Age-related changes in the chemical composition of gallstones.

BACKGROUND: The association between pigment cholelithiasis and advancing age has been previously described but little is known about the time-course of these changes. AIM: To determine the specific changes that occur in the chemical composition of gallstones with increasing age. METHODS: Gallstones were collected from 387 non-cirrhotic patients and visually classified as either cholesterol or pigment. All stones were quantitatively analyzed by Fourier transform infrared spectroscopy for cholesterol, bilirubin, carbonate and phosphate and the results correlated with stone type and patient age. RESULTS: Forty-five patients had pigment stones (12 %) and 342 had cholesterol stones (88 %). No patient had both types. There was a reciprocal relationship between the mean cholesterol and bilirubin contents of stones over time with cholesterol accounting for 54% of the weight of gallstones before age 30 and only 17% after age 70. Similarly, the mean content (by weight) of bilirubin was 35% before age 30 but 61% after age 70. In addition, the fraction of gallstones containing carbonate or phosphate salts increased sequentially with age (6% at age 30 to 57% at age 70). CONCLUSIONS: (1). The ratio of pigment to cholesterol gallstones increases directly with age. (2) The cholesterol content of stones steadily decreases after age 50 while the content of bilirubin, phosphate and carbonate gradually increases. (3) These data suggest that, during aging, cholesterol may become solubilized and may be replaced by calcium salts of carbonate, phosphate or bilirubinate.

Gallstone size and risk of pancreatitis.

BACKGROUND: The treatment of patients with gallstones who have suffered a first episode of acute biliary pain is controversial. Recent guidelines suggest that such patients may choose to observe the "pattern" of their pain over time before deciding about therapy. OBJECTIVE: To determine clinical factors that would identify patients at high risk for 2 important complications: acute biliary pancreatitis and acute cholecystitis. METHODS: We collected sociodemographic and clinical data on patients undergoing cholecystectomy after acute biliary pancreatitis, acute cholecystitis, or uncomplicated biliary pain. The physical characteristics of gallstones recovered at surgery were also recorded. Patients with pancreatitis and patients with cholecystitis were compared with patients with uncomplicated pain. RESULTS: In univariate analyses, patients with acute pancreatitis were significantly more likely to have at least 1 gallstone smaller than 5 mm in diameter, 20 or more gallstones, gallstones described as mulberry shaped, and a lower total gallstone weight than patients with uncomplicated pain. Pancreatitis was unrelated to patient age, sex, race or ethnicity, use of alcohol or tobacco, or clinical comorbidity. In a logistic regression model, acute pancreatitis was associated with a stone diameter of less than 5 mm (odds ratio, 4.51; P = .007) and with mulberry-shaped gallstones (odds ratio, 2.25; P = .04). No sociodemographic, clinical, or gallstone characteristics were consistently associated with acute cholecystitis. CONCLUSIONS: Patients with at least 1 gallstone smaller than 5 mm in diameter have a more than 4-fold increased risk of presenting with acute biliary pancreatitis. A policy of watchful waiting in such cases is unwarranted.

The effect of an ambulatory internal medicine rotation on students' career choices.

PURPOSE: To assess the effect of an ambulatory care experience on medical students' perceptions of internal medicine and their choices of careers (as measured by residency selections). METHOD: In 1990-91, the 196 third-year students enrolled in the 12-week internal medicine clerkship at the University of Texas Medical School at San Antonio were randomized to a curriculum that included a three-week ambulatory care component or to a traditional, exclusively inpatient curriculum. The ambulatory curriculum included the evaluation of walk-in-patients, exposure to community internists, and a lecture series. The students' perceptions of internal medicine were surveyed before and after the clerkship. Their career choices were determined by their residency selections at graduation. Data analysis employed chi-square tests, t-tests, and logistic regression. RESULTS: Of the 196 students, 184 (76 in the ambulatory and 108 in the traditional curricula) provided complete data. The ambulatory care students were somewhat more likely to enter an internal medicine residency (odds ratio = 1.49; 95% CI, 0.72 to 3.09) than were the traditional students. The ambulatory care students' perceptions of internal medicine did not change significantly from before to after the clerkship. CONCLUSION: The ambulatory curriculum had a modest but favorable effect on the students' selections of careers in internal medicine, but was not associated with changes in their perceptions of internal medicine.

Appendicitis: higher risk in Mexican Americans?

OBJECTIVES: Mexican Americans (MAs), compared to white non-Hispanics (WNHs), have higher rates of biliary disease, noninsulin dependent diabetes, and endstage renal disease but lower rates of lung cancer, hip fractures, and mortality from coronary heart disease. Relatively little research has been done to identify other ethnic differences in disease incidence. We used surgical procedure rates to confirm known ethnic differences and to explore our clinical suspicion that MAs have higher rates of appendectomy than WNHs. METHODS: We used a registry of surgical procedures at two teaching hospitals in South Texas to calculate proportional operation ratios (PORs) for MAs versus WNHs. These two hospitals are the primary source of acute hospital care for the indigent in the area. The POR is arithmetically identical to proportional incidence and mortality ratios. RESULTS: MAs underwent appendectomy proportionally more often than WNHs at both hospitals (POR = 1.41 and 1.75, p < 0.0001). Other significant PORs were consistent with known ethnic disease differences in biliary tract operations, vascular access for chronic hemodialysis, lung cancer, and coronary artery bypass. CONCLUSIONS: These findings support the hypothesis that MAs may undergo appendectomy more often than WNHs and so may be at higher risk of appendicitis.

Changing indications for laparoscopic cholecystectomy. Stones without symptoms and symptoms without stones.

In less than a decade, laparoscopic methods have dramatically improved the safety and convenience of cholecystectomy. As a result, the number of cholecystectomies performed nationwide has increased significantly. Whether this increase is a reflection of any major change in operative indications is unclear; the actual answer may vary from community to community. Silent gallstones continue to represent a sometimes contentious therapeutic dilemma. Because their natural history is unlikely to have changed, the management guidelines previously established for open cholecystectomy continue to have relevance today. Thus, it can be agreed that the majority of patients with silent gallstones do not require a cholecystectomy. The changing risk-benefit ratio suggests that some liberalization of these guidelines may now be in order. Already a number of transplantation surgeons have begun to recommend pretransplant cholecystectomy for asymptomatic patients who are found to have gallstones during screening. Available evidence also appears to support the use of pre-emptive laparoscopic cholecystectomy for other indications such as in selected women of childbearing age, young children, and patients with very large gallstones. The problem of silent gallstones in diabetics continues to be more enigmatic, but some complicated diabetics are probably best managed with operation. Other patient groups who are at high risk of having adverse outcomes from expectant management will be more precisely identified by future research efforts. Laparoscopic cholecystectomy should also be helpful in patients with various forms of acalculous biliary disease. However, special caution is advisable in approaching chronic acalculous cholecystitis until more specific and reproducible diagnostic methods are further validated.

Prevalence of gallbladder disease and associated clinical variables in a low income population of Mexico City.

We present the results of a population-based survey carried out in a low income area of Mexico City. The aim of this study is to characterize the prevalence of clinically significant gallbladder disease (CSGD) using the self-reported history of cholecystectomy (CG) or cholelithiasis (CL) demonstrated by cholecystography and/or ultrasonography. The population of the studied area was 15,532 inhabitants, of whom 3505 (22.6%) were age eligible (35-64 year-old men and non-pregnant women). Home interviews were obtained in 2810 (80.2%). A physical and laboratory examination was performed in 2282 individuals (65.1%; 941 men and 1341 women). The prevalence of CSGD in men was 2.0% (95% confidence intervals 1.1-2.9%) and 9.2% in women (95% confidence intervals 7.7-10.7%). Patients with CSGD were older, men (p < 0.003) and women (p < 0.001). Women with CSGD had higher waist to hip circumference ratio (p < 0.06), higher fasting glucose (p < 0.03) as well as 2 h post challenge glycemia (p < 0.04) and insulinemia (p < 0.03). In the multiple logistic regression model only age (p < 0.001) and sex (p < 0.001) remained significantly associated. We conclude that CSGD is quite prevalent in this population. It is associated with age in both genders and in women, higher glucose and insulin levels. The prospective follow-up of this cohort is important since it could generate the information needed to implement a preventive program to diminish the impact of this condition.

Clinical correlates of gallstone composition: distinguishing pigment from cholesterol stones.

OBJECTIVES: The prevalence of cholelithiasis has been established in population-based surveys employing ultrasonography, and major risk factors have been identified. However, the clinical and epidemiological features that distinguish patients with pigment gallstones from those with cholesterol stones have received little attention. METHODS: We prospectively surveyed 551 patients undergoing cholecystectomy for gallstones at two teaching hospitals. Clinical and epidemiological data were collected during patient interviews and by chart review. Gallstones were collected at surgery; physical measurements were recorded, and stone composition was determined by visual inspection and infrared spectroscopy. RESULTS: Patients with pigment stones were older than patients with cholesterol stones (p < 0.00001). Almost all patients under age 40 yr old had cholesterol stones, but most patients over 70 had pigment stones. Cirrhosis was strongly associated with pigment gallstones (p < 0.00001), although alcohol consumption was unrelated. Univariate analyses suggested associations of stone composition with male sex, diabetes mellitus, educational attainment, and use of thiazides or oral contraceptives, but these were not significant in a logistic regression that adjusted for age, cirrhosis, and other variables. Patients with pigment cholelithiasis had stones that were generally smaller in diameter and fewer in number than those with cholesterol stones. CONCLUSIONS: Compared to patients with cholesterol gallstones, those with pigment stones are older and more likely to have a diagnosis of cirrhosis. In addition, their stones are smaller in size and fewer in number than those from patients with cholesterol cholelithiasis.

Gallstone characteristics in Mexican Americans and non-Hispanic whites.

Mexican Americans have an elevated risk of gallstones. Their increased rates may be due to genetic admixture with Native Americans, who have extremely high prevalences of cholelithiasis. Native Americans are believed to have almost exclusively cholesterol stones, whereas only 73% of non-Hispanics are reported to have such stones. Hence we hypothesized that Mexican Americans would have a higher proportion of cholesterol stones than would non-Hispanic whites. We interviewed 398 Mexican Americans and 93 non-Hispanic whites undergoing cholecystectomy and analyzed the composition of their gallstones. Mexican Americans were younger than non-Hispanic whites (P < 0.05). However, the age-sex standardized proportion of cholesterol stones was 89.7% in Mexican Americans and 87.2% in non-Hispanic whites. We conclude that Mexican Americans and non-Hispanic whites have gallstones of similar composition. The higher stone prevalence of Mexican Americans may be due to factors that predispose to both cholesterol and pigment stones.

Clinical gallbladder disease in NIDDM subjects. Relationship to duration of diabetes and severity of glycemia.

OBJECTIVE: To examine the relationship between the prevalence of gallbladder disease and severity of glycemia among diabetic individuals and to provide insight into whether the diabetes-gallstone association is a causal one, because NIDDM patients have an increased prevalence of clinical gallbladder disease. RESEARCH DESIGN AND METHODS: We examined 462 diabetic individuals identified during the San Antonio Heart Study, a population-based survey of diabetes and cardiovascular disease in Mexican Americans and non-Hispanic whites. Diabetes was diagnosed according to National Diabetes Data Group criteria. RESULTS: The prevalence of self-reported gallbladder disease was 34.2% in diabetic women and 7.2% in diabetic men. Although duration of diabetes was positively related to the prevalence of gallbladder disease (P < 0.01), type of therapy was not associated, and fasting glucose concentration was inversely associated with gallbladder disease. CONCLUSIONS: Factors other than hyperglycemia may account for the increased prevalence of gallbladder disease in diabetic subjects.

Clinical and sociocultural determinants of gallstone treatment.

Cholecystectomy remains the principal treatment for gallstones. Many gallstone patients do not undergo surgery within 6 months of diagnosis. To determine factors associated with cholecystectomy, treated and untreated patients were compared with respect to clinical and sociodemographic factors. The study population was comprised of outpatients of a public system evaluated in an emergency room or at a community health center. All were interviewed in English or Spanish before completing imaging studies. Of 121 found to have gallstones, 75 underwent early cholecystectomy. Patients reporting episodes of prolonged abdominal pain more often had surgery (p < 0.003). Patients evaluated in the emergency room underwent surgery more often than those from the community health center (p < 0.04). Patient ethnicity was unrelated to treatment, but Mexican Americans who requested interviews in Spanish were less likely to undergo cholecystectomy (p < 0.05). After logistic regression, prolonged abdominal pain was the only significant predictor of surgical management, although relationships with language use and site of diagnosis persisted. It was concluded that clinical presentation largely determines surgical treatment for gallstones but site of diagnosis is also a factor. Patients with poor English language skills undergo cholecystectomy less often. This may be due to poor doctor-patient communication, or it may be a reflection of cultural factors linked to language use.

Symptoms of gallstone disease.

The most certain symptomatic manifestation of gallstones is episodic upper abdominal pain. Characteristically, this pain is severe and located in the epigastrium and/or the right upper quadrant. The onset is relatively abrupt and often awakens the patient from sleep. The pain is steady in intensity, may radiate to the upper back, be associated with nausea and lasts for hours to up to a day. Dyspeptic symptoms of indigestion, belching, bloating, abdominal discomfort, heartburn and specific food intolerance are common in persons with gallstones, but are probably unrelated to the stones themselves and frequently persist after surgery. Many, if not most, persons with gallstones have no history of pain attacks. Persons discovered to have gallstones in the absence of typical symptoms appear to have an annual incidence of biliary pain of 2-5% during the initial years of follow-up, with perhaps a declining rate thereafter. Gallstone-related complications occur at a rate of less than 1% annually. Those whose stones are symptomatic at discovery have a more severe course, with approximately 6-10% suffering recurrent symptoms each year and 2% biliary complications. The far higher rates of symptom development reported in a few studies raise the possibility that these incidence estimates may be too low. The best predictors of future biliary pain are a history of pain at the time of diagnosis, female gender and possibly obesity. The risk of acute cholecystitis appears to be greater in those with large solitary stones, that of biliary pancreatitis in those with multiple small stones, and that of gallbladder cancer in those with large stones of any number. Drugs that inhibit the synthesis of prostaglandins may now be the treatment of choice in patients with gallstones who are suffering acute pain attacks. Persistent dyspeptic symptoms occur frequently following cholecystectomy. A prolonged history of such symptoms prior to surgery and evidence of significant psychological distress appear to be the best predictors of unsatisfactory outcome.

Admission stool guaiac test: use and impact on patient management.

PURPOSE: A stool guaiac test is often performed on newly hospitalized patients as part of the admission evaluation. However, little is known regarding the value of testing stool obtained by digital rectal examination. We sought to document the use of the admission stool guaiac test in a teaching hospital, to determine its diagnostic yield, and to assess its potential benefit to patients. MATERIALS AND METHODS: We performed a retrospective review of the medical records for 264 consecutive patients admitted to internal medicine services during a single month, of whom 202 received a stool guaiac test on admission. Information was collected on the frequency of guaiac testing, indications for testing, test results, and diagnoses established. RESULTS: Criteria were established to distinguish "clinically indicated" from "routine" use of the admission stool guaiac test. Indicated tests were positive more often than routinely performed tests (35% versus 11%, p less than 0.001). Most patients with positive tests received further testing for gastrointestinal disease, whether or not the test was indicated. Of 104 patients with indications, 25 were ultimately found to have gastrointestinal lesions, most of which were clinically important. Of 98 patients tested routinely, only four had diagnoses established, of whom three had benign conditions. Four of five patients with cancer had clinical indications for testing. The fifth was diagnosed only after he experienced gross rectal bleeding several days after admission. CONCLUSIONS: Like other commonly applied diagnostic tests, the stool guaiac test obtained during the admission physical examination is best reserved for patients whose clinical presentation provides a reason for testing. In patients without clinical indications, the test is of uncertain value and only infrequently leads to important diagnoses.

Epidemiology and natural history of gallstone disease.

Gallstones are common, affecting about one fourth of women and 10% to 15% of men over the age of 50. They are more prevalent in Amerindians and Mexican-Americans and less common in blacks. Principal risk factors are age, sex, and obesity. Lesser risk factors include childbearing, abstinence from alcohol, and some medications. The rate at which asymptomatic gallstones become symptomatic is low but significant, while patients with mildly symptomatic stones are at even greater risk for future pain and complications.