Essential fatty acid sufficiency does not preclude fat-soluble-vitamin deficiency in short-bowel syndrome.

Patients with extensive small-bowel resection may experience malabsorption and nutrient deficiencies. We evaluated the ability to absorb fat and fat-soluble vitamins in a short-gut patient. For 18 wk after stopping intravenous lipid, while consuming a low-lactose, low-fat diet, he exhibited no clinical manifestations of essential fatty acid deficiency (EFAD). Serum 20:4n-6 (20:4 omega-6) and 18:2n-6 fatty acid concentrations were normal, whereas the concentration of 20:3n-9 remained less than or equal to 0.1% of total serum fatty acids. Although serum vitamin A was normal, beta-carotene was undetectable despite oral supplementation. Prothrombin time was elevated until parenteral vitamin K was given. This patient has fat absorption adequate to prevent EFAD but inadequate absorption of fat-soluble vitamins. In patients with short bowel, the requirements for parenteral lipids and fat-soluble vitamins should be determined independently.

Diarrhea in tube-fed patients: feeding formula not necessarily the cause.

PURPOSE: This study of diarrhea in tube-fed patients was undertaken to determine the proportion of cases in which feeding formula is not responsible for the diarrhea, the causes other than the feeding formula, and the diagnostic approach to diarrhea in tube-fed patients. PATIENTS AND METHODS: Inpatients at the Truman Memorial Veterans Hospital who received nasoenteric feeding during the time period from October 1986 through May 1988 were eligible for this study. Of 123 patients who received nasoenteric feeding, 32 patients had documented diarrhea (greater than 500 mL per day for at least two consecutive days) and were enrolled. Three of these patients received hypertonic feeding formula, whereas the remaining 29 received isotonic feeding formula. Prospective determinations of the causes of diarrhea were performed. Laboratory tests included fecal leukocytes, stool osmolality, stool electrolytes, and Clostridium difficile toxin assay. Diarrhea was considered osmotic if the stool osmotic gap was greater than 100 mmol/L. Clinical management involved reducing or stopping the feeding formula, stopping suspected medications, or administering appropriate antibiotics. RESULTS: There were 32 episodes of diarrhea in tube-fed patients during the study period. A single cause could be specified in 29 cases. The tube feeding formula was responsible for diarrhea in only 21% of these cases. Medications were directly responsible in 61% and C. difficile in 17% of cases. Stool osmotic gap correctly distinguished osmotic from non-osmotic diarrhea in all cases. CONCLUSION: When diarrhea develops in properly tube-fed patients, the feeding formula is usually not responsible for the diarrhea. Patients receiving nasoenteric tube feeding are frequently placed on liquid forms of medications. Many medicinal elixirs contain sorbitol, which is often the cause of diarrhea in tube-fed patients. Review of the medications and determination of the stool osmotic gap are the initial diagnostic steps of highest yield.

Nosocomial diarrhea: beware the medicinal elixir.

An unusual case of osmotic diarrhea that persisted despite fasting led to the discovery of an unexpected source of hospital-acquired diarrhea. Numerous patients were subsequently found to have onset of diarrhea shortly after the initiation of treatment with theophylline elixir. Although theophylline can promote gastrointestinal secretion and motility, this effect should be independent of the route of theophylline administration and the stool should be characteristic of secretory rather than osmotic diarrhea. Patients taking no food orally while taking theophylline elixir continued to have osmotic diarrhea in excess of 1,000 ml/24 hr. Patients whose therapy was switched to intravenous or solid oral theophylline had resolution of diarrhea within 24 hours. The brand of theophylline elixir used was formulated with 30 gm of sorbitol per 240 mg of theophylline; thus a standard regimen of theophylline elixir was delivering four laxative doses of sorbitol daily. A cursory review revealed that many medicinal elixirs are formulated with sorbitol, despite being designated "sugar-free." When patients have osmotic diarrhea in the hospital, beware the medicinal elixir.