Bariatric surgery is misnamed. Weight control is only one of the objectives of the surgery. The others, such as the control of diabetes, sleep apnea, asthma, and gastroesophageal reflux disease, are in the long run much more important. Metabolic surgery would be a far more appropriate name for the discipline. No matter which of the common procedures is done—the vertical banded gastroplasty, adjustable gastric banding, gastric tube, Roux-en-Y gastric bypass (RYGB), or biliopancreatic diversion—the goal of all of these operations is to induce controlled malnutrition.
All of the procedures induce malnutrition by a reduction in volume as well as a change in the type of food. The gastroplasty and the bands not only reduce the gastric reservoir to the size of a golf ball but also limit the choice of foods to those that do not require a lot of chewing, such as water soluable starches and fats. Beef and those food that form lumps like white bread may be difficult to pass. The malabsorptive procedures, in addition, exclude various sections of the foregut, dumping undigested food into the small bowel that can induce dumping, thus forcing the avoidance of foods rich in sugar.
Since most vitamins and minerals are absorbed in the upper small intestines, namely the duodenum and jejunum,1 it should not be surprising that some patients may develop malabsorptive syndromes, some induced by variations in the operations, by differences in patient response, by starvation by strictures of the gastroenterostomy, by bowel obstructions caused by adhesions, internal hernias, or kinking of the enteroenterostomy, or by the failure of the patient to comply with the instructions to take nutritional supplements on a regular basis. While most nutritional problems are minor and readily managed by doubling vitamin and mineral supplements for a month, some patients develop serious deficiencies that can lead to life-threatening complications and permanent disabilities.
An example of a complication is demonstrated by the case of a 46-year-old woman, a composite of several such patients seen in our clinics who had undergone an intestinal or gastric bypass. Note that the onset can often be subtle and confusing.
A 46-year-old white woman, 5′2″ tall who weighed 308 lb with a BMI of 48.4, underwent a gastric bypass to treat her morbid obesity as well as her diabetes, GERD, and sleep apnea. Her early postoperative course was marked by frequent emesis due to a stricture that required dilatation on three occasions. Three months after gastric bypass surgery, she presented with tingling and numbness of her lower extremities. She was reassured by her referring physician that these “kinds of symptoms” are not infrequent after bariatric surgery. Even though she was seen by a number of other specialists, her symptoms continued to worsen. When she developed diplopia and gait difficulty, she was referred to a neurologist.
Neurological examination revealed horizontal nystagmus with intact extraocular movements, bilateral lower-extremity weakness, and diminished light touch, pinprick, ...