U10C1 Eating Disorders

Question 1

What factors drive eating disorders?

Answer 1

Question 2

What is the developmental model of eating behaviours?

Answer 2

• exposure
• social learning
• association
  focuses on development of food preferences and emphasises the role of exposure and learning, suggests acquisition and maintenance of eating habits is learned. The Barker hypothesis states that intrauterine growth restriction or a low birth weight might predispose children to obesity and metabolic syndrome. The deprived fetus develops a phenotype to survive in a nutrient-poor environment (Thrifty phenotype hypothesis). If there is a mismatch between the intra- and extra-uterine environment the neonate may be maladapted and therefore be at higher risk of obesity and metabolic syndrome

Question 3

What is the weight concern model?

Answer 3

meaning of food, weight and body dissatisfaction and dysmorphia, can measure body dissatisfaction with stunkard scale

Question 4

What is the cognitive model of eating behaviours?

Answer 4

extent cognitions predict and explain eating behaviours, behavioural attitudes and subjective norms lead to intention whic leads to eating behaviour

Question 5

What is the binge-purge cycle in bulimia?

Answer 5

Question 6

What are the risk factors and prevalence of eating disorders?

Answer 6

Question 7

How is vomiting triggered and what is the process of it?

Answer 7

• Chemoreceptor trigger zone in the area postrema responds to abnormal levels of toxins e.g. bacterial/metabolic products. Sends signals to emetic centre to trigger vomiting.
• Prior to vomiting retroperistaltic response moves food from the duodenum back into the stomach = distension of duodenum. The pyloric sphincter and stomach relax to accommodate
• At the onset of vomiting, contractions occur in the duodenum and stomach, and the upper oesophageal sphincter opens
• contraction of skeletal muscle including abdominal wall muscles and downward contraction of the diaphragm, squeezes the stomach between the diaphragm and the abdominal muscles propelling contents out of the stomach
• The increase in abdominal pressure and decrease in thoracic pressure also help propel contents out of the stomach
• Oesophageal-stomach sphincter relaxation allows contents to move from the stomach into the oesophagus and out of mouth

Question 8

What is a somatogenic vs psychogenic gag reflex?

Answer 8

A somatogenic gag reflex follows direct physical contactwith a trigger area, which may include the base of the tongue, posterior pharyngeal wall, or tonsillar area. A psychogenic gag reflex presents following a mental trigger, typically without direct physical contact. The gag reflex is controlled by the glossopharyngeal and vagus nerves.

Question 9

What would an ECG show for bulimia?

Answer 9

prominent U waves (could be caused by bradycardia and severe hypokalaemia) and QT prolongation (could be caused by diuretics and hypokalaemia)

Question 10

What would bloods show for bulimia?

Answer 10

Na (lowered), K (lowered), CI (lowered) due to frequent vomiting and use of laxatives/diuretics, Urea (raised) due to vomiting and use of diuretics causing loss of water and electrolytes leading to dehydration. Urea is osmotically active so normally in medullary CD of nephron, urea draws water out and because of the dehydration, urea is raised as there is no counter gradient

Question 11

What would ABG show for bulimia?

Answer 11

pO2 (normal), pCO2 (raised), HCO3 (raised), pH (raised), Base excess (raised) caused by GI loss of H+ ions via vomiting and diarrhoea

Question 12

What would K:creatinine ratio show for bulimia?

Answer 12

(raised) after oral rehydration and oral potassium solutions as he was till using diuretics at the time of admission, these deplete volume which triggers aldosterone release part of RAAS, this leads to and increased K+ excretion in urine

Question 13

What is the SCOFF questionnaire?

Answer 13

two or more positive answers to the following questions are suggestive of anorexia nervosa or bulimia nervosa.

‘Do you ever make yourself sick because you feel uncomfortably full?’

‘Do you worry that you have lost control over how much you eat?’

‘Have you recently lost more than one stone in a 3-month period?’

‘Do you believe yourself to be fat when others say you are too thin?’

‘Would you say that food dominates your life?’

Question 14

What might an endoscopy find in bulimia?

Answer 14

found Mallory-Weiss tear (Longitudinal mucosal tear of the mucous membrane in the gastroesophageal junction/gastric cardia which occurs due to forceful/recurrent vomiting, coughing, etc

Question 15

What is oral rehydration?

Answer 15

a solution containing sodium, potassium, glucose and other carbs. Patient given solution via spoon or syringe. In small intensities solution is absorbed into lining ep cell using Na+/glucose co-transport pump (2Na+/glucose). Na+/K+ ATPase then pumps 3Na+ & 2K+ from Si lining ep cell into blood. Glucose moves via FD from SI lining ep cell into blood. Makes blood more hvertonic. This draws water across from small intestine lumen -> through small intestine ep cells -> into blood

Question 16

Why did Brett faint?

Answer 16

It is possible that Brett suffered a transient arrhythmia causing him to faint. The prolongation of ventricular repolarisation can be a cause of cardiac arrhythmias including torsades de pointes (ventricular tachycardia that causes distortions in QRS complexes) as it facilitates the appearance of early afterdepolarisations, possibly due to inappropriate reactivation of the L- type Voltage-gated Ca2+ channel during the repolarisation phase. This can create a secondary action potential which can trigger an abnormal re-excitation cycle of the ventricular myocytes leading to these cells stimulating themselves independently of the sino-atrial leading leading to an uncontrolled ventricular tachycardia. As the heart fails to fill properly with blood between beats, this fast pumping of the ventricle is ineffective = can lead to fainting

Question 17

What are the long term effects of bulimia?

Answer 17

• Acid can cause tooth enamel to wear away, teeth decay or gum disease
• Blood vessels can burst in the eye if there is constant purging due to increased BP
• Vomiting can irritate or tear the esophagus (Mallory-Weiss tear)
• There can be calluses or scars on fingers due to purging
• Long term purging can lead to acid reflux due to the esophageal sphincter becoming damaged
• Laxative use can worsen constipation, cause nerve damage or cause haemorrhoids as they work by irritating the nerves of the small intestine
• Over-exercise can lead to malnourishment, increased risk of injury, muscle fatigue, bone damage and reduced healing
• Dehydration and lack of nourishment can lead to electrolvte imbalances - dizziness, concentration, irregular heartbeat, cardiomyopathy, heart disease
• Unfortunately, 3.9% of those with bulimia nervosa die

Question 18

What are the clinical features of bulimia?

Answer 18

Mallory-Weiss tear is a superficial mucosal tear of the oesophagus

Question 19

What is rumination disorder?

Answer 19

is an illness that involves repetitive, habitual bringing up of food that might be partly digested. It often occurs effortlessly and painlessly, and is not associated with nausea or disgust.

Question 20

What is anorexia?

Answer 20

• BMI (Body Mass Index (kg/m2)) of 18.5 or less
• Persistent pattern of behaviours to prevent restoration of normal weight
• Dietary restriction
• Excessive exercise
• Purging – Self induced vomiting, diuretics/laxatives/appetite suppressants/enemas
• Body image distortion – perceived to be normal/excessive
• Low body weight/shape central to person’s self evaluation
• Intense fear of gaining weight

Question 21

What is bulimia?

Answer 21

• Not significantly underweight
• Preoccupation with body shape/weight which strongly influences self-evaluation
• Episodes of binge-eating (at least once a week for a month)
• Discrete period of time
• Subjective loss of control
• More than usual
• Recurrent compensatory behaviours
• Purging
• Restricting
• Exercise
• Neglect insulin treatment

Question 22

What is binge eating disorder?

Answer 22

• Frequent binges
• Distressing and accompanied by negative emotions
• Not associated with compensatory behaviours

Question 23

What is ARFID?

Answer 23

• Abnormal eating/feeding resulting in insufficient quantity/variety
  of food
• Significant weight loss/failure to gain weight
• Negatively affective the health of the person/impaired
  functioning
• Not due to concerns about body weight or shape
• It isn’t about lack of food availability/effects of meds/substance
  use/underlying physical health condition
• Sub types: specific phobia, picky eating and lack of appetite

Question 24

What is orthorexia?

Answer 24

refers to an unhealthy obsession with eating “pure” food. Food considered “pure” or “impure” can vary from person to person. Note- this is not an official diagnosis.

Question 25

What is pica?

Answer 25

is a feeding disorder in which someone eats non-food substances that have no nutritional value, such as paper, soap, paint, chalk, or ice. For a diagnosis of pica, the behaviour must be present for at least one month, not part of a cultural practice, and developmentally inappropriate – generally, it’s not diagnosed in children under the age of two, as it is common for babies to “mouth” objects, which can lead to them accidentally eating substances that aren’t meant to be eaten. Often, pica is not revealed until medical consequences occur, such as metal toxicity, cracked teeth, or infections.

Question 26

What is OSFED?

Answer 26

is very common. OSFED accounts for the highest percentage of eating disorders. As OSFED is an umbrella term, people diagnosed with it may experience very different symptoms.

Question 27

What are the long term effects of starvation?

Answer 27

 Cardiac arrhythmias
 Postural hypotension
 Hypothermia
 Bone marrow suppression
 Sepsis
 Electrolyte imbalance
 Renal Failure
 Liver failure / Hepatitis
 Hypoglycaemia
 Lagopthalmos
 Muscle wasting
 Pressure sores
 Osteoporosis
 Impaired fertility
 Thyroid abnormalities
 Hypercortisolaemia
 Dermatological complications
 Impaired cognitive function

Question 28

What are the red flags?

Answer 28