Perianal fistulas occur in up to 43% of patients with Crohn disease. Diagnostic evaluation to determine the location and type of fistulas and the presence or absence of rectal inflammation is required. A combined medical and surgical approach to the management of such patients is the optimal treatment plan. Perianal abscesses must be drained. Superficial, low transsphincteric, and low intersphincteric fistulas are usually treated with fistulotomy and antibiotics. High transsphincteric, suprasphincteric, and extrasphincteric fistulas are usually treated with noncutting setons, antibiotics, and azathioprine or 6-mercaptopurine and, in many cases, infliximab.

Evidence-based medicine guidelines based on venographic end points recommend in-hospital prophylaxis with low-molecular-weight heparin (LMWH) in patients having elective hip surgery. Emerging data suggest that out-of-hospital use may offer additional protection; however, uncertainty remains about the risk-benefit ratio. To provide clinicians with a practical pathway for translating clinical research into practice, we systematically reviewed trials comparing extended out-of-hospital LMWH prophylaxis versus placebo.

Medicine has traditionally focused on relieving patient symptoms. However, in developed countries, maintaining good health increasingly involves management of such problems as hypertension, dyslipidemia, and diabetes, which often have no symptoms. Moreover, abnormal blood pressure, lipid, and glucose values are generally sufficient to warrant treatment without further diagnostic maneuvers. Limitations in managing such problems are often due to clinical inertia-failure of health care providers to initiate or intensify therapy when indicated. Clinical inertia is due to at least three problems: overestimation of care provided; use of "soft" reasons to avoid intensification of therapy; and lack of education, training, and practice organization aimed at achieving therapeutic goals. Strategies to overcome clinical inertia must focus on medical students, residents, and practicing physicians. Revised education programs should lead to assimilation of three concepts: the benefits of treating to therapeutic targets, the practical complexity of treating to target for different disorders, and the need to structure routine practice to facilitate effective management of disorders for which resolution of patient symptoms is not sufficient to guide care. Physicians will need to build into their practice a system of reminders and performance feedback to ensure necessary care.

This review addresses myocardial infarctions that escape clinical recognition. It focuses on the prevalence, predisposing factors, and prognosis of these unrecognized infarctions, and incorporates data from relevant epidemiologic studies, basic science investigations, and review articles. These data indicate that at least one fourth of all myocardial infarctions are clinically unrecognized. The demographic characteristics and coronary risk factor profiles of persons with previously unrecognized myocardial infarctions appear to be similar to those of persons whose infarctions are clinically detected. Impaired symptom perception may contribute to lack of recognition, but both patients' and physicians' perceptions about the risk for myocardial infarction may also play an important role. Finally, mortality rates after unrecognized and recognized myocardial infarction are similar. Given the public health implications of unrecognized myocardial infarction, future studies should address screening strategies, risk stratification after detection of previously unrecognized myocardial infarction, and the role of standard postinfarction therapies in affected patients.

Studies relating certain chemokine and chemokine receptor gene alleles with the outcome of HIV-1 infection have yielded inconsistent results.

The dual aims of treating patients with chronic stable angina are 1) to reduce morbidity and mortality and 2) to eliminate angina with minimal adverse effects and allow the patient to return to normal activities. In the absence of contraindications, beta-blockers are recommended as initial therapy. All beta-blockers seem to be equally effective. If the patient has serious contraindications to beta-blockers, unacceptable side effects, or persistent angina, calcium antagonists should be administered. Long-acting dihydropyridine and nondihydropyridine agents are generally as effective as beta-blockers in relieving angina. Long-acting nitrates are considered third-line therapy because a nitrate-free interval is required to avoid developing tolerance. All long-acting nitrates seem to be equally effective. Patients with angina should take 75 to 325 mg of aspirin daily unless they have contraindications. Such risk factors as smoking, elevated low-density lipoprotein cholesterol level, diabetes, and hypertension should be treated appropriately. Coronary revascularization has not been shown to improve survival for most patients with chronic angina but may be required to control symptoms. However, coronary artery bypass grafting (CABG) is often indicated for symptomatic patients with left-main disease, three-vessel disease, or two-vessel disease including proximal stenosis of the left anterior descending coronary artery; it improves their survival. Percutaneous transluminal coronary angioplasty is an alternative to CABG for patients with normal left ventricular function and favorable angiographic features. Coronary artery bypass grafting is initially more effective in relieving angina than medical therapy, but the two procedures yield similar results after 5 to 10 years. Eighty percent of patients who undergo CABG remain angina-free 5 years after surgery. In low-risk patients, percutaneous transluminal coronary angioplasty seems to control angina better than medical therapy, but recurrent angina and repeated procedures are more likely than with CABG. Patient education is an important component of management. Long-term follow-up should be individualized to ascertain clinical stability at regular intervals and to reassess prognosis when warranted.

The transformation of digitalis from a folk medicine, foxglove, to a modern drug, digoxin, illustrates principles of modern pharmacology that have helped make drugs safer and more effective. Digitalis was improved because its preparation was standardized, first by bioassay and then by chemical methods; however, few of today's herbs are standardized by methods that can ensure a consistent product and, hence, consistent safety and efficacy profiles. Many herbs have been evaluated in randomized, controlled trials, and several-St. John's wort and ginkgo, for example-are apparently effective. Yet, many trials of herbs have limited value because of poor design, small samples, and, above all, use of products of uncertain composition and consistency. The uncertain composition of many herbal products raises questions about their safety, as does evidence indicating that herbs may have harmful interactions with prescription drugs. Such adverse effects of herbs are probably underreported. Meanwhile, systematic studies, such as those identifying adverse reactions to drugs, are hindered because herbal preparations are not standardized-one brand of St. John's wort, for example, will differ chemically from another-and, unlike for prescription drugs, there are no databases linking herb consumption to later medical problems. Since herbal medicines are regulated as dietary supplements, they are not subject to the premarketing regulatory clearance required for drugs. The burden of proof is on the U.S. Food and Drug Administration to show a dietary supplement is unsafe, unlike for drugs, which cannot be approved until the manufacturer has demonstrated safety and effectiveness.

Patients with suspected chronic stable angina can be evaluated in three stages. In stage one, the clinician uses information from the history, physical examination, laboratory tests for diabetes and hyperlipidemia, and resting electrocardiography to estimate the patient's probability of coronary artery disease (CAD). In stage two, additional testing for patients with a low probability of CAD focuses on diagnosing noncoronary causes of chest pain. Patients with a high probability of CAD have stress tests to assess their risk from CAD, and patients with an intermediate probability of CAD have stress tests to estimate the probability of CAD and assess their risk from CAD. Most patients with new-onset angina can start stress testing with exercise electrocardiography. The initial stress test should be a stress imaging procedure for patients with rest ST-segment depression greater than 1 mm, complete left bundle-branch block, ventricular paced rhythm, preexcitation syndrome, or previous revascularization with percutaneous coronary angioplasty or coronary artery bypass grafting. Patients who cannot exercise can have an imaging procedure with stress induced by pharmacologic agents. In stage three, patients with a predicted average annual cardiac mortality rate between 1% and 3% should have a stress imaging study or coronary angiography with left ventriculography. Those with a known left ventricular dysfunction should have cardiac catheterization. Patients with CAD who have an estimated annual mortality rate greater than 3% should have cardiac catheterization to determine whether their anatomy is suitable for revascularization. Patients with an estimated annual mortality rate less than 1% can begin to receive medical therapy.

A reflection on the scientific behavior of adherents of conventional medicine toward one form of alternative medicine-homeopathy-teaches us that physicians do reject seemingly solid evidence because it is not compatible with theory. Further reflection, however, shows that physicians do the same within conventional medical science: Sometimes they discard a theory because of new facts, but at other times they cling to a theory despite the facts. This essay highlights the seeming contradiction and discusses whether it still permits the building of rational medical science. We propose that rational science is compatible with physicians' behavior, provided that physicians acknowledge the subjective element in the evaluation of science, as exemplified in the crossword analogy by the philosopher Haack. This type of thinking fits very well with the Bayesian approach to decision making that has been advocated for decades in clinical medicine. It does not lead to complete and uncontrollable subjectivity because discernment between rivaling explanations is still possible through argument and counterargument.

Abnormalities in insulin and glucose metabolism do not seem to entirely account for the high frequency of cardiovascular disease in patients with type 2 diabetes mellitus. An important additional factor may be hypertriglyceridemic hyperapoB, an atherogenic dyslipoproteinemia that is common in these patients. The major features of hypertriglyceridemic hyperapoB are hypertriglyceridemia; low levels of high-density lipoprotein cholesterol; and increased numbers of small, dense low-density lipoprotein (LDL) particles. This article reviews the pathophysiology of this disorder, focusing on the changes in lipoprotein particle number and composition rather than lipoprotein lipid levels. The in vitro and in vivo evidence that small, dense LDL are more atherogenic than normal larger, buoyant LDL is summarized, and the particularly high-risk state conferred by increased numbers of small, dense LDL is delineated. This review demonstrates how abnormalities in the plasma lipoproteins may relate to the effectiveness with which adipose tissue traps and retains fatty acid. The effects of increased fatty acid flux on the hepatic metabolism of lipids and apoB secretion are detailed, and the mechanisms by which fibrates and statins may improve these are described. An understanding of these principles should provide the physician with a more physiologic basis on which to choose appropriate therapy.

To summarize and compare the validity of computed tomography angiography, magnetic resonance angiography, ultrasonography, captopril renal scintigraphy, and the captopril test for diagnosis of renal artery stenosis in patients suspected of having renovascular hypertension.

Discovery of the factor V Leiden and prothrombin G20210A mutations has greatly increased the percentage of patients in whom venous thrombosis can be attributed to hereditary thrombophilia. The first step in the diagnostic approach to all patients with venous thrombosis consists of a careful history and physical examination combined with routine laboratory testing to characterize the severity of the thrombotic condition and determine the presence of any of the acquired causes of hypercoagulability. The second step is to consider screening for the causes of hereditary and acquired thrombophilia in selected subsets of patients. The selection of patients for testing, the choice of tests to perform, and the timing of the testing are important and challenging issues to consider. Routine testing would be warranted if the identification of abnormalities led to an alteration in the type or duration of initial anticoagulant therapy or the use of long-term prophylactic anticoagulation. The available data, however, do not yet indicate that most patients with defined thrombophilic states should be managed any differently than patients without identifiable abnormalities. On the basis of relative prevalences of the various thrombophilias, patients can be classified as "strongly" or "weakly" thrombophilic depending on their thrombotic histories. Management considerations and guidelines are offered for patients who are found to have one or more defined abnormalities, hereditary or otherwise. The future identification of additional laboratory abnormalities predisposing patients to thrombosis, coupled with prospective clinical trials, should enable us to better identify patients at high risk for recurrence who will benefit from prolonged anticoagulant prophylaxis.

The cause of racial disparities in the use of invasive cardiac procedures remains unclear. To summarize, evaluate, and clarify gaps in the literature, studies examining racial differences in cardiac catheterization, percutaneous transluminal coronary angioplasty (PTCA), and coronary artery bypass grafting (CABG) were reviewed.

T cells play an important role in the pathogenesis of chronic and autoimmune inflammatory diseases. They are found in high numbers in involved tissues, such as the lamina propria of the gut in patients with Crohn disease. Modifying T-cell number and function may therefore be of therapeutic value. In principle, two mechanisms may be responsible for the development of such T-cell infiltrates: 1) an increased rate of T-cell immigration into involved tissues or 2) an increased proliferation rate, decreased T-cell death (apoptosis) rate, and prolonged retention of T cells already in the tissue. Based on the theory that T cells selectively target affected tissues through organ-specific adhesion-molecule pathways, current anti-adhesion-molecule therapy aims to interfere selectively with T-cell entry to stop tissue damage. However, the traffic of labeled T cells in unmanipulated animals shows that the entry of T-cell subsets into tissues is not organ-specific, even under conditions of differing adhesion molecule and chemokine receptor expression. In contrast, within various tissues, both movement and survival of T-cell subsets differ considerably. These observations suggest that the differential expression of adhesion molecules and chemokine receptors on T cells serves at least two functions in vivo. First, during migration of T cells out of the bloodstream, the different adhesion-molecule pathways provide redundancy, which guarantees that T-cell subsets are able to enter the different tissues in sufficient numbers (security). Second, adhesion molecules and chemokine receptors mediate T-cell interactions within the tissue that are characteristic for each subset and each microenvironment and determine the nature of the ensuing immune response (selectivity). Shifting the focus of anti-adhesion-molecule therapy toward the T cells in diseased tissue may lead to new treatment options.