**Question:** True about autonomic neuropathy are all except

A. Autonomic neuropathy is a rare condition affecting the autonomic nervous system.
B. Symptoms of autonomic neuropathy include excessive sweating and rapid heart rate.
C. Autonomic neuropathy can be caused by vitamin B12 deficiency.
D. Autonomic neuropathy is characterized by loss of bladder and bowel control.

**Correct Answer:** .

**Core Concept:** Autonomic neuropathy refers to a group of disorders that affect the autonomic nervous system, which controls involuntary functions such as heart rate, blood pressure, digestion, and sexual function. This system has two branches: sympathetic and parasympathetic, which work together to maintain homeostasis in the body.

**Why the Correct Answer is Right:** Option A is incorrect because autonomic neuropathy is not rare; it can be caused by various factors such as diabetes, infections, medications, and hereditary conditions. Symptoms can indeed include excessive sweating and rapid heart rate (bradycardia), but some patients may present with different symptoms like orthostatic hypotension and erectile dysfunction.

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because autonomic neuropathy can be caused by a variety of factors, making it a common condition rather than rare.

B. While excessive sweating is a common symptom in some forms of autonomic neuropathy, rapid heart rate (bradycardia) is not a universal symptom. Autonomic neuropathy can present with a wide spectrum of symptoms, and bradycardia is not typically a defining feature.

C. Vitamin B12 deficiency is a rare cause of autonomic neuropathy, so this statement is incorrect. Autonomic neuropathy from vitamin B12 deficiency usually presents with neurological symptoms affecting the peripheral nerves (peripheral neuropathy), rather than autonomic dysfunction.

D. Loss of bladder and bowel control is a common manifestation of autonomic neuropathy; however, this statement is incorrect because autonomic neuropathy may have various presentations and not solely involve bladder and bowel control.

**Clinical Pearl:** Autonomic neuropathy can present with various symptoms depending on the affected nerves and the underlying cause. Understanding the clinical scenario, symptoms, and investigations can help narrow down the differential diagnosis and guide treatment decisions.