Pathoma-Renal Flashcards
Horseshoe Kidney
Kidney develops in pelvis then ascends to abdomen ** Gets caught on IMA
Renal agenesis (Potter sequence)
Absence of kidney formation ** Unilateral or bilateral ** Unilateral - kidney lacking one kidney, so existing kidney undergoes hypertrophy; becomes problem down the line with hyperifltration injury ** Bilateral - oligohydramnios. Consequence of this is lung hypoplasia (baby in womb is breathing in and out amniotic fluid… stretching and collapsing allows for development of lung to occur); flat face w/ low set ears; developmental defects of extremities
Dysplastic Kidney
noninherited, congenital malformation of renal parenchyma characterized by cysts and abnormal tissue (e.g. cartilage) ** Must be distinguished from inherited PCKD
PCKD
Inherited defect ** Bilateral enlargement of kidneys ** Cysts in renal cortex and medulla
Autosomal recessive PCKD
Classically juvenile form ** Presents with renal failure and HTN ** Newborns can present with Potter sequence ** Associated with congenital hepatic fibrosis and hepatic cysts (think ab this when have baby with portal hypertension)
Autosomal dominant PCKD
- young ADults ** - defect in Adult Polycystic Kidney Disease 1 or 2 ** - HTN, hematuria, or worsening renal failure ** - Increased plasma renin ** - Associated w/ berry aneurysm, hepatic cysts and mitral valve prolapse ** - Cysts in brain (cystic dilatations from berry aneurysms), cysts in liver and cysts in kidney
Medullary Cystic Kidney Disease
Inherited defect ** Cysts in kidney ** But cysts in medullary collecting ducts ** Shrunken kidneys ** PCKD - have large kidneys ** In this dz, kidneys are shrunken and kids present with worsening renal failure
Acute Renal Failure
Hallmark is azotemia (increase in BUN and creatinine) and often with oliguria ** Pre renal, post renal, intra renal
Pre renal azotemia
Decrease blood flow ** Results in: ** decreased GFR, azotemia, oliguria ** Both BUN and creatinine rise, but if BUN:Cr > 15 can help w diagnosis ** - Creatinine does not have ability like BUN to be resorbed ** - With low BF, RAAS activated and adlosterone causes absorption of sodium, leading to absorption of water, leading to absorption of BUN out of tubule, leading to B:C > 15 ** - Tubular function remains intact so FENa remains < 1% ** - Urine osm > 500 indicating kidney able to fxn and resorb sodium
Post renal azotemia
Output obstruction causing back pressure ** Backpressure decreases GFR because can’t filter as much ** Early stages: Increased tubular pressure forces BUN into blood increasing BUN:Cr > 15 ** Tubular function remains intact in early stage so FENa < 1% and urine osmolality >500 ** Long standing: Decreased reabsorption of BUN so BUN:Cr < 15 because tubule epithelial damaged ** Ability to reabsorb sodium is damaged so FENa > 2% and urine osmolality is <500
Intrarenal azotemia
Problems within kidney ** 1. Acute tubular necrosis
ATN
Injury and necrosis of tubular epithelial cells; most common cause of ARF ** Necrotic cells plug tubules; obstruction decreases GFR ** Brown, tubular casts seen in urine ** Intrarenal azotemia created
Ischemic ATN
Proximal tubule and thick ascending limb are particularly susceptible b/c require most energy
Nephrotoxic ATN
Proximal tubule is most susceptible ** Causes: ** Aminoglycosides ** Heavy metals (lead) ** Myoglobinuria (crush injury) ** Ethylene glycol (antifreeze) - can also see crystals in urine ** Radiocontrast dye ** Urate - can happen with tumor lysis syndrome; hydrate patients and use allopurinol to prevent accumulation of uric acid
Clinical features of ATN
Oliguria with brown, granular casts ** Elevated BUN and creatinine ** Hyperkalemia with metabolic acidosis - due to decreased renal excretion of potassium ** associated with increased anion gap
Acute interstitial nephritis
Hypersensitivity reaction ** Renal papillae necrosis ** Causes: ** chronic analgesic abuse ** DM ** Sickle cell traite ** Severe acute pyelonephritis
MCD
Only protein loss is albumin ** Excellent response to steroids (b/c damage is mediated by cytokines from T cells… can be caused by Hodgkin b/c of R-S cells)
Focal Segmental Glomerular Sclerosis
Most common in hispanics and AA ** Associated with HIV, heroin use, and sickle cell disease ** If patient with minimal change disease given steroids and progress instead of get better, progresses to FSGS ** negative IF also (not driven by immune complex deposition)
Membranous nephropathy
Most common nephrotic syndrome in Caucasian adults ** May be associated w/ hep B or C, solid tumors, SLE, or drugs ** If lupus patients have nephrotic syndrome, they have membranous nephropathy ** Key finding - thick glomerular basement membrane on H and E ** Thickening of membrane due to immune complex deposition ** Deposition at level of podocyte - sub epithelial ** Detected by IF ** Podocyte will try to lay down extra BM and get spike and dome appearance on EM
Membranoproliferative Glomerulonephritis
- thick capillary on H and E (due to immune complex deposition… graunlar IF) ** - mesangial cell holding capillary loops will have increased cytoplasm, separating deposit and creating tram track deposit ** - Immune complex can be under endothelium or in basement membrane ** Mesangial cell proliferates cytoplasm and cuts through middle of deposit, separating deposit into tram track appearance
Types of MPGN
Type I - subendothelial (under endothelial); associated with HBV and HCV; more often associated with formation of tram tracks ** Type II - deposition of immunocomplexes in basement membrane; associated with C3 nephritic factor (stabilizes C3 converstase leading to overactivation of complement causing inflammation and causing this disorder)
C3
- C3 –> C3a + C3b via C3convertase ** - Type II MPGN has immunglobulin that stabilizes C3 convertase so it’s not broken down as fast ** This leads to overactivation of complement so get decrease serum C3
Membranotype diseases
Always have immune complex deposits ** In 1 of 3 locations ** - Membranous glomerulonephropathy: subepithelium ** - TI MPGN: Sub endothelium ** - TII MPGN: In basement membrane ** Get granular on IF
Six types nephrotic syndrome
- MCD ** - FSGN ** - MEMG ** - MPGN (two types) ** - DM ** -
