Disorders of Appetite Flashcards
What are the two types of appetite disorders?
Water intake- thirst
Food intake- appetite (less or more than normal)
Define polydipsia
Excessive thirst or excess drinking
Define adipsia
Inappropriate lack of thirst with consequent failure to drink in order to correct hyperosmolality
Define anorexia
Lack or loss of appetite for food
What is the difference between anorexia and anorexia nervosa?
Anorexia nervosa is the psychological condition
Anorexia is just a loss of appetite for food, it can be a result of other physiological conditions
What are the 2 classes of thirst disorders?
Polydipsic
Adipsic
What are the types of polydipsia or adipsia?
Primary or secondary
What are some causes of secondary polydipsia
Medical conditions that disrupt osmoregulation or alter ADH. E.g :
Chronic conditions (eg diabetes, kidney failure, Conn’s, Addison’s, sickle cell)
Medications (diuretics, laxatives, antidepressants)
Dehydration (acute illness, sweating, fevers, vomiting, diarrhoea)
What is the difference between diabetes insipidus and mellitus?
Mellitus= Common, related to high blood sugar Insipidus= Uncommon, pituitary problems and impaired ADH production
What is the role of ADH?
Acts on the kidneys to regulate the volume & osmolality of urine
Acts at collecting duct - Aquaporin 2 channel
When plasma ADH is low a large volume of urine is excreted (water diuresis)
When plasma ADH is high a small volume of urine is excreted (anti diuresis).
What are some causes of primary polydipsia?
Mental illness (psychogenic, schizophrenia, mood disorders, anorexia, drug use)
Brain injury
Organic brain damage
How many types of adipsia are there? Which is most common?
There are 4 types (A, B, C and D) and A is the most common
Define the term eating disorders
Mental disorders defined by abnormal eating habits
What disorders do eating disorders encompass?
Binge eating disorder Anorexia nervosa Bulimia nervosa Pica Rumination syndrome Avoidant/restrictive food intake disorder
What is pica?
People eat non food items of no nutritional value eg hair, paint chips
What is rumination syndrome and how is it different to bullimia nervosa?
It is a condition where people regurgitate food that is undigested and not acidic, in bullimia nervosa food is digested and acidic and regurgitation involves cycles of binging and purging
What are some signs of eating disorders?
Low BMI Continuous weight loss Amenorrhea Halitosis Mood swings Dry hair, skin & hair thinning
What is the BMI range for mild anorexia?
over 17
What is the BMI range for moderate anorexia?
16-16.99
What is the BMI range for severe anorexia?
15-15.99
What is the BMI range for extreme anorexia?
less than 15
Out of diet and exercise, what is most effective for weight reduction in obesity?
Diet more than exercise but a combination of both is best (10.8% weight loss)
How do hormone levels change with bariatric surgery?
Ghrelin reduces so decreases appetite
GLP1, GLP2 and PYY increase
Define obesity
Abnormal or excessive fat accumulation that presets risk to health
What are the 3 groups which can cause secondary polydipsia?
Chronic medical conditions
Medications
Dehydration
What chronic medical conditions can cause secondary polydipsia?
Diabetes insipidus & mellitus Kidney failure Conn’s syndrome Addison's disease Sickle cell anaemia
What medications conditions can cause secondary polydipsia?
Diuretics
Laxatives
Both result in dehydration
Antidepressants
What methods of dehydration can cause secondary polydipsia?
Acute illness Sweating Fevers Vomiting Diarrhoea Under Hydration
What are other medical conditions which can lead to polydipsia?
Acute kidney failure Conn’s syndrome Primary aldosteronism Addison's disease Hypoadrenocorticism
What can polydipsia lead to?
Kidney and bone damage Headache Nausea Cramps Slow reflexes Slurred speech Low energy Confusion Seizures
What is the mechanism of adipsia?
Increasedosmolality of urine ->
Stimulates secretion of ADH ->
Water retention ->
Sensation of thirst decreases
What is the role of osmoreceptors in ADH release?
- Cells shrink when plasma more concentrated
- Proportion of cation channels increases – membrane depolarizes
- Send signals to the ADH producing cells to increase ADH
- Fluid retention
- Invokes drinking
How has epidemiology of eating disorders changed?
Global eating disorderprevalence ↑ed from 3.4% to 7.8% between 2000 and 2018.
70 million people live with eating disorder
What are causes of anorexia?
Genetic, environmental, psychological, sociological
WHat is the mechanism of anorexia?
Associated with dec. levels of serotonin
WHy is obesity increasing?
It is not lack of exercise: Physical activity started to decline prior to obesity epidemic
Due to cheap, calorie-rich/nutrient poor beverages, sweets and fast food
How is obesity screened?
Height, weight and abdominal girth
Medical history:
Dietary and physical activity patterns, psychosocial factors, weight-gaining medications, familial traits
BMI = kg/m2
BMI of ≥30 or ≥25 + comorbidity or risk factor
When is surgical treatment of obesity implemented?
People with a > BMI 40 or 35+ comorbidities
What is the most common surgery for obesity?
Roux-en-Y gastric bypass & sleeve gastrectomy
What is the weight loss decrease after bariatric surgery?
5 yrs after BS: 30% - 35% weight loss
What is a downside of bariatric surgery?
Remission rates are high for diabetes (80%) and obstructive sleep apnoea (80-85%)
