Since the autumn and winter of 2023, there has been an endless stream of patients suffering from acute respiratory infections, with a variety of symptoms, such as fever that does not go away, cough that drags on, or cold symptoms that have reappeared after symptoms have subsided or even recovered. With the unpleasant weather brought by early spring, warm and cold, and constantly changing weather, these symptoms have brought great trouble to everyone's life.
Clinically, most of these diseases are manifested as similar cold-like symptoms, but the efficacy is different, some people use medicine but do not get better, and some patients have recurring, why is this? The main reason is that the pathogens of acute respiratory infections are different, and the severity of the symptoms is different, if we do not understand it properly, or treat it without evaluation, it may have little effect.
Today, I will take you to know what are the pathogens of acute respiratory infections and what are their clinical manifestations?
1. What are the pathogens of acute respiratory tract infection and what are the clinical manifestations?
At present, the main pathogens causing acute respiratory infections are viruses, bacteria and mycoplasma, including respiratory viruses such as rhinovirus, influenza virus, respiratory syncytial virus, adenovirus, enteroviruses such as coxsackievirus, as well as Mycoplasma pneumoniae and novel coronavirus.
The common cold is the most common acute respiratory tract infectious disease, related to the season, more common in winter and spring, according to statistics, the incidence is 20.4%-33.2%, adults will occur an average of 2-3 times per year, mainly rhinovirus infection is the most common, there are more than 100 serotypes in clinical research, bacteria and mycoplasma can also cause the common cold, the clinical manifestations are mild and the onset is more acute, mainly including runny nose, sneezing or nasal congestion, dry throat or sore throat, cough or accompanied by a small amount of sputum and other upper respiratory tract infection symptoms, as well as chills, headache, With or without systemic symptoms such as mild to moderate fever (usually body temperature < 38.5°C), there are usually no serious complications, and recovery can be achieved within 5-10 days.
In addition, there are many cases of colds caused by respiratory viruses such as respiratory syncytial virus, adenovirus, and coxsackievirus infection in clinical practice. Among them, respiratory syncytial virus infection in the elderly, people with underlying diseases and immunocompromised people can lead to pneumonia, bronchitis and other lower respiratory tract infections.
Adenovirus infection in adults is more common in young people, can affect different parts of the body, the most common symptoms of upper respiratory tract infection, less common characteristic conjunctivitis and gastroenteritis with pharyngeal symptoms, etc., usually improve spontaneously, immunocompromised people are relatively seriously ill after infection.
Coxsackievirus is an enterovirus that is often asymptomatic or has nonspecific febrile respiratory symptoms, is difficult to distinguish from other infectious causes, and is mostly self-limited.
In fact, due to the wide range of potential viral etiologies and the fact that pathogens can rarely be quickly identified clinically, it is difficult to take targeted antiviral therapy, and the mild disease is mainly supported by symptom relief.
Influenza (influenza) occurs seasonally in winter and spring with the rapid spread of influenza viruses, and due to the antigenic and variable nature of influenza viruses, it can cause widespread transmission at regular intervals, and it is reported that the positive rate of surveillance influenza virus tests reached 49.3% during the peak period in December 2023, and it became the main cause of acute respiratory infections in winter and spring.
Influenza viruses are divided into four types according to their core proteins: A, B, C, and D, and influenza A (H1N1 subtype and H3N2 subtype) and B (Yamagata and Victoria strain) influenza viruses are seasonally circulating in the population, and the clinical manifestations and infection severity of different types of influenza are different, including high fever (body temperature > 38.5°C), muscle aches, Fatigue and other obvious systemic symptoms, a small number of high-risk patients can rapidly progress to critical illness leading to multi-organ failure, shock and sepsis, and high-risk groups with chronic underlying diseases can aggravate the primary disease after infection, especially in elderly patients over 65 years old, atypical symptoms such as mental changes, anorexia, dizziness and discomfort are more common, which can easily lead to delayed medical treatment and poor prognosis.
Pneumonia is the most common complication of influenza, including viral pneumonia and secondary bacterial pneumonia, according to statistics, at least 2.5% of elderly patients and influenza-susceptible people have secondary bacterial pneumonia, clinically common in patients with fever lasting for more than 3-5 days or fever again after the fever has subsided, cough and sputum with dyspnea and other symptoms aggravated.
In addition, acute cardiovascular complications also occur from time to time, mostly 4-7 days after influenza virus infection, clinical studies have found that 12% of high-risk patients develop acute heart failure and acute ischemic heart disease, and 2%-5% of influenza patients can develop viral myocarditis, in addition to influenza virus, coxsackie group B virus infection is also one of the common causes, mild patients are asymptomatic or fatigue, severe patients are dyspnea, chest tightness and chest pain, Fulminant myocarditis with refractory heart failure, such as peripheral edema and irritability, when there are patients with pre-existing viral infection prodromal symptoms such as fever and muscle aches and chest discomfort, and at the same time cardiac biomarkers such as troponin are elevated, and the electrocardiogram shows acute myocardial injury and arrhythmia, most patients can obtain partial or full clinical recovery, and some patients may have a subclinical course all the time, and the prognosis is very poor.
Therefore, high-risk groups such as the elderly, people with chronic underlying diseases, and obese people must seek medical attention in time after they have flu symptoms, and undergo virus testing and other related examinations and comprehensive assessment of symptom severity, so as to give them early (within 48 hours of symptom onset). A full course of antiviral therapy and combination of antibiotics and other comprehensive treatments need our attention to the fact that influenza virus testing is not only necessary for diagnosis, but also can rationally use anti-influenza virus drugs, such as oseltamivir and mabaloxavir, to block viral replication and transmission, and at the same time prevent the emergence of drug resistance in the use of antiviral drugs after exposure.
The clinical presentation of Mycoplasma pneumoniae and novel coronavirus infection is similar to that of a cold or flu. The most common clinical manifestations of Mycoplasma pneumoniae infection are upper respiratory tract infection and acute bronchitis syndrome, with the most obvious symptoms being a progressive dry cough with headache, Sore throat and fever, and asymptomatic carrier for a long time after infection, as well as co-infection with other pathogens are also more common, and it is also one of the most common bacterial causes of community-acquired pneumonia, the course of the disease is self-limited, most patients with mild disease can fully recover, and macrolides such as azithromycin are the first choice for treatment.
According to reports, the current new crown epidemic in the mainland continues to maintain a low level of wave epidemic situation, the positive rate of the new crown virus in early March 2014 was 14.3%, of which JN.1 (Omicron subclade BA.2.86.1.1) variant infection is the mainstay, most of the symptoms after infection are mild, more common than the common cold fatigue, pain, diarrhea, olfactory disorders (loss or loss or loss) and taste disorders (loss or reduction), mostly moderate and low fever and no more than 3 days, the elderly, impaired immune function, People with chronic underlying diseases and other immunocompromised people may still be critically ill if they are infected, and if such patients are found to be positive for new coronavirus antigen or nucleic acid, anti-new coronavirus treatment should be started as soon as possible to avoid damage to important organs and affect the prognosis.
2. Can respiratory pathogens be infected at the same time?
Clinically, we often find that some patients are re-infected with influenza B virus after being cured of influenza A virus infection, and there are also patients who are co-infected with other pathogens such as influenza A virus or influenza B virus and Mycoplasma pneumoniae, and this kind of "superimposed" infection is not uncommon, which also causes a complex situation of recurrence or delay or aggravation of clinical symptoms. So, why is that?
Because the human body does not have cross-immunity to influenza A and B viruses and the establishment of immunity to infection is not sustainable, it is possible to be infected with another subtype of influenza virus after re-exposure after a previous influenza infection, with mild symptoms and a shorter course of illness. Due to the rotational transmission of a variety of respiratory pathogens in winter and spring and the lack of population protection measures, especially for high-risk groups with low immunity, upper respiratory tract symptoms appear after a viral infection, and the respiratory mucosa is easy to be secondarily infected with other pathogens before it is repaired. Therefore, only symptomatic treatment according to different causes and severity can achieve good results.
Some patients even test negative for influenza virus and respiratory virus for the first time, and their symptoms do not improve within 3-5 days.
Because pathogen detection technology and patient testing timing determine the sensitivity and results of the test. Clinical studies have found that after viral infection, the average detoxification time in human respiratory secretions generally lasts for 4.5 days, for example, the incubation period of influenza virus is 1-4 days, and the virus excretion reaches its peak 24-48 hours after the onset of symptoms, and then declines rapidly, and the rhinovirus excretion is consistent with the peak of symptoms, so it is best to carry out virus testing within 4 days after the onset of cold symptoms, and the best way to collect nasopharyngeal swabs for virus detection is to collect nasopharyngeal swabs. At present, influenza antigen test results are rapid, with low to moderate sensitivity, but high specificity, and false-negative results are common, which need to be interpreted carefully, and antiviral therapy cannot be discontinued.
Therefore, it is necessary to observe the patient's symptoms carefully, accurately detect them, and properly screen the drugs used, which is particularly important in early diagnosis and treatment.
3. Do I need to keep common cold medicines on hand and what are the cold symptoms that need to be seen in time?
It is okay to bring your own cold medicine, but it is prudent to take it strictly according to the instructions of the drug, including over-the-counter expectorant cough medicines and combination cold medicines, and commonly used antipyretic and analgesic drugs such as acetaminophen or ibuprofen.
It is particularly noteworthy that since most compound cold medicines contain one or more of acetaminophen, pseudoephedrine, dextromethorphan hydrobromide and other ingredients, antipyretics and compound cold medicines containing antipyretic ingredients should not be taken at the same time, and acetaminophen tablets and ibuprofen should not be taken alternately or at the same time, nor should they be taken more than the recommended dose, which will not only not enhance the efficacy, but will lead to the overlapping and overdose of some drug ingredients, increasing the risk of adverse reactions such as liver and kidney damage.
4. What should be paid attention to when using drugs for special groups such as children and the elderly?
Special populations such as children, pregnant women, and the elderly with chronic underlying diseases should also pay attention to drug safety, and again, there is no need for antibiotic treatment when there is no clinical evidence of concurrent secondary bacterial infection.
These commonly used drugs can help improve cold symptoms and relieve fever, but it is necessary to realize that these are only symptomatic treatments, if the symptoms are more and more and gradually worsening, you need to go to the hospital in time to treat the cause, for example, we know that fever is not a disease but a symptom, it is an important physiological defense response of the human body to resist disease, simple fever will not lead to aggravation of the disease, if the fever persists or high fever is accompanied by other symptoms, cough, dyspnea, palpitations, chest pain and even dizziness, When consciousness is impaired, it is necessary to find the cause of the fever in time for early treatment.
Although the symptoms of a cold are similar, each person's constitution is different, resulting in different severity.
5. How to do a good job of prevention?
In addition to seasonal influenza vaccination, which can reduce morbidity and symptom severity, we can do the following:
1. Emphasize that everyone is responsible for their own health, develop and maintain good hygiene habits, because the virus can be transmitted through hand contact with contaminated environmental surfaces, droplets or aerosols, and close contact with patients, etc., the main way of hand-to-hand transmission is particularly high, studies have found that the virus that causes colds may survive on human skin for up to 2 hours, so good hand hygiene can significantly reduce respiratory viral infections.
2. In crowded places or during the epidemic of the virus, wearing a mask correctly can reduce the risk of the virus spreading through the respiratory tract, and a well-sealed mask can prevent 94.8%-99.6% of infectious viruses.
3. We can adopt a healthy lifestyle to improve immunity, maintain adequate sleep, relax mental and emotional, engage in regular physical activity, eat a nutritious and balanced diet, and consume more foods rich in vitamins and minerals.
The above measures all help to strengthen the immune system, reduce the stress damage of the immune system and enhance the ability to adapt, with a scientific attitude to understand the pathogen and our immune response, only continue to grow their own physique, pay more attention to their diet, health, early prevention, less sickness, I wish everyone a smooth flu season every year.