Department of Nephrology, Peking Union Medical College Hospital
Acute interstitial nephritis (AIN) is a group of kidney diseases characterized by acute tubular interstitial inflammationrenal failureThe glomerulus and renal vessels are generally not affected or are relatively slightly affected.In the cases of acute renal failure, acute interstitial nephritis accounts for 10%~20%.
Foreign name
acute interstitial nephritis,AIN
Alias
Acute tubular interstitial nephritis
Visiting department
Department of Nephrology
Common causes
Drug allergy, infection related, acute rejection of kidney transplantation, concomitant systemic diseases, etc
The causes of acute interstitial nephritis are various, includingDrug allergy, infection relatedrenal transplantAcute rejection, concomitant systemic diseases, etc;In addition, the etiology of idiopathic acute interstitial nephritis is not completely clear, but it has been clear that some of its pathogenesis is related to viral infection.
one
There are more than 100 drugs that may cause acute interstitial nephritis, and antibiotics account for more than half of the pathogenic drugs, among which - lactam antibiotics (such as penicillin family, cephalosporin family, etc.) are the most common.
two
The AIN associated with systemic infection is called infection related AIN. Generally, there is no evidence of direct kidney infection.Pathogenic microorganisms that can cause infection related AIN include bacteria (LegionellaTyphoid bacillusEtc.), virus（Hantavirus、EB virus、Cytomegalovirus）Mycoplasma（mycoplasma pneumoniae ）Chlamydia, Rickettsia, Spirochaeta（Treponema pallidum、Leptospira）, parasites, etc.
three
The etiology of idiopathic AIN is unclear, and about 1/3 of the patients are complicated with anterior uveitis, also known as tubulointerstitialnephritis-Ochromatitis syndrome.
four
Multiple systemic diseases such as systemic diseasesLupus erythematosus、Sjogren's syndromeAll kinds of immunoglobulin diseases can be accompanied by AIN. Malignant tumors can cause AIN due to immune reaction induced by tumor antigen.partrenal transplantThe acute rejection reaction is also related to the pathogenesis of immune reaction.
clinical manifestation
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Acute interstitial nephritis often accompanied by systemic anaphylaxis, which is mainly seen in AIN caused by drug allergy. It can be manifested as skin rash, fever, and increased eosinophil count in peripheral blood. Some cases can also have arthralgia, lymphadenopathy, etc.The specific expression of idiopathic AIN is recurrent“Red eye disease”The patient may be accompanied by fever, rash, myositis or fatigue, anorexia, weight loss and other symptoms of varying degrees, and granulomatous lesions of bone marrow and lymph nodes can be seen in some patients.
The manifestations of AIN renal damage are mainly rapidacute renal failure (oliguria or non oliguria).
inspect
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1. Serum creatinine and urea nitrogen can be seen to increase.Urine abnormalities includehematuria, leucocynuria and proteinuria (mostly mild proteinuria, mainly low-molecular-weight proteinuria).Leukonuria is usually sterile leucocyanuria, sometimes eosinophilic leucocyte can be found, occasionally leucocyte tube type can be seen.It is often accompanied by obvious impairment of renal tubular functionRenal glycosuriaLow osmolality urine, sometimes with distal or renal tubulesAcidosis, occasionallyFanconi syndrome(diabetes, amino acid urine, phosphate urine, uric acid urine, etc.).
A few patients had elevated IgE or positive anti TBM antibody in serological examination.Patients with idiopathic AIN may haveanemia, rapid erythrocyte sedimentation rate, positive C-reactive protein and increased γ - globulin during protein electrophoresis.
2. Imaging (B ultrasound, etc.) examination often found that the patient's bilateral kidney volume was increased or normal.
diagnosis
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Typical drug allergic AIN cases can be clinically diagnosed according to the recent medication history, drug allergy performance, abnormal urine test and rapid deterioration of renal function (significant renal tubular dysfunction).The diagnosis of atypical cases must rely on pathological examination of renal biopsy.
The diagnosis of this disease depends on renal biopsy pathology.The typical pathological changes examined by light microscopy are renal interstitial edema, diffuse infiltration of lymphocytes and monocytes, and eosinophilic leukocyte infiltration in varying numbers. Sometimes scattered epithelial granulomas can be seen.The epithelial cells of renal tubules showed degeneration, while the glomeruli and renal vessels were normal.Immunofluorescence test is generally negative, but linear deposition of IgG and C3 along glomerular basement membrane can be seen in patients caused by methicillin.Under electron microscope, foot process fusion of glomerular visceral epithelial cells can be seen in some cases caused by NSAIDs.
treatment
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The goal of treatment of acute interstitial nephritis is to remove the cause, promote the recovery of renal function and prevent complications.
Etiological treatment: different causes of acute interstitial nephritis should be treated accordingly.Once the clinical diagnosis of drug allergy AIN is established, the suspected pathogenic drugs should be stopped immediately.If the pathogenic drugs cannot be determined, all suspicious drugs shall be stopped in time.For acute interstitial nephritis caused by other reasons, targeted treatment can be carried out for different situations, such as treatment of infection and treatment of primary disease.
At the same time, support and symptomatic treatment should be given to maintain the balance of water, electrolyte and acid-base, as well as strengthen nutritional support, and reasonably give protein, calories, vitamins, etc.
In the early and middle stages of AIN, glucocorticoid therapy can be given.Relevant studies have confirmed that 4-6 weeks of corticosteroid treatment can accelerate the recovery of renal function in patients with drug allergic AIN, especially in patients with diffuse inflammatory cell infiltration in renal interstitium, rapid deterioration of renal function, or patients with granulomatous interstitial nephritis.Generally, prednisone can be taken orally, and the dosage will be gradually reduced when the disease gets better. Most of them can be stopped after 4-6 weeks, usually not more than 3 months.In the case of serious renal interstitial disease, accompanied by granuloma and rapid deterioration of renal function, intravenous methylprednisolone pulse therapy can be considered.Idiopathic AIN is also an indication of glucocorticoid treatment. Hormone treatment can not only promote the recovery of renal function, prevent or reduce renal interstitial fibrosis, but also improve the uveitis.
When severe acute renal failure (especially oliguria) has dialysis treatment indications, blood purification treatment should be given as soon as possible, generally hemodialysis. In some special cases, continuous renal replacement therapy (CRRT) can be considered to help patients get through the dangerous period.
prognosis
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If the AIN treatment is timely and effective, the prognosis of most cases is good.The glomerular filtration function usually returns to normal first, and the tubular function can gradually return to normal within a few months.However, the glomerular filtration function of a few severe patients is often difficult to fully recover, and it changes intoChronic renal failure。
