Outbreak Investigation of Adverse Health Effects Following Use of Synthetic Marijuana, Colorado, September 2013

BACKGROUND: On August 30, 2013, the Colorado Department of Public Health and Environment (CDPHE) received calls from local public health departments regarding an unusual increase in patients presenting to emergency departments (EDs) with mental status change following use of synthetic marijuana. Reported symptoms were severe, with some affected patients requiring hospitalization, including ICU admission. Because the outbreak involved multiple county jurisdictions, CDPHE took the lead on conducting an epidemiologic investigation.

METHODS:   CDPHE sent Health Alert Network (HAN) announcements requesting all Colorado EDs use EMResource (an Emergency Preparedness communications system) to report patients with altered mental status after use of synthetic marijuana. CDPHE began developing an epidemiologic questionnaire and medical chart review instrument, along with a corresponding database. Teams were convened to abstract medical charts, enter data electronically, and conduct patient interviews by phone. Frequent situational briefs were organized via teleconference. CDPHE also officially requested federal resources and an Epi Aid team from the Centers for Disease Control and Prevention (CDC) was deployed to provide assistance. Data gathered from initial chart reviews were analyzed by investigators to create a case definition and gather further information related to the outbreak. A preliminary report was distributed to all partners on September 23, 2013 and an evaluation of the outbreak response was conducted on November 12, 2013.

RESULTS:   In just ten days, 58 charts from five hospitals around the Denver metro area, and nine patient interviews, were available for in-depth analysis of clinical symptoms and exposure details. A total of 263 patient reports were received from EDs around the state between August 21 and September 19, 2013. Of the 263 reports, 221 (84%) were classified as probable cases, 27 (10%) as suspect cases, and 15 (6%) did not meet our case definition. CDPHE released messaging regarding the dangers of synthetic marijuana via social media and traditional press. Because teens and young adults represented a large percentage of patient reports, focus groups and key informant interviews with drug-using youth were conducted to develop a public awareness campaign. Public Service Announcements were displayed on buses in the Denver Metro area, and in restaurants and bars within targeted ZIP codes.

CONCLUSIONS:   CDPHE’s rapid response to further describe and characterize this novel outbreak may have helped prevent further morbidity and mortality. Other state agencies may benefit from the process developed during the epidemiologic investigation in Colorado in the case of a similar outbreak event.