Excretory System

Question 1

All of the following about xanthogranulomatous pyelonephritis are true except
A. On cut section yellowish nodules are seen
B. Associated with tuberculosis
C. Foam cells are seen
D. Giant cells are seen

Answer 1

Answer- B. Associated with tuberculosis

Xanthogranulomatous pyelonephritis

1. Unusual variant of chronic pyelonephritis. Most cases occur in the setting of obstruction due to infected renal stones.
2. Grossly - yellow, lobulated masses diffusely replace renal architecture.
3. Microscopically - There is massive destruction of the kidney due to granulomatous tissue containing lipid-laden macrophages(foam cells)
4. Clinical features - occurs most often in middle aged women, with history of recurrent UTIs, typical presentation - flank pain, fever, malaise, anorexia and weight loss.
5. Diagnosis - Examination of urine confirms the presence of UTI. Urine culture typically demonstrates enterobacteriaceae. The most common organisms associated with XPN are E.coli, Proteus mirabilis, Pseudomonas, Streptococcus faecalis and Klebsiella.

Question 2

The pathological feature in Wegener's granulomatosis on renal biopsy is 
A. Nodular glomerulosclerosis
B. Focal necrotizing glomerulonephritis
C. Granulomas in the vascular wall
D. Granuloma of parenchyma of kidney

Answer 2

Answer- B. Focal necrotizing glomerulonephritis

Wegener’s granulomatosis is an necrotizing vasculitis which is characterized by triad of

1. Acute necrotizing granulomas of either upper or lower respiratory tract or both
2. Focal necrotizing or granulomatous vasculitis , most commonly affecting lungs and upper airways.
3. Renal involvement in the form of focal necrotizing, often crescentic glomerulonephritis.

c-ANCA is present in upto 90% cases.
Necrotizing vasculitis of small arteries and veins with granuloma formation is seen in pulmonary tissue whereas granuloma formation in rarely seen on renal biopsy.

Question 3

The cytogenetics of chromophilic renal cell carcinoma is characterized by
A. Mutant VHL gene
B. Loss of 3p 
C. Trisomy 7/17
D. Loss of 5q 3

Answer 3

Answer- C. Trisomy 7-17

Chromophilic renal cell cancer is the other name of papillary renal cell cancer because 80% of chromophilic renal cell cancers show a tubulopapillary architecture.

Question 4

What is the cause of hypercoagulation in nephrotic syndrome -
A. Loss of anti thrombin III
B. Decreased fibrinogen 
C. Decreased metabolism of vitamin K
D. Increase in protein C

Answer 4

Answer- A. Loss of antithrombin III

Thrombotic and thromboembolic complications are common in nephrotic syndrome due to loss of anticoagulant factor (e.g. Antithrombin III, protein C and protein S) combined with increased platelet activation.
Renal vein thrombosis is most often a consequence of this hypercoagulative state. There is also increased synthesis of fibrinogen in liver.

Question 5

Finnish types of nephrotic syndrome is associated with 
A. Nephrin
B. Podocin
C. Alpha actinin
D. CD2 activated protein

Answer 5

Answer- A. Nephrin

A mutation in nephrin (NPHS 1) gene causes a hereditary form of congenital nephrotic syndrome (Finnish type) with minimal change glomerular morphology whereas mutations in NPHS 2 coding for podocin results in steroid resistant nephrotic syndrome.

NPHS 1 - 19q 13 - nephrin - steroid sensitive/ Finnish type nephrotic syndrome.
NPHS 2 - 1q25 - podocin - steroid resistant nephrotic syndrome.