Question

Patient presenting with cutaneous vasculitis, glomerulonephritis, peripheral neuropathy, Which investigation is to be performed next that will help you diagnose the condition?

• A. ANCA
• B. RA factor
• C. Hbsag
• D. MIF

Answer 1

The Correct Option is A

To diagnose the condition involving cutaneous vasculitis, glomerulonephritis, and peripheral neuropathy, one must focus on both the symptoms and the appropriate diagnostic tests. The key investigation to perform is an ANCA (Anti-Neutrophil Cytoplasmic Antibodies) test. This urinary and serological test is crucial for diagnosing autoimmune conditions such as microscopic polyangiitis and granulomatosis with polyangiitis (Wegener's granulomatosis), both conditions associated with systemic vasculitis.

• Rationale: The presence of cutaneous vasculitis and glomerulonephritis is often associated with ANCA-associated vasculitis. Since our primary goal is to distinguish this specific set of possible conditions, ANCA is the logical choice.
• The alternatives do not directly link the symptoms:

Options	Reasons
ANCA	Helps identify conditions like granulomatosis with polyangiitis, crucial for matching symptoms.
RA factor	Related to rheumatoid arthritis, less relevant for glomerulonephritis or peripheral neuropathy.
Hbsag	Differentiates hepatitis infections, not immediately relevant to vasculitis.
MIF	Less standard for this symptom triad.

By centering the investigation on ANCA, we find congruence between rapid-diagnostic strategy and clinical symptomatology, providing an efficient pathway to diagnosis.