J Med Assoc Thai Vol. 90 No. 12 2007 2669 Correspondence to : Niempoog S, Department of Orthopaedic Surgery, Faculty of Medicine, Thammasat University, Klong Luang, Pathum Thani 12120, Thailand. Phone: 0-2926-9775, Fax: 0-2926-9793. E-mail: sunyarn@yahoo.com Local Injection of Dexamethasone for the Treatment of Carpal Tunnel Syndrome in Pregnancy Sunyarn Niempoog MD*, Prakasit Sanguanjit MD*, Thanapong Waitayawinyu MD*, Chayanin Angthong MD* * Department of Orthopaedic Surgery, Faculty of Medicine, Thammasat University, Klong Luang, Pathum Thani Objective: To evaluate the results of 4 mg of dexamethasone acetate injections for the treatment of carpal tunnel syndrome in pregnancy. Material and Method: Twenty-four pregnant volunteers who suffered from carpal tunnel syndrome occurring in the third trimester of their pregnancies were injected with 4 mg of dexamethasone acetate combined with 1% lidocaine into the carpal tunnels. The volunteers filled the Boston symptom severity questionnaire and were examined by Phalen’s test, Semmes-Weinstein monofilament test, grip strength, and pinch strength before injection, one month after injection, and one month after delivery. Results: There was significant improvement of symptoms, grip strength and pinch strength of the injected hand compared with the opposite side at one month after injection (p < 0.01). However, after delivery, the symptoms of carpal tunnel syndrome improved on both the injected and opposite hands. Conclusion: Carpal tunnel syndrome in pregnancy is generally resolved after delivery and, therefore, should be treated conservatively. The patient with severe symptoms can be treated with dexamethasone injection in the third trimester with good results. Keywords: Carpal tunnel syndrome, Pregnancy, Steroid injection Carpal tunnel syndrome results from com- pression of the median nerve at the wrist joint level. The most common cause of carpal tunnel syndrome is idiopathic. Among the other causes of carpal tunnel syndrome (wrist trauma, diabetes mellitus, hypothy- roidism, rheumatoid arthritis, occupation, contracep- tion and pregnancy), pregnancy is the most frequent physiologic cause (1) . The incidence of carpal tunnel syndrome in pregnancy, which varies between 1-50% of pregnant women (2-4) , depends on method of diag- nosis. The majority of cases occurs during the third trimester of pregnancy, and involves the bilateral hand (5-7) . The most common symptoms are paresthesia and nocturnal pain (3) . Fluid retention and musculo- skeletal changes in transverse carpal ligament have been proposed as the cause of carpal tunnel syndrome in pregnancy (3,5) . These mechanisms are different from idiopathic carpal tunnel syndrome, resulting in difference of progression and prognosis. Generally, the symptoms of carpal tunnel syndrome in pregnancy diminish after delivery (1-9) . Statistically, 75% of symp- tomatic women suffer from severe pain, numbness, tingling sensation or sleep disturbance during the third trimester (2) , while only 16% are treated by a physician (2) . Previous reports emphasized that women who suffered carpal tunnel syndrome during pregnancy should be treated conservatively (1-12) . The conservative treatments are composed of wrist splinting (3,10) and local steroid injection (5-7,11-12) , which is similar to the idiopathic carpal tunnel syndrome (13,14) . Even splinting alone is effective; it is cumbersome and causes discomfort. The treatment with a single dose of steroid injection without splinting seems to be more acceptable by pregnant patients. Although, steroid injection is widely used for treatment of carpal tunnel syndrome, there is no consensus about type and dose of injected steroid for the treatment in pregnancy induced carpal tunnel syndrome. Usually the type of steroid used is based J Med Assoc Thai 2007; 90 (12): 2669-76 Full text. e-Journal: http://www.medassocthai.org/journal Preliminary Report