8.14 Proteinuria, Nephrotic & Nephritic Syndrome

Question 1

What structures of the glomeruli is normally damaged?

Answer 1

• Basal membrane
• epithelium

Question 2

Normal urine protein

Answer 2

<150 mg/d

Question 3

Why don’t you normally get albumin and IgG in urine?

Answer 3

Molecules are to big in normal instances

Question 4

Mechanisms preventing protein loss

Answer 4

• physical filtration barrier (proteins = macromolecules)
• electrical barrier (protein negatively charged)
• tubular reabsorption ±1.5 g/d LMW proteins filtered reabsorbed by proximal tubule

Question 5

If there is tubular damage what happens?

Answer 5

Glomerulus “holes” gets bigger and albumin leak
Holes between prodocytes processes become bigger

Proteinuria = glomeruli damage

Question 6

NB Quantification of urinary protein

Answer 6

Semi-quantitive: only roughly
- Urine dipstick
- sulphosalicylic acids

Quantitative:
- 24hr urine collection (not very acurate)
- spot sample urine protein: creatine ratio (UPCR)

Question 7

What protein does urine dipsticks pick up?

Answer 7

Only pick up Albumin when it is in excess of >300 mg/day
NO OTHER PROTEIN; not immunoglobulins

Trace = <300mg/day

Question 8

What proteins does sulfosalicylic acid (SSA)?

Answer 8

ALL proteins

If urine dip ➖ & SSA ➕ = not albumin but IMMUNOGLOBULINS

Question 9

Why is the 24hr urine protein sample collection not used anymore?

Answer 9

• inaccurate
• cumbersome
• cannot be used in out pt setting
• UPCR have perfect correlation with the 24hr protein (when pt is in steady state)
• there it doesn’t matter how much urine is used for the test, the results will stay the same (not nesseasary for 24hr urine collection)

Question 10

Causes of proteinuria

Answer 10

Non-pathological / functional = hemodynamic effects on kidney
- heart failure
- fever
- strenuous exercise
- autostaic proteinuria (young women)

Pathological
- overflow proteinuria (Bens-jones / immunoglobins light chain in urine)
- Glomerular damage (leak albumin)
- tubular damage (>1.5 reabsorbed)

Question 11

Glomerular injury

Answer 11

1. Infam
- cells infiltrate kidney and damage
- swelling
- leaks proteins and other blood component (RBC, WBC) = Nephritis / Glomerular nephritis

2. Structural damage
- to podocytes
- genetic causes (missing structural podocytes)
- only protein leaks
- Nephrotic syndrome

Asym haematuria/proteinuria ➡️ Acute glomerulonephritis / nephrotic syndrome

Question 12

NB Nephritis syndrome
Def

Answer 12

• haematuria ± proteinuria
• renal failure
• oedema
• hypertention
• Oliguria (<400 ml/day)
• RBC cast pathonemonic of NS

Proteinuria >3.5 g/day = can’t diagnose without THIS!!!

Question 13

Glomerular disease
Causes

Answer 13

Needs to exclude secondary cause first
Slide 23

Primary Diagnosis of exlusion
- Membranous GN
- FSGS
- Mesangiocapillary GN
- Minimal change disease

Secondary
- DM
- SLE
- Infec: HIV, Hep B & C
- pre-eclampsia
- drugs
- amyloids
- malignancies

Question 14

Finish on slides

Answer 14

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