Term
| what is acute tubular interstitial nephritis? |
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Definition
| an inflammatory lesion of the kidney marked by intense accumulation of PMNs, eosinophils, and lymphocytes induced by immunologic injury (often accompanied by rash/fever - can be due to drugs) |
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Term
| what is chronic tubular interstitial nephritis? |
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Definition
| a fibrosis of the renal tubulointerstitium from immunologic or toxic injury (usually has to do with impairment of blood flow for long periods of time - mostly caused by ischemic events) |
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Term
| what are ddxs when considering acute tubulointerstitial nephritis? |
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Definition
| acute tubular necrosis (ATN - ischemic/toxic) or acute glomerulonephritis |
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Term
| what are the causes of acute renal failure and their associated prevalence? |
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Definition
| ATN (45%, ischemic event causing cells to necrose, not necessarily inflammatory), prerenal (21%, kidney is getting less bloodflow and it thus lowers GFR), acute on chronic renal failure (13%, mostly due to ATN and prerenal disease), urinary tract obstruction (10%, think about this w/sudden deterioration of kidney function - check w/ultrasound, happens w/prostate), glomerulonephritis/vasculitis (4%, post-strep, wegners, goodpastures - see lots of glomerular bleeding), and finally acute interstitial nephritis (2% - uncommon) |
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Term
| what is the pathophysiology of renal injury in acute tubular necrosis? |
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Definition
| intact tubular epithelium -> loss of polarity, tight junction integrity, cell-substrate adhesion, simplification of the brush border -> cell death (necrosis/apoptosis) -> sloughing of viable/nonviable cells w/intraluminal cell-cell adhesion -> cast formation/tubular obstruction |
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Term
| what is seen histologically with acute tubular necrosis? |
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Definition
| necrosis and cell sloughing in the tubulointerstitium. denuding of the GBM |
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Term
| how does acute tubulointerstitial nephritis appear histologically? |
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Definition
| the capillary loop is clear, but the interstitium is filled with inflammatory cells. the chronic is scarred in these areas where inflammatory cells were. (think of it as a rash in the kidney) |
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Term
| what is the most important cause of acute tubulointerstitial nephritis? |
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Definition
| drugs, which can form neoantigens: complex of drugs and cell proteins, which mimics antigens in the kidney - which induces an inflammatory allergic response. NSAIDs, including selective COX-2 inhibitors. PCN (including ceph). rifampin. sulfa drugs. cipro, other quinolongs. cimetidine. allopurinol. proton pump inhibitors. 5-aminosalicylates. |
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Term
| what is the only way to be sure that a pt has acute tubulointerstitial nephritis? how is a clinical dx made? |
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Definition
| renal bx - however most of the time this is not realistic to do, given the precarious health of most pts suspected of this. therefore if a pt has severe hypotension, was just put on PCN, a day later, kidney function deteriorates, they get fever, rash, eosinophila - acute tubulointerstitial nephritis is the clinical dx. |
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Term
| what is the most important infection that can lead to acute tubulointerstitial nephritis? other infections? |
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Definition
| most important: legionella, which is a common cause of pneumonia (accompanied by acute renal failure). leptospirosis, CMV (in immune compromised pts), strep, etc |
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Term
| can autoimmune diseases lead to acute tubulointerstitial nephritis? |
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Definition
| yes - sarcoid (usually seen with respiratory issues) can affect the kidneys, also tubulointerstitial nephrotis and uveitis |
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Term
| what is the clinical presentation of acute tubulointerstitial nephritis? |
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Definition
| urinalysis: pyuria, eosinophila (inflammation - this is a very useful determinant). renal function: acute rise in BUN, creatinine. systemic: fever, rash, malaise. |
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Term
| what is tx for acute tubulointerstitial nephritis? |
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Definition
| remove inciting agent, monitor and consider anti-inflammatories or immunosuppressives (steroids can be very helpful) |
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Term
| how is chronic tubulointerstitial nephritis separated from acute tubulointerstitial nephritis? |
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Definition
| the chronic is not inflammatory, rather it is mainly an ischemic process |
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Term
| what is the spectrum of pathologic findings in chronic renal failure? |
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Definition
| chronic interstitial nephritis: 75% (HTN, chronic ischemia - DM, toxic nephropathies - lead), glomerulonephritis: 15%. cystic disease: 10% |
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Term
| what is thyroidization of the kidney? |
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Definition
| a name for the histologic appearance of chronic fibrosing tububulointerstitial nephropathy - large dilated tubules w/colloid material in them, also scarring |
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Term
| how does chronic tubulointerstitial nephritis associate with renal failure in general? |
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Definition
| chronic tubulointerstitial nephritis as a pathologic entity is a final common pathway for a number of, if not all, disorders causing renal failure. however, it may represent a specific series of disorders originating with a toxic, metabolic, or immune injury to the renal tubules and interstitium |
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Term
| what is the mechanism of renal fibrosis? |
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Definition
| tubular injury leading to recruitment/activation of fibroblasts and epithelial-mesenchymal transformation (tubular cells transforming into fibroblasts) |
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Term
| what is the how is the kidney affected clinically by chronic tubulointerstitial nephritis? |
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Definition
| declining GFR, loss of tubular functions. decreased NH4 (ammonia) production: acidosis. decreased EPO: anemia. disordered medulla: polyuria. decreased vit D activation: osteodystrophy. |
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Term
| what the clinical presentation of chronic tubulointerstitial nephritis? |
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Definition
| slowly developing uremia, minimal proteinuria (glomeruli can be intact, mainly involves interstitium), HTN (due to RAA activation), and chronic anemia |
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Term
| what are the main causes for chronic tubulointerstitial nephritis? |
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Definition
| chronic reflux nephropathy (defect in ability to empty bladders), heavy metal poisoning, analgesic abuse, chronic ischemic nephropathy, and the final common pathway for ESRD etiologies (DM, HTN, chronic hypoxia/ischemia) |
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Term
| do UTIs/pyelonephritis cause chronic tubulointerstitial nephritis? |
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Definition
| no, as long as there is no obstruction or foreign bodies |
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Term
| what is an important cause of chronic renal failure? |
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Definition
| cystic diseases (10% of pts in dialysis units) such as adult polycystic kidney disease (PKD) |
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Term
| what is the etiology of PKD? |
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Definition
| it has a genetic locus - chr 16 + 2 other loci. there is an association with genes for cilia, which are important mechanotransducers. the theory is that every cell has this genetic defect, however not every cell develops into a cyst - therefore it is a 2-hit disease dependent on other mutations. these pts are at risk of developing problems with cilia systemically, aneurysms are a risk - particularly in the brain |
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Term
| what is the pathogenesis of PKD? |
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Definition
| altered tubular development, altered cellular development, altered membrane protein insertion -> all due to crowding from cysts |
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Term
| what is the pathogenesis of analgesic abuse leading to nephropathy? |
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Definition
| no proteinuria (glomerulus normal), bland urinalysis, and renal biopsy showed chronic fibrosis (looked like ischemic effect in interstitium), necrosis of the papilla (very bottom part of the kidney that empties into the calyx) - ultimately the papilla slip out and deposit in the collecting system (looked like stones) |
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Term
| what is the problem with chronic interstitial nephritis tx? |
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Definition
| nothing works once the disease is present |
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