Color of hand change to following color, when a patient of Raynaud’s disease puts his hand in cold water:
**Core Concept**
Raynaud's disease is a vasospastic disorder characterized by episodic vasospasm of the small arteries and arterioles in response to cold temperatures or emotional stress, leading to reduced blood flow to the affected areas. The condition is often associated with an imbalance between vasodilatory and vasoconstrictive signals in the sympathetic nervous system.
**Why the Correct Answer is Right**
When a patient with Raynaud's disease exposes their hand to cold water, the cold stimulus triggers the release of norepinephrine from sympathetic nerve endings, causing intense vasoconstriction of the arterioles. This vasoconstriction leads to a significant reduction in blood flow to the hand, resulting in a characteristic color change. The subsequent reduction in oxygen delivery to the tissue leads to the characteristic color change, which typically progresses from white (ischemic), to blue (cyanotic), and finally to red (reactive) as the body attempts to restore blood flow.
**Why Each Wrong Option is Incorrect**
* **Option A:** There is no direct association between Raynaud's disease and the color change described in this option.
* **Option B:** This option is not related to the pathophysiology of Raynaud's disease or the color changes associated with it.
* **Option C:** This option does not accurately describe the sequence of color changes seen in Raynaud's disease.
**Clinical Pearl / High-Yield Fact**
In Raynaud's disease, the sequence of color changes (white, blue, red) is often remembered using the mnemonic "White, Blue, Red" to indicate the progression from ischemia, to cyanosis, and finally to reactive hyperemia.
**Correct Answer:** C.