3. Differential diagnosis in nephrology

Question 1

What are the main renal symptoms?

Answer 1

Most renal diseases present insidiously without pain, frequently only with laboratory abnormalities.

Question 2

What are some urological causes of hematuria?

Answer 2

• Renal/ uroepithelial tumor,
• stone,
• UTI ( eg.cystitis),
• renal cyst rupture,
• papillary necrosis.

Question 3

What are some nephrological causes of hematuria?

Answer 3

• Glomerulonephritis (!!!)
• Alport -syndrome,
• thin basement membrane disease,
• acute interstitial nephritis.

Question 4

How can microscopic urinary sediment examination help differentiate between urological and nephrological causes of hematuria?

Answer 4

Urological causes have similar RBCs (isomorphic), while nephrological causes have variable appearance of RBCs (dysmorphic)

Question 5

What is the differential diagnosis for acute cholecystitis?

Answer 5

• Pancreatic tumor,
• pancreatitis,
• colon neoplasm,
• spleen infarct.

Question 6

What is the normal protein excretion in urine per day?

Answer 6

Up to 200 mg/day (20 mg/mmol).

Question 7

What is the main protein secreted in the loop of Henle?

Answer 7

Tamm-Horsfall protein (uromodulin).

Question 8

What is the normal albuminuria per day?

Answer 8

<30mg/day (<3mg/mmol).

Question 9

What is the normal protein/creatinine ratio in spot urine?

Answer 9

20 mg protein/mmol creatinine.

Question 10

What is the normal albumin/mmol creatinine in spot urine?

Answer 10

3mg albumin/mmol creatinine (normoalbuminuria).

Question 11

What is the corresponding amount of proteinuria for a spot urine protein/creatinine ratio of 100 mg/mmol?

Answer 11

1 g/day proteinuria.

Question 12

What is the term for hematuria with normal RBC morphology?

Answer 12

Isomorphic hematuria.

Question 13

What is the definition of “clinically significant” proteinuria?

Answer 13

> 500mg/day (>50mg/ mmol creatinine).

Question 14

What is the treatment target for most glomerular diseases?

Answer 14

Less than 500mg/day.

Question 15

What is the definition of albuminuria?

Answer 15

> 30mg/day (3 mg/mmol).

Question 16

What does a urine dipstick detect mainly?

Answer 16

Albumin.

Question 17

What is the range of “nephrotic” range proteinuria?

Answer 17

> 3-3.5g/day (0.3 -0.35 g/ mmol).

Question 18

What is the differential diagnosis for proteinuria if it is >200mg/day or >20mg/mmol?

Answer 18

• Spurious proteinuria (non-renal),
• functional : fever, orthostatic
• glomerular : glomerulonephritis,
• tubular : tubulointerstitial disease,
• “overflow”

Question 19

What is a “differential diagnosis” in nephrology?

Answer 19

It is the process of distinguishing between different diseases that have similar symptoms in the kidneys.

Question 20

What are the frequently used immunological tests in the diagnosis of renal diseases?

Answer 20

ANA (anti-nuclear antibody) and ANCA (anti-neutrophil cytoplasmic antibody).

Question 21

What is Fanconi syndrome?

Answer 21

It is a condition where there is damage to the proximal tubule in the kidneys, leading to a failure to reabsorb small molecular weight proteins.

Question 22

What is Bence-Jones proteinuria?

Answer 22

It is a type of “overflow” proteinuria where there is a high amount of small molecular weight protein in the serum that overflows reabsorption, such as kappa/lambda light chains.

Question 23

What is the significance of ANA (anti-nuclear antibody)?

Answer 23

It is associated with SLE and other systemic autoimmune diseases.

Question 24

What is the significance of ANCA (anti-neutrophil cytoplasmic antibody)?

Answer 24

It is associated with small vessel vasculitis (pauci-immune crescentic GN).

Question 25

What is the significance of anti-dsDNS antibody?

Answer 25

It is associated with SLE.

Question 26

What is the significance of anti-GBM antibody?

Answer 26

It is associated with Goodpasture syndrome.

Question 27

What is the significance of anti-streptolysin antibody?

Answer 27

It is associated with poststreptococcal glomerulonephritis.

Question 28

What is the significance of complement 3 and 4 decrease?

Answer 28

It is associated with SLE and cryoglobulinemia.

Question 29

What is the significance of phospholipase A2 receptor antibody?

Answer 29

It is associated with membranous nephropathy.

Question 30

What are the defining characteristics of nephrotic syndrome?

Answer 30

- Proteinuria (usually > 3.5g/day), - hypalbuminemia, - edema, - hyperlipoproteinemia, - thromboembolic events, - GFR may be normal.

Question 31

What are the primary renal diseases that can cause nephrotic syndrome?

Answer 31

- Primary membranous glomerulopathy (usually anti-PLA2 receptor antibody positive), - minimal change nephropathy, - focal segmental glomerulosclerosis.

Question 32

What are the systemic diseases that can cause renal manifestation of nephrotic syndrome?

Answer 32

- Diabetic nephropathy, - amyloidosis, - secondary FSGS (HIV, extreme obesity), - secondary membranous glomerulopathy (lupus nephritis, mixed cryoglobulinemia).

Question 33

What is the further differentiation process for nephrotic syndrome?

Answer 33

It involves immunoserology and kidney biopsy.

Question 34

What are the possible causes of secondary membranous glomerulopathy?

Answer 34

Lupus nephritis, malignancy, drugs, hepatitis B/C, syphilis, NSAIs, TNF-inhibitors.

Question 35

What are the possible causes of proliferative glomerulonephritis?

Answer 35

- Immune complex and/or complement disregulation mechanisms, - poststreptococcalis glomerulonephritis, - postinfectiosus glomerulonephritis, - membranoproliferative glomerulonephritis.

Question 36

What are the symptoms of nephritic syndrome?

Answer 36

- Hematuria - Urinary casts - Hypertension - Edema - Oliguria - Decreased GFR

Question 37

What are some symptoms of Rapidly Progressive Glomerulonephritis Syndrome (RPGN)?

Answer 37

- Rapid worsening of kidney function, - nephritic urinary findings, - frequent systemic symptoms such as vasculitis, pulmonary bleeding, arthritis, fever, and neuropathy.

Question 38

What is the prognosis for untreated RPGN?

Answer 38

The prognosis for untreated RPGN is dismal.

Question 39

What is the typical finding in light microscopy for RPGN?

Answer 39

Light microscopy usually shows crescents with parietal cell proliferation (extracapillary proliferation).

Question 40

What are some contraindications to renal biopsy?

Answer 40

Uncooperative patient, single kidney, multiple renal cysts, renal neoplasm, acute pyelonephritis, uncontrolled bleeding diathesis, and uncontrolled blood pressure (BP > 160/95 mmHg).

Question 41

What are the different patterns observed in immunofluorescent microscopy in the evaluation of a biopsy sample in nephrology?

Answer 41

Granular pattern, Linear pattern, Pauci-immune pattern.

Question 42

What is an asymptomatic urinary abnormality in nephrology?

Answer 42

Non-nephrotic proteinuria and/or hematuria without nephritic syndrome, usually 0.5-2g/day

Question 43

What are some causes of asymptomatic proteinuria?

Answer 43

- early diabetic nephropathy, - secondary FSGS, - hypertensive nephropathy

Question 44

What are some causes of asymptomatic hematuria?

Answer 44

glomerular diseases such as - IgA nephropathy - Alport syndrome, - thin-basement membrane abnormality

Question 45

What are some signs and symptoms of chronic kidney disease?

Answer 45

- decreased GFR, - usually small kidneys with echogenic parenchyma, - variable urinary abnormalities, - complications according to the stages of CKD such as hypertension, electrolyte-acid base alterations, anemia, and cardiovascular diseases.

Question 46

What should be done in cases of slow progression of chronic kidney disease?

Answer 46

In cases of slow progression of chronic kidney disease, preparation for renal replacement therapy and prevention of complications should be done.