Management of the patient with gastroparesis

Idiopathic and Diabetic Gastroparesis

The management of both diabetic and idiopathic gastroparesis often represents a substantial clinical challenge. In formulating recommendations for therapy, it should be recognized that these are based on less than optimal evidence; in particular, there are substantial deficiencies in current knowledge relating to the pathophysiology of gastroparesis, as well as the natural history of gastrointestinal symptoms, and the majority of pharmacologic trials have been short term and associated with methodologic limitations. Although the etiologic factors differ, the overall management principles are similar in the two conditions. Maintenance of adequate nutrition is pivotal, and parenteral nutrition may be required in severe cases associated with malnutrition. In patients with diabetes, rigorous attempts should be made to optimize glycemic control--hyperglycemia slows gastric emptying and may exacerbate symptoms and attenuate the effects of prokinetic drugs. Despite the relatively poor predictive value of symptoms, it is reasonable to suggest a trial of prokinetic therapy for about 4 weeks, rather than initially establishing the diagnosis by measurement of gastric emptying. However, it should be recognized that there is a substantial placebo response, a lack of evidence to support the cost effectiveness of such an approach, and that most patients will require prolonged therapy. In type 1 diabetic patients, prokinetic therapy may potentially benefit glycemic control, and this forms an additional rationale (albeit not established) for therapy. Some patients with diabetes and idiopathic gastroparesis with severe vomiting are unable to tolerate oral medication; in such cases subcutaneous metoclopramide may prove useful. Patients with intractable symptoms should be hospitalized and given intravenous erythromycin. The repertoire of prokinetic agents available in the United States is limited and includes metoclopramide, erythromycin, and cisapride (available by special program from its manufacturer); all of these drugs are associated with side effects. The use of metoclopramide may represent the first choice for chronic oral therapy, although it has been studied less comprehensively than cisapride. Combination therapy may be potentially more efficacious than the use of single agents. Dehydration and metabolic derangements should be corrected. The choice of chronic medical therapy should be individualized, taking factors such as age, presence of diabetes, concurrent medications, and comorbidities into account. In a small number of patients in whom medical treatment fails, surgery should be considered, and, if performed, done in a specialized center. A number of novel therapies, including gastric electrical stimulation, are currently being evaluated.

Diagnosis and treatment of chronic gastroparesis and chronic intestinal pseudo-obstruction

Chronic gastroparesis and CIP are debilitating disorders that are difficult to treat with currently available therapies. Failure of proper migration and differentiation of enteric neurons or ICC can result from specific genetic mutations and lead to phenotypes of CIP with or without concomitant gastroparesis. Intestinal dysfunction in diabetes may reflect a depletion of NO production (and perhaps other neurotransmitters or modulators), which is manifest as a syndrome of gastroparesis, diarrhea, or constipation in individual patients. As the key molecular changes underlying these disorders are defined, clinicians will begin to understand their precise etiology and rational medical therapy may become possible. In the future, testable hypotheses regarding the etiology of other functional bowel disorders (e.g., functional dyspepsia, irritable bowel syndrome, and so forth) may be developed.

Diabetic gastropathy and prokinetics

The treatment of diabetic gastropathy, which here refers to a clinical syndrome of upper GI tract symptoms suggestive of an upper motility disturbance in diabetes whether or not there is delayed gastric emptying, remains suboptimal. New prokinetics and other motility-modifying agents may prove useful, but adequate clinical trials will be required to establish a role for them. However, diabetic gastropathy seems to represent a heterogenous syndrome in terms of pathophysiology, which potentially complicates the design of new randomized, controlled trials. This review aims to provide guidelines for future trials in this field. The evidence that delayed gastric emptying is a cause of symptoms in diabetic gastropathy is critically evaluated. The trial evidence supporting the short and long term efficacy of prokinetics is reviewed. Based on the available literature, it is concluded that improvement in gastric emptying does not equate with symptom relief in diabetic gastropathy. It is suggested that although gastric emptying should still be measured in clinical trials, it should not represent the primary outcome. The withdrawal treatment design applied in studies of diabetic gastropathy might be suboptimal. Double blind, parallel group studies remain the trial design of choice, but incorporation of validated outcome assessments and measurement of potential confounders of treatment response need attention in future trials.

Chronic metoclopramide therapy for diabetic gastroparesis

OBJECTIVE

To review the safety and efficacy of chronic metoclopramide for diabetic gastroparesis.

DATA SOURCES

Medical literature was accessed through MEDLINE (1965 to October 2002) and PubMed (1965 to October 2002). Key search terms included metoclopramide; diabetic gastroparesis; and dyskinesia, drug induced.

DATA SYNTHESIS

Metoclopramide is often used for diabetic gastroparesis, despite the risk of tardive dyskinesia. Published information is limited regarding long-term efficacy and toxicity of metoclopramide. The literature was assessed concerning these topics.

CONCLUSIONS

Limited data do not provide sufficient evidence to conclude whether metoclopramide is efficacious for chronic use. Routine monitoring may mitigate the risk associated with metoclopramide therapy.