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NP26 Nephrology
Parenchymal Kidney Diseases Toronto Notes 2019
Clinical Features
• AKI
• ifhypersensitivityreaction(commonwithantibiotics):mayseefever,skinrash,arthralgia,serum
sickness-like syndrome (particularly rifampin)
• ifpyelonephritis:flankpainandcostovertebralangle(CVA)tenderness
• ifdrugreaction,AKIusuallyoccurs7-10dafterexposure
• othersignsandsymptomsbasedonunderlyingetiology
• HTNandedemaareuncommon
Findings
• urine
■ mild, non-nephrotic range proteinuria and microscopic hematuria ■ sterile pyuria, WBC casts
■ eosinophils if AIN
• bloodwork
■ increased Cr and urea
■ eosinophilia if drug reaction (high negative predictive value, common in beta-lactam reactions) ■ normal AG metabolic acidosis (RTA)
■ hypophosphatemia, hypo- OR hyperkalemia, hyponatremia
• galliumscanoftenshowsintensesignalduetoinflammatoryinfiltrate
• renalbiopsydefinitive–showsinterstitialinfiltratesandedemaonbiopsy
Treatment
• treatunderlyingcause(e.g.stopoffendingmedications,antibioticsifpyelonephritis) • corticosteroids(maybeindicatedinallergicorimmunedisease)
Prognosis
• recoverywithin2wkifunderlyinginsultcanbeeliminated
• thelongerthepatientisinrenalfailure,thelesslikelytheywillhaveafullrenalrecovery
2 . CHRONIC TUBULOINTERSTITIAL NEPHRITIS
Definition
• characterizedbyslowlyprogressiverenalfailure,moderateproteinuria,andsignsofabnormaltubule function
Etiology
• persistenceorprogressionofacuteTIN
■ may also involve concurrent glomerular involvement
• urinarytractobstruction:mostimportantcauseofchronicTIN(tumours,stones,bladderoutlet obstruction, vesicoureteral reflux)
• chronicpyelonephritisduetovesicoureteralrefluxorUTIwithobstruction
• nephrotoxins
■ exogenous
◆ analgesics: NSAIDs (common), acetaminophen
◆ cisplatin, lithium, cyclosporine, tacrolimus
◆ heavy metals (lead, cadmium, copper, lithium, mercury, arsenic) ◆ Chinese herbs (aristolochic acid)
■ endogenous
◆ hypercalcemia, hypokalemia, oxalate, uric acid
• vasculardisease:ischemicnephrosclerosis,atheroembolicdisease
• malignancies:multiplemyeloma,lymphoma
• granulomatous:TB,sarcoidosis,granulomatosiswithpolyangiitis
• immune:SLE,Sjögren’s,cryoglobulinemia,Anti-GBMDisease,amyloidosis,renalgraftrejection,
vasculitis
• hereditary:cysticdiseasesofthekidney,sicklecelldisease
• others:radiation,Balkan(endemic)nephropathy
Pathophysiology
• fibrosisofinterstitiumwithatrophyoftubules,mononuclearcellinflammation
Signs and Symptoms
• dependentonunderlyingetiology
Findings
• normalAGmetabolicacidosis
• hyperkalemia(outofproportiontodegreeofrenalinsufficiency)
• polyuria, nocturia
• partialorcompleteFanconi’ssyndrome
• progressiverenalfailurewithazotemiaanduremia
• urine:mildproteinuria,fewRBCsandWBCs,noRBCcasts
• U/S:shrunkenkidneyswithirregularcontours(differentiatesacutefromchronicetiology)