Obesity Flashcards
What is obesity?
abnormal or excess fat accumulation that presents a risk to health, commonly defined by Body Mass Index being greater than 30 and in 3 classes (30.1-34.9 ≈ I; 35.1-39.9 ≈ II and 40 < ≈ III).
List 3 ways to measure body composition and the categories.
Direct: In-vivo neutron activation analysis (IVNAA)
- Nuclear process relying on neutron activation in fat
Indirect:
Densitometry: Difference between FM and FFM
Deuterium oxide dilution: Calculation of body water by ingesting water radiolabelled with deuterium
DEXA: Calculated from absorption of X-Rays calculating values of fat and FFM
V indirect:
Skin-fold thickness
Waist circumference
BMI-based prediction
How do you calculate BMI?
Weight/height(^2)
Why is BMI useful?
Objective figure for body mass (adiposity) + risk predictor of disease
Is there a link between BMI and health risk and what are the ranges for determining public health and clinical action based on BMI?
Varying degrees of risk with associated BMIs so low to moderate risk between underweight and overweight (18.5-23) compared to moderate to high risk (23 to 33) and high to very high risk (28 to 38)
What is the gross/general equation for obesity?
Energy expenditure < Calorie intake
List 5 health effects of being obese.
- Insulin resistance
- Atherosclerosis
- Obstructive Sleep Apnoea
- Osteoarthritis
- Polycystic Ovarian Syndrome
- Cancer (e.g. Breast Cancer)
- Non-alcoholic fatty liver disease
- Cholecystitis
- Chronic Kidney disease
- Focal Sclerosing Glomerulosclerosis
- Depression
What is atherosclerosis?
Give 3 Sx.
Outline the Rx.
Chronic, hardening of arteries due to lipoprotein deposition in the endothelium (tunica intima whilst endothelium is penetrated leading to lumen occlusion) which has an increased risk when a patient is obese
- Cx pain
- SOB
- Fatigue
- Confusion
- Muscle weakness
- Claudication
- TIA
Rx:
- Statins
- ACEi/CCB/ARB
- Stop smoking
- ∆ Diet
- Exercise
- Stress reduction
What is Obstructive Sleep Apnoea?
Give 3 Sx.
Outline the Rx.
breathing repeatedly stopped for 10 seconds < during sleep causing reduced oxygen saturation in the blood commonly due to excess body weight + obesity ≈ enlarged tonsils or adenoids Sx: - Chronic Snoring - Sleep deprivation - Difficulty concentrating - Depression - Irritability - Sexual dysfunction - Falling asleep at work - High blood pressure - Cardiac arrhythmia
Rx:
- Sleep hygiene
- Weight loss
- Continuous Positive Airway Pressure
What is Osteoarthritis?
Give 3 Sx of OA.
Outline the Rx.
multifactorial disease, with differing aetiologies, of the entire joint, involving cartilage, bone and synovium featuring: progressive loss of articular cartilage, new bone formation and synovial proliferation which results in pain, loss of joint function and disability. OA commonly affects the large joints: knees, hips and small joints: hands and spine.
Sx:
- Unilateral arthralgia
- Crepitus
- Inflammation
- Stiffness
- Tenderness
Rx:
- NSAIDs
- Weight loss
- TKR surgery
What is NAFLD?
Give 3 Sx.
Outline the Rx.
NAFLD: is a heterogeneous spectrum of liver abnormalities from benign steatosis to nonalcoholic steatohepatitis (NASH) caused by accumulation of abnormal amounts of intra-hepatocyte lipid ≈ 5% of liver weight, which can progress to cirrhosis or hepatocellular carcinoma, compromising the functionality of the liver, causing significant decline in hepatic function as well as other systems e.g hepatobiliary system or protein synthesis etc and RBC count. A major cause of NAFLD is obesity, high sugar and high fat diet and physical inactivity.
Sx:
- Palmar erythema
- Hepatic flap
- Splenomegaly
- Jaundice
- Ascites
- Telangiectasia
- Spider naevi
- RUQ pain
Rx:
- Lifestyle ∆: Exercise
- Statins
- Orlistat
- Ezetimibe
- PCSK9 Ab
What is CKD?
Give 3 Sx.
Outline the Rx.
gradual loss of kidney function over a period of months to years of which obesity is a risk factor due to its association with hypertension, diabetes and renovascular disease which all exacerbate and increase risk of CKD.
Sx:
- Asymptomatic**
- Oedema
- Hyperphosphatemia
- Metabolic acidosis
- HTN
- Anaemia
- Azotemia
- Uremia
- Hyperkalemia
Rx:
- ACEi
- Statins
- Dietary ∆
- Zinc supplements
What is Cushing’s Syndrome?
Give 3 clinical features.
Outline the Rx.
endocrine disorder whereby excessive cortisol mediates its systemic effects to cause a phenotypic spectrum. This cortisol surplus may be caused by iatrogenic means e.g. prednisone or a tumour such as pituitary or adrenal.
Sx:
- Weight gain
- Central adiposity
- Buffalo hump
- Excess sweating
- Erythema
- Thinning skin
- Amenorrhoea/Oligomenorrhoea
- Fragile bones
- Hirsutism
- Hypocalcemia
- Insomnia
Rx:
- Remove causative agent e.g. Medication/Tumour
- Prednisolone (if adrenals removed)
- Metformin
What is Pseudocushing’s Syndrome?
medical condition where patients present with symptoms associated with Cushing’s syndrome however not caused by HPA axis as Cushing’s, mainly an idiopathic condition causing elevated cortisol.
Give 3 examples of genes which are implicated in the aetiology of Obesity.
FTO gene (Chromosome 16): FTO enzyme –> satiety
ApoE gene (Chromosome 19): ApoE –> LDL uptake
LDL-r (Chromosome 19): LDLr-/- ≈ defective uptake of LDL
Which tissues appear to be significantly enriched for genes with BMI-associated loci?
Nervous tissue e.g. DLG3 protein complex, NGF signalling, NMDA receptor etc
What is the hypothalamic control of energy balance?
Hypothalamus is the controller of hormone system which contributes to control of satiety and appetite through two opposing systems: POMC/CART and AgRP/NPY. Capillaries at median eminence are fenestrated therefore endogenous, blood-born signals can reach the Arcuate Nucleus to act on either NPY neurones or POMC/CART neurones which are orexigenic and anorexigenic respectively and relay the information to the PVN; outputs involve Anterior Pituitary Hippocampus and Cerebral cortex.
What is a craniopharyngioma?
Give 3 clinical features of a craniopharyngioma.
rare type of brain tumour (2 per 1,000,000) derived from pituitary gland embryonic tissue which occurs most commonly in children but affects adults too. Patients may present with bitemporal inferior quadrantanopia leading to bitemporal hemianopia as tumour may comprise optic chiasm.
Sx:
- Headache
- Hypersomnia
- Polydipsia
- Polyuria
- Bitemporal hemianopia
- Vomiting
- GH insufficiency
- Pituitary insufficiency
- Diabetes insipidus
- Fatigue
- Hypotension
- Electrolyte abnormalities
What does a leptin deficiency cause?
Leptin is a satiety hormone produced by adipose tissue thus deficiency ≈ shift balance towards orexigenesis
What proof is there in animal models regarding leptin deficiency?
Ob/Ob mouse + leptin ≈ ob/ob mouse
List 3 medications which can be used in the Rx of Obesity.
- Orlistat
- Naltrexone
- Atorvastatin
- Ezetimibe
- Buproprion
List 3 examples of surgical interventions used in Obesity.
- Sleeve gastrectomy
- Gastric baron
- Endobarrier
- Gastric Bypass: Roux-en-Y (bisect stomach at greater curvature into two pouches. Gastric pouch joined to jejunum (roux limb) and duodenum joined to jejunum (Roux limb))
- Gastric Bypass: Laparoscopic adjustable gastric banding
- Gastric Bypass: Biliopancreatic diversion with duodenal switch (Sleeve gastrectomy + Pyloric valve joined to distal intestine (alimentary limb) and distal colon joined to alimentary limb (biliopancreatic limb)
Which of the following surgical interventions is described here ‘Sleeve gastrectomy + Pyloric valve joined to distal intestine (alimentary limb) and distal colon joined to alimentary limb (biliopancreatic limb)’?
A. Sleeve gastrectomy
B. Roux-en-Y
C. Laparoscopic adjustable gastric banding
D. Biliopancreatic Diversion with Duodenal Switch
D. Biliopancreatic Diversion with Duodenal Switch
Which of the following surgical interventions is described here ‘changeable band fitted around cardia region’?
A. Sleeve gastrectomy
B. Roux-en-Y
C. Laparoscopic adjustable gastric banding
D. Biliopancreatic Diversion with Duodenal Switch
C. Laparoscopic adjustable gastric banding
Which of the following surgical interventions is described here ‘bisect stomach at greater curvature into two pouches. Gastric pouch joined to jejunum (roux limb) and duodenum joined to jejunum (Roux limb’?
A. Sleeve gastrectomy
B. Roux-en-Y
C. Laparoscopic adjustable gastric banding
D. Biliopancreatic Diversion with Duodenal Switch
B. Roux-en-Y
Which of the following surgical interventions is described here ‘GI lined with plastic to reduce SI absorption and increase satiety’?
A. Sleeve gastrectomy
B. Endobarrier
C. Laparoscopic adjustable gastric banding
D. Biliopancreatic Diversion with Duodenal Switch
B. Endobarrier
