The Kidney

Question 1

Most common cause of nephritic syndrome in children LM: diffuse hypercellularity (almost, if not all glomeruli); EM: subepithelial humps on GBM; IF: granular deposits of IgG and complement within the capillary walls mesangium

Answer 1

Acute Postinfectious (Poststreptococcal) Glomerulonephritis (PSAGN)

Question 2

1. Hematuria (with dysmorphic RBCs and red cell casts indicating glomerular pathology); 2. Oliguria and azotemia; and 3. Hypertension

Answer 2

Nephritic syndrome

Question 3

Type of RPGN associated with anti-GBM antibodies; associated with Goodpasture syndrome (glomerular and pulmonary involvement); uninvolved segments shows no proliferation; EM: ruptures in the GBM; IF: linear IgG and C3 deposits along the GBM

Answer 3

RPGN Type I

Question 4

Syndrome of progressive loss of renal function, characterized by nephritic syndrome often with severe oliguria; histologic hallmark is presence of crescents, thus crescentic GN

Answer 4

Rapidly progressing glomerulonephritis

Question 5

Type of RPGN associated with immune complex deposition; usually a secondary event of immune complex-mediated nephritides; uninvolved segment shows immune complex deposition; EM: lumpy bumpy appearance of GBM (due to deposits); IF: granular deposition of Ig and complement in GBM

Answer 5

RPGN Type II

Question 6

Type of RPGN associated with ANCA; sometimes a component of ANCA vasculitides (Microscopic polyangiitis and Wegener granulomatosis); uninvolved segments shows no proliferation; EM: no detectable deposits; IF: negative for Ig and complement

Answer 6

RPGN Type III

Question 7

An important cause of ESRD; grossly, kidneys are symmetrically contracted, surfaces are red-brown and diffusely granular; histologically, glomeruli are obliterated with marked interstitial fibrosis.

Answer 7

Chronic glomerulonephritis

Question 8

Most common cause of nephrotic syndrome in children; responsive to corticosteroids. LM: none; EM: uniform and diffuse effacement of foot processes of the podocytes

Answer 8

Minimal change disease/Lipoid nephrosis

Question 9

1. Massive proteinuria (3.5g/dL; 2. Hypoalbuminemia (<3g/dL); 3. Generalized edema; 4. Hyperlipidemia and lipiduria

Answer 9

Nephrotic syndrome

Question 10

Most common cause of nephrotic syndrome in adults; involves only some glomeruli (focal), and only a part of glomerulus (segmental) is affected; associated with HIV and heroin abuse. LM: increased mesangial matrix, obliterated capillary lumina, and deposition effacement of foot processes of hyaline masses (hyalinosis) and lipid droplets. IF: nonspecific trapping of immunoglobulins, usually IgM, and complement in the areas of hyalinosis.

Answer 10

Focal segmental glomerulosclerosis (FSGS)

Question 11

Associated with infections (HBV, Syphilis, Schistosomiasis, Malaria), Malignant solid tumors (lung and colon), SLE, Gold and Mercury, and drugs (Penicillamine, Captopril, NSAIDs); LM: diffuse thickening of the capillary wall; EM: subepithelial deposits along the GBM (spike and dome appearance); effacement of foot processes; IF: granular deposits of immunoglobulins and complement along the GBM.

Answer 11

Membranous nephropathy

Question 12

Associated with HBV, HCV, SLE, and infected AV shunts; LM: Thickened split GBM (Tram track appearance); EM: subendothelial electron-dense deposits; IF: Irregular granular C3 deposits, with IgG and early complement components (C1q and C4)

Answer 12

Membranoproliferative glomerulonephritis (MPGN) Type I

Question 13

Formerly called MPGN Type II; fundamental abnormality is excessive complement activation; LM: Thickened split GBM (Tram track appearance); EM: lamina densa and glomerular capillary wall transformed into irregular, ribbon-like, extremely electron-dense structure; IF: Irregular chunky and segmental linear foci of C3 deposits in GBM and mesangium, without IgG and early complement components (C1q and C4)

Answer 13

Dense deposit disease

Question 14

One of the most common causes of recurrent microscopic or gross hematuria; most common glomerular disease revealed by renal biopsy worldwide. LM: mesangial widening and segmental inflammation; EM: mesangial electron-dense deposits; IF: mesangial deposition of IgA, often with C3 and properdin and smaller amounts of IgG or IgM

Answer 14

IgA nephropathy (Berger disease)

Note: Berger disease and Henoch-Schonlein purpura have the same renal manifestations and morphology, but HSP involves systemic deposition of IgA, has extrarenal symptoms

Question 15

Nephritis associated with hearing and visual defects; defect in Type IV collagen synthesis; X-linked dominant pattern of inheritance; LM: glomerulosclerosis, vascular sclerosis, tubular atrophy, and interstitial fibrosis; EM: thin GBM (early); irregular foci of GBM thickening or attenuation (late); basket-weave appearance

Answer 15

Alport syndrome

Question 16

Clinicopathologic entity characterized clinically by acute renal failure and often, but not invariably, morphologic evidence of tubular injury, in the form of necrosis of tubular epithelial cells; has two forms: ischemic and toxic, which vary in terms of affected segments of the nephron and distribution of necrosis.

Answer 16

Acute tubular injury/necrosis

Question 17

Most common cause of acute kidney injury; a common suppurative inflammation of the kidney and renal pelvis caused by bacterial infection, either by hematogenous spread or through ascending infection (more common and more important mode); principal causes are Gram-negative enteric rods; grossly, there is discrete, yellowish, raised abscesses grossly apparent on the renal surface; histologically, there is liquefactive necrosis with abscess formation within the renal parenchyma.

Answer 17

Acute pyelonephritis

Question 18

Hallmark of this disease is scarring involving the pelvis or calyces, or both, leading to papillary blunting and marked calyceal deformities; an important cause of chronic kidney disease; forms include: reflux nephropathy (more common), and chronic obstructive pyelonephritis.

Answer 18

Chronic pyelonephritis

Question 19

Second most common cause of acute kidney injury; T-cell mediated immune reaction of the kidneys to an offending agent, characterized by interstitial inflammation, with abundant eosinophils and edema.

Answer 19

Drug-induced interstitial nephritis

Question 20

Form of nephrosclerosis associated with essential hypertension; histologically, hyaline arteriolosclerosis; renal insufficiency is uncommon except in patients of African descent, severe HPN, and other diseases e.g. DM.

Answer 20

Nephrosclerosis

Question 21

Form of nephrosclerosis associated with malignant hypertension; histologically, hyperplastic nephrosclerosis and fibrinoid necrosis.

Answer 21

Malignant nephrosclerosis

Question 22

Most common causes of renal artery stenosis.

Answer 22

Atherosclerosis and fibromuscular dysplasia

Question 23

Nephron segments most susceptible to ischemia, and therefore, most affected in ischemic ATN.

Answer 23

Short; straight segments of PT and AL LOH

Question 24

Autosomal dominant; kidneys are enlarged, composed solely of cysts without intervening parenchyma; cysts are filled with clear or turbid fluid; cysts may arise at any level of the nephron, with variable, often atrophic lining; pathology is defective gene PKD1, which codes for polycystin-1; a protein that is involved in cell-cell or cell-matrix adhesion; most common cause of death: CAD or HHD (40%).

Answer 24

Adult Polycystic Kidney Disease (ADPKD)

Question 25

Autosomal recessive; numerous small cysts in the cortex and medulla, giving the kidney a “sponge-like” appearance; cysts have uniform cuboidal epithelium; associated with multiple cysts in the liver; pathology is defective PKHD1, which codes for fibrocystin; a protein found in cilia in tubular epithelial cells.

Answer 25

Childhood Polycystic Kidney Disease (ARPKD)

Question 26

Most common composition of kidney stones.

Answer 26

Calcium oxalate and/or Calcium phosphate (80%)

Question 27

Most important cause of kidney stone formation.

Answer 27

Supersaturation

Question 28

Kidney stones occurring in patients with alkaline urine due to UTI, particularly Proteus vulgaris and staphylococci; most common composition of staghorn calculi.

Answer 28

Struvite (Magnesium ammonium phosphate);

Question 29

Kidney stones seen in patients with gout and leukemias; urine pH is decreased; radiolucent.

Answer 29

Uric acid stones

Question 30

Kidney stones associated with a defect in the renal transport of certain amino acids; forms in acidic urine.

Answer 30

Cystine stones

Question 31

Tumors derived from renal tubular epithelium, located primarily at the cortex; with three common forms, clear cell, papillary renal cell and chromophobe carcinomas; most common primary malignant tumor of the kidney.

Answer 31

Renal cell carcinoma (RCC)

Question 32

Most important risk factor for renal cell carcinoma.

Answer 32

Smoking

Question 33

Most common form (70-80%) of renal cell carcinoma and associated with homozygous loss of the VHL tumor suppressor gene; thought to arise from proximal tubule cells; usually solitary and large, spherical masses reaching up to 15 cm in diameter; cut surface shows yellow orange to gray-white masses, with prominent areas of cystic softening and hemorrhage; cells appear vacuolated or may be solid; often invades the renal vein.

Answer 33

Clear cell RCC

Question 34

Accounts for 10-15% of cases of RCC; throught to arise from distal tubule cells; characterized by varying degrees of papilla formation with fibrovascular cores; cells have clear to pink cytoplasm; associated with increased activity of MET oncogene; tends to be bilateral.

Answer 34

Papillary RCC

Question 35

Accounts for 5% of cases of RCC; thought to arise from intercalated cells of collecting ducts; grossly tan-brown; microscopically, cells have clear, flocculent cytoplasm with very prominent, distinct cell membranes; nuclei surrounded by halos of cleared cytoplasm.

Answer 35

Chromophobe RCC

Question 36

Most common site of metastases of RCC.

Answer 36

Lungs (>50%), followed by bones (33%)