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Mycoplasma pneumoniae says: I don't want to be a man with chronic cough
Written by | Mimi
"My child tested positive for Mycoplasma pneumoniae (MP) antibodies, and has taken four courses of azithromycin as instructed by the doctor, but he still has a cough, doctor, what should I do?" In outpatient clinics, it is common to hear similar complaints from parents.
Two cases were misdiagnosed:
What is the disease of a child with recurrent cough?
Case 1: The child had recurrent cough and sputum for more than 1 month
3-year-old Xiaohao has repeated cough and phlegm for more than 1 month, his parents didn't pay attention to it at first, and he didn't take Xiaohao for treatment, and by the 3rd week, Xiaohao's cough became more and more serious, and he pricked his finger in the hospital for examination, and Chamycoplasma antibody was positive, and the doctor and Xiaohao's mother were very happy, thinking that they had finally found the cause of the cough, so let's treat it according to MP infection.
So azithromycin was taken for four courses, but Xiaohao still coughed repeatedly, coughed up phlegm, and the cough improved during the medication, but the cough increased after stopping the drug, which made my mother sad. For detailed examination and treatment, Xiaohao's mother admitted Xiaohao to the hospital.
After being admitted to the pediatric respiratory department, Xiaohao completed bronchoscopy, and a large amount of yellow sputum was found in the nasal cavity and bronchi, and the sputum bacteria were cultured with Streptococcus pneumoniae, and the diagnosis was protracted bacterial bronchitis and sinusitis. In response to the disease, Xiao Hao was treated with bronchoalveolar lavage and antibacterial drugs for 2 weeks, and Xiao Hao was finally cured.
Case 2: Recurrent cough for more than 2 months and dry cough were the main symptoms
Like Xiaohao, it is common for patients with minor illnesses who have a long cough to persist in the Children's Respiratory Clinic. 3-year-old Xiaohua (pseudonym) also had a repeated cough for more than 2 months, the cough was obvious in the morning and evening, and the dry cough was the mainstay.
After visiting our hospital, blood was drawn to improve MP, allergens, and pulmonary function tests, considering that in addition to mycoplasma infection, the child also had cough variant asthma, and according to the standard treatment of cough variant asthma, Xiaohua's cough was completely cured.
Is a positive MP antibody an MP infection?
MP infection is very common, and 10%~40% of children with community-acquired pneumonia are caused by MP infection, which is also a common cause of chronic cough.
Therefore, MP examination is the most common examination for patients with recurrent cough, and most primary hospitals can also check MP antibodies by pricking their fingers, and clinicians hope to identify the possibility of MP infection through serum antibody testing.
However, does the result indicate that a positive MP antibody means an MP infection? First of all, let's review the relevant knowledge points about MP.
What is 1.MP?
MP belongs to the class Filuscoplasma of Mycoplasma in the Mycoplasma family, and is the smallest microorganism found to date that can grow on solid culture media in vitro and survive without relying on living cells [1].
Mycoplasma do not have the cell wall structure that bacteria have, so antibiotics that target the bacterial cell wall (such as the most common penicillins, cephalosporins) do not kill mycoplasma.
2. If the blood test is positive for MP antibody, is it mycoplasma infection?
Once the MP antibody result is "positive" or "weakly positive", the diagnosis of "MP" infection is made and treatment with azithromycin, clarithromycin, or erythromycin is presented.
Some children were found to be positive for MP antibodies more than once, so they were named "recurrence of MP infection" and were given multiple courses of azithromycin treatment, which is a misunderstanding that many doctors have stepped on.
In fact, a single blood test with positive MP antibodies cannot determine that the symptoms that appear this time are caused by MP infection.
Because after MP infection, the corresponding antibodies produced by the human body can exist in the blood for 6~12 months, so the positive blood MP antibody may be either previous or recent MP infection.
If the child does have symptoms, and is positive for mycoplasma antibodies, and the patient's symptoms disappear after anti-mycoplasma therapy, it is a mycoplasma infection; However, if the cough symptoms still recur after three to four courses of treatment, it is necessary to look for other causes of chronic cough in children.
These causes may also be considered for chronic cough in children
1. Chronic cough in children is easily misdiagnosed
Cough is a common symptom in pediatrics. Because it is also common, it can easily be misdiagnosed as "upper respiratory tract infection", "bronchitis", "MP infection" or even "pneumonia".
Chronic cough is diagnosed if cough is the only or predominant symptom, has been more than 4 weeks, and there is no obvious abnormality on chest x-ray.
When the parents saw that the child's cough was not cured, they sought medical treatment everywhere, and used cough medicines, phlegm medicines, and antibiotics, but the child still coughed repeatedly.
Frequent and severe coughing can have a serious impact on a child's learning, life, and social activities. Parents will also rush to the doctor when they are anxious, and blindly use antibiotics and various cough and expectorant drugs to their children.
2. Causes of chronic cough in children
The causes of chronic cough in children usually include cough variant asthma, upper airway cough syndrome, post-infectious cough, prolonged bacterial bronchitis, gastroesophageal reflux, allergic cough, and heart sound cough, among which the first three accounts for 87.3% of chronic cough in children [2].
Like Xiao Hao in the previous case, he is an upper airway cough syndrome with persistent bacterial bronchitis; Xiaohua is cough variant asthma.
The etiology of chronic cough in children is different from that of adults, and varies with different ages, and some causes of chronic cough have 2-3 causes, which increases the difficulty of diagnosis and treatment of chronic cough based on its complexity and variability.
Bibliography:
[1] Pediatric Drug Professional Group of the Expert Committee on Rational Drug Use of the National Health and Family Planning Commission. Chinese Journal of Pediatrics,2020,58:366-373.
[2] Chronic Cough Collaborative Group, Respiratory Group, Chinese Society of Pediatrics. Editorial Board of Chinese Journal of Pediatrics. Guidelines for the diagnosis and treatment of chronic cough in children in China (2013 edition)[J].Chinese Journal of Pediatrics,2014,52:184-188.
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