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.
History
The approval of pexidartinib was based on the results of a multi-center international clinical trial of 120 subjects, 59 of whom received placebo. The primary efficacy endpoint was the overall response rate (ORR) analyzed after 25 weeks of treatment. The clinical trial demonstrated a statistically significant improvement in ORR in subjects who received pexidartinib, with an ORR of 38%, compared to no responses in subjects who received placebo. The complete response rate was 15% and the partial response rate was 23%. A total of 22 out of 23 responders who had been followed for a minimum of six months following the initial response maintained their response for six or more months, and a total of 13 out of 13 responders who had been followed for a minimum of 12 months following the initial response maintained their response for 12 or more months.The U.S. Food and Drug Administration (FDA) granted the application for pexidartinib breakthrough therapy designation, orphan drug designation, and priority review designation. The FDA granted the approval of Turalio to Daiichi Sankyo. References
Further reading
"Pexidartinib". LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases. October 2019. PMID 31869194. NBK551730. Lamb YN (November 2019). "Pexidartinib: First Approval". Drugs. 79 (16): 1805–1812. doi:10.1007/s40265-019-01210-0. PMC 7044138. PMID 31602563. Roskoski R (February 2020). "Properties of FDA-approved small molecule protein kinase inhibitors: A 2020 update". Pharmacol. Res. 152: 104609. doi:10.1016/j.phrs.2019.104609. PMID 31862477. S2CID 209435035. External links
"Pexidartinib". Drug Information Portal. U.S. National Library of Medicine.