Obesity

Question 1

Obesity Mx

Answer 1

Mx of Obesity = Stepwise approach

• CONSERVATIVE
• MEDICAL
• SURGICAL

Orlistat = Pancreatic lipase inhibitor (decreases absorption of lipids from the intestine) used in the Mx of obesity 
SE = Faecal urgency, flatulence

A lower dose version is now available without prescription (Alli). NICE have defined criteria for use of Orlistat. It should be prescribed as part of an overall plan for managing obesity in adults who have:

• BMI of 28kg/m2 or more assoc with RFs
• BMI of 30kg/m2 or more
• Continued weight loss e.g. 5% at 3 months
• Orlistat normally used for <1 year

Question 2

Drugs that have been withdrawn from Medical Mx of Obesity

Answer 2

Sibutramine - centrally acting depressant, was withdrawn in Jan 2010 due to increased risk of CV events

Rimonabant - a specific CB1 cannabinoid antagonist was also withdrawn > Psychiatric SE inc suicide

Question 3

Bariatric Surgery

Answer 3

BMI 30-39 kg/m2 = Gastric Band

BMI > 40 kg/m2 = Gastric Bypass or Sleeve Gastrectomy

Question 4

Obesity - Physiology

Answer 4

HORMONES
Leptin Lowers Appetite
Ghrelin Gains Appetite

LEPTIN:

• Thought to play a key role in regulation of body weight
• Produced by adipose tissue and acts on satiety centres in the hypothalamus and decreases appetite
• More adipose tissue (ie in obesity) therefore results in HIGH LEPTIN LEVELS
• Leptin stimulates release of Melanocyte-Stimulating hormone (MSH) and Corticotrophin releasing hormone (CRH)
• Low levels of Leptin stimulate release of Neuropeptide Y (NPY)

GHRELIN:

• Whereas Leptin induces satiety, Ghrelin stimulates HUNGER
• Produced mainly by P/DI cells lining fundus of stomach and epsilon cells of pancreas
• Ghrelin levels increase before meals and decrease after meals

Question 5

Bariatric Surgery - NICE cut offs for referral

Answer 5

WITH RISK FACTORS (T2DM, HTN etc)
= BMI > 35kg/m2

NO RISK FACTORS
= BMI > 40kg/m2

Question 6

Bariatric Surgery - Types

Answer 6

1) Primarily restrictive: Laparoscopic-adjustable gastric banding (LAGB) or sleeve gastrectomy
2) Primarily malabsorptive: Classic biliopancreatic diversion (BPD) has now been replaced by biliopancreatic diversion with duodenal switch
3) Mixed: Roux-en-Y gastric bypass surgery

Question 7

Bariatric surgery - which surgery for whom?

Answer 7

1) Produces less weight than 2) or 3) but fewer Cx so usually 1st line in patients with BMI of 30-39 kg/m2
2) Patients w BMI > 40kg/m2 may be considered for gastric bypass or sleeve gastrectomy. Latter may be done on its own or pre-bypass
3) Primarily malabsorptive procedures are usually reserved for v obese patients (e.g. BMI > 60kg/m2)

Question 8

Bariatric Surgery - who gets it?

Answer 8

The use of bariatric surgery in Mx of obesity has developed significantly over past decade. It is now recognised that for many obese patients who fail to lose weight w lifestyle and drug interventions, the risks and expense of long term obesity outweigh those of surgery

NICE Guidelines:
Consider surgery for ppl w severe obesity IF:
- they have a BMI > 40kg/m2 or more, or are between 35 - 40 kg/m2 and other significant disease (e.g. T2DM, HTN) that could be improved if they lost weight
- all appropriate non-surgical measures have failed to achieve or maintain adequate clinically beneficial weight loss for at least 6m
- they are receiving or will receive intensive specialist Mx
- they are generally fit for anaesthesia and surgery
- they commit to the need for long term FU

Consider surgery as first line option for adults with BMI > 50kg/m2 in whom surgical intervention is considered approp
Start Orlistat if waiting time is long