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34yo homeless alcoholic brought in with vomiting and prolonged oliguria, renal biopsy shows ballooning and vacuolar degeneration of tubules with oxalate crystals observed in tubular lumen?

Ethylene glycol ingetsion/intoxication leading to acute tubular necrosis (form of intrarenal AKI so hallmarks of azotemia and oliguria)

1

What is the most important prognostic factor in post-streptococcal glomerulonephritis?

Age

Children rarely progress to renal failure (less than 1% get rapidly progressive glomerulonephritis)
Adults much more likely to develop RPGN (25%) or chronic glomerulonephritis

2

Pt with back pain, constipation, easy fatigue, low Hb, and high creatinine. Atrophic tubules with large obstructing eosinophilic casts on biopsy. What disease? Hallmarks?

Multiple myeloma

CRAB
hyperCalcemia
Renal insufficiency (due to toxic Bence Jones protein in tubules - precipitation leads to large, glassy eosinophilic casts)
Anemia
Bone lytic lesions/Back pain

3

When does ADPKD manifest? ARPKD?

ADPKD manifests in pts 40-50yo and cannot be seen in newborns - cyts are too small to be detected and kidneys are normal size, but grow over the years

ARPKD presents at birth or during first year with bilateral flank masses

4

42yo with HTN and hematuria undergoes renal biopsy - LM shows cellular proliferation, focal necrosis, crescent formation of most glomeruli. IF shows no immunoglobulin or complement deposits. How to figure out cause?

ANCA test
Pauci-immune rapidly progressive glomerulonephritis (RPGN)

due to:
- Wegener's (positive c-ANCA; nasopharynx, lung, kidney involvement)
- microscopic polyangiitis (positive p-ANCA)
- Churg-Strauss (positive p-ANCA; granulomatous, eosinophils, and asthma vs. microscopic polyangiitis)

5

What is the main LM finding for RPGN? What are the three IF patterns seen in rapidly progressive glomerulonephritis?

Crescent-moon shape comprised of fibrin and macrophages

IF patterns:
- linear: due to anti-BM antibodies (Goodpasture, will also have hemoptysis since attacks alveolar BM as well as renal)
- granular: due to PSGN or Diffuse Proliferative Glomerulonephritis
- pauci-immune: due to anti-ANCA antibodies (Wegener's, MP, C-S)

6

Rapidly progressive glomerulonephritis with pulmonary involvement? With pulmonary and upper respiratory involvement?

Goodpasture (type II hypersensitivity to glom. and alv. BM)

Wegener's (c-ANCA antibodies)

7

5yo with abdominal pain and loose stools with altered mental status - only one urination (red in color) in past 10 hours. PE shows conjunctival pallor but otherwise normal. Diagnosis? Caused by?

Hemolytic uremic syndrome

Triad of:
- hemolytic anemia
- thrombocytopenia
- acute renal failure

Most cases due to bowel infection by Shiga toxin-producing organisms like E. coli O157:H7 or Shigella dysenteriae.

8

Which nephrotic syndrome shows selective proteinuria? Selective for what?

Minimal change disease
largely loss of albumin and other low MW proteins
(immunoglobulins not lost)

9

Describe the differences in time course, complement levels, and complex deposition in IgA nephropathy vs. post-Strep glomerulonephritis?

IgA nephropathy
- develops a few days after mucosal infection
- complement levels normal
- deposition in the mesangium of the glomeruli

PSGN
- takes a few weeks to develop (antibodies to strep must form, bind antigen in blood, and subsequently fix complement in glomeruli = takes time!!)
- C3 levels low
- deposition as subepithelial "humps" (NO MESANGIAL DEP.)

10

Explain the relationship between IgA nephropathy and Henoch-Schonlein Purpura.

When IgA nephropathy associated with extra-renal symptoms, it is considered a component of HSP (IgA vasculitis).

HSP:
- skin: purpuric lesions on extensor arms, legs, and buttocks
- GI: abdominal pain, vomiting, intestinal bleeding, intussusception
- joints: joint pain, arthralgias
- renal: IgA nephropathy (IgA deposition in mesangium)

11

Pt whose serum contains IgG4 antibodies to phospholipase A2 receptor (PLA2R), a transmembrane protein abundant on podocytes?

Membranous nephropathy

12

Pt with renal problems undergoes surgery for chronic knee pain and no longer needs analgesics. Resolution of renal problems -- pt had? Classic finding? May have progressed to?

Chronic interstitial nephritis (intrarenal injury) due to chronic NSAID use

Eosinophils may be found in urine - this is pathognomonic for interstitial nephritis! (drug-induced hypersensitivity)

Reversible injury, but can progress to renal papillary necrosis

13

What are some causes of renal papillary necrosis?

- chronic analgesic abuse (phenacetin/acetominophen or aspirin)
- diabetes mellitus
- sickle cell trait or disease
- severe acute pyelonephritis

14

What are granular depositions on IF and the subepithelial humps on EM composed of in PSGN?

antigen-antibody complexes of IgG, IgM, and C3

15

What cells express the IL-2 receptor? What is muromonab/OKT3?

activated lymphocytes
IL-2 simulation of the receptor induces T lymphocyte proliferation

anti-CD3 antibody used in treatment of acute rejection in transplant (targets T cells)

16

Causes of acute tubular necrosis? What cells are damaged and what is the characteristic finding in urine? What is the treatment?

ISCHEMIA
or
NEPHROTOXIC:
- aminoglycosides (most common)
- heavy metals
- myoglobinuria from crush injury to muscle
- ethylene glycol (look for oxalate crystals in urine)
- radiocontrast dye
- urate (e.g., in tumor lysis syndrome - hydrate and allopurinol)

Injury/necrosis of tubular epithelial cells
Brown granular casts seen in urine - pathognomonic!

Reversible state, but often needs supportive dialysis since tubular cells are stable cells that need time to re-enter the cell cycle and regenerate.
Oliguria may persist for 2-3 weeks before tubular epithelial cells regenerate.

17

Pt with nephritic syndrome shows c-ANCA staining - diagnosis?

rapidly progressive glomerulonephritis caused by Wegener's

18

Linear pattern on IF in pt with nephritic syndrome? Other findings?

anti-BM antibodies - Goodpasture syndrome (RPGN = crescents on LM)
also expect pulmonary hemorrhages (hemoptysis) as part of Goodpasture

19

Pt with painless hematuria - biopsy shows polygonal clear cells. Diagnosis? Origin? Appearance on gross/macroscopic exam?

Renal clear cell carcinoma
(clear spaces = lipids and glycogen)

originates from tubular epithelium of the proximal tubule

Gross examination of tumor: golden-yellow mass due to high glycogen and lipid content

20

Serum markers in post-Strep glomerulonephritis? LM findings?

- elevated antistreptolysin O
- elevated antiDNAase B
- low serum complement levels

glomeruli enlarged (proliferation) and hypercellular (leukocyte infiltration)

21

Pt with right-sided flank pain that radiates to groin shortly after hysterectomy? Why?

Hydronephrosis

Ureters pass under uterine artery (and ductus deferens), which is vulnerable to unintentional ligation or transection.

22

Pt with antibodies against alpha3 of collagen type IV? Findings?

Goodpasture syndrome
hemoptysis and oliguria

23

Defect in type IV collagen? Findings?
Antibodies against type IV collagen?

Alport syndrome - defect in type IV collagen
(isolated hematuria, sensory hearing loss, ocular disturbances)

Goodpasture syndrome - antibodies against alpha3 of type IV collagen / renal and alv. BM

24

7yo stung by a bee 2 weeks ago and now has puffy face, foamy urine, high proteinuria? How to diagnose? Treatment?

Minimal change disease
EM of podocytes
Corticosteroids give excellent response

25

How do you screen for early stage diabetic nephropathy in DM pts?

Microalbuminuria detection

early stages of hyperfiltration (preferential hyaline arteriolosclerosis of efferent arteriole) leads to micoalbuminuria (non-nephrotic proteinuria)

could also look at nonenzymatic glycosylation of vascular BM very early!

26

In the early stages of diabetic nephropathy, what slows progression of hyperfiltration-induced damage?

ACE inhibitors (-pril) or ARBs (-sartan)

Angiotensin II also causes constriction of the efferent arteriole, so blocking this action relieves some of the construction at the efferent arteriole (in addition to that caused by diabetic hyaline arteriolosclerosis)

27

6yo with facial puffiness and hematuria 3wks after sore throat?

PSGN

28

Pt with hematuria with crescents seen on biopsy - crescents consist of?

fibrin and macrophages
(plus plasma proteins like C3b, glomerular parietal cells, monocytes)

Rapidly progressive glomerulonephritis

29

68yo man with gradual reddening of urine, takes ibuprofen, gardens, worked at a rubber manufacturing plant, normal creatinine?

Transitional cell carcinoma

Occupational exposure to rubber manufacturing
(also plastics, aromatic amine-containing dyes, textiles, leather)