11. Eating Disorders

Question 1

What is anorexia nervosa?

Answer 1

Compulsive need to control eating and body shape deliberate weight loss, intense fear of fatness, distorted body image, endocrine disturbance

Belief in being fat even when weight is very low, BMI <17.5

Underlying need for control

Males tend to want high muscle mass rather than being thinner

Ego syntonic (feels right)

1) restrictive type
2) purging type

Question 2

How should anorexia nervosa be assessed and Dx?

Answer 2

SCOFF questionnaire (>2 clinical sig)
1 = do you make yourself SICK because you feel to ill?
2 = do you worry you've lost CONTROL over eating?
3 = lost >1 stone in 3m?
4 = do you believe you are FAT when others say you are thin?
5 = does FOOD dominate your life?

DSM-5

• Restriction en energy intake
• Intense fear of weight gain, even though underweight
• Distorted body image, weight/shape has undue influence on self-evaluation or denial of seriousness

Question 3

Outline the management of anorexia nervosa

Answer 3

Risk assessment

BIO

• Weight gain 0.5-1kg/w (~3500 - 7000 extra calories/w) IV/NG
• Complications = electrolyte disturbance
• SSRIs (depression/OCD)

PSYCHO
Children:
- Family therapy (1st line for children/young people)
- CBT-ED focused (2nd line for children/young people)
Adults:
- individual CBT-ED
- MANTRA (Maudsley Anorexia Nervosa Tx for Adults)
- SSCM (Specialist supportive clinical Mx)

SOCIAL

• Voluntary organisations
• Self-help groups

** harder to treat then BN

Question 4

How does anorexia nervosa present?

Answer 4

Most due to starvation/vomiting

• fatigue
• decreased cognition
• altered sleep cycle
• sensitivity to cold, hypothermia, lanugo hair
• dizziness
• constipation
• psychosexual probs
• subfertility
• amenorrhoea
• Haem: decreased WCC, anaemia, decreased plt
• CVS: brady, prolonged QT interval
• NS: decreased visual mem, peripheral neuropathy

Question 5

What are the red flags of anorexia nervosa?

Answer 5

BMI <13

Wt loss >1kg/w

Temp 34.5

BP 80/50, BPM >40, sats <92%

Peripheral cyanosis

Unable to get up without using arms

Purpura

ECG: long QT interval, flat T waves

Question 6

Outline refeeding syndrome

Answer 6

Starvation = decreased insulin due to low carb = body switches to met fat/protein = loss of intracellular electrolytes, in particular phosphate

Refeeding = switch from met of fat to carb, insulin increases = stim cellular uptake of phosphate = profound hypophosphataemia

***phosphate is needed for ATP

S+S = rhabdomyolysis, resp/cardiac failure, hypotension, arrhythmias, seizures, sudden death

Mx = slow re-feeding, monitor electrolytes

Question 7

What is bulimia nervosa?

Answer 7

Recurrent ep of BINGE EATING characterised by uncontrolled overeating

Preoccupation with control of body weight

Regular use of mechanisms to overcome the fattening effects of binges

BMI >17.5

TYPES:

1) purging type (induced vomiting, laxative)
2) non-purging type (exercise, fasting)

Question 8

How does bulimia present?

Answer 8

Fatigue
Lethargy
Feeling bloated
Constipation
Abdo pain
Oesophagitis 
Gastric dilation with risk of gastric rupture 
Heart conduction abnormalities, cardiomyopathy (laxative use)
Tetany
Irregular menstruation 
Russell's sign 
Abnormal ECG

Question 9

Describe the management of bulimia

Answer 9

Risk assessment

Biological =
- SSRI (fluoxetine)

Psychological =

• Psychoeducation
• CBTe (enhanced - 20 sessions)
• IPT

Social =

• Self-help books
• Food diary
• Regular eating

Binge analysis (?causes)

Referral to EDU (eating disorder unit)

Question 10

What are the physical effects of having an ED?

Answer 10

Low body weight = adjusts free T4 to reduce its metabolic requirement (sick euthyroid syndrome) = reduced resting metabolic rate, reduced temp, bradycardia

With time multiple systems are unable to adapt and start to show -ve consequences =

• amenorrhagia
• myocardial thinning, hypotension, brady, prolonged QT, HF
• osteopenia/porosis
• low K (cardiac arrest), Na, Ca, phos, zinc, thiamine, Mg
• BM suppression: WCC, Hb, plt
• delayed GI motility, constipation, malloery weis tears, pancreatitis, peptic ulcers
• fatty liver, hepatitis, risk of re-feeding

Question 11

Which investigations should be performed for suspected AN?

Answer 11

Bloods = FBC (anaemia, thrombocytopenia, leukopenia), U+Es (elevated urea and creatinine if dehydrated, decreased K phos Mg Cl), TFT (dec T3/4), LFTs (dec albumin), lipids (in cholesterol), cortisol (in), sex hormones (FSH low), hypoglycaemia, GH (in),

VBG = met alk (vom), met acid (laxatives)

DEXA scan = rule out osteoporosis

ECG = sinus brady, prolonged QT

Questionnaire = eating attitudes test (EAT)

Question 12

How is BMI calculated?

Answer 12

Weight (kg) / height (m)^2

Normal = 18.5-24.9kg/m^2

Question 13

How is BN Dx?

Answer 13

ICD-10 = Bulimia Patients Fear Obesity

1) Compensatory Behaviours = self-induced vom, alternating starvation/drugs/excessive exercise
2) Preoccupation with eating (craving) = sense of compulsion leads to bingeing
3) Fear of fatness = includes self-perception of being too fat
4) Overeating (binges) = at least 2 ep/w over period of 3m

Question 14

What are the complications of repeated vomiting?

Answer 14

CVS = arrhythmias, mitral valve prolapse, peripheral oedema

GI = Mallory-Weiss tears, increased size of salivary glands (esp parotid)

Met/renal = dehydration, hypoK, renal stones, renal failure

Dental = erosion on dental enamel

Endo = amenorrhoea, irregular menses, hypogly, osteopenia

Derm = russells sign

Resp = aspiration pneumonitis

Neurp = cognitive impairment, peripheral neuropathy, seizures