Pediatric purpura nephritis

　　Pediatric allergic purpura nephritis is a leukocyte-mediated small vessel vasculitis, mainly caused by the deposition of immunoglobulin (IgA) leading to immune complex disease. The etiology is still not fully understood and may be related to the following factors: infection, vaccination, insect bites, cold stimulation, drug allergy, and food allergy, etc. Although these factors may trigger allergic purpura nephritis, it is still difficult to identify the allergen clinically, and the effectiveness of desensitization treatment is often unsatisfactory.

　　Children with allergic purpura nephritis occasionally have intussusception, intestinal obstruction, even intestinal necrosis and perforation; occasionally, facial nerve paralysis, neuritis, transient hemiplegia; pulmonary hemorrhage, subarachnoid hemorrhage; hypertension, myocarditis, and other conditions.

　　1. Intussusception:Intussusception refers to a segment of the intestine being pulled into the lumen of the connected intestinal cavity, causing an obstruction in the passage of intestinal contents. Intussusception accounts for 15% to 20% of intestinal obstructions. There are primary and secondary types. Primary intussusception mostly occurs in infants and young children, while secondary intussusception is more common in adults. The vast majority of intussusceptions involve the proximal intestine being pulled into the distal intestine, with retrograde intussusception being rare, accounting for less than 10% of the total cases.

　　2. Intestinal obstruction:Intestinal obstruction (intestinal obstruction, ileus) refers to the obstruction of the passage of intestinal contents in the intestines. It is a common acute abdominal condition that can be caused by various factors. In the early stages of the disease, the obstructed intestinal segment undergoes anatomical and functional changes first, followed by fluid and electrolyte loss, intestinal wall circulation disorders, necrosis, and secondary infection. Ultimately, it can lead to sepsis, shock, and death. Of course, timely diagnosis and active treatment can usually reverse the progression of the disease and lead to recovery.

　　3, Facial Palsy:Abbreviated as facial paralysis, its scientific name is facial neuritis, also known as Bell's palsy, Ramsay Hunt syndrome, and is commonly referred to as 'crooked mouth', 'twisted mouth', 'string pull wind', 'crooked wind', 'facial neuritis', or 'twisted mouth wind'. It is a common disease characterized by dysfunction of the facial expression muscle group. The general symptoms are distortion of the mouth and eyes. It is a common and frequently occurring disease, not restricted by age or gender. Patients often cannot perform even the most basic facial expressions such as raising the eyebrows, closing the eyes, blowing out the cheeks, or sticking out the tongue.

　　4, Neuritis:Neuritis refers to inflammation, degeneration, or deterioration of nerves or nerve groups, and the symptoms vary depending on the cause. General symptoms include pain, tenderness, pricking, itchy pain in infected nerves, and loss of sensation, with redness and swelling in the infected area and severe spasms.

　　5, Pulmonary Hemorrhage:The most important manifestation is hemoptysis, with approximately 49% of patients experiencing hemoptysis as the initial symptom, ranging from slight hemoptysis to massive hemoptysis. Severe cases (especially smokers) may have persistent massive hemoptysis and even asphyxial death. Patients often have symptoms such as shortness of breath, cough, dyspnea, and sometimes chest pain. The lung percussion sound is dull, and wet rales can be heard on auscultation. The pulmonary CO uptake rate (Kco) is an early and sensitive indicator of pulmonary function changes.

　　6, Subarachnoid Hemorrhage:The main clinical manifestations occur during emotional excitement, physical labor, coughing, straining during defecation, drinking, sexual intercourse, etc. The main symptoms are sudden severe headache, vomiting, and disturbance of consciousness. Examination reveals a positive meningeal irritation sign, and brain CT scanning shows hemorrhagic changes. Lumbar puncture shows uniform hemorrhagic cerebrospinal fluid. The severity of symptoms depends on the location of the lesion, the amount of bleeding, and is related to the age of onset.

　　7, Hypertension:In the absence of antihypertensive medication, systolic blood pressure ≥139mmHg and/or diastolic blood pressure ≥89mmHg, hypertension is classified into stages 1, 2, and 3 according to blood pressure levels. Systolic blood pressure ≥140mmHg and diastolic blood pressure

　　8, Myocarditis:Myocarditis refers to localized or diffused acute, subacute, or chronic inflammatory lesions in the myocardium. In recent years, the relative incidence of viral myocarditis has been increasing. The severity of the condition varies greatly, with infants and young children often experiencing more severe symptoms, while adults tend to have milder symptoms. Mild cases may not show any obvious symptoms, while severe cases may lead to serious arrhythmias, heart failure, or sudden death. The prodromal symptoms of myocarditis during the acute or subacute phase may include fever, fatigue, excessive sweating, palpitations, shortness of breath, and chest pain. Examination may reveal premature contractions, conduction blocks, and other arrhythmias. Elevated levels of aspartate aminotransferase, creatine phosphokinase, and an accelerated erythrocyte sedimentation rate are observed. Electrocardiogram and X-ray examinations are helpful for diagnosis. Treatment includes rest, improving myocardial nutrition, controlling heart failure, correcting arrhythmias, and preventing secondary infections.

　　Pediatric purpura nephritis can occur at any age, but it is more common in school-age children, with the most common onset age being 7 to 14 years, and it is rare in infants. The main clinical manifestations are as follows:

　　First, extrarenal manifestations:

　　1, Skin: Recurrent skin purpura appears during the course, manifested as unequal size, slightly prominent on the skin surface, purple-red macules, symmetrically distributed in the lower limbs, buttocks, and may involve the upper limbs, even the whole body. Some children may also have purpura on the ear and oral mucosa. Some children may have angioneurotic edema, manifested as local asymmetric swelling of the skin, appearing and disappearing intermittently. The rash can appear in batches, with a duration of up to one month, and some children may have repeated occurrences, even one to two years later.

　　2, Gastrointestinal manifestations: Belong to emergencies and should be paid attention to. Abdominal pain is common, mostly around the umbilicus or lower abdomen. Some children have severe abdominal pain, without fixed tenderness points on physical examination. Some children may have melena or dark red stools, with positive occult blood in stool. Severe cases may have intussusception, manifested as paroxysmal severe abdominal pain, accompanied by jam-like stools. A small number of patients may have abdominal pain before the rash appears, which is easily misdiagnosed as surgical acute abdomen.

　　3, Joint symptoms: Manifested as joint pain and swelling, mostly involving ankle, knee, and elbow joints, affecting activity, mostly transient symptoms, leaving no sequelae after subsidence.

　　4, Brain: Some children have convulsive manifestations, some of which are related to hypertension, and some are related to central nervous system vasculitis. Blood pressure should be measured when convulsive manifestations occur.

　　5, Others: There are also cases involving the pancreas, manifested as abdominal pain, how to deal with blood urine amylase, involving skeletal muscles, manifested as muscle pain, lung involvement can be manifested as pulmonary hemorrhage, and heart involvement may have increased myocardial enzymes.

　　Second, renal manifestations:

　　Kidney involvement is an important factor affecting the prognosis of allergic purpura, seen in 90% of children with allergic purpura. The severity of kidney involvement varies, with mild cases showing red blood cells in urine examination without edema or hypertension. Some children may present with hematuria and non-nephrotic level proteinuria, accompanied by edema and hypertension. Severe cases may show significant foam in urine, large amounts of proteinuria, accompanied by hypoalbuminemia, reaching nephrotic syndrome. More severe cases may have persistent gross hematuria at onset, accompanied by decreased renal function, and may be accompanied by hypertension and edema. Some children may have hidden symptoms, and when discovered, chronic renal insufficiency and hypertension have already occurred. For children with allergic purpura, attention should be paid to the color of urine and the foam in urine, and early examination should be conducted.

　　It is believed that the onset and recurrence of pediatric purpura nephritis are related to respiratory tract infections, so it is necessary to actively prevent and treat infectious diseases. In daily life, it is necessary to strengthen physical exercise and pay attention to hygiene to reduce the incidence of infectious diseases, avoid allergen stimulation, and eat less greasy food. In case of infection, it should be treated promptly and thoroughly. Two to three weeks after infection, routine urine examination should be conducted to detect any abnormalities in time, and various preventive vaccination tasks should be carried out.

　　The clinical examination of pediatric purpura nephritis mainly includes urine examination and blood examination, and it is also necessary to screen for allergens.

　　1. Blood routine

　　May have an increase in total white blood cells and neutrophils, while platelet count is normal or increased.

　　2. Urinalysis

　　May have red blood cells, protein.

　　3. Stool routine

　　Patients with abdominal pain may have occult blood.

　　4. Hemostasis and coagulation function

　　Mostly normal.

　　5. Biochemistry

　　Blood creatinine may be normal or elevated. Albumin may be normal or below 30g/L.

　　 Blood IgA may be elevated, while C3 and C4 are normal.

　　6. Allergen screening

　　May be allergic to certain components in the air or food.

　　7. Kidney ultrasound

　　In the acute stage, the size of both kidneys is normal or increased, while in chronic cases, the kidneys can shrink.

　　8. Auxiliary examination:Other checks should include ultrasound, X-ray, etc., and electrocardiogram, CT, etc. if necessary.

　　Pediatric purpura nephritis should prevent colds, overexertion, emotional excitement, etc., and attention to dietary adjustment principles is also very important.

　　1. Immediate cessation of contact and use of potential allergens such as foods, drugs, pollen, paint, etc. Foods such as milk, crabs, shrimps, eggs, lamb, etc.; drugs such as sulfonamides, penicillin preparations, antipyretic analgesics, rimifon, insulin, antischistosomiasis drugs, etc.

　　2. According to the different dialectical types of purpura nephritis, different drugs should be selected. For those with blood-heat due to heat-toxin invasion and hyperactivity of yin fire, foods with a cool and cold nature should be chosen, such as fresh lotus root, water chestnuts, shepherd's purse, pears, kiwi, lotus seeds, black fungus, lotus leaves, etc.; for those with qi deficiency and non-absorption, it is advisable to choose tonifying the spleen and kidney, nourishing blood and invigorating deficiency, such as animal liver, lean meat, skimmed milk powder, quail eggs, soy products, etc.

　　3. Diet should be light and nutritious, easy to digest and absorb, and avoid some irregular eating habits. Avoid rich and greasy foods, and do not overeat at each meal to avoid increasing the burden on the gastrointestinal tract and triggering or aggravating intestinal bleeding; the diet should be refined, and try to use as few coarse foods and foods rich in rough fibers as possible, such as celery, rapeseed, bamboo shoots, chives, pineapples, etc., which can wear away the gastrointestinal mucosa and trigger or worsen gastrointestinal bleeding; uncooked beef, mutton, pork, etc., should also be avoided; avoid smoking, drinking, and spicy刺激性 substances to prevent triggering and aggravating gastrointestinal bleeding.

　　The treatment of pediatric purpura nephritis is divided into two aspects: the treatment of allergic purpura and the treatment of purpura nephritis.

　　First, the treatment of allergic purpura

　　1. General treatment: During the acute stage, pay attention to rest and avoid strenuous exercise. Try to find the allergen, and remove the focus of infection such as chronic sinusitis, caries, gastritis, etc. Stop using suspicious foods or drugs. Avoid fish, shrimp, eggs, and milk in the diet. Vitamin C and calcium can be used, and cimetidine, an H2 receptor antagonist, can have a certain effect on controlling recurrent rashes and reducing kidney damage.

　　2. Treatment of abdominal pain: Patients with severe gastrointestinal bleeding should temporarily avoid food intake, and gradually resume diet after bleeding stops, paying attention to the supplementation of physiological fluid volume. Oral hormones can be used, and severe cases can be treated with intravenous methylprednisolone. Severe abdominal pain can be treated with symptomatic treatment, such as cimetidine, gastric mucosal protective agents, and antispasmodic drugs. Be vigilant about the occurrence of intussusception.

　　3. Treatment of joint swelling and pain: In addition to general treatment, short-term use of glucocorticoids can be considered for treatment, and the dose can be reduced or stopped after 1 to 2 weeks.

　　4. Anticoagulation therapy: There are reports that low-dose heparin can reduce the incidence of purpura nephritis.

　　Second, the treatment of purpura nephritis

　　The medication varies according to the degree of kidney involvement.

　　If there is no pathological diagnosis, the treatment plan can be selected according to the clinical classification.

　　For patients with microscopic hematuria, there is no specific treatment, and regular urine routine and renal function tests should be performed.

　　For patients with microscopic hematuria and mild proteinuria, angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists can be used for treatment.

　　For patients with clinical manifestations of nephrotic syndrome, it is recommended to treat with hormone combined with immunosuppressants, the choice of immunosuppressants can be considered from multiple aspects such as the condition, family economic bearing capacity, and the child's tolerance to drugs. The Chinese guidelines recommend hormone combined with cyclophosphamide as the first-line treatment.

　　For children with persistent gross hematuria and acute renal insufficiency at onset, most advocates for active treatment, using intravenous methylprednisolone pulse therapy for 1 to 2 courses, and then changing to oral hormone combined with CTX pulse + heparin + dipyridamole treatment. Before using methylprednisolone, severe infection, hypertension, thrombosis, and tuberculosis should be excluded. Dialysis treatment may be necessary if acute renal insufficiency occurs.

　　It should be emphasized that pathological diagnosis and clinical phenotype are not always consistent. It is recommended to clarify the pathological type as much as possible and determine the treatment accordingly, similar to tailoring to fit.

　　According to the Chinese guidelines, for pathological stage I, there is no specific treatment. For pathological stage IIa, angiotensin-converting enzyme inhibitors and angiotensin receptor antagonists can be used. There are also reports of the use of tripterygium. For pathological stage IIb or IIIa, there are reports in China of the use of tripterygium, combined hormone and cyclophosphamide or cyclosporine A. For pathological stage IIIb or IV, the most effective treatment is combined hormone and cyclophosphamide, in addition, there are studies reporting the efficacy of mycophenolate mofetil, and cyclosporine A also has efficacy. For pathological stage IV or V, combined medication is often used, that is, methylprednisolone pulse + cyclophosphamide pulse + heparin + dipyridamole.