Diagnosis and diagnosis of respiratory diseases

The core logic of respiratory disease diagnosis and identification has never been to check the numbers on the symptom list, but through cross-validation in four dimensions: "Characteristics of the first symptoms + triggers of onset + changes in disease course within 3 days + past basic medical history", combined with necessary laboratory and imaging examinations and judgments. More than 90% of common respiratory diseases can be initially differentiated at the first visit to avoid misdiagnosis and missed diagnosis.

I didn’t say this out of thin air. I just met a 28-year-old young man in the respiratory clinic last week. When he came in, he held up his mobile phone to show me the “Premonitory Signs of Severe Influenza A” that he had searched for. He said that he had a fever of 38.5°C, coughed up yellow sputum, and tested negative for A Influenza antigen, fearing that he was infected by some rare virus. I asked a few more questions and was relieved - the day before, he went to a camping ground with his friends to set up a tent and sat in the spring breeze all afternoon. The first symptom was that his throat was as dry as sandpaper when he returned home at night. He started to have a fever the next day. There was no obvious muscle soreness all over his body. He had a history of chronic pharyngitis. He didn't even need to check his blood. It was just an ordinary bacterial upper respiratory tract infection. He was prescribed some symptomatic soothing and cough medicines. After three days of follow-up, he was almost healed.

Don't tell me, during the recent period, no matter whether it is online consultation or offline outpatient service, the most frequently asked question is "I have a bad cough, do I have mycoplasma pneumonia?" There is really no need to panic. The cough characteristics of mycoplasma infection are actually very easy to recognize: most people cough for two or three days before starting to have a fever, and half of the people even have no fever throughout the whole process. The cough is an irritating dry cough that cannot be stopped, and it will be significantly worse when lying down at night. Many children cough until they even vomit out their dinner, without much phlegm. If your fever reaches over 39°C as soon as you come in, and your bones all hurt, and you don’t even have the strength to get out of bed, then it’s most likely the flu, which is not related to mycoplasma.

Interestingly, there are still many differences in the use of mycoplasma antibody testing in the industry. Many grassroots hospitals test for mycoplasma IgM antibodies whenever they encounter patients with coughs. However, in fact, the positive rate of this antibody is very low within 1 week of the onset of illness, and it is easy to produce false negatives. And even if it is positive, it may be the antibody residue left by your Mycoplasma infection 3 months ago, which is not a problem now. The current consensus in our department is that the antibody results can only be used as a reference, and the core is to look at the symptoms and course of the disease, otherwise it is easy to misjudge.

Another condition that is particularly easy to treat as a cold is allergic airway hyperresponsiveness. Last month, an aunt in her 50s came to me and said that she had been coughing for half a month. She had taken three boxes of cephalosporins and four different cold medicines, but they were of no use at all. I asked a few questions and laughed. She would cough for more than half a month every spring when the poplar trees were in bloom. She happened to go for a walk in the park before she got sick this time. In addition to coughing, she sneezed seven or eight times in a row in the morning, her nose and eyes were itchy, and she didn't have a fever at all. This is not an infection. It is an airway hyperresponsiveness induced by pollen allergy. I was prescribed some oral anti-allergy medicine and atomized it for 3 days. The next day, they sent me a message saying that I basically stopped coughing.

By the way, there are always people on the Internet who say "if you don't have a fever, it's not pneumonia." This may be fine for healthy young people, but it can really kill people if it's applied to the elderly and children. A while ago, a 72-year-old man was transferred to the Department of Pediatrics. His family said he had a slight cough, did not want to eat, was in low spirits, and had never had a fever. As a result, a CT scan showed a large amount of pneumonia. The elderly have weak immunity and cannot mount an immune response. Even if there is an infection in the lungs, they may not have a fever. Instead, they may suffer from listlessness, breathlessness, and the inability to walk. Elderly people with underlying chronic obstructive pulmonary disease and asthma should be particularly careful. Don’t take “no fever” as a gold medal to avoid death.

When I usually make preliminary judgments for relatives and friends, I don’t even ask them to go to the hospital. I ask three questions first: First, what were the symptoms when the disease first started? Have you caught a cold, been in contact with patients with fever, or been to places with a lot of catkins and pollen? Second, how will you feel after the fever is gone? Can you eat and work normally? Third, did the cough affect my sleep, and did I feel out of breath? If the fever is gone and you can eat and play, and your cough does not affect your rest, then you can just take some symptomatic medicine at home, drink plenty of warm water and have a good rest. There is no need to go to the hospital and risk cross-infection.

Of course, there are special circumstances. For example, we have encountered several cases of mixed infections recently. First, we got influenza, and then mycoplasma infection was combined after the immunity was weakened. The symptoms will be very atypical, and any situation may occur. If you have been carrying it at home for 3 days, but your symptoms are getting worse instead of getting better, such as coughing so hard that you can't sleep, can't breathe, or have a high fever that can't go down, then don't carry it, go to the hospital to check the blood routine, and take a chest X-ray if necessary. It is much better than trying to look up the symptoms on Baidu and scare yourself.

In fact, the identification of respiratory diseases is not that mysterious to put it bluntly. It is essentially about finding a cause-and-effect relationship. Don’t just blindly judge the symptoms of a cough or fever. Think more about the triggers before the onset of the disease and observe the changes in the course of the disease in two days. If you are really not sure, it is better to see a professional doctor than anything else.