Allergic purpura nephritis in children

Introduction to allergic purpura nephritis in children Henoch-Schonleinpurpura (HSP) is a clinical syndrome characterized by skin purpura, hemorrhagic gastroenteritis, arthritis and glomerulonephritis. Allergic purpura nephritis is an allergic disease in which small vasculitis is the main disease associated with autoimmune damage of blood vessels. The underlying lesion is IgA deposition in the mesangial area, mesangial cell proliferation with or without crescent formation. Renal damage occurred more than 3 months (95%) in the presence of skin purpura, although it has been reported that kidney damage can occur before skin purpura, and after 1 year of skin purpura, kidney damage should not occur after 6 months. It is easy to see as purpuric nephritis. About half of children with HSP develop kidney damage, which is called anaphylactoid purpuranephritis. basic knowledge Sickness ratio: 0.0001% Susceptible people: children Mode of infection: non-infectious Complications: intussusception, intestinal obstruction, facial neuritis, hypertension

Causes of allergic purpura nephritis in children

May be related to a variety of predisposing factors, but direct pathogenic factors are often difficult to affirm.

Infection factor (35%):

The most common bacterial infection is -hemolytic streptococcus, followed by Staphylococcus aureus, Mycobacterium tuberculosis, Salmonella typhi, Pneumococcal and Pseudomonas. The above respiratory tract inflammation is more common, also seen in pneumonia, tonsillitis, scarlet fever. , bacillary dysentery, urinary tract infections, impetigo, tuberculosis and focal infections (skin, teeth, mouth, middle ear). There are rubella, flu, measles, chickenpox, mumps, hepatitis, etc. in the virus infection. Parasitic infections can also cause the disease, which is more common with aphid infections, as well as hookworms, whipworms, aphids, schistosomiasis, vaginal trichomoniasis, and malaria parasite infections.

Other factors (25%):

Insect bites, plant pollen, cold, trauma, menopause, tuberculin test, vaccination, and mental factors can all be caused. In addition, hemodialysis patients, lymphoma chemotherapy patients and Guillain-Barre syndrome patients have also reported allergic purpura.

Food factor (15%):

Mainly due to animal allergy protein caused by allergies to the body, fish, shrimp, crab, sputum, eggs, chicken and milk can cause this disease.

Drug factors (15%):

Drugs such as chloramphenicol, streptomycin, isoniazid, aminopyrine, aspirin, sulfonamides, etc. have all reported this disease.

Pathogenesis

Under the sensitization of the above factors, allergic reactions occur in the body, and the mechanism is as follows:

1. Immediate allergic reaction

After the allergen enters the body, it combines with the protein in the body to form an antigen. After a certain incubation period (5-20 days), the antigen stimulates the immune tissue and plasma cells to produce IgE. IgE is adsorbed on the mast cells of various organs of the body (perivascular, gastric cavity, skin). When the same antigen is stimulated again, the antigen binds to IgE adsorbed on the mast cells, activates the enzyme system in the cell, and causes the mast cells to release a series of biologically active substances, such as histamine, 5-TH, Bradykinin, an allergic slow-reacting substance (SRS-A), can also excite sympathetic nerves and release acetylcholine. SRS-A is composed of leukotriene C4 (LTC4) and its metabolites LTE and LTD4. LTC4 is converted to LTD4 by the action of -glutamyltranspeptidase, which is converted to LTE4 by the action of dipeptidase. This series of biologically active substances mainly acts on smooth muscles, causing small arteries, telangiectasia, increased permeability, tissue and organ bleeding, and edema.

2. Antigen-antibody complex reaction

This is the main pathogenesis. The allergen stimulates the plasma cells to produce IgG (also producing IgM and IgA), which binds to the corresponding antigen to form an antigen-antibody complex, the small molecule part of which is soluble and can be deposited on the blood vessel wall or the glomerular basement membrane in the blood. C3a, C5a, C5, C6, and C7 produced by the activation of the complement system can attract neutrophils, which phagocytose the antigen-antibody complex, release lysosomal enzymes, cause vasculitis, and involve the corresponding organs. In another part of the immune complex, the antibody is more than the antigen, and the complex has a large molecular weight, is precipitated by non-soluble, and is cleared by the mononuclear macrophage system, and generally does not produce pathological changes.

3. The role of cytokines

It has been reported that TNF and soluble TNF receptor (sTNFR) in the serum of patients with allergic purpura are in the normal range, while sIL-2R levels are elevated. In renal local tissue cells of patients with allergic purpura associated with kidney damage, there are various expressions of proinflammatory factors such as IL-1, IL-1, TNF- and LT. Recently, it has been reported that the levels of IL-4 in patients with allergic purpura, especially in the acute phase, are significantly increased, which is 5 to 40 times higher than the upper limit of normal people, suggesting that cytokines are involved in the pathogenesis of allergic purpura. IL-4 promotes IgE synthesis and may be an important factor in the course of the disease.

Pediatric allergic purpura nephritis prevention

Because the disease and condition of the disease are often related to respiratory infections, it is necessary to actively prevent and treat infectious diseases. On weekdays, exercise should be strengthened, and cleanliness should be paid to reduce infectious diseases. For example, once infected, it should be thoroughly treated in time. 2~ At 3 weeks, urine should be checked and abnormalities should be found, and various vaccination work should be done.

Pediatric allergic purpura nephritis complications Complications, intussusception, intestinal obstruction, facial neuritis, hypertension

Pediatric allergic purpura nephritis occasionally intussusception, intestinal obstruction, and even intestinal necrosis, occasional facial nerve spasm, neuritis, transient hemiplegia, pulmonary hemorrhage, subarachnoid hemorrhage, hypertension, myocarditis.

intussusception

Intussusception refers to the insertion of a segment of the intestine into the lumen of the intestine and causes the contents of the intestine to pass through the barrier. Intussusception accounts for 15% to 20% of intestinal obstruction. There are two types of primary and secondary. Primary intussusception occurs mostly in infants and young children, and secondary intussusception is more common in adults. The vast majority of intussusception is the insertion of the proximal intestine into the distal intestine. The reverse intussusception is rare, less than 10% of the total number of cases.

intestinal obstruction

Intestinal obstruction (ileus) refers to the intestinal contents being blocked in the intestine. For common acute abdomen, it can be caused by many factors. At the beginning of the onset, the obstructed intestine segment has anatomical and functional changes first, followed by loss of body fluids and electrolytes, intestinal wall dysfunction, necrosis and secondary infection, and finally can cause toxemia, shock, and death. Of course, if timely diagnosis and active treatment can mostly reverse the development of the disease, it will cure.

Facial nerve

Abbreviation for facial paralysis, scientific name facial nerve paralysis, also known as facial neuritis, Bell's palsy, Hunter syndrome, commonly known as "squeaky mouth", "spoken mouth", "hanging wind", "hanging wind", "facial neuritis", " "Pouting the wind", etc., is a common disease characterized by facial dysfunction of facial muscles. The general symptom is the distortion of the mouth and eyes. It is a common and frequently-occurring disease that is not limited by age and gender. The patient's face often fails to complete the basic eyebrow lifting, eye closing, drumsticks, and mouth.

Neuritis

Neuritis refers to inflammation, decline, or deterioration of a nerve or nerve group, and its symptoms vary with the disease. The general symptoms are pain, tenderness, tingling, infected nerve itching and loss of consciousness, partial redness of the infection and severe spasms.

Pulmonary bleeding

The most important manifestation is hemoptysis. About 49% of patients have hemoptysis as the first symptom, ranging from hemoptysis to massive hemoptysis. Severe (especially smokers) have massive hemoptysis and even suffocation. Patients with multiple shortness of breath, cough, asthma, difficulty breathing, sometimes chest pain symptoms, lung percussion was voiced, auscultation can smell wet voice, lung CO uptake rate (Kco) is an early and sensitive indication of lung function changes.

Subarachnoid hemorrhage

The main clinical manifestations are episodes of emotional agitation, physical labor, coughing, forced bowel movements, drinking, sexual intercourse, etc. The main manifestations are sudden severe headache, vomiting, disturbance of consciousness, examination of meningeal irritation, and CT scan of the brain. Performance, waist wear has a uniform blood cerebrospinal fluid. The severity of the symptoms depends on the location of the lesion, the amount of bleeding, and is related to the age of onset.

hypertension

In the absence of antihypertensive drugs, systolic blood pressure 139 mmHg and / or diastolic blood pressure 89 mmHg, according to blood pressure levels, high blood pressure is divided into 1, 2, and 3. Systolic blood pressure 140mmHg and diastolic blood pressure <90mmHg are listed as simple systolic hypertension. The patient has a history of hypertension and is currently using antihypertensive drugs. Blood pressure, although lower than 140/90mmHg, should also be diagnosed as hypertension.

Myocarditis

Myocarditis refers to a localized or diffuse acute, subacute or chronic inflammatory lesion in the myocardium. The relative incidence of viral myocarditis has increased in recent years. The severity of the disease is different, the performance is very different, the infants and young children are more severe, the adults are lighter, the lighter can have no obvious symptoms, and the severe ones can be complicated by severe arrhythmia, cardiac insufficiency or even sudden death. For the prodromal symptoms of acute or subacute myocarditis, the patient may have fever, fatigue, sweating, palpitation, shortness of breath, and pain in the precordial area. Check for arrhythmias such as contraction and conduction block before the visible period. Aspartate aminotransferase, creatine phosphokinase increased, and erythrocyte sedimentation rate increased. Electrocardiogram and X-ray examination are helpful for diagnosis. Treatment includes rest, improving myocardial nutrition, controlling cardiac insufficiency and correcting arrhythmia, and preventing secondary infections.

Pediatric allergic purpura nephritis symptoms common symptoms rash is a systemic allergies and fever... edema protein urine black stool blood nausea and vomiting edema with proteinuria systemic persistent edema nasal discharge

Clinical manifestation

1, kidney performance

Mainly with hematuria and proteinuria.

(1) Hematuria: Hematuria includes microscopic hematuria and gross hematuria. The former refers to normal urine color, which can be determined by microscopic examination. Usually, urine microscopy after centrifugation has more than 3 red blood cells per high power field. The latter means that the urine is washed with water or blood, and the naked eye can be seen as hematuria. About half of the patients had gross hematuria and microscopic hematuria.

(2) Proteinuria: varying degrees. The normal glomerular filtrate contains a small amount of small molecular protein, the content of 20mg/100ml. Reabsorption through the renal tubules, and finally the protein remaining in the urine is very small, no more than 70 ~ 100mg / 24h. It can not be detected by ordinary urine routine examination. When the protein content in the urine increases, the routine urine examination can be measured, which is called proteinuria.

(3) edema: generally mild to moderate, non-depressed, with a large amount of proteinuria can be depressed edema. Excessive body fluids accumulate in interstitial spaces or body cavities called edema. There is only a small amount of fluid in the normal body cavity. The edema fluid is generally interstitial fluid. According to the amount of protein contained in the edema fluid, the edema fluid can be divided into exudates, the relative density of which is >1.018, and the transudat, the relative density of which is <1.015. .

(4) Hypertension: In the absence of antihypertensive drugs, systolic blood pressure 139 mmHg and / or diastolic blood pressure 89 mmHg, according to blood pressure levels, high blood pressure is divided into 1, 2, and 3. Systolic blood pressure 140mmHg and diastolic blood pressure <90mmHg are listed as simple systolic hypertension. The patient has a history of hypertension and is currently using antihypertensive drugs. Blood pressure, although lower than 140/90mmHg, should also be diagnosed as hypertension.

2, extrarenal performance

Mainly caused by allergic purpura caused by skin, gastrointestinal, joint and other symptoms and signs.

(1) rash: distributed on the side of the two legs, showing symmetry, when the condition is severe, it can affect the buttocks, lower abdomen and elbow. When the rash began to appear, it was bright red, slightly higher than the leather surface, and it could be accompanied by itching and wheal, and it appeared repeatedly in batches.

(2) Common symptoms of joints: Half of the patients will have joint swelling and pain. The knee joint and ankle joint are more common, and the activity can be limited. Generally, the normal activity function can be restored within a few days.

(3) gastrointestinal symptoms: 1/3 of patients with abdominal cramps, paroxysmal, intermittent, mainly pain around the navel, may be accompanied by vomiting, melena, hematemesis, etc., individual intestinal obstruction, intestinal Perforation, intussusception, etc.

(4) Others: such as nosebleeds, hemoptysis, myocarditis, a few with headache, convulsions.

3. Other performance

Allergic purpuric nephritis can affect the central nervous system, the cardiovascular system, and the external thoracic gland, and the corresponding symptoms appear.

Examination of allergic purpura nephritis in children

Urine check

Mainly for hematuria and/or proteinuria, mostly low selectivity, such as interstitial tubule damage, small molecule proteins such as RBP, 2 microglobulin, lysozyme, etc. may increase.

2. Blood test

Both blood routine and coagulation tests can be normal, platelet count and functional tests are normal, ESR is elevated, blood biochemistry and renal function can be normal due to different clinical manifestations, or corresponding abnormal changes occur.

3. Blood special examination

Blood complement C3, C4 are normal, early IgA can be elevated, and IgA rheumatoid factor can be detected. Others such as IgG, IgE can be increased or normal, and some patients are positive for immune complex.

4. Pathological examination

Common mesenteric hyperplasia, severe diffuse proliferation and crescent formation, immunofluorescence is characterized by IgA granule-like deposition in the mesangial area, and skin biopsy is helpful in identifying nephritis other than IgA nephropathy.

5. Capillary fragility test: About half of them are positive, others should be B-ultrasound, X-ray and other tests, if necessary, do ECG, CT and other tests.

Diagnosis and differential diagnosis of allergic purpura nephritis in children

diagnosis

The diagnosis of allergic purpuric nephritis is mainly based on hemorrhagic rash and kidney damage. A typical rash is helpful in the diagnosis of this disease. If the rash is sparse or the rash has subsided when kidney symptoms appear, the medical history (including joint and gastrointestinal symptoms) and rash morphology should be investigated in detail. For the appearance of typical renal symptoms, such as edema, hypertension, hematuria, proteinuria, nephrotic syndrome and renal insufficiency, the diagnosis is easier. For mild urine changes, the urine protein (+) and urinary red blood cells in China are generally more than 5 /Hp, or 2 ~ 3 / Hp as a diagnostic criteria. Acute capillary fragility test is positive, and platelet count and functional test are normal, which has certain reference significance for the diagnosis of this disease. Renal biopsy can help diagnose the disease and help to understand the extent of the disease and assess the prognosis. Skin biopsy helps to differentiate from nephritis outside of IgA nephropathy.

The basic pathological changes of allergic purpuric nephritis are glomerular mesangial hyperplasia and mesangial area immunoglobulin (IgA) deposition. Severe fashion has crescent formation and tubular necrosis. The pathological changes vary greatly. International pediatric kidney The disease research will classify allergic purpuric nephritis into 6 types according to the changes of glomeruli under light microscope:

1, I glomerular ball slightly changed.

2, II simple mesangial hyperplasia, without focal changes of capillary vasospasm and crescent. (1) IIa: focal segmental mesangial hyperplasia. (2) IIb: diffuse mesangial hyperplasia.

3, III mesangial hyperplasia and focal changes (thrombosis, necrosis, crescent, sclerosis). (1) IIIa: focal changes. (2) IIIb: The crescent appears, but <50%.

4, IV mesangial hyperplasia, 50% ~ 75% of glomeruli have crescent or focal changes. (1) IVa: focal lesions. (2) IVb: Crescent body 50% to 75.

5, V> 75% glomerular with crescent or focal lesions. (1) Va: focal lesions. (2) Vb: Crescent body.

6, VI membrane proliferative glomerulonephritis.

Differential diagnosis

When the clinical manifestations are not typical, it should be differentiated from acute glomerulonephritis, IgA nephropathy, lupus nephritis and acute interstitial nephritis.

Acute glomerulonephritis

Primary acute glomerulonephritis is the first time in the kidney that the immune injury is caused by sudden hematuria, proteinuria, edema, hypertension, and/or oliguria and azotemia. Acute nephritic syndrome. Light is edema of the eyelids or mild edema of the lower extremities. In severe cases, chest and ascites may occur, and systemic edema may occur. More with light, moderate blood pressure increased. The proteinuria is light and heavy (1~3g/d). There are microscopic hematuria. The red blood cells are pleomorphic and diverse. Sometimes, red blood cell casts, granular casts and renal tubular epithelial cells can be seen. Urinary fibrin degradation products (FDP) can be positive. Blood urea nitrogen and creatinine may increase transiently, serum total complement (CH50) and C3 decrease, return to normal within more than 8 weeks, and serum anti-streptolysin "O" titer may increase.

IgA nephropathy

In children with allergic purpura nephritis and IgA nephropathy, although the immune pathogenesis is similar, there is a clear clinical difference. IgA nephropathy lacks extrarenal manifestations of HSP nephritis. Allergic purpura nephritis in children is an acute onset process, the clinical manifestations are different, the course of disease is shorter, and the degree of renal damage depends on the number of glomerular crescents. IgA nephropathy is chronic and persistent, and it is easy to develop into renal insufficiency. The formation of crescent is not obvious, and segmental glomerular sclerosis is more prominent.

Lupus nephritis

Lupus nephritis (Ipusnephretis (LN)) Overview Lupus nephritis refers to a systemic lupus erythematosus with immunopathic damage of different pathological types of the kidneys, accompanied by a clinical manifestation of significant renal damage. Its clinical manifestations are complicated. Except for common rash, joint pain, fever, photophobia, hair loss and multiple organ or system damage, kidney damage is more prominent, manifested as hematuria, proteinuria, edema, hypertension, and renal dysfunction.

Acute interstitial nephritis

Acute tubulointerstitial nephritis is a syndrome caused by multiple causes of renal interstitial inflammation and edema, inflammatory cell infiltration, renal tubular degeneration with renal insufficiency, and habitually referred to as acute Qualitative nephritis. Clinical manifestations vary in severity. The incubation period is 2 to 44 days, with an average of 15 days. Often have fever, rash, joint pain and low back pain. 80% of patients had elevated peripheral blood eosinophils, but it was short-lived. 95% of patients have hematuria, of which about 1/3 are gross hematuria; some patients may have aseptic pyuria, and a few patients may have eosinophilic urine. The amount of proteinuria is often light to moderate. 20% to 50% of patients may have oliguria or no urine, may be associated with varying degrees of nitrogen retention, about 1/3 of patients with severe uremia symptoms.

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