Anorexia Nervosa Flashcards
how many criteria are there for AN
3
criterion A for AN
restriction of energy intake relative to requirements, leading to a singificantly LOW BODY WEIGHT in the context of age, sex, developmental trajectory and physical health
how do you define “significantly low weight” in AN
a weight that is less than minimally normal or, for kids and teens, less than minimally expected
criterion B for AN
INTENSE FEAR of gaining weight or of becoming fat or persistent behaviour that interferes with weight gain, even though at significantly low weight
criterion C for AN
disturbance in the way in which ones body weight or shape is experienced, undue influence of body weight or shape on self evaluation, or persistent lack of recognition of the seriousness of the low body weight
what are the subtypes of AN that should be specified (using DSM specifiers)
- restricting type
2. binge eating/purging type
what is the definition of AN, restricting type
during the last THREE MONTHS, the individual has NOT engaged in recurrent episodes of binge eating or purging behaviour (i.e self induced vomiting or misuse of laxatives, diuretics or enemas)
–> this subtype describes presentations in which weight loss is accomplisged primarily through DIETING, FASTING, and/or EXCESSIVE EXERCISE
what is the time criterion for AN
three months
what is the definition of AN, binge/purge subtype
during the last THREE MONTHS, the individual HAS engaged in recurrent episodes of binge eating or purging behaviour
what is purging behaviour
self induced vomiting
misuse of laxatives, diuretics, enemas
what is the definition of AN, in partial remission
after full criteria for AN were PREVIOUSLY met, criterion A (low body weight) has NOT been met for a sustained period
BUT, either criterion B or C is still met
what is the definition of AN, in full remission
after the full criteria were previously met, none of the three criteria have been met for a sustained period of time
what measure does the DSM use to rate the severity of AN
BMI (adults) BMI percentile (kids/teens)
- derived from WHO categories for thinness in adults
- the level of severity may be increased to reflect clinical symptoms, the degree of functional disability and the need for supervision
define mild AN
BMI above to equal to 17
define moderate AN
BMI 16-16.99
define severe AN
BMI 15-15.99
define extreme AN
BMI less than 15
what is the unit of measurement for BMI
kg/m2
do those with the binge/purge subtype with AN always display both binging and purging
no
most with this subtype who binge eat ALSO purge
but there are some people who purge but do not binge eat
is there crossover between AN subtypes?
yes, this is common
thus, subtypes should be sued to describe current symptoms rather than longitudinal course
what are the 3 essential features of AN
- persistent energy intake restriction
- intense fear of gaining weight or becoming fat, or persistent behaviour that interferes with weight gain
- a disturbance in self perceived weight or shape
what does BMI describe
the relationship between someones weight and height
what is the lower limit of normal for normal body weight
BMI of 18.5 kg/m2
do you have to be underweight to be dx with AN?
yes–> criterion A
are there situations in which someone with a BMI from 17-18.5 (or even above 18.5) would be considered to have significantly low weight?
yes, if clinical history or other physiological information supports this judgment
what is the standard lower limit of normal for children (when using BMI-for-age percentile)
BMI-for-age percentile BELOW the 5th percentile –> suggests the child is underweight
*however, kids/teens above this benchmark may be considered underweight in light of failure to maintain expected growth trajectory
what should the clinician consider when deciding if a patient is significant underweight?
- available numerical guidelines (i.e BMI or BMI-for-age percentile)
- individuals body build, weight history, physiological disturbances
is the intense fear of becoming fat seen in AN alleviated by weight loss?
typically no
–> in fact, concern about weight gain may INCREASE even as weight falls
(adolescents and some adults may not recognize, or may not acknowledge, a fear of weight gain)
how might body image be distorted in those with AN
some feel globally overweight
others recognize they are thin but have persistent concern about certain body parts being “too fat” i.e buttocks, thighs, abdomen
might employ multiple techniques to measure and evaluate body shape/size
how might weight loss vs weight gain be perceived by those with AN
weight loss viewed as impressive achievement, sign of extraordinary self discipline
weight gain perceived as unacceptable failure of self control
how do those with AN typically get brought to clinical attention
brought by family members after marked weight loss or failure to achieve expected weight gains
–> those with AN, even if they recognize they are thin, usually do not recognize the serious medical implications of their malnourished state
in what situations might those with AN seek help on their own
usually because of distress over the somatic and psychological sequelae of starvation
it is rare for someone with AN to complain of weight loss per se–> in fact frequently have lack of insight into, or deny the problem outright
are the impacts of malnutrition reversible?
most are, with nutritional rehabilitation
some, like LOSS OF BONE MINERAL DENSITY, are often not completely reversible
list some psychological impacts of starvation/malnutrition
depressed mood
irritability
insomnia
depressed sex drive
*many people with AN present with depressive signs and symptoms–> must determine if secondary to starvation or worth a separate dx of MDD
are OCD features, often prominent in AN, always related to food?
no–> both related and unrelated to food
most individuals with AN are preoccupied with thoughts of food
when display obsessions and compulsions unrelated to food, dx of OCD may be warranted
how does undernutrition/starvation affect obsessive and compulsive symptoms i.e in AN?
obsessions and compulsions related to food may be EXACERBATED by undernutrition
*these behaviours have been observed associated with other forms of starvation, not just AN
list some features that are sometimes associated with AN
concerns about eating in public
feelings of ineffectiveness
strong desire to control one’s environment
inflexible thinking
limited social spontaneity
overly restrained emotional expression
what features are more likely to be found in those with AN binge/purge type compared to those with restricting type?
in binge/purge type:
higher rates of impulsivity
more likely to abuse alcohol and other drugs
what is the 12 month prevalence of AN
among young females–> 0.4%
less known about prevalence among young males
what is the gender ratio in presentations of AN
much less common in men
clinical population generally has 10:1 female:male ratio
what is typical age of onset for AN
typically begins during adolescence or young adulthood
rarely begins before puberty or after age 40 (though it can on rare occasions)
what psychosocial features/events are often associated with onset of AN
onset often associated with a stressful life event i.e leaving home for college
what is the natural course of AN
highly variable
some recover fully after single episode
some exhibit fluctuating pattern of weight gain followed by relapse
others experience chronic course over many years
should you exclude AN from the ddx based on older age?
no
how might presentation differ based on age at presentation for AN
younger individuals may have more atypical features, like denying “fear of fat”
older individuals more likely to have a longer duration of illness and may have more signs and symptoms of a longer standing disorder
most individuals with AN experience remission within what time period
within 5 years of presentation
*among those admitted to hospital, overall remission rates may be lower
what is the crude mortality rate (CMR) for AN
5% per decade
what are the most common causes of death in AN
most commonly from medical complications from the disorder itself or from suicide
list temperamental risk factors for AN
those who develop anxiety disorders or display obsessional traits in childhood are at higher risk of AN
list environmental risk factors for AN
cultures and settings in which thinness is valued increase risk of AN
–> this is supported by fact that historical and cross cultural variability in prevalence of AN is marked
occupations and avocations that encourage thinness increase risk (modeling, elite athletics)
list genetic and physiologic risk factors for AN
- increased risk of AN and BN among first degree biological relatives of those with the disorder
- higher concordance rates among mono vs dizygotic twins
- unclear if there are brain abnormalities associated w AN vs whether these abnormalities are due to AN course (seen on fMRI, PET)
having a first degree biological relative with AN increases risk of what other psychiatric disorder?
bipolar disorder (and depressive disorders)
–> increased risk among those with first degree relatives with AN, especially those with binge/purge type
in which societies/cultures is AN most prevalence
probably most prevalent in post-industrialized, high income countries–> USA, Europe, Australia, NZ, Japan
–> however incidence in low to middle income countries is uncertain
in which ethnic populations in the USA is incidence of AN comparatively low
among latinos, african americans and asians
–> note however that mental health service utilization among individuals with an eating disorder is significantly lower in these ethnic groups and that low rates may reflect ascertainment bias
how might concerns about weight be voiced among populations in Asia (compared to the USA)
absence of an expressed intense fear of weight gain (“fat phobia”) appears to be relatively more common in populations in Asia–> rationale for dietary restriction is commonly related to a more culturally sanctioned complaint such as GI discomfort
what HEMATOLOGIC abnormalities are seen on blood work in the presence of AN
- eukopenia–> common
- -loss of all cell types but usually with apparent lymphocytosis - mild anemia
- thrombocytopenia (rarely bleeding problems)
what SERUM CHEMISTRY abnormalities are seen on blood work in the presence of AN
- elevated blood urea nitrogen (BUN)–> likely due to dehydration
- hypercholesterolemia –> common
- hypomagnesemia –> occasional
- hypophosphatemia–> occasional
- hepatic enzymes may be elevated
- metabolic alklalosis (elevated serum bicarb)–> can be due to vomiting
- hypochloremia–> due to vomiting
- hypokalemia–> due to vomiting
what metabolic disturbance may be caused by laxative abuse
mild metabolic acidosis
how might AN affect serum phosphate and magnesium
low
what ENDOCRINE abnormalities are seen on blood work in the presence of AN
- serum thyroxine (T4) usually in low-normal range
- T3 levels decreased
- women have low estrogen levels
- males have low serum testosterone
how does AN affect serum estrogen? testosterone?
low for both
how does AN affect serum T3 levels
low
what ECG changes can be noted in AN
sinus bradycardia–> common
significant QTc prolongation can be noted
(rarely) arrhythmias can be noted
what changes in bone mass are seen due to AN
low bone mineral density–> with specific areas of osteopenia or osteoporosis –> often seen
risk of # significantly elevated
what might be seen on EEG in AN
diffuse abnormalities, reflecting metabolic encephalopathy, may result from significant fluid and electrolyte disturbances
list physical signs and symptoms of AN that the patient may complain of
- amenorrhea–> common
- -appears to be indicator of physiological dysfunction - constipation
- abdominal pain
- cold intolerance
- lethargy
- excess energy
list findings of AN on physical exam
- emaciation
- significant hypotension
- hypothermia
- bradycardia
- lanugo–> fine, downy body hair
- -some people - peripheral edema
- -especially during weight restoration or cessation of laxative/diuretic abuse - petechiae, ecchymoses on extremities
- -may indicate bleeding diathesis - yellowing of skin–> due to hypercarotenemia
if are purging and inducing vomiting:
9. hypertrophy of salivary glands
- dental enamel erosion
- scars, calluses on dorsal surface of hand from repeated contact with teeth while inducing vomiting
what is the relationship between suicide risk and AN
suicide risk = elevated in AN
what is the rate of suicide in AN
12 per 100 000 per year
when, especially, should you consider other causes of low body weight/weight loss?
in atypical presentations i.e older than 40 at onset
ddx AN
medical conditions
MDD
schizophrenia
substance use disorders
social anxiety disorder
OCD
body dysmorphic disorder
bulimia nervosa
ARFID
list some medical conditions that may be associated with serious weight loss
GI disease
hyperthyroid
occult malignancies
AIDS
what distinguishes AN from most conditions on the differential
fear of gaining weight and body image disturbance
in which substance-using patients should you seriously consider possibility of AN
in those that use appetite-suppressing drugs like cocaine, stimulants and who ALSO endorse fear of gaining weight/body image disturbance–> the substance use may represent a behaviour that interferes with weight gain
when should you consider additional dx of body dysmorphic disorder in addition to AN
consider only if the distortion is unrelated to body shape and size (i.e preoccupation that one’s nose is too big)
what distinguishes BN from AN
those with BN MAINTAIN BODY WEIGHT at or above a minimally normal level
which psychiatric disorders commonly co-occur with AN
bipolar
depressive
anxiety disorders
OCD–>moreso in those with restricting type
substance use disorders–> more common among binge/purge type
