Acute psychotic disorder after gastric bypass surgery: differential diagnosis and treatment.

Many psychiatric complications after gastric bypass surgery, such as severe psychotic disorders, Wernicke’s encephalopathy, and Korsakoff’s syndrome, have been reported in the medical literature. Gastric bypass surgery, also known as bariatric surgery or gastroplasty for morbid obesity, has gained popularity because of the obesity epidemic in this country (1). Morbid obesity, which correlates with a body mass index (weight [kg]/height [m]2) of 40 or higher, is a chronic, intractable disease that, if left untreated, results in morbidity, mortality, and a decreased lifespan (2). Traditional nonsurgical weight-loss methods that attempt to decrease weight through dietary and behavioral interventions often result in disappointing outcomes with a high rate of relapse (3). Therefore, the popularity of surgical treatment for weight loss has increased. Surgery to treat morbid obesity was recognized by the National Institutes of Health in 1998 as an approach for wellinformed and motivated patients for whom the surgical risks are acceptable (4, 5). Using the 2000 National Health Interview Survey database, Livingston (6) estimated that over 5 million Americans (2.8% of the U.S. population) met eligibility criteria for gastric bypass surgery using the standard definition of morbid obesity. Buckwald et al. (1) estimated that 5% of the U.S. population meets these criteria at present. Overall, the number of gastric bypass surgeries performed annually increased from about 16,000 in the early 1990s to about 103,000 in 2003 (7). Operations available for the treatment of morbidly obese patients include simple operations that restrict the amount of food a patient can eat as well as more complex operations that bypass portions of the digestive tract to create a degree of malabsorption. The two surgical weightloss procedures most commonly performed in the United States for morbid obesity are gastric bypass, also known as the Roux-en-Y gastric bypass, and vertical banded gastroplasty (2, 8). The Roux-en-Y gastric bypass is both restrictive (i.e., limits the amount of solid food the patient is able to ingest) and malabsorptive (i.e., decreases intestinal absorption). During a Roux-en-Y gastric bypass, staples are used to construct a small restrictive upper gastric pouch that then is anastomosed directly to the small intestine, usually bypassing 40–60 cm, although some surgeons may bypass greater lengths of small intestine for increased weight reduction. Vertical banded gastroplasty is a restrictive procedure in which staples are used to create a small stomach pouch with no rerouting of the digestive tract. Both procedures can be performed laparoscopically. Vomiting and reflux are common risks associated with both procedures, and nutritional deficiencies and “the dumping syndrome” occur at higher rates in patients who have Roux-en-Y gastric bypass (7). Although it is believed to be a safe procedure, life-threatening psychiatric complications associated with rapid weight reduction and hyperemesis can occur after gastric bypass surgery. These complications can be insidious, and clinical presentations vary along a spectrum from neurological abnormalities to psychiatric manifestations. Such variability is thought to be related to the individual vulnerability of the CNS to nutritional decline or possibly the length of time until medical evaluation and treatment. Lack of awareness of complications and their symptoms can result in delays in diagnosis and effective treatment. The following case of a patient who developed acute psychosis 52 days after gastric bypass surgery illustrates some of the complexities encountered in managing such a situation.