Postvagotomy diarrhea

Postgastrectomy Syndromes and Nutritional Considerations Following Gastric Surgery

Postgastrectomy syndromes result from altered form and function of the stomach. Gastrectomy disrupts reservoir capacity, mechanical digestion and gastric emptying. Early recognition of symptoms with prompt evaluation and treatment is essential. Many syndromes resolve with minimal intervention or dietary modifications. Re-operation is not common but often warranted for afferent and efferent loop syndromes and bile reflux gastritis. Preoperative nutritional assessment and treatment of common vitamin and mineral deficiencies after gastrectomy can reduce the incidence of chronic complications. An integrated team approach to risk assessment, patient education, and postoperative management is critical to optimal care of patients with gastric cancer.

Gastric motor physiology and pathophysiology

The stomach has two distinct physiologic motor areas: the proximal stomach and the distal stomach. The proximal stomach, with its slow, sustained contractions, has a key role in regulating intragastric pressure and gastric emptying of liquids, while the distal stomach, with its peristaltic contractions, has a major role in mixing, trituration, and emptying of solids. Diseases and operations that disturb the motility of these two areas can result in unique adverse motor sequelae. For example, operations that impair proximal gastric motility, such as proximal gastric resection, may cause rapid gastric emptying of liquids and subsequent dumping and diarrhea. In contrast, operations that impair distal gastric contractions, such as truncal vagotomy, may cause slow gastric emptying of solids and chronic gastric atony. Knowledge of the physiology of the stomach in health and of the pathophysiology with disease and after operation provides a basis for the successful treatment and prevention of these disorders.

Postgastrectomy syndromes

Anatomic and physiological changes introduced by gastric surgery result in postgastrectomy syndromes in approximately 20% of patients. Most of these disorders are caused by operation-induced abnormalities in the motor functions of the stomach, including disturbances in the gastric reservoir function, the mechanical-digestive function, and the transporting function. Division of the vagal innervation to the stomach and ablation or bypass of the pylorus are the most significant factors contributing to postgastrectomy syndromes. Either rapid or slow emptying may result, depending on the relative importance of lack of a compliant gastric reservoir, loss of an effective contractile force, and loss of controlling factors that slow or speed gastric emptying and result in duodenal-gastric reflux. Clearly defining which syndrome is present in a given patient is critical to developing a rational treatment plan. In syndromes with slow gastric emptying, bilious vomiting, or alkaline reflux gastritis, the use of endoscopy is essential to rule out mechanical causes of the syndrome. Contrast radiography and scintigraphic gastric emptying studies are useful to document rapid or delayed gastric emptying. Postgastrectomy syndromes often abate with time. Conservative measures, including medical, dietary, and behavioral therapy, should be given at least a 1-year trial. If these nonoperative measures fail, surgical therapy is recommended. The Roux-en-Y gastrojejunostomy is useful for patients with dumping, because it slows gastric emptying and the transit of chyme through the Roux limb. The same operation helps patients with alkaline reflux gastritis, because it diverts pancreaticobiliary secretions away from the gastric remnant. Near-total gastrectomy, which reduces the size of a flaccid gastric reservoir, can be used to treat delayed gastric emptying. This operation should be combined with the Roux procedure to prevent postoperative reflux gastritis and esophagitis. Newer techniques, such as gastrointestinal pacing and the uncut Roux operation, may improve the treatment of the postgastrectomy syndromes in the future.