Neuraxial morphine might also reactivate herpes labialis (oral herpes or cold sores). (Image source: Thinkstock)

Neuraxial morphine might also reactivate herpes labialis (oral herpes or cold sores). (Image source: Thinkstock)

Anesthesiologists know that morphine is a powerful analgesic and are familiar with its side effects: apnea, itchiness, drowsiness, nausea and vomiting, bile duct spasm, and constipation, plus the risk of addiction when taken chronically. There are more and if we were examining you, we might ask you to list them.   For example, morphine may promote cancer growth, though it might additionally have proapoptotic and antiangiogenic effects.  Neuraxial morphine might also reactivate herpes labialis (oral herpes or cold sores).

Drs. M. Cecilia De Guzman and Kaylene Duttchen, Department of Anesthesia, University of Calgary, Calgary, Alberta, Canada, and Dr. Rupesh Chawla, Department of Pediatric Infectious Disease, Alberta Children’s Hospital, Calgary, Alberta, Canada, describe an infant who acquired oral herpes simplex virus (HSV) infection from the infant’s mother whose HSV reactivation was possibly related to the risk of neuraxial morphine reactivating oral HSV.  Their case study is described in the article “Possible Neonatal Herpes Simplex Virus (HSV) Acquired Postpartum from Maternal Oral HSV Reactivation after Neuraxial Morphine”and was featured in the 1 May 2014 issue of A&A Case Reports.

The mother was 37 years old and had a history of oral HSV with recurrences approximately twice yearly.  Delivery of her child was via elective cesarean section and a spinal anesthetic was used that contained hyperbaric bupivacaine 0.75%, 1.3 cc with 15-mcg fentanyl, and 150 mcg morphine. On the third day after delivery, the mother noted HSV lesions around her mouth area for which she took oral valacyclovir.  On the fifth day after delivery, however, the mother noticed 4 lesions on the newborn’s lower lip and immediately brought him to the hospital where 4 vesicular ulcers on the left inner lip were confirmed.  HSV could not be cultured from the ulcers because of technical issues.  Intravenous acyclovir was started: the oral lesions improved after 1 dose and completely resolved after 1 week.

It’s not clear if reactivation of the mother’s HSV was due to the use of morphine, fentanyl, or simply the stress due to her pregnancy.  As Dr. Jeanette Bauchat, Department of Anesthesiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, notes in the accompanying editorial titled “Editorial Comment: Possible Neonatal Herpes Simplex Virus (HSV) Acquired Postpartum from Maternal Oral HSV Reactivation after Neuraxial Morphine,”“Mothers should be made aware that HSV reactivation occurs after cesarean delivery with or without the use of intrathecal morphine.  Anesthesiologists, obstetricians, and nurses should attempt to elicit a history of herpes labialis from women undergoing cesarean delivery and advise them to monitor themselves for signs of reactivation, request antiviral treatment if reactivation is suspected, and adhere to strict hand hygiene while refraining from kissing infants’mucous membranes or open wounds (e.g., fetal scalp monitoring site) even without evidence of reactivation.”