A 60-year-old woman presents with generalized edema, skin ulceration and hypertension. Urine examination shows subnephrotic proteinuria (<2gm) and microscopic haematuria. Serum complement levels are decreased and she is positive for anti-hepatitis c antibodies. The likely diagnosis is –

**Core Concept**
The patient's presentation of generalized edema, skin ulceration, hypertension, subnephrotic proteinuria, and microscopic haematuria in the context of decreased serum complement levels and positive anti-hepatitis C antibodies suggests an immune-mediated glomerulonephritis.

**Why the Correct Answer is Right**
The patient's symptoms and laboratory findings are consistent with membranoproliferative glomerulonephritis (MPGN), a type of glomerulonephritis characterized by the deposition of immune complexes and complement activation. The presence of anti-hepatitis C antibodies suggests that the patient's MPGN is secondary to chronic hepatitis C infection, which is a known cause of MPGN. The decreased serum complement levels are consistent with the activation of the complement system in MPGN. The subnephrotic proteinuria and microscopic haematuria are also consistent with MPGN.

**Why Each Wrong Option is Incorrect**
**Option A:** Focal segmental glomerulosclerosis (FSGS) typically presents with nephrotic range proteinuria (>3.5g/day) and is not typically associated with decreased serum complement levels or positive anti-hepatitis C antibodies.

**Option B:** IgA nephropathy typically presents with episodic hematuria and is not typically associated with decreased serum complement levels or positive anti-hepatitis C antibodies.

**Option C:** Lupus nephritis can present with a wide range of renal manifestations, but the presence of anti-hepatitis C antibodies is not a typical feature.

**Clinical Pearl / High-Yield Fact**
Chronic infections such as hepatitis C can trigger the development of immune-mediated glomerulonephritis, including MPGN, emphasizing the importance of screening for underlying infections in patients with unexplained renal manifestations.

**Correct Answer:** C.

✓ Correct Answer: B. Essential mixed cryoglobulinemia