An 18 year old boy presents with digital gangrene In third and fouh fingers for last 2 weeks. On examination the blood pressure is 170/110 mm of Hg and all peripheral pulses were palpable. Blood and urine examinations were unremarkable. Antinuclear antibodies, antibody to double stranded DNA and antineutrophil cytoplasmic antibody were negative. The most likely diagnosis is:

**Core Concept**
The patient's presentation of digital gangrene in the setting of hypertension and palpable peripheral pulses suggests a vasculopathic process, specifically involving the microvasculature of the fingers. This condition is characterized by inflammation and thrombosis of the small and medium-sized blood vessels.

**Why the Correct Answer is Right**
The diagnosis of **Buerger's disease** (Option B) is likely due to the combination of digital gangrene, hypertension, and palpable peripheral pulses. Buerger's disease, also known as thromboangiitis obliterans, is a non-atherosclerotic, segmental inflammatory disease of the blood vessels, primarily affecting the small and medium-sized vessels of the limbs. The inflammation and thrombosis of these vessels lead to reduced blood flow, resulting in gangrene of the affected digits.

**Why Each Wrong Option is Incorrect**
**Option A:** **Raynaud's phenomenon** is a condition characterized by vasospasm of the digital arteries in response to cold temperatures or emotional stress, leading to digital ischemia. However, it is typically associated with normal peripheral pulses and does not usually result in gangrene.

**Option C:** **Scleroderma** is a chronic autoimmune disease characterized by fibrosis and vascular damage, leading to digital ischemia and gangrene. However, the presence of antinuclear antibodies, antibody to double-stranded DNA, and antineutrophil cytoplasmic antibody would be expected in a patient with scleroderma, which is not the case here.

**Option D:** **Diabetic microangiopathy** is a complication of diabetes mellitus, characterized by damage to the small blood vessels, leading to digital ischemia and gangrene. However, the patient's blood and urine examinations were unremarkable, making diabetes an unlikely diagnosis.

**Clinical Pearl / High-Yield Fact**
Buerger's disease is a smoking-related disease, and smoking cessation is essential for managing the condition. Patients with Buerger's disease often present with symptoms of claudication, pain at rest, and gangrene of the digits.

**Correct Answer:** B. Buerger's disease.

✓ Correct Answer: B. Polyaeritis nodosa