Gastrointestinal symptoms in chronic renal failure. Prevalence and pathophysiological mechanisms

Abstract: Chronic renal failure (CRF) has a varying etiology and is characterised by an increasing accumulation of toxic metabolic waste products in the blood. Malnutrition is a common finding in uraemic patients and is regarded as a marker for morbidity and mortality. Many factors, including gastrointestinal (GI) symptoms, lead to malnutrition in CRF. The aims of the present study were to evaluate the prevalence of GI symptoms in CRF patients and to find possible pathophysiological mechanisms behind these symptoms. Gastrointestinal symptoms and psychological well-being were assessed with the aid of two questionnaires. The use of acid-suppressive therapy was evaluated by interviewing the patients and by reviewing medical records. Motility of the small intestine was measured by means of antroduodenojejunal manometry. Radiopaque markers were used to assess gastric emptying. Aspirate from the jejunum for culture was obtained through the manometry catheter.Gastrointestinal symptoms were more common in CRF compared with reference values from the general population. A relationship between GI symptoms in CRF patients and reduced psychological well-being was observed.There was an overuse of acid-suppressive drugs in dialysis patients and the majority of the indications were inappropriate, with non-specific GI symptoms as a dominating indication. Long-term treatment, more than eight weeks, was predominant. Manometry of the small intestine revealed neuropathic-like motor patterns in 50% of patients. A high proportion of long clusters was observed during phase II as well as a high proportion of retrograde pressure waves in phase II and post-prandially in CRF, both in symptomatic and asymptomatic patients. Accelerated propagation velocity of the activity front of MMC in the duodenum correlated with GI symptoms. Small intestinal bacterial overgrowth (SIBO) was found in 36% of CRF patients irrespective of GI symptoms. A neuropathic-like motor pattern was more commonly observed in CRF patients with SIBO.A delay in gastric emptying was disclosed in patients with CRF, especially in men. Gastric emptying was not correlated to GI symptoms. A delay in emptying was more common in patients on peritoneal dialysis. Helicobacter pylori did not affect gastric emptying.Conclusions: Gastrointestinal symptoms are common in CRF patients and are associated with impaired psychological well-being. Overuse of acid-suppressive therapy is common in CRF patients. Abnormal small bowel motility, delayed gastric emptying and SIBO are common findings in CRF patients. Some abnormal motility findings were related to GI symptoms and may be involved in the pathophysiology of GI symptoms in CRF.

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