Pathoma - Kidney and Urinary Tract Flashcards
Horseshoe kidney is caused by fusion of the kidneys where?
The lower pole
How does fusion of the kidneys at the lower pole affect its development?
Kidneys will be abnormally located in the lower abdomen due to the horseshoe kidney getting caught on the inferior mesenteric artery
Bilateral renal agenesis will lead to what?
Oligohydramnios - leading to lung hypoplasia, flat face with low set ears (Potter’s sequence)
What are the characteristics of a dysplastic kidney?
Noninherited - congenital malformation in the renal parenchyma characterized by cysts - tends to be unilateral
What are the basic principles of PKD?
Inherited defect leading to bilateral enlarged kidneys with cysts in the renal cortex and medulla
Autosomal recessive PKD is characterized by?
Presenting in infants as worsening renal failure and hypertension - congenital hepatic fibrosis and hepatic cysts
ADPKD is characterized by?
Presenting in young adults as hypertension - HTN (increased renin), hematuria, and worsening renal failure ADPKD mutation
What is the hallmark associated with acute renal failure?
Azotemia - increased BUN and Creatinine often with oliguria
Prerenal azotemia is due to what?
Decreased blood flow to the kidneys
Decreased blood flow to the kidneys will do what to the GFR?
Decrease GFR leading to azotemia and oliguria
In prerenal kidney injury, what causes the elevation of the BUN:Cr ratio?
Decreased blood flow results in increased aldosterone
Aldosterone leads to increased H2O reabsorption
BUN is reabsorbed with H2O
How does prerenal injury affect the FENa and urine osmo?
Tubular function remains intact and urine osmo is within normal limits
What is postrenal kiney injury?
Decreased outflow results in decreased GFR, azotemia, and oliguria
During the early stages of post renal azotemia, what happens to BUN:Cr, FENa, and urine osmo?
Increased back pressure leads to increased BUN forced into reabsorption
Tubular function is intact leading to normal FENa and urine osmo
Long standing post renal obstruction will due what to the BUN:Cr?
With long standing obstruction there will be damage to the epithelium leading to a decrease in the amount of BUN that can be reabsorbed. Decrease BUN:Cr.
Damage to epithelium will also lead to a decrease in Na reabsorption and increase FENa and an inability to concentrate urine
What is acute tubular necrosis?
Injury and necrosis of tubular epithelial cells
What are the key urinary finding associated with acute tubular necrosis? Why do these occur?
Brown granular casts
Caused by epithelium “slouging off” and forming a cast within the tubulum
Dysfunctional tubular epithelium associated with acute tubular necrosis leads to what?
Decreased reabsorption of BUN due to damage to epithelium
Decreased reabsorption of Na leading to increased FENa and the inability to concentrate urine
How can ischemia lead to ATN?
Decreased blood supply leads to necrosis of the proximal tubule and think ascending limb
What are the clinical features of ATN?
Oliguria with brown granular casts
Elevated BUN and creatinine but ratio less than 15
Hyperkalemia due to decreased renal excretion
Metabolic acidosis
What are the characterisitcs associated with acute interstitial nephritis?
Drug induced hypersensitivity leading to intrarenal azotemia
Eosinophils may be found in the urine
What is this an image of?
Acute tubular necrosis
What is this an image of?
Foot process effacement associated with minimal change dz
What is the main characteristic of nephrotic syndrome?
Proteinuria > 3.5g/day
Why does can nephrotic syndrome lead to:
Pitting edema
Increased risk of infection
Fatty cast in urine
Increased risk of blood clots
Pitting edema - loss of albumin leading to decreased oncotic pressure, and fluid staying in the tissue
Risk of infection - loss of gammaglobulin
Fatty casts - Hyperlipidemia and cholesteremia from the liver
Clots - loss of AT3 in the urine
Who is minimal change disease most likely to affect?
This is the most common cause of nephrotic syndrome in children
How would minimal change dz appear on light micro?
Normal glomeruli with H&E staining
Minimal change disease will show what on electron microscopy?
Foot process effacement (flattening of the podocyte)
How will minimal change disease show up on IF?
No immune complex deposition leading to negative IF
Who is most commonly affected by Focal Segemental Glomerulosclerosis?
Hispanics and African Americans
FSGS can be associated with what?
HIV, heroin use and sickle cell disease
How will FSGS show up on light micro?
Focal and segemental glomerulosclerosis
How will FSGS show up on EM
Foot process effacement
How will FSGS show up on IF?
No immune complex
What are some associations of membranous nephropathy?
Caucasian adults, Hep B or C, SLE or drugs
How will membranous nephropathy show up on light micro?
Thick basement membrane
How will membranous nephropathy show up on EM and IF?
IF - granular deposits due to immune complex deposition
EM - spike and dome appearance due to subepithelial deposits
Membranoproliferative glomerularnephritis will tend to have what appearance on H&E?
Thick glomerular basement membrane yielding tram track appearance
Due to immune complex deposition
What are the two types of MPGN?
Type 1 - subendothelial associated with HBV and HCV
Type II - C3 autoantibody that stabilized C3 convertase leading to overactivation of complement, inflammation and decreased circulating C3
What is the initial event in diabetes leading to nephrotic syndrome?
Elevated serum glucose leads to non-enzymatic glycosylation of vascular basement membrane and hyaline arteriosclerosis
What is the most affected region of the kidney in diabetes?
Efferent arteriole leading to increased glomerular filtration pressure
What causes the Kimmelstiel-Wilson nodules in DM?
Sclerosis of the mesangium
What is the hallmark of amyloidosis?
Green-apple birefringence under congo red staining
What are the basic principles of Nephritic Syndrome?
Glomerular inflammation and bleeding leading to RBC casts and dysmorphic RBCs in Urine
Periorbital edema
HTN
Oliguria and Azotemia
Biopsy will reveal hypercellular and inflamed glomeruli
Why are there neutrophils in glomerulus during nephritic syndrome?
Immune complex deposition leads to activation of complement. C5a will attract neutrophils which mediate damage
What are the important characteristics of Post-strep glomerulonephritis?
2-3 wks after infection
Cola colored urine (Hematuria)
What is the IF and EM findings on PSGN?
Sub-epithelial humps on EM
Granular IF
What are the characteristics of RPGN?
Crescents in the Bowman’s space that are comprised of fibrin and macrophages
What 5 diseases can lead to RPGN?
Goodpastures
PSGN
Diffuse proliferative
c-ANCA
p-ANCA
How will Goodpasture’s present on IF?
Linear deposits on the GBM
What causes the linear deposition associated with Goodpastures?
auto-Ab against collagen in the BM of the glomeruli
What are two key clinical symptoms of goodpasture’s?
Hemoptysis and hematuria
What is the cause of diffuse proliferative GN presentation?
Due to diffuse antigen-antibody complex deposition - usually sub-endothelial and most commonly associated with SLE presenting as Nephritic syndrome
Granular IF pattern due to subendothelial immune complex deposition
A negative IF in a patient with RPGN will make a physician think?
ANCA associated RPGN
How can you distinguish Wegener’s from Goodpasture’s?
c-ANCA - Wegener’s - will present with nasopharyngeal, lung and kidney problems
Goodpastures - Lung and kidney
How can you distinguish the two p-ANCA diseases?
Churg-Strauss - Allergic reaction, granulomatous inflammation
Microscopic polyangiitis - Does have that
IgA nephropathy (Berger Disease) will present as what?
IgA complex deposition in mesangium leading to mesangial proliferation
Why will IgA nephropathy present the way it does?
IgA immune complex deposition will lead to hematuria
IgA deposition will occur post mucosal infection
What are the characteristics of Alport’s Syndrome?
Inherited defect in type IV collagen (X-linked)
Thinning of the BM
What are the classic symptoms of Alport Syndrome?
Isolated hematuria, sensory hearing loss, and ocular disturbances
What is the main result of chronic pyleonephritis?
Interstitial fibrosis and atrophy of tubules due to multiple bouts of acute pyelonephritis
What is a major morphological change associated with Chronic pyleonephritis?
Thyroidization of the Kidney
What is the most common cause of clacium oxalate/calcium phosphate kidney stones?
Idiopathic hypercalcuria
What is the cause of ammonium magnesium phosphate kidney stones?
Urease-positive organisms - leading to alkaline urine and formation of a stone
Angiomyolipoma is comprised of what?
Blood vessels, smooth muscle, and adipose tissue
RCC can present with involvement of what?
The left renal vein which can lead to blockage of the left spermatic vein
What is the pathogenesis of RCC?
Loss of VHL gene leading to increased IGF-1, HIF (increasing VEGF and PDGF)
Wilms Tumor is most common in who and presents with what?
Most common malignant renal tumor in children, comprised of blastema (immature kidney mesenchyme)
Presents with Hematuria and hypertension due to renin secretion
What is WAGR syndrome?
Common syndrome associated with WT1 mutation
W - Wilms tumor
A - Aniridia
G - Genital abnormalities
R - Mental and growth retardation
What are the major risk factors for Urothelial (transitional cell) carcinoma
Smoking
Papillary Urothelial cell carcinoma tend to be associated with?
p53 mutations
Squamous cell carcinoma is most common associated with?
Bacterial infection with Schistosoma haematobium infection (Egyptian male)
