PREFACE The general medical officer, flight surgeon, and undersea/diving medical officer serves in many operational commands by providing tip-of-the-spear medical care for military operations in peacetime, war, and during operations other than war. Whether on an amphibious assault ship in the Persian Gulf, in the field with Marines, with Seabees in Europe, or assigned to a branch medical clinic stateside, the GMO meets the challenges of providing quality medical care for Sailors and Marines worldwide. The medical officer serving in the fleet understands the differences between fixed facility medicine and clinical care while on deployment. Onboard ship, the medical officer will eat, work, relax, and sometimes share a compartment with patients and potential patients. Working in close quarters increases the physician’s knowledge and understanding of their shipmates and the environment in which they work. This unique experience challenges the medical officer and enhances their future career as a naval officer and specialist. This fourth edition of the GMO Manual continues to provide an operational approach to the management of commonly encountered medical conditions and administrative topics. By bridging the gap between the hospital environment and the operational setting, the GMO Manual fills a niche in the operational medical officer’s reference library. The updated manual has been trimmed, reorganized, and rewritten with a focus on ease of use and enhancing the clinical practice of the general medical officer. Exhaustive efforts have been made to ensure this reference is as accurate and current as possible. As new information becomes available, changes in policy, medical research, military operations, and medical care may necessitate further research by the reader. The medical officer should individualize patient therapy while considering local resources and operational constraints. This manual is not meant to replace training, experience, or clinical judgement. Check with the instructions, other resources, and the chapter author/reviewers annotated at the end of each chapter for additional information. NEW TO THIS EDITION The format is redesigned to allow users easier access the clinical and administrative subject material. New administrative chapters have been added for the following subjects: Medical Planning for Liberty and Working Port Visits Navy Personnel Command References TRICARE New clinical chapters have been added for the following subjects: Acute Altitude Illnesses Acute Diverticular Disease Acute Scrotal Pain Anaphylaxis Anthrax Anthrax Vaccine Immunization Program Command-Directed Mental Health Evaluations Environmental Health for Ground Forces Motion Sickness Rhinitis Submersion Injuries Urinary Tract Infections Urolithiasis All chapters have undergone some form of minor or major revision. Some chapters have been deleted because of redundancy or changes in policy. Color graphics and additional charts have been added throughout the manual. ACKNOWLEDGEMENTS I wish to thank the over 80 authors, reviewers, and subject matter experts for their time and effort in providing inputs and recommendations for the 4 th edition of the manual. All contributors are recognized at the end of each respective chapter. I also wish to thank Rear Admiral Potter, Rear Admiral Arthur, Mrs. Barbara Gates, and the entire staff at the Office of the Chief Medical Corps for their support and assistance with this project. Comments and recommendations are welcomed and may be directed to Chief, Medical Corps, CODE 00MC, Bureau of Medicine and Surgery, 2300 E. St. N.W., Washington, D.C. 20372-5300. COMM: 202-762-3064 DSN: 762-3064 FAX: (202) 762-1626. LT Denis Ashley, MC, USNR Editor, GMO Manual GMO Policy and Plans Office of the Chief, Medical Corps Bureau of Medicine and Surgery Washington, D.C.