Obesity Flashcards
What controls appetite regulation
peripheral hormones and neural signals that interact with the CNS appetite circuits
In what ways do messages from the periphery reach the brain
circulation: products cross the blood-brain barrier
neural circuits: vagal afferents from GI tract
What produces leptin and what is the function of leptin
Adipocytes (fat cells)
It signals to the brain about the quantity of fat stored
It indicates whether fat stores are sufficient for survival and reproduction
Where is ghrelin produced and what does it do
peptide produced in the stomach that increases food intake and stimulates GH
What parts of the CNS are important in the regulation of appetite
Nucleus of the tracts solitaires
Arcuate nucleus (base of hypothalamus)
Paraventricular nucleus
What does damage to the ventromedial hypothalamus lead to
increased food intake and obesity
What does damage to the lateral hypothalamus lead to
reduced food intake and lower body weight
What disorders is obesity linked with
insulin resistance diabetes mellitus hypertension dyslipidaemia coronary heart disease stroke sleep apnoea cancer
How is obesity defined
BMI of 30+
What BMI signals overweight
25-29.9
Describe the link between ethnicity and sex
White men are more likely to be obese than black men
Black women are more likely to be obese than white women
What are some causes of obesity
Lifestyle and social Dietary factors genetic factors drugs neuroendocrine disorders prenatal factors psychological factors
What is the most common monogenic cause of obesity in childhood
Heterozygous mutations in the gene encoding the Melanocortin-4 receptor
What gene mutation increases the risk of obesity in the general population
A variant in the FTO gene (fat mass and obesity associated) on chromosome 16
What sorts of drugs can cause weight gain
atypical antipsychotics tricyclic antidepressants anti epileptic drugs insulin sulphonylureas thiazolidinediones glucocorticoids
What neuroendocrine disorders may be associated with the development of obesity
hypothalamic obesity: rare syndrome in humans
Cushing’s syndrome: stimulation of food intake by excess glucocorticoids contributes to weight gain
Hypothyroidism: the slowing of metabolic activity
PCOS
GH deficiency: increased abdominal and visceral fat
What does the clinical evaluation of overweight and obese individuals involve
height, weight and BMI
waist circumference in patients with a BMI
What should obese patients receive counselling on
diet
lifestyle
exercise
What are the measurements of an increased waist circumference
> 102cm in men
>88cm in women
Levels of what increase following a diet induced weight loss
Serum ghrelin levels
If drug therapy is used for obesity, how much weight should be loss in the first month
2kg
How does orlistat work
It inhibits pancreatic lipase and prevents the hydrolysis of ingested fat to fatty acids and glycerol, resulting ing increased faecal fat excretion
How is orlistat to be taken
120mg TD before meals
What are the main side effects of orlistat
intestinal cramps
flatus
faecal incontinence
oily spotting
What should be given along side orlistat
vitamin A and E
Sibutramine is contraindicated in what patients
those with a history of any cardiac disease or stolen
How does sibutramine work
it inhibits food intake but its thermogenic effect in humans is controversial
What should patients with T2DM be started don
metformin
What do glucagon-like peptide-1 agonists do
Reduced food intake as well as improving glycemic control
Who should be considered for bariatric surgery
those with a BMI of 40+who are well informed and motivated
failed previous non-surgical weight loss
Those with a BMI of 35+ and obesity -related comorbidities e.g. hypertension, DM, dyslipidaemia
What are some contraindications to bariatric surgery
patients with untreated major depression or psychosis
binge eating disorders
drug or alcohol abuse
severe coagulopathy
severe cardiac disease with an excessive anaesthetic risk
What is the mean overall percentage of excess weight lost in bariatric procedures
60%
Surgical therapies are based on what two mechanisms
Restrictive procedures: restriction of caloric intake via a small stomach reservoir
Malabsorptive procedures: shortened functional small bowel
Mixed restrict and malabsorptive procedures: roux-en-Y gastric bypass
What are the most widely performed procedures for bariatric surgery
roux-en-y (RYGB)
Adjustable gastric banding
What are some complications of bariatric surgery
Blleding bowel perforation obstruction wound infections PE MI pneumonia UTI Prolonged vomiting
What is dumping syndrome characterised by
nausea shaking sweating diarrhoea all immediately after eating foods containing high levels of glucose
How long should females avoid pregnancy post op
12-18 months
Patients are at risk of nutritional deficiencies after bariatric surgery. What should they receive daily
multivitamin calcium vitamin D vitamin B12 Iron supplements (those at risk of iron deficiency e.g. menstruating females)
What should be reviewed at every follow up appointment
protein and food intake and patterns of eating psychological or eating disorders BP and weight FBC, U&E, creatinine LFT glucose albumin and serum
