Interstitial renal damage, also known as tubulointerstitial nephritis, is a clinicopathologic syndrome of acute and chronic tubulointerstitial damage caused by various causes. It is often clinically divided into acute interstitial nephritis and chronic interstitial nephritis. Acute interstitial nephritis is characterized by inflammatory cell infiltration, interstitial edema, and varying degrees of tubular damage with renal insufficiency occurring within a short period of time due to a variety of causes, and the clinical manifestations can be mild or severe. The main features of chronic interstitial nephritis pathology are interstitial fibrosis, interstitial single nucleated cell infiltration and tubular atrophy. 1. Infections Pathogenic infections can be bacterial, fungal and viral infections of pathogenic microorganisms, including Staphylococcus aureus sepsis, severe streptococcal infection, diphtheria, fishy red fever, mycoplasma pneumonia, syphilis, brucellosis, legionellosis, hepatitis B virus antigenemia, cytomegalovirus infection, typhoid fever, measles, pyelonephritis, etc. 2. Systemic diseases such as systemic lupus erythematosus, dry syndrome, nodular disease, primary cryoglobulinemia. Hematological system diseases, such as multiple myeloma, paroxysmal hemoglobinuria, lymphoproliferative disorders, sickle cell disease, etc. 3.Drug pathogenesis May be associated with long-term application of cyclosporine, aminoglycoside antibiotics, amphotericin B, analgesics, non-steroidal anti-inflammatory drugs, cisplatin, etc. 4, heavy metal salts May be related to long-term exposure such as cadmium, lithium, aluminum, gold, beryllium, etc. 5.Chemical poison or biotoxin Such as carbon tetrachloride, tetrachloroethylene, methanol, ethylene glycol, coal phenol, nitrosourea or history of poisoning by snake venom, fish bile venom, bee venom, mycotoxin, etc. 6, metabolic diseases such as cystinosis, hypokalemic nephropathy, uric acid nephropathy, diabetic nephropathy and history of amyloid nephropathy.