**Question:** Sympathectomy is indicated in all of the following except: a) Ischaemic ulcers, b) Intermittent claudication, c) Anhidrosis, d) Acrocyanosis.

**Core Concept:** Sympathectomy is a surgical procedure that involves the removal or destruction of sympathetic nervous system neurons. In certain conditions, sympathetic nerve activity can exacerbate the disease process, and reducing this activity can improve symptoms.

**Why the Correct Answer is Right:** Sympathectomy is generally not indicated in conditions that primarily affect skin blood flow regulation. In ischaemic ulcers (A), intermittent claudication (B), and acrocyanosis (D), the primary issue is impaired blood flow due to atherosclerosis, peripheral arterial disease, and Raynaud's phenomenon, respectively. Sympathectomy would not address the underlying cause of these conditions but could potentially worsen them by reducing blood flow further.

**Why Each Wrong Option is Incorrect:**

- Anhidrosis (C): This refers to a reduced sweating caused by impaired sweat gland function. While sympathetic activity might contribute to hyperhidrosis (excessive sweating), it is not the primary issue in anhidrosis, making sympathetic denervation unnecessary in this case.

**Clinical Pearl:** Sympathectomy is usually considered in conditions like pheochromocytoma, essential hypertension, or hyperthyroidism where excessive sympathetic activity plays a significant role in the disease pathogenesis.

**Correct Answer:** .

Answer: C (Anhidrosis)

Explanation: Sympathectomy is typically not indicated in cases where hypohidrosis (reduced sweating) is the primary concern, such as in anhidrosis. In anhidrosis, the reduced sweating results from impaired sweat gland function, making sympathetic denervation less relevant and unnecessary in this context.