform appropriate bedside activities if you are able to do so. Perform moderate exercise such as jogging, brisk walking, yoga, square dancing and other aerobic exercises when you are in good health.
Influenza vaccination, new coronavirus vaccine, and pneumococcal vaccine can reduce the incidence of double lung infections, but care needs to be taken with the indications for vaccination.