Serum anti-GBM antibody positive

Introduction Pulmonary hemorrhagic-nephritis syndrome, also known as anti-base glomerulonephritis, Goodpasture syndrome or Goodpasture disease, may be caused by viral infection and/or inhalation of certain chemical substances. It is a serious damage of the glomerular and alveolar wall basement membrane caused by anti-base membrane antibody, clinical manifestations of pulmonary hemorrhage, rapid glomerulonephritis and serum anti-glomerular basement membrane (GBM) antibody-positive triad. Most patients progress rapidly and the prognosis is dangerous.

Cause

Serum anti-GBM antibody positive cause

The exact cause is unclear and may be the result of a combination of multiple causes. It is generally considered to be related to the following factors:

1. Infection: Respiratory infections, especially with influenza virus infection, are the most common cause of this disease. Recent studies have found that patients with acquired immunodeficiency disease are infected with Pneumocystis Carinii Pneumonia, and the body is prone to produce anti-GBM antibodies. Calderon et al reported that 3 of 4 HIV-infected patients were positive for anti-type IV collagen 3 chain antibody (anti-GBM antibody), suggesting that alveolar damage can induce pulmonary hemorrhagic-nephritis syndrome in Pneumocystis carinii pneumonia.

2. Contact with gasoline vapor, hydroxylate, turpentine and inhalation of various hydrocarbons.

3. Inhalation of cocaine: Perez et al reported that a patient with long-term smoking developed pulmonary hemorrhagic-nephritis syndrome after 3 weeks of cocaine use.

an examination

Related inspection

Ultrasound examination of the kidney

Serum anti-GBM antibody positive test

The disease can occur at any age, but most of the young men between the ages of 20 and 30, the general performance of the patient unless there is a cold, more fever, often fatigue, weakness, weight loss, etc., its clinical characteristics are triad: lung Bleeding, rapid glomerulonephritis and serum anti-GBM antibody positive.

1. Pulmonary hemorrhage: typical patients do not have fever unless they are infected, the most important manifestation of the lungs is hemoptysis. About 49% of patients have hemoptysis as the first symptom, ranging from hemoptysis to massive hemoptysis, severe (especially smokers) Hemoptysis does not stop or even suffocate death, patients with shortness of breath, cough and asthma, difficulty breathing, sometimes chest pain symptoms, lung percussion is voiced, auscultation can smell wet, lung CO uptake rate (Kco) for early and sensitive lung function The indication was changed, and this value decreased in patients with renal failure and pulmonary edema, and this value increased during pulmonary hemorrhage.

General lung symptoms can occur several days, weeks, or years before the kidneys. Pulmonary hemorrhage can be light or severe, or severely life-threatening. Iron deficiency anemia can occur in large or persistent bleeding. Once chest pain occurs, Should pay attention to the exclusion of systemic lupus erythematosus, vasculitis or pulmonary embolism and other lesions, lung X-ray shows diffuse point-like infiltration shadow, scattering from the hilar to the periphery, the lung tip is often clear, hemoptysis and lung infiltration is a lung lesion feature.

2. Renal lesions: The clinical manifestations of renal lesions are diverse. Patients with mild glomerular damage, urine analysis and renal function can be normal. The main clinical manifestations are repeated hemoptysis. Renal biopsy can still show typical anti-basement membrane linear deposition. The immunological characteristics, typical patients with renal dysfunction develop faster, with oliguria or no urine, serum creatinine concentration increased day by day, reaching uremia level within 3 to 4 days; no oliguria, kidney damage is often rapid Development, serum creatinine concentration increased weekly, to uremia within a few months, the majority of patients characterized by progressive renal impairment, according to statistics, 81% of patients developed renal failure within 1 year, normal blood pressure or Mild elevation, urine analysis showed hematuria and proteinuria, often red blood cell cast, a small number of patients with a large number of proteinuria and nephrotic syndrome.

3. Special performance

(1) Pulmonary hemorrhage-nephritis syndrome is transformed into glomerular diseases of other pathological types: Elder et al reported that one patient had typical lung-kidney pathological manifestations and clinical manifestations, renal function remained good, and serum and tissue anti-GBM antibodies were present. Positive, significant iron deficiency anemia, anemia improved after immunosuppressive therapy, serum anti-GBM antibody disappeared, nephrotic syndrome occurred 9 months later, renal biopsy showed membranous nephropathy without anti-GBM antibody intrarenal deposition.

(2) Other pathological types of glomerular disease to pulmonary hemorrhagic-nephritis syndrome: Thitiarchakul reported a case of idiopathic membranous nephropathy, acute deterioration of renal function during the course of the disease, accompanied by hemoptysis, severe hypertension and serum anti-GBM The antibody was positive, and the renal tissue examination showed typical anti-GBM immunopathological manifestations. The use of large doses of hormones, CTX and plasma exchange were ineffective.

(3) Pulmonary hemorrhagic-nephritis syndrome is limited to one lung or kidney: Patron et al reported 1 case of simple pulmonary hemorrhagic-nephritis syndrome, Perez et al reported 1 case of cocaine-induced pulmonary hemorrhagic-nephritis syndrome, only typical kidney Change, alveolar basement membrane without IgG and C3 line-like deposition, other anti-basement membrane antibody binding to the choroid, eyes, ears, even can cause corresponding performance, such as fundus hemorrhage and exudation, the incidence can be as high as 11%, It may be due to the rapid development of high blood pressure.

Differential diagnosis

diagnosis

1. The key to the diagnosis of pulmonary hemorrhagic-nephritis syndrome is to determine whether the body has anti-GBM-alveolar basement membrane autologous immunity process, and the characteristic performance of this process:

(1) Serum anti-GBM antibody is positive.

(2) IgG was deposited in the alveolar and renal basement membranes.

2. The diagnosis of a typical patient is in full compliance with the following triads

(1) Pulmonary hemorrhage, alveolar basement membrane IgG is linearly deposited.

(2) Rapid progressive nephritic syndrome, a large number of crescentic formation of the kidney (extravascular proliferative nephritis), may be associated with capillary necrosis, and GBM has IgG deposition.

(3) Serum anti-GBM antibody is positive.

3. Pulmonary hemorrhage - the diagnosis of nephritis syndrome

(1) Some patients have mild manifestations of lungs and/or kidneys, or two organs are not synchronized, and sometimes the anti-basement autoimmune process occurs only in any organ in the lungs or kidneys.

(2) Anti-GBM nephritis sometimes changes with other types of glomerular diseases (mainly membranous nephropathy) (see clinical manifestations).

(3) Occasionally, autoimmune dysfunction produces non-specific basement membrane antibodies and can cause organ damage other than lung and kidney.

(4) In some cases, if the autoimmune is highly active, a large amount of anti-GBM antibody deposition may occur, and a transient serum anti-GBM antibody may be negative. One patient with typical pulmonary hemorrhagic-nephritis syndrome clinical and pathological findings has been reported. At the same time, with lung damage, serum anti-GBM antibody is negative, he believes that this may be due to a large amount of antibody deposition in the target organs during high activity.

(5) pulmonary hemorrhage-nephritis syndrome and vasculitis coexist, Rydel et al reported a case of 18-year-old male pulmonary hemorrhagic-nephritis syndrome, refractory epilepsy occurred during plasma exchange and cytotoxic drugs, MRI showed Multiple Lacunar Infarcts, cerebrospinal biopsy showed vasculitis, but serum ANCA continued to be negative, after administration of high-dose corticosteroids and cytotoxic drugs, anti-epileptic drugs can be used for symptomatic control, Kalluri et al. 1 patient with nodular pulmonary infiltration and acute renal failure, c-ANCA positive, renal tissue examination showed crescentic and necrotizing nephritis, IgG and C3 in the glomerular line-like deposition, serum with high titer anti-GBM - IgG.

Serum anti-GBM antibody positive confusing symptoms

The main manifestations of pulmonary hemorrhagic-nephritis syndrome are pulmonary and renal syndrome and acute nephritis, so this disease needs to be differentiated from various diseases characterized by these two manifestations.

1. Pulmonary and renal syndrome: Diseases that can cause pulmonary and renal syndrome include a variety of pulmonary hemorrhagic-nephritis syndromes, such as ANCA-associated systemic vasculitis, SLE, and nephritis caused by infection. In addition, hemoptysis can also occur in pulmonary embolism caused by renal vein thrombosis and congestive heart failure caused by end-stage renal failure. Ent et al reported that in 2 children, immune complex deposition caused pulmonary hemorrhage and glomerulonephritis. Hernandez reported that a patient with idiopathic Bronchiolitis Obliterans had a progressive nephritis, and histological examination showed extensive deposition of IgA in both the lung and kidney.

In immune complex nephritis, glomerular capillaries have granular deposits. Electron microscopy shows electron dense substances, serum anti-GBM antibodies are negative, and circulating immune complexes can be positive, which is not difficult to distinguish from pulmonary hemorrhagic-nephritis syndrome.

2. Lupus nephritis: Patients with acute onset nephritis may have symptoms of acute renal failure with pulmonary hemorrhage, which is easily confused with pulmonary hemorrhagic-nephritis syndrome. However, the disease is more common in young women, generally with multiple systemic damage such as skin and joints. Serum immunological examination can help diagnose.

3. Small vasculitis nephritis: This type of disease may have pulmonary hemorrhage and approximate pulmonary hemorrhage-nephritis syndrome. However, the disease is more common in middle-aged and elderly people aged 50-70 years. It has obvious systemic symptoms such as fatigue, hypothermia, and weight loss. Anti-neutrophil ytoplasmic antigens (ANCA) are positive. Among them, Wegener's granulomatosis may be interstitial inflammation, and both may exist at the same time.

In many vasculitis, there are two types of small vasculitis, Wegener granulomatosis and microscopic vasculitis. The target antigens of these two small vasculitis are Proteinase 3 and Myeloperoxidase, respectively. Antibodies (c-ANCA and p-ANCA) are the original sin antigens that cause small vessel damage and have important diagnostic value for small vasculitis. In Wegener granulomatosis and microscopic vasculitis, the upper and lower respiratory tract and kidney are most often involved. Wegener granulation The morphological changes of the swelling are various, and the ulceration changes mainly in the oropharynx, paranasal sinus, trachea, etc., and the granulomatous changes are optional. Therefore, histological examination, especially small biopsy Wegener granulomatosis cannot be easily ruled out. Wegener granulomatosis and microscopic vasculitis can be characterized as focal segmental necrotic glomerulonephritis in the kidney, often accompanied by crescent formation, within the glomerulus. Immunoprecipitation is rare.

4. Acute nephritis with left heart failure: This disease may have blood stasis and dyspnea, similar to pulmonary hemorrhagic-nephritis syndrome, but the disease is more common in adolescent patients. There is a history of streptococcal infection, often due to severe hypertension, water and sodium retention, edema, congestive heart failure. Renal biopsy can be identified.

5. Rapid progressive nephritis: The immune pathogenesis of acute nephritis (Crescent nephritis) In addition to anti-GBM nephritis, immune complex nephritis and cellular immune vasculitis can also cause typical crescentic nephritis and progressive renal failure. .

6. Idiopathic pulmonary hemosiderosis: The hemoptysis, hemosiderin cells and lung X-ray findings of this disease are very similar to pulmonary hemorrhagic-nephritis syndrome. However, this disease occurs mostly in adolescents under the age of 16 with slow progression and good prognosis. Lung and kidney biopsy can help identify.

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