USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 16-year-old girl comes to the office because of decreased mood and tiredness. Her mother says that she has not been doing any of her schoolwork, and often displays a sudden loss of interest in her extracurricular activities. Her pulse is 90/min and her blood pressure is 110/75. Her BMI is 22. Physical examination shows decaying enamel on teeth and drying skin. Thickened skin is found around the knuckles of her right hand. A complete metabolic panel would most likely show which of the following electrolyte disturbances?
Contributors:Brooke Miller, PhD
Purging can take a couple of different forms: one is self-induced vomiting, performed by manually stimulating the gag reflex or drinking ipecac syrup; the other is defecation with the aid of laxatives or diuretics.
To fit the diagnosis, the cycle of binging and purging must be repeated consistently at least once a week for a period of 3 months, but can happen as often as multiple times per day.
The onset of bulimia typically happens around adolescence, usually in individuals with low self-esteem who have a strong desire to have control over key aspects of their life including their weight.
They are often fixated on food, including the amount of food they consume as well as the caloric and fat content of that food.
The pattern of bulimia is often cyclical, with someone setting unrealistic goals for themselves (like getting a 100 percent on every exam they take).
When they don’t reach those goals, they binge, and then they purge to try to “fix” the binging episode.
Individuals with bulimia will also try to control their weight in other ways—by taking stimulants, by going on extreme diets such as “water fasts” where they consume only water, and by exercising excessively.
These symptoms of binging and purging with bulimia nervosa can be confused with another eating disorder, anorexia nervosa, where they might also binge and purge.
The main distinction between these two disorders has nothing to do with this act of binging and purging; it’s actually defined by an individual's weight.
People with bulimia are usually normal weight or overweight, whereas people with anorexia are underweight.
Because of this, people can more easily hide the fact that they suffer from bulimia, and can also potentially start out with bulimia, which progresses into anorexia over time.
The binging and purging cycles associated with bulimia can result in a number of serious side effects.
The skin of the knuckles can develop callouses from grating against the teeth when the hand is used to induce vomiting; this is called Russell’s sign.
If the vomiting is forceful enough it can lead to tears forming in the distal esophagus and stomach itself; this is called Mallory Weiss syndrome, and it can cause abdominal pain and hematemesis, the presence of blood in the vomit.
The purging involved in bulimia can also result in a depletion of electrolytes.
This leads to low levels of sodium, chloride, magnesium, phosphate, and potassium in the blood, as well as general metabolic alkalosis, where the pH of the body rises above its normal level of 7.35–7.45.