Such bundles are able to send an action potential from the autonomic nervous system to the rest of the body. However, action potentials in this system are not being received by the second or third thoracic vertebrae which innervates the face, neck, and upper chest. Damage or lesions near T2 or T3 could be between the stellate ganglion and superior cervical ganglion. This is where we would observe absence of sweat and skin flushing on one side of the face, neck, and upper chest. Diagnosis
Diagnosis of Harlequin syndrome is made when the individual has consistent signs and symptoms of the condition, therefore, it is made by clinical observation. In addition, a neurologist or primary care physician may require an MRI test to rule out similar disorders such as Horners syndrome, Adies syndrome, and Ross syndrome. In an MRI, a radiologist may observe areas near brain or spinal cord for lesions, or any damage to the nerve endings. It is also important that the clinician rules out traumatic causes by performing autonomic function tests. Such tests includes the following: tilt table test, orthostatic blood pressure measurement, head-up test, valsalva maneuver, thermoregulatory sweat test, tendon reflex test, and electrocardiography (ECG). CT scan of the heart and lungs may also be performed to rule out a structural underlying lesion. The medical history of the individual should be carefully noted. Treatment and prognosis
Harlequin syndrome is not debilitating so treatment is not normally necessary.
Harlequin syndrome is a condition characterized by asymmetric sweating and flushing on the upper thoracic region of the chest, neck and face. Harlequin syndrome is considered an injury to the autonomic nervous system (ANS). The ANS controls some of the bodys natural processes such as sweating, skin flushing and pupil response to stimuli. Such individuals with this syndrome have an absence of sweat skin flushing unilaterally; usually on the one side of the face, arms and chest. It is an autonomic disorder that may occur at any age. Harlequin syndrome affects fewer than 200,000 people in the United States. Symptoms associated with Harlequin syndrome are more likely to appear when a person has been in the following conditions: exercising, warm environment and intense emotional situation. Since one side of the body sweats and flushes appropriately to the condition, the other side of the body will have an absence of such symptoms. This syndrome has also been called the "Harlequin sign" and thought to be one of the spectrum of diseases that may cause Harlequin syndrome. It can also be the outcome of a one sided endoscopic thoracic sympathectomy (ETS) or endoscopic sympathetic blockade (ESB) surgery.Harlequin syndrome can also be seen as a complication of VA (veno-arterial) extracorporeal membrane oxygenation (ECMO). This involves differential hypoxemia (low oxygen levels in the blood) of the upper body in comparison to the lower body. Signs and symptoms
The "Harlequin sign" is unilateral flushing and sweating of the face, neck, and upper chest usually after exposure to heat or strenuous exertion.