Pathoma - Kidney and Urinary Tract

Question 1

Horseshoe kidney is caused by fusion of the kidneys where?

Answer 1

The lower pole

Question 2

How does fusion of the kidneys at the lower pole affect its development?

Answer 2

Kidneys will be abnormally located in the lower abdomen due to the horseshoe kidney getting caught on the inferior mesenteric artery

Question 3

Bilateral renal agenesis will lead to what?

Answer 3

Oligohydramnios - leading to lung hypoplasia, flat face with low set ears (Potter’s sequence)

Question 4

What are the characteristics of a dysplastic kidney?

Answer 4

Noninherited - congenital malformation in the renal parenchyma characterized by cysts - tends to be unilateral

Question 5

What are the basic principles of PKD?

Answer 5

Inherited defect leading to bilateral enlarged kidneys with cysts in the renal cortex and medulla

Question 6

Autosomal recessive PKD is characterized by?

Answer 6

Presenting in infants as worsening renal failure and hypertension - congenital hepatic fibrosis and hepatic cysts

Question 7

ADPKD is characterized by?

Answer 7

Presenting in young adults as hypertension - HTN (increased renin), hematuria, and worsening renal failure ADPKD mutation

Question 8

What is the hallmark associated with acute renal failure?

Answer 8

Azotemia - increased BUN and Creatinine often with oliguria

Question 9

Prerenal azotemia is due to what?

Answer 9

Decreased blood flow to the kidneys

Question 10

Decreased blood flow to the kidneys will do what to the GFR?

Answer 10

Decrease GFR leading to azotemia and oliguria

Question 11

In prerenal kidney injury, what causes the elevation of the BUN:Cr ratio?

Answer 11

Decreased blood flow results in increased aldosterone

Aldosterone leads to increased H2O reabsorption

BUN is reabsorbed with H2O

Question 12

How does prerenal injury affect the FENa and urine osmo?

Answer 12

Tubular function remains intact and urine osmo is within normal limits

Question 13

What is postrenal kiney injury?

Answer 13

Decreased outflow results in decreased GFR, azotemia, and oliguria

Question 14

During the early stages of post renal azotemia, what happens to BUN:Cr, FENa, and urine osmo?

Answer 14

Increased back pressure leads to increased BUN forced into reabsorption

Tubular function is intact leading to normal FENa and urine osmo

Question 15

Long standing post renal obstruction will due what to the BUN:Cr?

Answer 15

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

Question 16

What is acute tubular necrosis?

Answer 16

Injury and necrosis of tubular epithelial cells

Question 17

What are the key urinary finding associated with acute tubular necrosis? Why do these occur?

Answer 17

Brown granular casts

Caused by epithelium “slouging off” and forming a cast within the tubulum

Question 18

Dysfunctional tubular epithelium associated with acute tubular necrosis leads to what?

Answer 18

Decreased reabsorption of BUN due to damage to epithelium

Decreased reabsorption of Na leading to increased FENa and the inability to concentrate urine

Question 19

How can ischemia lead to ATN?

Answer 19

Decreased blood supply leads to necrosis of the proximal tubule and think ascending limb

Question 20

What are the clinical features of ATN?

Answer 20

Oliguria with brown granular casts

Elevated BUN and creatinine but ratio less than 15

Hyperkalemia due to decreased renal excretion

Metabolic acidosis

Question 21

What are the characterisitcs associated with acute interstitial nephritis?

Answer 21

Drug induced hypersensitivity leading to intrarenal azotemia

Eosinophils may be found in the urine

Question 22

What is this an image of?

Answer 22

Acute tubular necrosis

Question 23

What is this an image of?

Answer 23

Foot process effacement associated with minimal change dz

Question 24

What is the main characteristic of nephrotic syndrome?

Answer 24

Proteinuria > 3.5g/day

Question 25

Why does can nephrotic syndrome lead to: Pitting edema Increased risk of infection Fatty cast in urine Increased risk of blood clots

Answer 25

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

Question 26

Who is minimal change disease most likely to affect?

Answer 26

This is the most common cause of nephrotic syndrome in children

Question 27

How would minimal change dz appear on light micro?

Answer 27

Normal glomeruli with H&E staining

Question 28

Minimal change disease will show what on electron microscopy?

Answer 28

Foot process effacement (flattening of the podocyte)

Question 29

How will minimal change disease show up on IF?

Answer 29

No immune complex deposition leading to negative IF

Question 30

Who is most commonly affected by Focal Segemental Glomerulosclerosis?

Answer 30

Hispanics and African Americans

Question 31

FSGS can be associated with what?

Answer 31

HIV, heroin use and sickle cell disease

Question 32

How will FSGS show up on light micro?

Answer 32

Focal and segemental glomerulosclerosis

Question 33

How will FSGS show up on EM

Answer 33

Foot process effacement

Question 34

How will FSGS show up on IF?

Answer 34

No immune complex

Question 35

What are some associations of membranous nephropathy?

Answer 35

Caucasian adults, Hep B or C, **SLE** or drugs

Question 36

How will membranous nephropathy show up on light micro?

Answer 36

Thick basement membrane

Question 37

How will membranous nephropathy show up on EM and IF?

Answer 37

IF - granular deposits due to **immune complex deposition** **EM** - spike and dome appearance due to subepithelial deposits

Question 38

Membranoproliferative glomerularnephritis will tend to have what appearance on H&E?

Answer 38

Thick glomerular basement membrane yielding tram track appearance Due to **immune complex deposition**

Question 39

What are the two types of MPGN?

Answer 39

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

Question 40

What is the initial event in diabetes leading to nephrotic syndrome?

Answer 40

Elevated serum glucose leads to non-enzymatic glycosylation of vascular basement membrane and hyaline arteriosclerosis

Question 41

What is the most affected region of the kidney in diabetes?

Answer 41

Efferent arteriole leading to increased glomerular filtration pressure

Question 42

What causes the Kimmelstiel-Wilson nodules in DM?

Answer 42

Sclerosis of the mesangium

Question 43

What is the hallmark of amyloidosis?

Answer 43

Green-apple birefringence under congo red staining

Question 44

What are the basic principles of Nephritic Syndrome?

Answer 44

**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

Question 45

Why are there neutrophils in glomerulus during nephritic syndrome?

Answer 45

Immune complex deposition leads to activation of complement. C5a will attract neutrophils which mediate damage

Question 46

What are the important characteristics of Post-strep glomerulonephritis?

Answer 46

2-3 wks after infection Cola colored urine (Hematuria)

Question 47

What is the IF and EM findings on PSGN?

Answer 47

Sub-epithelial humps on EM Granular IF

Question 48

What are the characteristics of RPGN?

Answer 48

Crescents in the Bowman's space that are comprised of fibrin and macrophages

Question 49

What 5 diseases can lead to RPGN?

Answer 49

Goodpastures PSGN Diffuse proliferative c-ANCA p-ANCA

Question 50

How will Goodpasture's present on IF?

Answer 50

Linear deposits on the GBM

Question 51

What causes the linear deposition associated with Goodpastures?

Answer 51

auto-Ab against collagen in the BM of the glomeruli

Question 52

What are two key clinical symptoms of goodpasture's?

Answer 52

Hemoptysis and hematuria

Question 53

What is the cause of diffuse proliferative GN presentation?

Answer 53

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

Question 54

A negative IF in a patient with RPGN will make a physician think?

Answer 54

ANCA associated RPGN

Question 55

How can you distinguish Wegener's from Goodpasture's?

Answer 55

c-ANCA - Wegener's - will present with nasopharyngeal, lung and kidney problems Goodpastures - Lung and kidney

Question 56

How can you distinguish the two p-ANCA diseases?

Answer 56

Churg-Strauss - Allergic reaction, granulomatous inflammation Microscopic polyangiitis - Does have that

Question 57

IgA nephropathy (Berger Disease) will present as what?

Answer 57

IgA complex deposition in mesangium leading to mesangial proliferation

Question 58

Why will IgA nephropathy present the way it does?

Answer 58

IgA immune complex deposition will lead to hematuria IgA deposition will occur post mucosal infection

Question 59

What are the characteristics of Alport's Syndrome?

Answer 59

Inherited defect in type IV collagen (X-linked) Thinning of the BM

Question 60

What are the classic symptoms of Alport Syndrome?

Answer 60

Isolated hematuria, sensory hearing loss, and ocular disturbances

Question 61

What is the main result of chronic pyleonephritis?

Answer 61

Interstitial fibrosis and atrophy of tubules due to multiple bouts of acute pyelonephritis

Question 62

What is a major morphological change associated with Chronic pyleonephritis?

Answer 62

Thyroidization of the Kidney

Question 63

What is the most common cause of clacium oxalate/calcium phosphate kidney stones?

Answer 63

Idiopathic hypercalcuria

Question 64

What is the cause of ammonium magnesium phosphate kidney stones?

Answer 64

Urease-positive organisms - leading to alkaline urine and formation of a stone

Question 65

Angiomyolipoma is comprised of what?

Answer 65

Blood vessels, smooth muscle, and adipose tissue

Question 66

RCC can present with involvement of what?

Answer 66

The left renal vein which can lead to blockage of the left spermatic vein

Question 67

What is the pathogenesis of RCC?

Answer 67

Loss of VHL gene leading to increased IGF-1, HIF (increasing VEGF and PDGF)

Question 68

Wilms Tumor is most common in who and presents with what?

Answer 68

Most common malignant renal tumor in children, comprised of blastema (immature kidney mesenchyme) Presents with Hematuria and hypertension due to renin secretion

Question 69

What is WAGR syndrome?

Answer 69

Common syndrome associated with WT1 mutation W - Wilms tumor A - Aniridia G - Genital abnormalities R - Mental and growth **r**etardation

Question 70

What are the major risk factors for Urothelial (transitional cell) carcinoma

Answer 70

Smoking

Question 71

Papillary Urothelial cell carcinoma tend to be associated with?

Answer 71

p53 mutations

Question 72

Squamous cell carcinoma is most common associated with?

Answer 72

Bacterial infection with *Schistosoma haematobium* infection (Egyptian male)