A novel method to identify fat malabsorption: the Serum Retinyl Palmitate Test.

BACKGROUND: Malabsorptive etiologies of chronic diarrhea are important to identify. The 72-h stool for fecal fat test (FFT), the gold standard for diagnosing fat malabsorption, is fraught with limitations that impact its reliability. Vitamin A, a fat-soluble vitamin, parallels the absorption of lipids. We assessed the feasibility and validate a novel clinical test, retinyl palmitate (RP), for the diagnosis of fat malabsorption, and to compare the results to the FFT. METHODS: Using a case-control study design, patients with chronic diarrhea secondary to suspected malabsorption, and healthy control subjects were identified. A Dietitian taught subjects to consume a 100g fat diet for the FFT with measurements of stool fat after 72-h. Serum levels of Vitamin A (retinol) and RP were measured by reversed-phase high pressure liquid chomatography. Two-way comparisons were made between the groups using 2 sample Wilcoxon rank-sum tests. RESULTS: Sixteen patients completed this study (8 cases and 8 control subjects). Fecal fat results were available for 15/16 patients. The sensitivity of the FFT was 100% (identified all cases), but the FFT specificity was 42%, as 4/7 control patients were identified as malabsorbers. Cases with short bowel syndrome had the lowest RP levels but this did not meet statistical significance. There was no significant difference for serum RP levels when comparing cases and control patients' AUC. CONCLUSIONS: Serum RP is useful to identify malabsorption, albeit in severe cases. Furthermore, we have shown that the 72-hour FFT has poor performance characteristics, highlighting the need for more useful diagnostics in identifying malabsorption.

Gallbladder cancer: epidemiology and outcome.

Gallbladder cancer, though generally considered rare, is the most common malignancy of the biliary tract, accounting for 80%-95% of biliary tract cancers. An early diagnosis is essential as this malignancy progresses silently with a late diagnosis, often proving fatal. Its carcinogenesis follows a progression through a metaplasia-dysplasia-carcinoma sequence. This comprehensive review focuses on and explores the risks, management, and outcomes for primary gallbladder carcinoma. Epidemiological studies have identified striking geographic and ethnic disparities - inordinately high occurrence in American Indians, elevated in Southeast Asia, yet quite low elsewhere in the Americas and the world. Age, female sex, congenital biliary tract anomalies, and a genetic predisposition represent important risk factors that are immutable. Environmental triggers play a critical role in eliciting cancer developing in the gallbladder, best exemplified by cholelithiasis and chronic inflammation from biliary tract and parasitic infections. Mortality rates closely follow incidence; those countries with the highest prevalence of gallstones experience the greatest mortality from gallbladder cancer. Vague symptoms often delay the diagnosis of gallbladder cancer, contributing to its overall progression and poor outcome. Surgery represents the only potential for cure. Some individuals are fortunate to be incidentally found to have gallbladder cancer at the time of cholecystectomy being performed for cholelithiasis. Such an early diagnosis is imperative as a late presentation connotes advanced staging, nodal involvement, and possible recurrence following attempted resection. Overall mean survival is a mere 6 months, while 5-year survival rate is only 5%. The dismal prognosis, in part, relates to the gallbladder lacking a serosal layer adjacent to the liver, enabling hepatic invasion and metastatic progression. Improved imaging modalities are helping to diagnose patients at an earlier stage. The last decade has witnessed improved outcomes as aggressive surgical management and preoperative adjuvant therapy has helped prolong survival in patients with gallbladder cancer. In the future, the development of potential diagnostic markers for disease will yield screening opportunities for those at risk either with ethnic susceptibility or known anatomic anomalies of the biliary tract. Meanwhile, clarification of the value of prophylactic cholecystectomy should provide an opportunity for secondary prevention. Primary prevention will arrive once the predictive biomarkers and environmental risk factors are more clearly identified.

Colonic Dieulafoy's Lesion: A Rare Cause of Lower Gastrointestinal Hemorrhage and Review of Endoscopic Management.

Dieulafoy's lesions are a rare cause of gastrointestinal hemorrhage. Extragastric Dieulafoy's lesions are even more uncommon. We report the case of a 75-year-old woman who presented with gastrointestinal bleeding from a transverse colonic Dieulafoy's lesion. She presented with two episodes of melena followed by one episode of fresh blood per rectum. In addition, there was associated presyncope and anemia (hemoglobin 69 g/L) in the setting of supratherapeutic warfarin anticoagulation (INR 6.2) for nonvalvular atrial fibrillation. Esophagogastroduodenoscopy was negative for an upper GI source of bleeding but on colonoscopy an actively oozing Dieulafoy's lesion was identified in the transverse colon. Bipolar cautery and hemostatic endoclips were applied to achieve hemostasis. Clinicians should consider this rare entity as a potential cause of potentially life-threatening lower gastrointestinal bleeding and we review the endoscopic modalities effective for managing colonic Dieulafoy's lesions.