Differentials
Other specified feeding or eating disorder (OSFED), or unspecified feeding or eating disorder (UFED)
SIGNS / SYMPTOMS
Like bulimia nervosa, OSFED and UFED are characterised by disordered eating that negatively affects normal functioning. However, the symptoms for individuals with OSFED do not meet full criteria for bulimia nervosa, anorexia nervosa, or binge-eating disorder.
Examples of OSFED include: atypical anorexia nervosa (i.e., anorexic features without low weight); bulimia nervosa (of low frequency and/or limited duration); binge-eating disorder (of low frequency and/or limited duration); purging disorder; night eating syndrome. UFED is used to describe the symptoms of individuals who don’t fit into any of these 5 categories or for whom there is not enough information to make a specific OSFED diagnosis.
INVESTIGATIONS
No differentiating tests.
Anorexia nervosa, binge-eating/purging subtype
SIGNS / SYMPTOMS
Both bulimia nervosa and anorexia nervosa binge/purge subtype have the binge and purge behaviour. However, anorexia nervosa has as its key element a pathological fear of fat and weight gain leading to unhealthy weight loss. Bulimia nervosa does not.
Body mass index and body fat are low in anorexia nervosa but not in bulimia nervosa. Patients with anorexia nervosa are much more likely to have hypothermia, bradycardia, and anaemia.
INVESTIGATIONS
No differentiating tests.
Binge-eating disorder
SIGNS / SYMPTOMS
Binge eating occurs without any compensatory behaviours. Most patients with binge-eating disorder are obese. Most patients with bulimia nervosa are within normal weight range.
INVESTIGATIONS
No differentiating tests.
Rumination-regurgitation disorder
SIGNS / SYMPTOMS
Swallowed food is either re-chewed and re-swallowed (rumination) or spat out, but not as vomitus. In addition, the behaviour cannot be exclusively related to an eating disorder intended to control weight.
INVESTIGATIONS
No differentiating tests.
Kleine-Levin syndrome
SIGNS / SYMPTOMS
Presents with irregularly recurring hypersomnia episodes in men aged 10 to 25 years. It is associated with psychiatric symptoms that include bingeing, sexual behavioural disorders, personality disorders, and mood disorders. It is very rare and usually occurs in Jewish males. Hypersomnia is not typical of bulimia nervosa.[82]
INVESTIGATIONS
No differentiating tests.
Major depressive disorder (MDD)
SIGNS / SYMPTOMS
Occurs concurrently in ≥50% of cases of bulimia nervosa. Overeating can occur in MDD but the compensatory behaviours are fewer or absent.
Depressed mood, reduced interest, weight change, insomnia, agitation, fatigue, and impaired concentration can be seen in both MDD and bulimia nervosa. Early morning wakening, guilt, and thoughts of death suggest MDD.
INVESTIGATIONS
No differentiating tests.
Other psychiatric disorders, including borderline personality disorder
SIGNS / SYMPTOMS
Anxiety, substance misuse/dependence, and personality disorders are common in patients with bulimia nervosa.
Some patients may complain of or incorporate eating disordered behaviours to access treatment facilities available only to patients with eating disorders. These patients do not have a characteristic history (e.g., they may be able to go for periods of time without bingeing and purging).
Comorbid disorders are differentiated by the degree to which their symptoms have an independent course and severity from the bulimia nervosa. Concurrent substance misuse/dependence may become apparent only because of drug withdrawal and impaired attendance, cognition, or behaviour.
INVESTIGATIONS
No differentiating tests.
Hyperemesis gravidarum
SIGNS / SYMPTOMS
Weight loss greater than 5% may suggest hyperemesis gravidarum. In bulimia nervosa, there may be a precedent history; bulimia typically improves with pregnancy in about two-thirds of cases (while worsening in about one-third).
INVESTIGATIONS
Diagnosis is clinical.
Weight loss due to hCG-induced hyperthyroidism needs to be excluded. In these cases, hCG is elevated, thyroid-stimulating hormone is low, and thyroxine is elevated.
Presence of chromosomal abnormalities, multiple gestations, gestational trophoblastic disease or hydrops fetalis increases the risk of hyperemesis.
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