[ Pobierz całość w formacie PDF ]
.In Eating Disorders and Obesity: A Comprehensive Handbook, 2nd ed.(Eds C.G.Fairburn, J.D.Brownell), pp.340 344.Guilford Press: New York.3.2Medical Findings in Eating Disorders:Clinical Perspectives on Cause and ConsequenceDavid C.Jimerson1Among the major psychiatric syndromes, eating disorders have a notablyhigh association with physiological alterations, including serious medicalcomorbidities.The review by Brambilla and Monteleone provides asystematic overview and extensive reference list detailing the impact ofeating disorders on the body s physiological systems, from the gastro-intestinal tract through the immune and neuroendocrine pathways.Anorexia nervosa is often associated with potentially life-threateningmedical consequences that play a major role in influencing treatmentconsiderations in the low weight state, and call for collaborative effortsacross mental health, nutrition and medical disciplines [1].Although themedical problems associated with bulimia nervosa are generally less severe,the clinician needs to remain alert to the effects of dieting, binge eating andpurging, including the possibility of potentially life-threatening alterationsin electrolytes [2].1Beth Israel Deaconess Medical Center and Harvard Medical School, 330 Brookline Avenue, Boston,MA 02215, USA198 ___________________________________________________________________________ EATING DISORDERSOne prominent theme that surfaces repeatedly throughout the review isour current uncertainty regarding the precise relationship betweenphysiological symptoms and dysregulated eating patterns.For example,although amenorrhoea in women with anorexia nervosa is commonlyassumed to be a result of weight loss with an associated decrease in bodyfat, it is unclear why some women develop amenorrhoea prior to the onsetof the low weight episode.Additionally, a few studies have evaluated therole of decreased calorie intake and weight loss per se, in comparison toalterations in dietary macronutrient and micronutrient content, in themedical sequelae of anorexia nervosa.Changes in meal size and frequencyare likely to affect gastrointestinal physiology.Additionally, some medicalproblems have been linked to patients use of diet pills or purgatives (e.g.the cardiomyopathy associated with the use of syrup of ipecac).On a related matter, the authors call attention to the fact that medicalsymptoms and laboratory findings may be quite variable among anorexicpatients at a similar body mass index.Little is known regarding the extentto which these variations reflect the influence of age of onset, rate of weightloss, duration of the low weight state, exercise patterns and familial/geneticinfluences.Similarly, it is unknown why some systems seem to returntowards normal quite rapidly with weight restoration (e.g.the restoration ofserum leptin concentrations) [3], whereas other abnormalities (e.g.amenor-rhoea) are more persistent.It is also generally unknown whether the nutritional and physiologicalchanges associated with eating disorders may affect the course of illness,either through peripheral consequences or effects on central nervous system(CNS) neurotransmitters and neuromodulators.As the authors note,although the decrease in circulating leptin is not likely to contribute to thereduced food intake characteristic of anorexia nervosa, it may contribute toamenorrhoea and other neuroendocrine symptoms.In another example,dieting has been shown to lower blood tryptophan levels in healthy women,potentially resulting in decreased synthesis of the CNS neurotransmitterserotonin [4].This decrease in central serotonin function could contribute tothe impaired satiety response and high-calorie binge episodes associatedwith bulimia.A marked decrease in CNS serotonin function may play a rolein the lack of response to antidepressant medications in low-weight patientswith anorexia nervosa [5], in comparison with preliminary evidence fortherapeutic benefit following weight restoration and symptom remission [6].A challenge facing clinical investigators is the fact that physiologicalstudies during the acute phase of anorexia nervosa or bulimia nervosa arelikely to be influenced by patients nutritional abnormalities.Thus, for bothdisorders it is difficult to quantify the actual caloric, macronutrient andmicronutrient pattern of the diet [ Pobierz całość w formacie PDF ]