9/17- Glomerular Diseases I & II: Anatomy, Function, and Clinical Syndromes Flashcards Preview

MS2 Renal > 9/17- Glomerular Diseases I & II: Anatomy, Function, and Clinical Syndromes > Flashcards

Flashcards in 9/17- Glomerular Diseases I & II: Anatomy, Function, and Clinical Syndromes Deck (82)
1

Define:

- Glomerular diseases

- Glomerulonephritis

- Primary glomerular diseases

- Secondary glomerular diseases

- Glomerular diseases: diseases involving glomeruli primarily

- Glomerulonephritis: glomerular diseases in which glomerular inflammation is an important component

- Primary glomerular diseases: involves the kidneys only (e.g. membranous glomerulonephritis)

- Secondary glomerular diseases: involves the glomeruli as a component of a systemic disease (e.g. diabetic nephropathy, lupus nephritis)

2

What is seen here? 

Glomerulus- filtering units of the kidney

3

How many glomeruli per kidney?

1-1.2 million

4

What are the involved cells in the glomerulus?

- Mesangial cell

- Endothelial cell (lines inner side of GBM)

- Podocyte (epithelial cell, lines outside of GBM) 

5

What are mesangial cells?

- Function

- Properties

- Synthesis of mesangial matrix which acts as a structural support to the glomerulus

Properties

- Smooth muscle-like (contractile) properties: influences capillary surface area and filtration

- Macrophage-like properties: phagocytosis of immune complexes; secretion of cytokines, growth factors, proteases and oxidants

6

Describe the structure of the podocytes?

- Aka visceral epithelial cells

- Lines outside of GBM

- Interdigitates with the GBM via long "foot processes" which are separated by thin slit-diaphragms

7

What is the function of the glomerulus?

Filter (highly selective)

- Permeable to salt, water, and metabolic waste products (like creatinine, urea) Barrier to large molecules and proteins

- "Size" barrier (gap between endothelial cells 70-100 nm and between podocyte foot processes 30-40 nm)

- "Charge" barrier: negatively charged proteins coat the GBM (heparan sulfates) and podocytes (glycocalyx) 

8

What are clinical manifestations/syndromes of glomerular diseases? What causes them?

Abnormal protein excretion

- Isolated proteinuria

- Nephrotic syndrome

- Nephritic syndrome

Loss of filtration and reduction in the glomerular filtration rate (GFR) (losing ability of kidney to excrete things like urea, creatinine...)

- Acute kidney injury (AKI)

- Chronic kidney disease (CKD)

9

What is normal protein excretion? Abnormal?

< 20 mg/day is normal

- Abnormal is > 30 mg/day

10

What is microabluminuria?

- Suggestive of what?

Microalbuminuria = 30-300 mg/day

- Not detectable by routine urinalysis (have to test for albumin specifically)

- Suggests early glomerular damage

- Clinically used to predict development of diabetic nephropathy

11

What is subnephrotic-range proteinuria?

- Suggests what?

Subnephrotic range = 300 mg - 3.5 g/day

- May be due to glomerular or tubular diseases

12

What is nephrotic range proteinuria?

Nephrotic range = > 3.5 g/day

- Due to defect in glomerular filtration barrier

- Usually results in decreased serum albumin -> development of edema -> NEPHROTIC SYNDROME

13

What is the definition of nephrotic syndrome?

- Proteinuria (>3.5 g/day or >40 mg/hr/m2 in children)

- Hypoalbuminemia (under 3.0 g/dl)

- Edema

- Hyperlipidemia (elevated serum cholesterol)

- Lipiduria (fat globules in the urine)

14

What is the pathogenesis of nephrotic syndrome?

Major glomerular abnormality is an excessive leak of protein through the glomerular capillary wall into the urinary space due to disruption of the slit diaphragm

- Podocyte injury

- Specific defect of the slit diaphragm (e.g., nephrin mutation) 

15

What are the main processes of pathophysiology involved in nephrotic syndrome?

- Low serum albumin

- Edema/Anasarca

- Hyperlipidemia

- Lipiduria

- Increased risk for infections

- Increased risk for thrombosis

- Poor growth in children and osteomalacia

16

What causes low serum albumin in nephrotic syndrome?

- How does the body respond?

Low serum albumin

- Loss of albumin into the urine

- Increased reabsorption and degradation of protein by the proximal tubule

- Increased protein synthesis by the liver, but cannot compensate completely for the urinary losses

(even though urine loss only shows ~3.5 g and liver can make more, much more is lost in urine that has already been degraded by proximal tubule)

17

What causes edema/anasarca in nephrotic syndrome? - How does the body respond?

- Decreased plasma oncotic pressure -> filtration of fluid from the vascular compartment into the interstitial space

- Decrease in intravascular volume -> stimulation of renin-angiotension-aldosterone and vasopressin -> salt and water retention -> worsened edema 

18

What causes hyperlipidemia in nephrotic syndrome?

- Results/risks?

- Increased lipoprotein synthesis by the liver mediated by a decrease in plasma oncotic pressure

- Increased risk for coronary artery disease/atherosclerosis

19

What is lipiduria?

- How is it observed?

- Fat in the urine (appearance of "maltese cross" under polarized light)

- Due to higher synthesis of lipid by liver (with protein production) and more loss in urine since glomerular disease

20

What causes the icnreased risk for infection in nephrotic syndrome?

Urinary loss of IgG and complement

21

What causes increased risk for thrombosis in nephrotic syndrome?

Increased synthesis of coagulation factors by the liver and urinary loss of anti-thrombin III

- Protein C/S, and AT III are smaller molecules; more likely to be lost (these inhibit clotting)

22

What causes poor growth in children and osteomalacia?

Urinary loss of Vitamin D

23

What are frequent causes of nephrotic syndrome?

Primary

- Minimal Change Disease

- Membranous Nephropathy

- Focal Segmental Glomerulosclerosis

- Membranoproliferative Glomerulonephritis

Secondary

- Diabetic Nephropathy

- Amyloidosis

- Lupus nephritis

24

What is the definition of nephritic syndrome?

- Non-nephrotic range proteinuria (> 500mg and under 3.5 g/day)

- Reduced glomerular filtration rate (GFR): seen as increase in serum urea nitrogen and serum creatinine

- Active urine sediment (RBCs, WBCs, casts)

- Edema

- Hypertension

25

What is the pathogenesis of nephritic syndrome?

Characterized by active inflammation and injury within the glomerulus -> glomerular damage and loss of capillary surface area -> loss of filtration and blood flow to the glomeruli

- Mesangial cell proliferation

- Endothelial cell proliferation and injury

- Podocyte injury 

26

What are the main processes of pathophysiology involved in nephritic syndrome?

- Active urine sediment

- Reduction in glomerular filtrate rate (GFR)

- Proteinuria (usually under 3 g/day)

- Edema

- Hypertension

27

What causes active urine sediment in nephritic syndrome?

- Excretion of RBCs and WBCs into urine due to glomerular inflammation and disruption of GBM

- Hematuria with dysmorphic RBCs (projections; not nice and round; had to squeeze through GBM) 

28

What causes the reduction in glomerular filtrate in nephritic syndrome?

- Acute inflammation within the glomeruli -> Glomerular vasoconstriction, occlusion and thrombosis -> Reduced renal blood flow and filtrating surface area

- Increased serum creatinine, nitrogen, urea...

29

What causes the proteinuria in nephritic syndrome?

(Proteinuria usually under 3 g/day)

- Glomerular capillary wall injury focal vs. nephrotic syndrome where the entire capillary wall has increased permeability

- In other words, less protein loss in nephritic syndrome because etiology (e.g. inflammation due to Ig deposition) is not evenly spread; not all nephrons are compromised

- Decreased GFR -> less filtered protein

30

What causes the edema in nephritic syndrome?

Salt and water retention

31

What causes the hypertension in nephritic syndrome?

- Salt and water retention

- Vasoconstriction

32

What is Rapidly Progressive Glomerulonephritis (RPGN)?

- Severe glomerular injury often with presence of crescents (proliferation of cells in Bowman’s space)

- Presents with rapid deterioration of renal function (over days to weeks)

- Low urine output, hematuria, hypertension and edema (in addition to other Sx of nephritic syndrome)

- Losing fibrin and GFs in urine that cause tubular cells to overproliferate and block off tubule system

- Crescent sign (proliferation of parietal (?) epithelial cell) 

33

What are frequent causes of nephritic syndrome?

Primary

- IgA nephropathy

- Membranoproliferative glomerulonephritis

- Crescentic glomerulonephritis (or RPGN)

- Postinfectious glomerulonephritis

Secondary

- Lupus nephritis

34

What is Chronic Kidney Disease (CKD)/End-Stage Renal Disease (ESRD)

- Final pathway for what?

- Mechanism

- Presentation?

- Common final pathway for any chronic progressive injury to the kidneys/glomeruli

- Chronic activation of fibrocytes and deposition of extracellular matrix -> Irreversible glomerular sclerosis (scarring)

Presentation:

- Prolonged (spanning months to years)

- Progressive and irreversible decrease in glomerular filtration rate -> increased blood urea nitrogen and serum creatinine (azotemia) -> constellation of systemic signs and symptoms (uremia): nausea, vomiting, poor appetite, weight loss, confusion, coma 

35

What are the mechanisms of glomerular diseases?

- Glomerular diseases may results from multiple mechanisms

- Common mechanisms are shared by many different glomerular diseases

- Specific mechanisms for many human primary glomerular diseases are NOT known

- IMMUNE-MEDIATED MECHANISMS

- NONIMMUNE-MEDIATED MECHANISMS

36

What are some immune-mediated mechanisms of glomerular diseases (broadly)?

- IN SITU Immune Complex Deposition

- CIRCULATING Immune Complex Deposition

37

Describe IN SITU Immune Complex Deposition

- Mechanism

- Subtypes

Autoantibodies directed against an antigen located in the kidney

- Goodpasture disease (anti-GBM dz): antibodies against the glomerular basement membrane

- Membranous GN: antibodies against an antigen on glomerular epithelial cells (podocytes) (phospholipase A2 receptor)

38

Describe CIRCULATING Immune Complex Deposition

- Mechanism

- Subtypes

Antigens and antibodies form immune complexes within the circulation, and they are subsequently deposited in the kidney

- Postinfectious GN: due to glomerular deposition of circulating immune complexes composed of streptococcal antigens and their antibodies

39

What are some nonimmune-mediated mechanisms of glomerular diseases?

Cytokines or circulating factors causing injury to epithelial cells (podocytes)

- Minimal change disease; focal segmental glomerulosclerosis

Thrombosis of Glomerular Capillaries

- Thrombotic microangiopathy

Metabolic pathways (with deposition of - extracellular matrix)

- Diabetic nephropathy

Deposition of degenerative proteins

- Renal amyloidosis Ischemic/ Hypoxic Injury

- Hypertensive nephrosclerosis

40

Podocyte injury is seen in what diseases? Mechanism?

- Minimal change disease: circulating factors

- Membranous GN: immune complex deposition

41

Basement membrane injury is seen in what diseases? Mechanism?

- Goodpasture's disease: immune complex deposition

42

Endothelial injury is seen in what diseases? Mechanism?

- Lupus nephritis: immune complex deposition

- Cryoglobulinemia: immune complex deposition

43

Mesangial injury is seen in what diseases? Mechanism?

IgA nephropathy: immune complex deposition

44

What is the approach to diagnosing specific cause of glomerular didsease?

Patient History

- Age/sex: lupus nephritis most commonly occurs in young females

- Systemic symptoms/Chronic diseases

  • Long-standing diabetes: Diabetic nephropathy
  • Recent sore throat: post-infectious GN

Clinical Presentation

- Nephrotic vs. Nephritic syndrome

- Acute kidney injury vs. Chronic kidney disease

Laboratory Findings

- Lupus Nephritis: ANA, anti-dsDNA, complements (C3, C4)

- Goodpasture’s disease: anti-GBM antibody

- Post-infectious GN: ASO titers, complements (C3, C4)

Renal Biopsy

45

What are histologic (morphologic) patterns seen on renal biopsy in glomerular disease?

Light Microscopy (LM)

- General morphology

  • Inflammation, Cellularity
  • Sclerosis/scarring
  • Crescents Electron Microscopy (EM)

- Features not visible by light microscopy

  • Effacement of the podocyte foot processes
  • Morphology of the glomerular basement membrane
  • Presence and location of immune complex deposits Immunofluorescence (IF)

- Evidence of immune complexes in kidney tissue

- Immunoglobulins (IgG, IgA, IgM)

- Complement proteins (C3, C4)

46

Describe the results of

- Light microscopy

- Electron microscopy

- Immunofluorescence in minimal change disease (nephrotic syndrome)?

47

Describe the results of

- Light microscopy

- Electron microscopy

- Immunofluorescence in membranous nephropathy (nephrotic syndrome)?

48

What are primary glomerular diseases (involving the kidneys only) that result in nephrotic syndrome?

- Minimal Change Disease

- Focal Segmental Glomerulosclerosis

- Membranous GN

- Membranoproliferative GN

49

What are primary glomerular diseases (involving the kidneys only) that result in nephritic syndrome/acute renal failure?

- Post Infectious GN

- IgA Nephropathy

- Goodpasture’s Disease (Anti-GBM Nephritis)

- Membranoproliferative GN

50

What are secondary glomerular diseases (systemic disease) causing nephrotic syndrome?

- Diabetes

- Amyloidosis

- Multiple myeloma

- Systemic lupus

51

What are secondary glomerular diseases (systemic disease) causing nephritic syndrome/acute renal failure?

- ANCA-associated GN

- Vasculitis

- Systemic Lupus

- Henoch-Schönlein Purpura

- Cryoglobulinemia

52

Fun fact: Several glomerular diseases can cause features of both nephrotic and nephritic syndrome

(:

53

Describe Minimal Change Disease

- Etiology

- Pathogenesis

- The etiology is unknown

- May involve a T-cell derived circulating permeability factor that directly damages the podocytes and permeability barrier

- Evidence for a circulating factor

  • MCD can develop in normal kidneys immediately following transplant
  • Kidney with MCD becomes normal following transplant

54

Describe Minimal Change Disease

- Pt History: Age, Race, Sex, Associations

- Clinical Presentation

Age

- Most common cause of NS in children (peak 2-4 yrs old)

- Adults: 5th-6th decade

Race: no predominance

Sex: M > F (2x)

Associations:

- Most cases are “idiopathic”

- Rare cases associated with other diseases such as Hodgkin’s disease, use of NSAIDs

Clinical Presentation

- Nephrotic Syndrome

- Sudden onset of proteinuria (can be massive) and edema (esp periorbital)

- Normal renal function

- Hypertension and hematuria are uncommon (still have GBM and intact endothelium)

55

Describe Minimal Change Disease

- Lab findings

- Renal biopsy

Lab findings:

- Hypoalbuminemia

- Normal complement levels

- No specific serologies

Renal biopsy:

- LM: normal glomeruli (thus, "minimal change" disease)

- EM: podocyte foot process effacement/fusion

- IF: negative (no immunoglobulin or complement) 

56

Describe Focal Segmental Glomerulosclerosis

- What causes primary "idiopathic" FSGS?

Primary “idiopathic” FSGS may be caused by a circulating factor that causes direct injury to the podocytes

- Recurrence of NS shortly (sometimes within 24 hours) after renal transplantation

Recent studies suggest that SuPAR (soluble urokinase-type plasminogen activator receptor) is the circulating factor

57

Describe Focal Segmental Glomerulosclerosis

- Pt History: Age, Race, Sex, Associations

- Clinical Presentation

Age

- Young adults 20-40 years-old

- Can also develop in children with minimal change disease who keep relapsing and become steroid-resistant (may just be more severe form of minimal change disease, but we don't really know)

Race: Blacks

Sex: No predominance

Associations:

- HIV (viral infection of podocytes

- Obesity (glomerular hyperfiltration and stretching of podocytes)

- Heroin use

Clinical Presentation

- Nephrotic Syndrome

- Unlike minimal change disease, patients may have hypertension, renal failure or microhematuria (actually have some scaring of the glomeruli)

58

Describe Focal Segmental Glomerulosclerosis

- Lab Findings

(Same as Minimal Change Disease)

- Hypoalbuminemia

- Normal complement levels

- No specific serologies

59

Describe Focal Segmental Glomerulosclerosis

- Renal Biopsy Results

LM

- Focal: only some glomeruli show scarring (sclerosis)

- Segmental: only part of the glomerulus effected

EM

- Podocyte foot process effacement/fusion

IF

- Negative

- Sometimes, non-specific trapping of IgM and C3 in sclerotic areas

60

Describe Membranous Nephropathy?

- Etiology

- Pathogenesis

- Autoimmune, mediated by an antibody directed against an antigen on the podocytes (phospholipase A2 receptor).

- The immune complex activates complement system which injures the podocytes.

- The immune complex is deposited in the subepithelial space (between the podocytes and GBM).

61

Describe Membranous Nephropathy?

- Pt Hx: Age, Race, Sex, Associations

- Clinical Presentation

Age

- Most common cause of idiopathic nephrotic syndrome in adults (peak incidence in 5th and 6th decades)- population at higher risk for cancers

- Race: no predominance

- Sex: M > F (2x)

Associations

- Most are "idiopathic" (2/3)

- Often associated with cancer (lung, breast, and GI tract), Hepatitis B, systemic lupus

Clinical Presentation

- Nephrotic syndrome

- Hypertension and renal failure are uncommon

62

Describe Membranous Nephropathy?

- Lab Findings

- Renal Biopsy

Lab Findings

- Hypoalbuminemia

- Normal complement levels

- PLA2R antibodyies(staining on kidney biopsy; serum – for research use)

- Check hepatitis panel, ANA/anti-dsDNA, cancer screening Renal Biopsy

- LM: Thickening of glomerular basement membrane ("membranous")

- EM: Subepithelial (between podocytes and GBM) immune deposits

- IF: Granular deposits of immmunoglobulins and complements along the GBM 

63

Describe Membranoproliferative GN

- Etiology

- Pathogenesis

Immune mediated glomerular injury

- Trapping of circulating immune complexes in the subendothelial and mesangial areas -> complement activation and inflammation

- Circulating “nephritic factor” that spontaneously activates complements in the capillary wall

64

Describe Membranoproliferative GN

- Pt History: Age, Race, Sex, Associations

- Clinical Presentation

- Age: any

- Race: no predominance

- Sex: Female > male (2x) in idiopathic cases

Associations:

- Can be "idiopathic"

- Often associated with Hepatitis C, other infections (endocarditis, Hep B), systemic lupus, cryoglobulinemia

Clinical Presentation

- Nephrotic syndrome

- Many (20-30%) present with nephritic syndrome

- HTN frequently occurs early

65

Describe Membranoproliferative GN

- Lab Findings

- Renal Biopsy

Lab Findings

- Low complement levels

- No specific serologies

- HCV associated: cryoglobulins, rheumatoid factor, low complements

Renal Biopsy

- LM

1. Thickening of glomerular basement membrane (“membrano”)

2. Glomerular cell proliferation (usually mesangial – “cauliflower”) and leukocyte infiltration (“proliferative”)

- EM: subendothelial immune deposits

- IF: subendothelial pattern (C3 +/- IgG deposits

66

Describe Post-Infectious GN

- Etiology

- Pathogenesis

- Occurs after a group A streptococcal infection (throat or skin)

- May occur with other infections such as Staphylococcus endocarditis, infected shunts, abscesses and empyema

- Mediated by an antibody response to certain streptococcal antigens (endotoxin B, endostreptosin) -> circulating immune complexes that lodge in the glomeruli -> activate the complement system

67

Describe Post-Infectious GN

- Pt Hx: Age, Race, Sex, Associations

- Clinical Presentation

- Age: any

- Race: no predominance

- Sex: no predominance

Associations:

- Typically occurs 14 days (throat) to 21 days (skin) after infection

Clinical Presentation:

- Nephritic Syndrome

- Edema and sudden weight gain in children

- Hypertension may be severe

- Renal failure common

68

Describe Post-Infectious GN

- Lab Findings

- Renal Biopsy

Lab Findings

- ↑ASO titers; (+) streptozyme (50-70%)

- Low complement levels (alternative pathway activation: low C3, normal C4)

Renal Biopsy

- LM: diffuse proliferation and inflammation

- EM: Subepithelial "humps" subendothelial and mesangial deposits

- IF: "lumpy-bumpy" IgG and C3 deposits 

69

Describe IgA Nephropathy

- Etiology and Pathogenesis

Immune-mediated by IgA containing immune complexes

- IgA antibodies react to as yet unidentified antigens, but may include infectious agents or food products

- IgA antibodies are abnormally glycosylated -> impaired clearance -> high levels of circulating complexes

- IgA immune complexes deposit in the glomerular mesangium -> cell proliferation, matrix expansion and inflammation

70

Describe IgA Nephropathy

- Pt Hx: Age, Race, Sex, Associations

- Clinical Presentation

Age

- Most common cause of primary glomerulonephritis

- Young adults (15-35 yo)

Race

- Asians and Caucasians

- Rare in blacks

Sex: M > F (2x)

Associations

- May occur with a simultaneous pharyngitic or GI viral infection

- Occur as part of a syndrome (rash, liver disease, inflammatory bowel disease, ankylosing spondylitis)

- Henoch-Schonlein purpura (children)

Clinical Presentation:

- Most common: asymptomatic hematuria, nonnephrotic proteinuria and normal or only mildly reduced renal function

- Gross hematuria with pharyngitic or GI infection

- Rapidly progressive/crescentic GN (rare)

71

Describe IgA Nephropathy

- Lab Findings

- Renal Biopsy

Lab Findings

- ↑Serum IgA (50%)

- Normal complements

Renal biopsy

- LM: mesangial cell proliferation and matrix expansion

- EM: mesangial deposits

- IF: globular mesangial IgA deposits

72

Describe Anti-GBM Nephritis:

- Etiology and Pathogenesis

- Mediated by antibodies against type IV collagen within the glomerular basement membrane

- Disease may be renal limited or accompanied by pulmonary hemorrhage (Goodpasture’s syndrome) due to antibody deposition in alveolar basement membrane

73

Describe Anti-GBM Nephritis:

- Pt History and Clinical Presentation

Age: young adults (15-30 yo)

Race: no predominance

Sex: M > F (6x)

Associations

- Pulmonary hemorrhage (Goodpasture’s syndrome)

- ANCA-associated vasculitis (Wegener’s granulomatosis, Churg-Strauss syndrome)

Clinical Presentation

- Most commonly rapidly progressive glomerulonephritis (RPGN) with crescent formation

74

Describe Anti-GBM Nephritis:

- Lab Findings

- Renal Biopsy

Laboratory Findings

- (+) anti-GBM antibody

- Normal complements

Renal Biopsy

- LM: Crescent formation

- EM: Breaks in the glomerular basement membrane; no deposits

- IF: linear IgG deposits along the GBM

75

- A 30 yo male with no significant PMH comes in complaining of high BP (140s/90s using automated machine at pharmacy) and some swelling of his legs.

- On physical exam, BP is 145/90. Heart, lung, and abdominal exam are normal

- There is 1+ pitting edema in the lower extremities

Labs:

- Creatinine: 1.5 mg/dL (normal 1.0)

- Albumin 3.8 g/dL (normal 4.0)

- Urinary protein-creatinine ratio 1.5 g/g

- Urinalysis: 2+ blood, several dysmorphic RBCs/hbf

What is the LEAST likely cause of his symptoms?

A. IgA nephropathy

B. Postinfectious GN

C. Membranoproliferative GN

D. Minimal Change Disease

What is the LEAST likely cause of his symptoms?

A. IgA nephropathy

B. Postinfectious GN

C. Membranoproliferative GN

D. Minimal Change Disease

- HTN + edema + low GFR + Non-nephrotic range proteinuria + active urine sediment = Nephritic syndrome!

- Only minimal change disease is very unlikely to cause nephritic syndrome

76

- A 5 yo boy with no significant PMH is brought in by parents for facial and lower extremity swelling for 1 wk

- On physical exam, BP is normal

- Heart, lung, and abdominal exam are normal

- There is periorbital and 2+ lower extremity edema

Labs:

- Creatinine 0.4 mg/dL (normal)

- Albumin 2.5 g/dL (normal 4.0)

- C3 and C4 normal

- Urinalysis: 4+ protein, 0-1 RBCs/hpf, many fat oval bodies/hpf

Which of the following is the most likely diagnosis?

A. Membranous GN

B. Postinfectious GN

C. Minimal Change Disease

D. Focal Segmental Glomerulosclerosis

Which of the following is the most likely diagnosis?

A. Membranous GN

B. Postinfectious GN

C. Minimal Change Disease

D. Focal Segmental Glomerulosclerosis

- Young age + Sudden onset NEPHROTIC syndrome (low albumin, proteinuria, fat oval bodies, normal complement) + normal BP + normal renal function

- Age especially important here; in kids, MCD is no. 1 cause of nephrotic syndrome

77

- A 20 yo male with no significant PMH is evaluated for sudden-onset periorbital and pretibial edema, and hematuria.

- He had a recent episode of sore throat that has resolved, but is unsure how long ago.

- On exam, BP is 150/100

- Cardiac exam is normal

- There are crackles in both lung bases and bilateral lower extremity pitting edema. He has no rashes

Labs:

- Creatinine 1.5 mg/dL (normal 1.0)

- Albumin 3.8 g/dL (normal 4.0)

- Urinalysis: 1+ protein, several RBCs, and dysmorphic RBCs/hpf

Which of the following is the most likely diagnosis?

A. IgA Nephropathy

B. Postinfectious GN

C. Anti-GBM Nephritis

D. All of the above

B, but possibly A

Which of the following is the most likely diagnosis?

A. IgA Nephropathy

B. Postinfectious GN

C. Anti-GBM Nephritis

D. All of the above

- Young adult + Nephritic syndrome + Post-pharyngitic infection? + sudden-onset edema

- Anti-GBM nephritis tends to involve more acute symptoms?

78

Which set of lab tests would be most useful in making the diagnosis for the previous case? (Distinguishing between IgA Nephropathy, Postinfectious GN, anti-GBM nephritis)

A. Serum IgA level

B. Serum ASO titers, streptozyme, and copmlement levels

C. Anti-GBM antibody

A. Serum IgA level

B. Serum ASO titers, streptozyme, and copmlement levels

C. Anti-GBM antibody

- Complement levels only low in post-infectious GN

- Normal IgA levels would not rule out anything, since only positive in 50% of IgA Nephropathy cases

79

What would you expect to see on renal biopsy for Post-Infectious GN?

A. Mesangial proliferation (LM), mesangial deposits (EM), mesangial IgA deposits (IF)

B. Diffuse proliferation (LM), subepithelial "humps" (EM), IgG and C3 deposits (IF)

C. Crescent (LM), breaks in GBM (EM), IgG deposits along GBM (IF)

What would you expect to see on renal biopsy for Post-Infectious GN?

A. Mesangial proliferation (LM), mesangial deposits (EM), mesangial IgA deposits (IF)

B. Diffuse proliferation (LM), subepithelial "humps" (EM), IgG and C3 deposits (IF)

C. Crescent (LM), breaks in GBM (EM), IgG deposits along GBM (IF)

80

- 55 yo femal with no significant PMH is evaluated for generalized edema.

- Cardiac, pulmonary and abdominal exam are normal

- There is 3+ edema of the lower extremities. She has not had an annual exam/WWE in 5 years

Labs

- Creatinine 1.0 mg/dL (normal 1.0)

- Albumin 2.9 g/dL (normal 4.0)

- Urinalysis: 3+ protein, negative blood, no RBCs or WBCs

Which of the following is the most likely diagnosis?

A. Membranous Nephropathy

B. Focal Segmental Glomerulosclerosis

C. Minimal Change Disease

D. All of the above

Which of the following is the most likely diagnosis?

A. Membranous Nephropathy

B. Focal Segmental Glomerulosclerosis

C. Minimal Change Disease

D. All of the above

- Proteinuria + hypoalbuminemia + edema = likely NEPHROTIC SYNDROME

- Older female would perhaps favor Membranous Nephropathy

81

Which of the tests woudl be most useful in making the diagnosis for the previous case (distinguishing between Membranous Nephropathy, Focal Segmental Glomerulosclerosis, Minimal Change Disease)?

A. Serum complements

B. 24 hour urine collection for proteinuria

C. Lipid panel

D. Renal biopsy

Which of the tests woudl be most useful in making the diagnosis for the previous case?

A. Serum complements

B. 24 hour urine collection for proteinuria

C. Lipid panel

D. Renal biopsy

- Serum complements are normal in all 3 glomerular diseases

- Nephrotic-range proteinuria and hyperlipidemia can be present in all 3 diseases

82

What condition is expected from the following renal biopsy results:

- Thickening of GBM/glomerular cap wall (LM)

- Subepithelial deposits (EM)

- Granular deposits of Igs and complements along the GBM

Membranous GN

- Pt should be screened for malignancies