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Yan Xin Liang
Pediatrics
About me
Graduated from Nanhua University, engaged in pediatric work for over 10 years, and have further studied at Hunan Children's Hospital, Xiangya Hospital, and Beijing Children's Hospital.
Proficient in diseases
Diagnosis and treatment of common diseases in pediatric internal medicine, especially skilled in the diagnosis and treatment of pediatric respiratory system and neurological diseases, such as pediatric convulsions, epilepsy, asthma, and lung infections...
Voices
Phenylketonuria is caused by how?
Phenylketonuria is caused by how? It is an autosomal recessive genetic disease, mainly due to a mutation in the phenylalanine hydroxylase gene, which leads to a reduction in the activity of phenylalanine hydroxylase. Phenylalanine is an essential amino acid in the human body. The phenylalanine ingested is partly used for protein synthesis, and the rest is converted into tyrosine by the action of phenylalanine hydroxylase, with only a small amount of phenylalanine being converted into phenylpyruvic acid through a minor metabolic pathway under the action of transaminase. Due to the reduced activity of phenylalanine hydroxylase, phenylalanine cannot be converted into tyrosine, resulting in an extremely high concentration of phenylalanine in the blood, cerebrospinal fluid, and tissues. Through a bypass metabolism, a large amount of phenylpyruvic acid, phenylacetic acid, phenyllactic acid, and p-hydroxyphenylacetic acid are produced. High concentrations of phenylalanine and its metabolites thus lead to brain damage. Due to the synthesis disorder of tyrosine, this also leads to symptoms such as light skin and hair pigmentation.
Early symptoms of baby's scalp ringworm
Baby tinea capitis is a disease caused by fungal infection. The initial signs are an increase in dandruff and hair that breaks easily. Generally, there are different types based on these symptoms. However, with the gradual improvement of sanitary conditions, the incidence of tinea capitis is now very low and not commonly seen in clinical settings. If tinea capitis occurs, treatment should follow the principles of shaving the head, washing the hair, applying medication, disinfecting, and taking medication. Since fungi thrive in poor sanitary conditions, it is necessary to shave the child's hair and clean and disinfect the scalp, while also taking some antifungal medications. With these measures, the treatment of tinea capitis can achieve good results.
What is the cause of diarrhea in children?
Childhood diarrhea is divided into infectious diarrhea and non-infectious diarrhea, with the common type in children being infectious diarrhea, which includes rotavirus enteritis, bacterial enteritis, and bacterial dysentery, among others, with rotavirus enteritis being the most common. It is characterized by watery diarrhea or "egg-flower" style diarrhea. It is also accompanied by dry mouth, reduced urine output, and some can have symptoms such as vomiting and fever. Similarly, bacterial diarrhea can also present with vomiting, fever, and other symptoms. Other types of diarrhea, such as allergic diarrhea, commonly occur from milk allergies, and there are cases of lactose intolerance that also result in diarrhea. Therefore, there are many causes of childhood diarrhea, and each case should be analyzed specifically.
Clinical manifestations of childhood diarrhea
Pediatric diarrhea is caused by a variety of pathogens and factors, characterized by an increase in the frequency of bowel movements and changes in the characteristics of stools. It is one of the most common diseases in infants and young children in China, with a high incidence in infants and young children from six months to two years old, half of which are under one year old. It is one of the main causes of malnutrition and growth and development disorders in children. Diarrhea has some common manifestations, including loss of appetite, occasional regurgitation or vomiting, increased frequency of bowel movements, watery or thin stools that are yellow or yellow-green, some with a sour smell. In severe cases of diarrhea, it is important to check for dehydration and electrolyte disorders, as well as symptoms of systemic infection and intoxication, such as fever, irritability or lethargy, drowsiness, pale complexion, and even coma and shock.
The pathogenesis of phenylketonuria
Phenylketonuria is an autosomal recessive genetic disorder. Phenylalanine, which is an essential amino acid required by the human body, is partly used for protein synthesis after ingestion and partly converted into tyrosine via the action of phenylalanine hydroxylase, which is necessary for the synthesis of substances such as adrenaline, melanin, and thyroxine. Phenylketonuria is mainly caused by a deficiency of phenylalanine hydroxylase, which prevents the conversion of phenylalanine to tyrosine. This leads to increased levels of phenylalanine in the blood, cerebrospinal fluid, and various tissues. Additionally, as the primary metabolic pathway is blocked, secondary metabolic pathways are enhanced. Under the action of transaminases, phenylalanine undergoes deamination to produce large quantities of phenylpyruvic acid, which is further metabolized to produce phenylacetic acid, phenyllactic acid, and p-hydroxyphenylpyruvic acid, among other byproduct metabolites. These are excreted in large amounts in the urine. The high concentration of phenylalanine and its byproduct metabolites accumulates in brain tissue, leading to damage to brain cells and resulting in a range of clinical symptoms.
How many days will it take for a child to recover from a cold?
How long it takes for a child to recover from a cold depends on the specific circumstances. If it's just a minor cold, like a common viral cold with symptoms such as a runny nose and sneezing, the symptoms can generally be controlled within about 3 to 5 days. However, if the child's cold symptoms are more severe, including high fever, coughing, and a runny nose, it could take longer, possibly 5 to 7 days or more. This is because some colds can lead to bronchitis or even develop into pneumonia. It is difficult to specify an exact duration in such cases. For instance, bronchitis generally requires about 5 to 7 days of treatment to control the symptoms. If pneumonia is involved, the recovery might take even longer, around 7 to 10 days or up to 2 weeks. Therefore, an assessment based on the child's specific condition is needed to estimate how long it might take to recover. A typical mild cold can usually have its symptoms controlled within about 3 to 5 days.
How many days will it take for a child's diarrhea to get better?
Children's diarrhea can be divided into viral diarrhea and bacterial enteritis. Viral diarrhea, most commonly rotavirus enteritis, follows a specific disease course, where most cases gradually recover after 5-7 days with rehydration and symptomatic treatment. If it is bacterial enteritis, effective anti-infection treatment with sensitive antibiotics can also control the symptoms within 5-7 days. Additionally, some diarrheas caused by bacterial dysentery generally require 7-14 days of treatment, and fungal enteritis also typically needs one to two weeks of treatment.
How to deal with a child's cold and low fever
When a child has a mild fever due to a cold, it is often likely caused by a viral infection. In this case, it's important to monitor the child's temperature. Initially, physical methods to reduce fever can be adopted, such as encouraging the child to drink more warm water, giving warm water sponge baths, or bathing in warm water. Additionally, appropriate oral antiviral medications and some traditional Chinese medicines, such as those that clear heat and detoxify, can be administered. It is also vital to observe the child's behavior and check for symptoms like coughing, vomiting, runny nose, or diarrhea.
Principles for the Management of Childhood Asthma
Firstly, it is necessary to adhere to the principles of long-term, continuous, standardized, and individualized treatment. In the acute exacerbation phase, rapid relief of symptoms is required, primarily through anti-asthma treatment. During the remission phase, it is essential to maintain long-term control of symptoms, anti-inflammation, and reduce airway hyperresponsiveness, while also avoiding triggers and self-care. The treatment goal is to control and eliminate asthma symptoms as much as possible, reduce the number of asthma attacks, or even prevent them, maintain normal or near-normal lung function, allow participation in normal physical activities, including sports training, etc., minimize drug side effects, and prevent the development of irreversible airway obstruction.
Phenylketonuria Test Methods
The examination methods for phenylketonuria primarily include newborn screenings usually performed three to seven days after birth by drawing a blood sample from the heel and placing drops on specialized blood collection filter paper. Once dried, the sample is sent to a screening laboratory to determine the concentration of phenylalanine. If the phenylalanine concentration exceeds the cutoff value, further examinations and confirmatory tests are necessary, with the confirmatory test involving the measurement of phenylalanine concentration. Another method involves the analysis of urinary pterin profile, mainly used to differentiate dihydrobiopterin reductase deficiency. Additionally, gene analysis can be applied to detect mutations in genes such as phenylalanine hydroxylase, aiding in genetic diagnoses and prenatal diagnoses.