disorders of appetite Flashcards
define polydipsia?
excessive thirst
define adipsia?
inappropriate lack of thirst with consequent failure to drink in order to correct hyperosmolality
define anorexia?
loss of appetite for food
define obesity
excess fat accumulation that presents a risk to health
What is the name of the hormone responsible for the regulation of Osmolality?
ADH antidiuretic hormone
How does ADH work and where is it stored?
acts on collecting ducts of kidneys to regulate the volume and osmolality of urine
when plasma ADH is low a large volume of urine is excreted
posterior pituitary
If the plasma concentration of ADH is low will there be a water diuresis or an anti-diuresis?
diuresis
Which regions are sensory osmoreceptors found in the hypothalamus?
Organum vasculosum of the laminate terminalis
Subfornical organ
What is the most common disorder of thirst?
Secondary polydipsia
List at least 3 causes of primary polydipsia
Mental illness - psychogenic polydipsia, mood disorders such as depression and anxiety, anorexia, drug use
Brain injury - trauma
Organic brain damage - central pontine myelinolysis, Alzheimer’s disease
What is secondary polydipsia?
Medical issues that disrupt any step in osmoregulation or alter ADH can cause secondary polydipsia
What are the two types of disorders of thirst?
Polydipsic - primary or secondary
Adipsic - primary or secondary
What chronic medical conditions can cause secondary polydipsia?
Diabetes insipidus and mellitus
Acute kidney failure
Conns syndrome
Addisons disease
Sickle cell anaemia
What medications can cause secondary polydipsia?
Diuretics• Laxatives- Both result in dehydration• Antidepressants
What illnesses can cause dehydration leading to secondary polydipsia
Dehydration• Acute illness• Sweating• Fevers• Vomiting• Diarrhoea• Underhydration
Why is polydipsia a problem?
drinking too much water can upset the electrolyte balance in the body-hyponatraemia
What can hyponatraemia as a result of polydipsia lead to?
• Kidney and bone damage
• Headache
• Nausea
• Cramps
• Slow reflexes
• Slurred speech
• Low energy
• Confusion
• Seizures
What is the mechanism of adipsia?
Increased osmolality of urine, leading to stimulated secretion of ADH, water retention, sensation of thirst decrease
What are the different categorisations of adipsia?
Type A - most common (essential hyponatraemia)
Type B
Type C
Type D
List some examples of eating disorders?
Binge eating disorder
Anorexia nervosa
Bulimia nervosa
Pica
Rumination syndrome
Avoidant/ restrictive food intake disorder
what BMI is classed as underweight?
Below 18.5
What BMI is defined as the healthy weight range?
18.5 - 24.9
What BMI is classed as overweight?
25-29.9
What BMI is categorised as class 1 obesity?
30-35
What BMI is classed as type 2 obesity?
35-40
What BMI is classed as type 3 obesity?
40+
What are the signs and symptoms associated with anorexia nervosa?
Low BMI, continuous weight loss, amenorrhea, halitosis, mood swings, dry hair, skin & hair thinning
What are the different possible causes of anorexia nervosa?
Genetic, environmental, psychological, sociological
Q: Mr Thomas is a 45 year old with significant abdominal obesity and T2DM. Has tried dieting before without success, his BMI is 39. What therapy would you recommend?
Gastric bypass & sleeve gastrectomy
List some comorbidities associated with obesity?
Depression
Sleep apnoea
Stroke
MI
HTN
diabetes
Peripheral vascular disease
Gout
Osteoarthritis
Bowel and other cancer
What are the treatment options for obesity?
Life-style modification> Diet + Exercise• Surgical treatment> gastric bypass & sleeve gastrectomy> for people with a > BMI 40 or 35+ comorbidities> WL 5 yrs after BS: 30% - 35%> reduction of all cause mortality & morbidity after BS
What are the surgical treatments of obesity?
People with a> BMI 40 or 35+comorbidities
• Various procedures
• Most common Roux-en-Ygastric bypass & sleeve gastrectomy
• Weight loss 5 yrs after BS: 30% - 35%
• Remission of comorbidities
> Diabetes (80%)
> OSA (80%-85%)
What hormonal changes are often seen after bariatric surgery?
ghrelin reduces - reduced hunger
• GLP1, GLP2 & PPY increases - increased insulin, reduced glucagon, increased satiety
