Lecture_12_Disorders_of_negative_energy_balance_.pdf

🥒 Lecture 12: Disorders of negative energy balance Part 1: Psychiatric undereating - Anorexia and ARFID OVERVIEW Underweight Psychiatric: Anorexia Nervosa, Avoidant Restrictive Food Intake Dis...

🥒 Lecture 12: Disorders of negative energy balance Part 1: Psychiatric undereating - Anorexia and ARFID OVERVIEW Underweight Psychiatric: Anorexia Nervosa, Avoidant Restrictive Food Intake Disorder (ARFID) Hypermetabolism: cancer cachexia, hyperthyroidism Inability to appropriately grow/maintain a tissue type: lipodystrophy, muscular dystrophy, sacropenia of aging Being underweight is risky In terms of hazard ratio and BMI - being underweight (eg. BMI 16) would be just as risky on the hazard ratio as someone that is obese Lecture 12: Disorders of negative energy balance 1  Failure to eat enough – anorexia and ARFID Psychiatric disorders where food intake is ‘voluntarily’ restricted Anorexia and ARFID are psychiatric diseases where failure to eat enough to maintain body weight results in weight loss, malnutrition and psychosocial disability Energy expenditure drops to account for reduced food intake, but this is often not enough to maintain energy balance ⇒ weight loss LO: Define and contrast the clinical characteristics of anorexia nervosa (AN) and avoidant restrictive food intake disorder (ARFID) Lecture 12: Disorders of negative energy balance 2  Anorexia nervosa Deadliest psychiatric illness: Highest death rate (20% in 20 years) of all mental illnesses Death from physical causes is 5 times that expected in this age group Death by suicide is 32 times that expected Lifetime prevalence of 0.9% in women and 0.3% in men. Diagnostic criteria: (A) Restriction of energy intake relative to requirements, leading to a significantly low body weight in the context of age, sex, developmental trajectory, and physical health. Significantly low weight is defined as a weight that is less than minimally normal or, for children and adolescents, less than minimally expected. (B) Intense fear of gaining weight or of becoming fat, or persistent behaviour that interferes with weight gain, even though at a significantly low weight. (C) Disturbance in the way in which one’s body weight or shape is experienced, undue influence of body weight or shape on self- evaluation, or persistent lack of recognition of the seriousness of the current low body weight. Specify current severity: Mild: BMI more than 17 Moderate: BMI 16- 16.99 Severe: BMI 15-15.99 Extreme: BMI less than 15 Avoidant/Restrictive Food Intake Disorder (ARFID) Often described as extreme fussy eating and commonly comorbid with sensory processing issues, particularly in individuals with autism spectrum disorder. Premature birth or chronic childhood illness are risk factors Lecture 12: Disorders of negative energy balance 3  Diagnostic criteria: The primary manifestation is a feeding or eating disturbance, characterised by: Apparent lack of interest in eating. Avoidance of foods based on sensory characteristics. ^ This results in a persistent failure to meet nutritional or energy needs, associated with one or more of the following: (1) Significant weight loss or failure to gain weight in children. (2) Nutritional deficiencies, primarily involving micronutrients (though protein deficiencies can also occur). (3) Dependence on enteral/tube feeding. (4) Marked interference with psychosocial functioning, such as avoiding social events (e.g., birthday or Christmas parties) where uncomfortable or feared foods may be present. Unlike anorexia nervosa, there is no evidence of body image disturbance in ARFID. ARFID often presents alongside other conditions (e.g., autism, ADHD, sensory processing issues). The severity of ARFID must exceed what would be expected from any primary disorder. Development of ARFID as a Diagnosis ARFID emerged from efforts in DSM-V to clarify eating disorder classifications and reduce the use of the 'disorders not otherwise specified' (NOS) category. ARFID is particularly associated with hyperactive fear processing, where unfamiliar foods are perceived as genuinely frightening. Sufferers often describe unfamiliar foods as terrifying, akin to being confronted with a snake. Lecture 12: Disorders of negative energy balance 4  Preferred foods are usually predictable, heavily processed, and homogenous—with no surprises. Treatment for ARFID varies by age: For younger children: Techniques like the messy food picnic are used. In these settings, children are allowed to engage with food without external pressure, helping them feel safe around it. Over time, they may begin to eat some of the foods. For older sufferers: Cognitive behavioral therapy (CBT) is commonly employed to help break down fears surrounding food. LO: Describe the physiological and hormonal changes that occur in AN Cognitive and behavioural symptoms: Lecture 12: Disorders of negative energy balance 5  Perfectionism Rigid thinking and behaviours Preoccupation with details and perceived rules Significant diagnostic overlap with other disorders: Anxiety disorders Obsessive compulsive disorders Autism spectrum disorders Hormonal changes associated with AN Patients with anorexia nervosa exhibit a metabolic hormone profile consistent with low body weight: low leptin and insulin, high ghrelin Chronic starvation in anorexia nervosa leads to chronic stress (physical starvation & psychological stress), resulting in: elevated cortisol level, increased sympathetic nervous system These chronic stress responses cause remodeling of end organ receptors, such as: Beta-adrenal receptors, Glucocorticoid receptors. This receptor remodeling alters the body's response to noradrenaline and adrenaline, potentially leading to increased tissue breakdown. Cytokine levels are dysregulated - pro-inflammatory cytokines, including: IL-1 beta, IL-6, and TNF alpha are consistently elevated in anorexia nervosa This is in contrast to primary malnutrition, where these factors are typically lower, suggesting that anorexia represents an inflammatory state that is inappropriate given the normal response to malnutrition. Other physiological changes - low body weight often results in: amenorrhea and loss of fertility, alterations in bone marrow morphology result in in anaemia LO: Explain the concept of cognitive flexibility, and how it relates to maintenance of disordered eating in AN Definition of Cognitive Flexibility Lecture 12: Disorders of negative energy balance 6  Cognitive flexibility refers to the ability to: Switch between different concepts or tasks. Modify behavior in response to changing environments or task rules. Cognitive Inflexibility in Anorexia Nervosa Cognitive inflexibility is a key feature of anorexia nervosa, where sufferers often exhibit: Fixation on specific foods or body parts. Ritualistic behaviors. Improvements in cognitive flexibility are associated with improvements in anorexia nervosa symptoms. Cognitive Inflexibility as a Trait Starvation causes cognitive impairment, but research suggests that cognitive inflexibility is likely present before the onset of anorexia nervosa due to a potential genetic component. Studies show that unwell sufferers and their well sisters exhibit similar levels of cognitive inflexibility, indicating that it may be a predisposing trait rather than a consequence of starvation. Improving Cognitive Flexibility Psychotherapy is generally helpful in breaking down rigid thought patterns. A novel approach involves the use of psychedelic drugs such as psilocybin, DMT, or LSD, which are known for breaking down rigid thought patterns. Psilocybin, for example, is found in native Australian mushrooms and is currently being explored in clinical trials for treating anorexia nervosa. The approach combines psychedelic drug therapy with psychotherapy to enhance cognitive flexibility by opening the mind and allowing for more adaptive thought processes. Lecture 12: Disorders of negative energy balance 7  Part 2: Cachexia LO: Describe the clinical diagnostic criteria for cachexia Cachexia is a physiological illness secondary to chronic diseases (eg. cancer, AIDS, COPD, multiple sclerosis, heart failure, hormonal deficiencies). Involves alterations in both sides of the energy balance equation: Reduced appetite leading to decreased caloric intake. Increased energy expenditure, resulting in more calories being burned. From the consensus definition of cancer cachexia: Cachexia is a multifactorial syndrome associated with underlying illness, defined by the ongoing loss of skeletal muscle mass, with or without fat mass, that cannot be reversed through nutritional support. Characterised by negative protein and energy balance, driven by a variable combination of reduced food intake and abnormal metabolism. Clinical diagnostic criteria for cachexia: weight loss greater than 5%, or weight loss greater than 2% in individuals already showing depletion according to current bodyweight and height (BMI