Question 39

Question:

A 13-year-old figure skater botches a quadruple lutz and falls on her right outstretched hand. Several weeks later a cast is removed for a healed scaphoid fracture. She begins having episodes of intense burning pain, sweating, swelling, and redness that begin in her right hand and moves up her forearm, sometimes up to her shoulder. These episodes often occur when she is angry or upset. On exam her arm shows no visible abnormalities. Which of the following nerve types are involved in the pathogenesis of her disorder?

Correct Answer: C.  General visceral afferent

Correct Answer: C. General visceral afferent

Reflex sympathetic dystrophy (complex regional pain syndrome) is a mysterious disorder that often occurs after injury to an extremity. It is thought to be due to the formation of an abnormal sympathetic reflex arc that becomes modulated by cortical inputs in times of stress. The key to this diagnosis is that it does not obey any specific nerve distribution and the symptoms reflect vasospasm. Sympathetic reflexes are autonomic, consisting of a general visceral afferent (GVA) arm and general visceral efferent (GVE) arm. Even if you did not know the diagnosis, the episodic diaphoresis and vasodilation should point you towards an autonomic pathogenesis. Special somatic afferents (SSA) are only involved in the sensation of vision, hearing, and balance. General somatic afferents (GSA) provide sensation from all parts of the body except the gut, smooth muscle, and glands. Special visceral afferents (SVA) innervate taste and smell. General somatic efferents (GSE) innervate somatic muscles.