Renal Disorders

Question 1

Unilateral multicystic renal dysplasia

Answer 1

• MCC of abd mass in newborns

* Remove affected kidney

Question 2

ADPKD

Answer 2

• Manifests in 30s
• Bilateral, cystic parenchyma w/ enlarged kidneys
• Hepatic cysts and cerebral aneurysms also common

Question 3

ARPKD

Answer 3

• Extremely large, smooth kidneys w/ fibrosis
• Many die from pulmonary hypoplasia
• Hepatic fibrosis also common

Question 4

Minimal change disease

Answer 4

• Children
• Causes nephrotic syndrome
• Effacement of podocytes
• Excess lipids deposit as hyaline droplets in tubular epithelial cells
• Often resolves with steroids

Question 5

Focal segmental glomerulosclerosis

Answer 5

• Causes nephrotic syndrome
• Capillaries obliterated by ECM or accumulated cells
• Sclerotic segments show IgM and C3 under IF
• May be caused by pamidronate
• HIV can cause rapid variant of this disease

Question 6

Membranous glomerulonephritis

Answer 6

• Whites and Asians

* Subepithelial immune complex deposition in glomerular capillaries

Question 7

Nephronophthisis/medullary cystic disease

Answer 7

• Nephronophthisis: childhood-adolescence
• MCD: adolescence-adulthood
• Cysts at corticomedullary jxn, atrophic tubules with thick basement membranes
• Salt wasting, azotemia, renal failure

Question 8

Medullary sponge kidney

Answer 8

• Epithelium-lined cysts in papillae

* Sx at age 30-60; flank pain, dysuria, hematuria, “gravel” in urine (stones from cysts)

Question 9

Diabetic glomerulosclerosis

Answer 9

• Basement membrane thickening, mesangium expansion, Kimmelstiel-Wilson nodules, hyaline accumulations along capillaries
• IgG and other proteins trapped linearly in GBM

Question 10

Amyloidosis

Answer 10

• AA amyloid most common, assoc. w/ chronic inflammation
• Eosinophilic, Congo red stain
• Deposits in mesangium, then capillary walls

Question 11

Alport syndrome (hereditary nephritis)

Answer 11

• Type IV collagen mutation
• Also causes hearing loss
• Glomerular sclerosis, tubular atrophy, interstitial fibrosis, foam cells, thick GBM

Question 12

Postinfectious glomerulonephritis

Answer 12

• After beta-hemolytic strep or staph infections
• Complement-rich IC deposits in glomeruli
• “Humps” (subepithelial dense deposits)

Question 13

Membranoproliferative glomerulonephritis

Answer 13

• Late childhood/early adulthood
• Glomeruli distorted by monocyte infiltration and mesangial cell proliferation; cap wall and GBM thickening
• Granular deposits of complement (and sometimes Ig) in cap loops and mesangium

Question 14

C3 glomerulopathy

Answer 14

• Mostly children
• “Dense deposit disease”
• Ribbon-like zone of increased density in center of GBM and mesangium

Question 15

IgA nephropathy

Answer 15

• Exacerbations triggered by resp or GI infections
• IgA deposits in mesangium
• Occurs w/ Henoch-Schönlein purpura

Question 16

Anti-GBM Ab disease

Answer 16

• Abs versus type IV collagen in GBM
• With lung involvement: Goodpasture syndrome
• Diffuse linear GBM staining for IgG
• Crescents, fibrinoid necrosis common
• Rapid progression

Question 17

ANCA glomerulonephritis

Answer 17

• Glomerular necrosis and crescents

* Often presents with small-vessel vasculitis

Question 18

Hypertensive nephrosclerosis

Answer 18

• Small kidneys with granular surfaces, thin CTX

* Hyaline arteriolosclerosis

Question 19

Renal artery HTN

Answer 19

• Increased renin, angiotensin II, aldosterone

* Small kidneys

Question 20

Hemolytic uremic syndrome

Answer 20

• Children
• E. coli GI infections
• Thrombotic microangiopathy

Question 21

Drug-induced hypersensitivity tubulointerstitial nephritis

Answer 21

• Type IV hypersensitivity w/ eosinophils

* NSAIDs, diuretics, some Abx

Question 22

Light-chain cast nephropathy

Answer 22

• Multiple myeloma
• Hyaline, crystalline casts in distal tubule + collecting duct
• Interstitial Ca deposits

Question 23

Urate nephropathy

Answer 23

• Chronic: gout
• Acute: increased cell turnover from chemo, diuretics
• Uric acid crystals (yellow streaks) obstruct tubules

Question 24

Kidney stones

Answer 24

• Infection from Proteus or Providencia spp. creates stones from struvite (magnesium ammonium phosphate) or apatite (calcium phosphate); may become staghorns
• Uric acid stones: yellow and radiolucent
• Cystine stones: hereditary cystinuria in children

Question 25

Papillary renal adenoma

Answer 25

• Increased incidence with age

* Papillary growth

Question 26

Renal oncocytoma

Answer 26

• Derived from collecting duct intercalated cells

* Abundant, finely granular cytoplasm

Question 27

Medullary fibroma

Answer 27

• Common, small

* Small stellate or polygonal cells in loose stroma

Question 28

Angiomyolipoma

Answer 28

• Strong association with tuberous sclerosis

* Adipose tissue, smooth muscle, thick-walled vessels

Question 29

Mesoblastic nephroma

Answer 29

• Found in infancy

* Spindle cells; mass with irregular margins

Question 30

Wilms tumor

Answer 30

• Children

* Large tumors with mixed blastema, stroma, epithelium; possibly other components

Question 31

Renal cell carcinoma

Answer 31

• Middle age, men > women
• Common
• Can be associated w/ VHL
• Often produces ectopic hormones and paraneoplastic syndromes (PTH-like hormone, erythropoietin, renin)