Table of Contents
Abstract
Eating disorders (EDs) are one of the “great masquerades’” of the twenty-first century. Young men and women who looks healthy with underlying EDs walks most times to emergency department with numerous complaints that are specific to individuals with EDs. The challenge for the emergency department is to acknowledge that these complaint are as a result of EDs.
AN and BN are problematic psychiatric disorders with huge medical complications. Understanding the underlying psychopathology and pathophysiology is essential in the management of EDs patients. Individuals suffering from EDs are difficult to recognise. Failure to diagnose there disorders or manage symptoms with an understanding of their distinctive fundamental psychopathology and pathophysiology can be damaging to patients with EDs. Once an individual has been identified as EDs patient, medical complications highlighted in this article in the management of the underlying psychopathology and pathophysiology of EDs patients will help clinicians to implement an effective therapeutic intervention.
Definitions
Eating disorders (EDs) is defined by the Diagnostic and Statistical Manual of Mental Disorders 5th Edition (DMS-5) as a group of illnesses marked by severe disturbances in eating behaviours. The diagnostic criteria were expanded and made more flexible in this edition to capture all form of eating disorders which includes anorexia nervosa (AN), bulimia nervosa (BN), binge eating disorder (BED), and avoidance/restrictive food intake disorder (ARFID) which is usually common in children. In the second half of the twentieth century, the problem of EDs become more prominent from being in small paragraphs in medical textbooks to being perceived as a major public health problem
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Anorexia Nervosa (AN) the important features of AN is a low body weight (usually 15% less than the normal weight of that person age, height and sex accompanying with reluctant to gain weight) that is attainted by and individual withdrawal from food. In real life people who are diagnosed with AN are not suffering from anorexia, rather they are supressing the urge to eat that is deemed out of control. One of the key motivation from food withdrawal is concern about body weight and shape that forms the particular psychopathology of the disorder. Further features of AN includes disturbance of body image and physical changes such as amenorrhoea.
People who suffer from AN starts slowly with food withdrawal food pattern but some relapse in their food withdrawal and truly binge. Sufferers from AN adapt compensatory behaviours such as vomiting, and laxative abuse which is common with Bulimia nervosa (BN) sufferers. However, individuals will be diagnosed with AN with low weight.
There are two subtypes of AN; restrictive and binge-purge AN. Cross-over between the subtypes is common, with up to 62% of individuals with restrictive AN developing binge-purge AN and with 43% of individuals with binge-purge developing restrictive AN. Moreover, as many of 50% of individuals with AN eventually cross-over to BN.
Bulimia Nervosa (BN): The important characteristic of BN is recurrent binge eating.BN shares some common features with AN, such as intense obsession with weight and shape; however, it is categorised by episodes of unrestrained eating (>1000kcal in one sitting eating) linked with various methods of counteracting weight gain with vomiting and laxative abuse being most common.
There are two subtypes of BN; purging and non-purging. Purging is much more common. The position of non-purging type as a useful syndrome is doubtful.
Binge-eating disorder (BED); it was the publication of the DSM-5 in 2013, that BED was recognized as a distinct eating disorder. Many studies/researches has been received in this field, but there are doubt over whether the syndrome as defined is sufficiently coherent and stable over time to warrant being thought of as a third eating disorder. The diagnosis of BED approximates to lay concept of compulsive eating. Many but not all individuals who suffers from BED are obese.
In the diagnostic and statistical manual fourth revision (DMS-IV), BED is included only as a conditional diagnosis worthy of study. BED provide a diagnostic marker for individuals who binge-eat but show not the characteristic psychopathology nor the compensative behaviours essential for the diagnosis of bulimia.
Avoidance/restrictive food intake disorder (ARFID): Is characterized by restrictive eating or avoidance of food in the lack of cognitive restraint and the obsession of weight usually seen in anorexia nervosa. Generally the disinterest or selective eating characteristic due to sensory preferences, and or fear of adverse consequences such as choking, even though the diagnostic criteria allow for a number of other clinical presentations. Individuals who suffers from AFRID are often male and tend to be younger, and the illness tend to be longer when compared to other individuals who suffers other EDs
Epidemiology
EDs and related behaviours although rare in the overall adult population, are a common problems that are prevalence in pre-adolescents and adolescents. After obesity and asthma, AN is ranked as the third most chronic disorder in adolescent girls. Since the 1970, the general incidence of AN have been stable ranging from 5 to 5.4 in 100 000 per person-years.
For women, the peak incidence age is 15 to 19 and is 270 per person-years when narrowly defined (DSM-IV) and 490 per person-years when broadly defined (DSM-5). For men, the peak incidence of AN is from age 10 to 24 and is 15.7 per 100 000 person-years (DSM-IV). In women, the lifetime prevalence of AN ranges from 0.9% to 2.2% when narrowly defined (DSM-IV) and 2.4% to 4.3% when broadly defined (DSM-5). In men, lifetime prevalence ranges from 0.24% to 0.3% (DSM-IV). In a 2011 meta-analysis of 36 published studies on mortality rates in patients with eating disorders, the weighted crude mortality rate was 5.1 death per 1000 individual-years, and the standardized mortality ratio was 5.86. The causes of death in the meta-analysis was not reported because the death were inconsistently reported in the included study.
In few studies that tries to distinguishes the causes of death in patients with AN, medical causes accounted for most deaths (52.5-67.1%). AN is generally classified as disease of young white women, but has be shown to occur in non-western women. Among psychiatric disorders, AN has the highest mortality rate.
In 2012, a literature review on BN epidemiology showed peak incidence of BN in women is between age 16-20 years was estimated to be 200 per 100 000 person-years when narrowly defined by (DSM-IV) and 300 to 438 per 100 000 person-years when broadly defined by (DSM-5). Incidence of BN has decrease generally since the 1980s, with recent estimates of BN ranges from 6.1 to 6.6 per 100 000 person-year. BN lifetime prevalence is estimated at 1.7% to 2.9%. A meta-analysis of 12 published studies, BN crude weighted mortality was 1.74 deaths per 100 000 person-year, ration of standardized mortality was and standardized mortality ratio was 1.93 with 23% of deaths accounting to suicide in BN patients.
Significant difference in the prevalence of BN have been documented in the United States between racial and ethnic groups [11]. Lifetime prevalence of BN in African American (1.39%), Latinos (2.03%) is significantly higher than that in non-whites Latinos (0.15%). In the same study, a non-statistically significant difference showed increased lifetime prevalence of BN in Asian Americans (1.5%) compared to non-Latinos whites. In Latinos men, the prevalence of BN is significantly higher than that in non-Latinos whites.
An epidemiological survey indicate BED is considered the most common eating disorder and shows a smaller sex difference than AN and BN [11, 29, 30]. Holly E. Erskine and Harvey A. Whiteford in a found that the global pool prevalence of BED was 0.9%. The prevalence in women (1.4%, 1.1–1.7%) was higher than men (0.4%, 0.3–0.6%). No significant difference in prevalence between high-income countries (0.9%, 0.8–1.1%) and middle- and low-income countries (0.7%, 0.3–1.1%) was found.
Medical complications of EDs (Pathogenesis) Cardiopulmonary complications such as hypotension and bradycardia are common medical complications among patients with AN. Decreased in cardiac muscle mass causing reduced contractibility and cardiac output is as a result of severe malnutrition. Administration of intravenous fluids should be done taking into the account the patient’s weight in order not to overload a weakened heart with fluid and precipitate pulmonary edema. AN patients suffering from bradycardia is common and is thought to be due to increase in vagal tone and dominate in AN in an effort to converse energy. AN patients with asymptomatic bradycardia are recommended to be hospitalized when heart rate is less than 40 beat/min and adolescents when heart rate is less than 50 beat/min based on expert opinion.
