Prokinetic therapy: What can be measured by gastric scintigraphy?

Gastrointestinal involvement in systemic sclerosis: diagnosis and management

PURPOSE OF REVIEW

This review provides important updates in systemic sclerosis (SSc)-related gastrointestinal disease, with a particular focus on the diagnosis and management of dysmotility.

RECENT FINDINGS

In the past 2 years, several studies were published that present interesting diagnostic insights into SSc and gastrointestinal dysmotility. Studies focusing on new therapies and the novel application of existing therapies, both in SSc and non-SSc-associated gastrointestinal dysmotility syndromes, demonstrate progress in the management of these challenging complications.

SUMMARY

SSc gastrointestinal disease is heterogeneous in its clinical presentation, which presents a challenge in diagnosis and management. Objective studies may help to identify patterns of gastrointestinal dysmotility and more specifically target therapy. A variety of drugs are now available or are under study in the management of gastrointestinal dysmotility, such as prucalopride, intravenous immunoglobulin, pyridostigmine, linaclotide, relamorelin, and others. These drugs may improve symptoms and quality of life in SSc gastrointestinal patients. Combination therapies are also under study. Electroacupuncture, dietary intervention (e.g. medical nutrition therapy, low FODmap diet), and medical cannibus may also play a role in alleviating patient symptoms; however, more data are needed to define the role of these interventions in SSc.

Systemic sclerosis and the gut

Gastrointestinal involvement (GI) is increasingly recognized as a major cause of both morbidity and mortality in systemic sclerosis (SSc). GI complications are common, second only to skin involvement, and affect up to 90% of patients. Although treatment modalities have changed little for upper gut symptoms such as GI reflux, there are emerging treatment modalities for the common lower gut symptoms (constipation and fecal incontinence), which will be reviewed. The important link between reflux and interstitial lung disease in SSc is also addressed. The aim of this review is to help the clinician understand and manage GI symptoms in SSc.

Selected interventions in nuclear medicine: gastrointestinal motor functions

The measurement of gastrointestinal functions by the use of scintigraphy is established in clinical practice and research. The most commonly used test is the gastric-emptying test, which is acknowledged as the gold standard to measure gastric motility and is conducted according to a consensus statement from the national nuclear medicine and motility societies. Other techniques are somewhat more esoteric (eg, measurement of gastric accommodation with single-photon emission computed tomography) or the scintigraphic approach is not the acknowledged gold standard (eg, colonic transit, rectoanal angle, and emptying, esophageal transit). The performance characteristics of many of the scintigraphic measurements have been published and the pros and cons established in the literature. Pharmacologic interventions may also be used during scintigraphy to aid in diagnosis and treatment. Gastrointestinal scintigraphy is an integral and important component of the assessment of gastrointestinal function.

[Systemic sclerosis and the gastrointestinal tract. Diagnostic and therapeutic approach]

In systemic sclerosis esophagus is affected in 90% followed by anal and rectal involvement (50-70%), stomach (40-70%), colon (10-50%) and small bowel (40%). The main clinical findings are esophagic: dysphagia and sign of gastroesophageal reflux and its complications. Gastric symptomatology is a consequence of gastroparesis (postprandial fullness, nausea). Intestinal affection produces hypomotility (abdominal distention, deficient intestinal absorption, bacterial overgrowth). In colon there are diverticula, intestinal constipation, and fecal incontinence. For the diagnosis of GIT involvement the following are useful: studies of digestive tract with contrast media, endoscopy of upper GIT; gastric emptying; pH metry; esophageal and rectal manometry, as well as test to investigate deficient intestinal absorption syndrome. The prokinetic are a cornerstone for the treatment of hypomotility of GIT, along with pump proton inhibitors for the esophageal alteration and antibiotics for bacterial overgrowth.

Gastrointestinal manifestations of systemic sclerosis

Systemic sclerosis is a chronic disorder of connective tissue that affects the gastrointestinal tract in more than 80% of patients. Changes in neuromuscular function with progressive fibrosis of smooth muscle within the muscularis propria impair normal motor function, which may secondarily alter transit and nutrient absorption. Esophageal manifestations with gastroesophageal reflux and dysphagia are the most common visceral manifestation of the disease, often requiring more intense acid-suppressive medication. Gastric involvement may lead to gastroparesis, which can be found in up to 50% of patients. Severe small bowel disease can present as chronic intestinal pseudo-obstruction with distended loops of small intestine, bacterial overgrowth, impaired absorption and progressive development of nutritional deficiencies. While not studied as extensively, systemic sclerosis often also affects colorectal function resulting in constipation, diarrhea or fecal incontinence. Nutritional support and prokinetics have been used with some success to manage gastric and small or large bowel involvement in patients with systemic sclerosis. Despite advances in management, significant gastrointestinal manifestations of systemic sclerosis still carry a poor prognosis with a five-year mortality exceeding 50%.

Prophylactic octreotide and delayed gastric emptying after pancreaticoduodenectomy: results of a prospective randomized double-blinded placebo-controlled trial

AIMS

To evaluate the impact of prophylactic octreotide on gastric emptying in patients undergoing pancreaticoduodenectomy. Postoperative pancreatic fistula (POPF) and delayed gastric emptying (DGE) are common complications after pancreaticoduodenectomy. Whereas several prospective randomized trials propose the prophylactic use of octreotide to prevent pancreatic fistula formation, somatostatin has, however, been associated with delayed gastric emptying after partial duodenopancreatectomy.

METHODS

In this prospective, randomized, double-blinded, placebo-controlled trial we analyzed the influence of prophylactic octreotide on delayed gastric empting after pancreaticoduodenectomy. Patients were randomized to the placebo group (n=32) and the octreotide group (n=35). Primary endpoint was the incidence of delayed gastric emptying, secondary endpoints included perioperative morbidity other than DGE. DGE was measured by clinical signs, gastric scintigraphy and the hydrogen breath test. Risk factors for DGE other than octreotide were analyzed by univariate and multivariate analyses.

RESULTS

DGE measured by clinical signs was similar between both groups studied ( approximately 20% of the patients). Gastric scintigraphy (T(1/2)) was 76.3+/-15.2 min in the octreotide group and 86.7+/-18.0 min in controls at day 7, respectively. The H(2) breath test was 65.0+/-6.5 min in octreotide treatment group and 67.0+/-5.7 min in controls at day 8. POPF grade C occurred in approximately 3% of the patients, although prophylactic treatment of octreotide did not reduce the incidence of POPF. Multivariate analysis showed that postoperative intraabdominal bleeding and infection were independent risk factors for DGE. Furthermore preoperative biliary stenting reduced postoperative DGE after partial duodenopancreatectomy.

CONCLUSION

Prophylactic octreotide has no influence on gastric emptying and does not decrease the incidence of postoperative pancreatic fistula after pancreaticoduodenectomy.

[Gastrointestinal involvement in systemic sclerosis. An underestimated complication]

Systemic sclerosis (SSc) belongs to the family of autoimmune connective tissue diseases and is still a challenge to every practicing physician. The disorder is characterized by progressing fibrosis of the skin and internal organs, abnormal activation of the immune system, and distinct changes in microcirculation. Although it is rare--with a prevalence of about 20:100000--patients need to be cared for in a daily setting. In general thickening of the skin is the first sign of the disease, so dermatologists are most frequently consulted first. Two subtypes exist, limited and diffuse forms. Both entities usually involve internal organs, and therefore interdisciplinary cooperation is mandatory. The increased morbidity and mortality depend predominantly on the grade of involvement of the affected organs. Therefore it is essential to diagnose systemic sclerosis early and to identify and monitor all complications closely. In this respect gastrointestinal involvement is frequently neglected, owing to its primarily non-life-threatening character, resulting in substantially delayed therapy.

Gastric and enteric involvement in progressive systemic sclerosis

Progressive systemic sclerosis (PSS) is a chronic multisystem disease characterized by excess deposition of connective tissue in skin and internal organs, associated with microvasculature changes and immunologic abnormalities. Involvement of the gastrointestinal tract may occur in 2 stages, a neuropathic disorder followed by a myopathy. Gastric emptying is delayed in 10% to 75% of patients and correlates with symptoms of early satiety, bloating, and emesis. Compliance of the fundus is increased although perception of fullness is normal. Myoelectric abnormalities have been found in some studies. Treatments include metoclopramide, cisapride, and erythromycin. Bleeding from telangiectasias and watermelon stomach is treated endoscopically. Small bowel involvement in PSS occurs in 17% to 57% of patients. The migrating motor complexes are reduced or absent, predisposing to bacterial overgrowth. Malabsorption may also be due to pancreatic insufficiency. Barium enemas demonstrate pancolonic involvement in 10% to 50% of patients with PSS. Wide-mouthed diverticuli, involving all layers of the intestinal wall, are characteristic. Pseudoobstruction may respond to octreotide or prucalopride therapy. Complications include pneumatosis cystoides intestinalis, stercoral ulcerations, and perforation. Fecal incontinence may be due to dysfunction of the internal anal sphincter, a smooth muscle responsible for most of the resting anal sphincter pressure. Anal manometry may show a reduction or loss of the rectoanal inhibitory reflex. Treatments include biofeedback, sacral nerve stimulation, and surgery. PSS involves the gastrointestinal tract from the mouth to the anus. Studies are needed to define effective treatments in these diseases, which cause great morbidity.

Importance of changes in gastric emptying for postprandial plasma glucose fluxes in healthy humans

OBJECTIVE

Regulation of postprandial (pp) plasma glucose excursions is complex. Insulin and glucagon are thought to play the predominant role. Nevertheless, only 50% of the variation in pp plasma glucose excursions is explained by variations by the latter. Theoretically, gastric emptying (GE) should be another important factor. However, its impact on pp glucose homeostasis is unknown.

RESEARCH DESIGN AND METHODS

We examined the consequences of pramlintide-induced delay in GE on pp glycemia and glucose fluxes, determined isotopically. GE was recorded by scintigraphy. Fourteen healthy subjects (8 men, 6 women; age 40 +/- 3 yr, body mass index 27.8 +/- 1.1 kg/m2) ate a mixed meal, and 30 microg of pramlintide (PRAM) or placebo (PBO) were injected subcutaneously.

RESULTS

At 60 min, greater proportions of the initial gastric contents remained in the stomach (PBO vs. PRAM). Thereafter, GE slopes paralleled until 240 min. Fifty percent retention times were lower when PBO was given (P < 0.001). GE was greater from 240 min to the end of the PRAM experiments, so that only slightly greater proportions of the meal remained in the stomach at 330 min. Reductions of GE lowered pp glucose (7.5 +/- 0.3 vs. 6.0 +/- 0.2 mmol/l, P < 0.001), even though plasma insulin was lower with PRAM (164 +/- 13 vs. 138 +/- 13 pmol/ml, both P < 0.01). Reduction in total glucose appearance (P < 0.001) was due to reduced meal-derived glucose appearance (10.2 +/- 0.5 vs. 7.0 +/- 0.4 micromol.kg(-1).min(-1), P < 0.001). Endogenous glucose appearance was greater with PRAM (P < 0.001). Splanchnic glucose uptake was greater with PRAM (26.5 +/- 1.6 vs. 32.5 +/- 2.1%, P = 0.014).

CONCLUSIONS

These data support the concept that GE is an important physiological regulator of pp glucose homeostasis in humans.

Systematic review: pathophysiology and management of gastrointestinal dysmotility in systemic sclerosis (scleroderma)

Gastrointestinal dysmotility in systemic sclerosis (scleroderma) is prevalent in 90% of patients, increasing morbidity and in some cases mortality. The resultant gastrointestinal complications are usually extensive, involving many regions of the gut from the oesophagus to the anus. Collagen replacement of vascular and enteric smooth muscle results in hypomotility, lumen dilatation, tensile rigidity and eventual loss of organ functions. The aim of this paper is to provide an overview of systemic sclerosis-related gastrointestinal dysmotility and available/potential therapeutic options. We evaluated published data on the pathophysiology and management of gastrointestinal dysmotility in systemic sclerosis patients using the MEDLINE database for English and non-English articles from 1966 to July 2005. Based on this systematic review, lifestyle and medical therapy approaches are preferred as they often improve and/or ameliorate symptoms. Surgery is only recommended with serious, rare complications such as bowel perforation or ischaemia. Alternative therapies such as acupuncture-based therapies are well tolerated, with clinical improvement and may be of potential therapeutic benefit for systemic sclerosis gastrointestinal dysmotility. Further elucidation of initiating and persistent mechanisms of systemic sclerosis-related gastrointestinal dysmotility will optimize the development of a multidisciplinary and more directed treatment regimen.