Children's allergic purpura nephritis

　　First, Etiology

　　Allergic purpura nephritis is a leukocytoclastic small vessel vasculitis, mainly caused by the deposition of IgA immune complexes and leading to immune complex disease. The etiology is still not completely clear and may be related to the following factors: infection, vaccination, insect bite, cold stimulation, drug allergy, and food allergy, etc. Although these factors may induce allergic purpura nephritis, it is still difficult to identify the allergen in clinical practice, and the effect of desensitization treatment is often difficult to satisfy.

　　Second, Pathogenesis

　　1. Considering that the significant characteristic of the immunopathology of allergic purpura nephritis is the granular deposition of IgA in the mesangial area, which is extremely similar to the changes in IgA nephropathy, it is therefore speculated that IgA plays an important role in the pathogenesis, and some even believe that they are essentially the same disease. Further research has found that there is a surprising consistency in the immunopathogenic mechanisms of the two, such as the elevation of serum IgA, monomer and polymeric IgA, λ-IgAl, and both have circulating IgA immune complexes in the serum; the deposition on the glomerulus is mainly poly IgA1, and there is J-chain deposition; both have C4a, C4b subtype defects, and both have IgAlO type glycosylation abnormalities, etc. Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology conducted a comparative study on 120 cases of allergic purpura nephritis and 31 cases of IgA nephropathy, and found that 6.3% of allergic purpura nephritis had linear deposition of IgG along the glomerular capillary wall and positive membrane anti-glomerular basement membrane antibody, and 12.5% were not primarily composed of IgA. Therefore, at least in a part of allergic purpura nephritis, its pathogenesis is significantly different from that of IgA nephropathy. The complement plays an important role in the kidney injury of allergic purpura nephritis, and the activation of complement may be achieved through the bypass pathway:

　　2. IgA lacks the ability to activate C1q, but can directly activate C3.

　　(1) Iia: Focal and segmental mesangial proliferation.

　　(2) Iib: Diffuse mesangial proliferation.

　　(1) IIIa: Focal change.

　　(2) IIIb: Crescent body appears, but <50%.

　　(1) Ira: Focal lesion.

　　(2) Irb: Crescent body 50% to 75%.

　　(1) Va: Focal lesion.

　　(2) Vb: Crescent body.

　　Occasionally, intussusception, intestinal obstruction, or even intestinal necrosis and perforation may occur; occasionally, facial nerve palsy, neuritis, transient hemiparesis; pulmonary hemorrhage, subarachnoid hemorrhage; hypertension, myocarditis, etc. may occur.

　　1. Skin purpura The recurrence of skin purpura during the course of the disease is a characteristic of the disease, most commonly seen in the extremities and buttocks, symmetrically distributed, more on the extensor side, appearing in batches, less on the face and trunk; initially presenting as purple maculopapular eruptions, elevated above the skin surface, followed by brownish discoloration and regression, which may be accompanied by urticaria and angioneurotic edema. In severe cases, purpura may coalesce into large blisters with hemorrhagic necrosis.

　　2. Gastrointestinal symptoms More than half of the children have recurrent paroxysmal abdominal pain, located around the umbilicus or lower abdomen, severe pain, which may be accompanied by vomiting, but hematemesis is rare; some children have melena or hematochezia, diarrhea or constipation, and occasionally complications such as intussusception, intestinal obstruction, or intestinal perforation may occur.

　　3. Joint symptoms The appearance of swelling and pain in the knees, ankles, elbows, and wrists, with limited activity, may be solitary or multiple, with effusion in the joint cavity, which may disappear within a few months without sequelae.

　　4. Renal symptoms The renal lesions caused by this disease are the most common secondary glomerulonephritis in children, with varying degrees of renal symptoms. Most children have hematuria, proteinuria, and casts, accompanied by increased blood pressure and edema, known as purpura nephritis. A few present with nephrotic syndrome. The majority of renal symptoms appear within one month of onset, and may also occur at a later stage of the disease. A few present with nephritis as the first symptom. Although some children may have persistent hematuria and proteinuria for several months or even years, most can recover completely, and a few may develop chronic nephritis and die of chronic renal failure.

　　5. Other rare cases may occur intracranial hemorrhage, leading to convulsions, paralysis, coma, aphasia, and may also have nosebleeds, gum bleeding, hemoptysis, testicular hemorrhage, and other bleeding manifestations. Occasionally, it may involve the cardiovascular system, causing myocarditis, pericarditis, or involve the respiratory system, causing laryngeal edema, asthma, and pulmonary hemorrhage.

　　It is believed that the onset and recurrence of the disease are often 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 personal hygiene to reduce the incidence of infectious diseases. If infected, it should be treated promptly and thoroughly. Two to three weeks after infection, urine routine should be checked in time to detect abnormalities, and various preventive vaccination work should be done.

　　1. Blood count shows normal or increased white blood cells, neutrophils and eosinophils may be elevated; except for severe bleeding, anemia is generally absent; platelet count is normal or even elevated, bleeding and coagulation time are normal, blood clot retraction test is normal, and some children may have positive capillary fragility test.

　　2. Urinalysis may show red blood cells, protein, casts, and in severe cases, gross hematuria.

　　3. In patients with gastrointestinal symptoms, the occult blood test in feces is often positive.

　　4. Blood tests show normal or increased erythrocyte sedimentation rate, serum IgA may be elevated, IgG and IgM are normal or slightly elevated; C3 and C4 are normal or increased; antinuclear antibodies and RF are negative; severe cases show increased plasma viscosity.

　　5、腹部超声波检查有利于早期诊断肠套叠；头颅MRI对有中枢神经系统症状患儿可予确诊；肾脏症状较重和迁延患儿可行肾穿刺以了解病情给予相应治疗。

　　First, dietary therapy for allergic purpura nephritis

　　1. Chrysanthemum, purple grass, and grass decoction: 15g of chrysanthemum, purple grass, and grass each, boil the three herbs with an appropriate amount of water for 20 minutes, pour out the soup, and the dregs can be boiled again. Drink the soup, once or twice a day, for 7 days. Suitable for purpura nephritis with skin purpura and hematuria during the acute phase.

　　2. Dried cranberry, reed root stewed meat: 30g of dried cranberry, 30g of white reed root, 50g of lean pork, put the three ingredients in a pot, add 1000ml of water, boil to 500ml, and drink the soup in three servings. Suitable for purpura nephritis with recurrent attacks, persistent, scattered eruptions, and microscopic hematuria not resolved. Contraindicated during the acute phase.

　　3. Take 25g of winter melon peel, 25g of watermelon peel, 100g of corn silk, 50g of red bean, decocted in three servings, and take it for 10-15 doses.

　　4. Molasses and reed root water: 500g of sugarcane (sliced), 150g of white reed root, decocted as tea for drinking.

　　5. Live clam meat 150-250g, 100g of corn silk, cooked into soup for consumption.

　　6. Composition: 12g of ginger peel, 15g of winter melon peel, 15g of plantain grass. Usage: decocted in water.

　　7. Composition: 2-3 cloves, 70 seeds of rapeseed. Usage: Mashed together, applied to the sole of the foot, change the medicine every 12 hours, and use it for 1 week.

　　8. Composition: 1 black fish, 6g of tea. Usage: Clean the black fish last year, put the tea into the fish belly, simmer for 1 hour with low heat, and drink the soup and eat the fish.

　　Second, what foods are good for the patient's body

　　1. The diet should be rich in nutrition, easy to digest, and eat fresh vegetables and fruits.

　　2. Eat light, low-sodium, low-fat, high-quality low-protein, and high-vitamin diets.

　　Third, what foods are bad for the patient's body

　　1. Avoid foods that may induce allergies, such as fish, shrimp, crab, pollen, milk, etc.

　　2. Avoid smoking and drinking.

　　3. For hematuria patients, spicy, pungent, and stimulating foods such as seafood and hair-like foods such as rooster, sea fish, beef, mutton, goose, etc., should be avoided to prevent the exacerbation of the disease by aiding heat and fire.

　　4. For those with excessive proteinuria, attention should be paid not to consume high-protein diets excessively to prevent malnutrition from not being supplemented.

　　First, treatment

　　1. General treatment:

　　During the acute phase, bed rest should be maintained. If there is a clear allergen, desensitization treatment should be administered. For those without a clear allergen, attention should be paid to the possibility of infection or hidden infection, and anti-allergic treatment can be administered simultaneously. For those with bleeding symptoms, hemostasis treatment should be performed. Hematemesis patients can be treated with anti-acid drugs such as cimetidine (cimetidine hydrochloride) 10mg/(kg·d), or omeprazole (omprazolr; Losec) 0.3-0.5mg/(kg·time), twice daily. Hydrochlorothiazide, spironolactone, or furosemide, etc., can be used for edema.

　　2. Adrenal cortex hormones:

　　Adrenal cortical hormones have a good effect on abdominal pain, and have certain effects on controlling hemorrhagic rash, joint swelling and pain, and proteinuria. However, they are ineffective for hematuria in allergic purpura. They are generally used for patients with massive proteinuria in clinical purpura nephritis. For patients with pathological grade III and above, it is also necessary to actively apply adrenal cortical hormones for treatment, which can significantly improve the prognosis. Prednisone can be selected, with a dose of 2mg/(kg·d), and a course of 1-2 weeks.

　　3. Immunosuppressants:

　　For grade IV-VI allergic purpura nephritis, while using corticosteroids, cyclophosphamide (CTX) should be given for treatment.

　　4. Antithrombotic Agents:

　　Long-term oral administration of dipyridamole (dipyridamole,潘生丁，persantin) 5-8mg/(kg·d), taken 2-3 times a day, has certain efficacy in the prevention and treatment of allergic purpura nephritis.

　　5. Traditional Chinese Medicine and Chinese Herbs:

　　Tetrandrine tablets can be selected for use in grade I, II, and III allergic purpura nephritis. The initial dose is 2mg/(kg·d), which is changed to 1.5mg/(kg·d) after 1 month, taken for 1 month, and finally maintained at 1mg/(kg·d) for 1-2 months, which has a good therapeutic effect on allergic purpura nephritis.

　　6. Other:

　　Some reports indicate that the application of nifedipine (nifedipine,心痛定) 0.25-0.5mg/(kg·time), 3-4 times/d, can alleviate the vascular inflammation of allergic purpura nephritis. Vitamin E also has some therapeutic effect. Patients in stages IV-V can also try plasma exchange and immunoadsorption, which may improve renal function. Hemodialysis and renal transplantation can be performed for patients with renal failure.

　　II. Prognosis

　　It is generally believed that the prognosis of children with the disease is better than that of adults, most of whom can recover completely or only have mild urinary abnormalities. The prognosis is related to clinical and pathological types. Clinically, children with nephrotic syndrome and (or) nephritis syndrome, and pathological IIIb level and above children, often have persistent renal damage, and eventually lead to renal insufficiency. However, after a multicenter study on children with allergic purpura nephritis in recent years, it is considered that a large number of children have persistent nephritis or nephritis status, and 15% progress to end-stage renal failure 10 years later, and 20% progress to end-stage renal failure 20 years later, which should be paid attention to.