Clinical History:

A young man in his early 20's had a routine checkup by his family physician, which included a urinalysis. The urinalysis revealed a few RBC's. Physical examination was non-contributory. A repeat urinalysis shows dysmorphic RBC's and RBC casts, but no WBC's.

Image 3.1:

What does the light microscopy show?

There is mesangial proliferation. The capillaries appear normal.

Image 3.2:

What does the immunofluorescence show that represents the pattern seen with staining for both IgA and C3?

Mesangial deposition of IgA and C3. The C1q, IgM, and IgG are negative.

Image 3.3:

What does the urinalysis microscopic examination show?

These are dysmorphic red blood cells.

Questions:

1. What additional history do you want to know?

There was no history of trauma. He had no dysuria. He had a recent "flu-like" illness. There is no family history of renal disease. One maternal uncle is deaf.

2. What is the differential diagnosis?
• IgA nephropathy
• Alport's syndrome
• Vasculitis (Wegener's granulomatosis, SLE, polyarteritis nodosa)
• Urinary tract infection
3. What additional laboratory tests could be ordered?
• ANA - negative
• ANCA - negative
• Urine culture - negative
4. What diagnosis would you consider if the patient had presented with petechiae and purpura of the skin?

Henoch-Schönlein purpura