The medical problems associated with Bulimia are largely due to the process of compensating for binges most commonly with purging or laxative abuse. Both behaviors are very traumatic to the body. Most people will be able to adapt temporarily but the long term consequences are severe.
When we vomit in any way, the body loses a large amount of potassium at one time. Just being sick over a period of several hours or a day is a state we can overcome quite easily after a day or two of rest and replenishment. Regular purging over months and years leads to a constant norm of low blood potassium concentration. This electrolyte is necessary for normal human function, so the medical consequences of low potassium are great. The two organs most affected are the heart and kidneys.
The heart conduction system initiates each and every beat and is very sensitive to low potassium which can cause irregular beats or even lead to cardiac arrest. Although the body can adjust to chronically low potassium, this new state leads to a continued risk of cardiac abnormalities or even death.
Constant low potassium also causes chronic kidney damage over time. At first this leads to kidney dysfunction, but since we can all survive with one kidney, the damage doesn't lead to a change in lifestyle. However, a decade of this new steady state can lead to kidney failure and the need for a transplant, something that is a real possibility for someone with chronic bulimia.
Laxative abuse is another common form of compensation for binging for people with Bulimia. Laxatives draw water into the colon, the second main part of the gastrointestinal system, and cause the muscles of the colon to contract powerfully and thus evacuate the bowels. Overuse leads to addiction so that the GI system slows down and eventually cannot function without laxatives. Withdrawal then forces the colon to relearn how to function normally again.
Laxative abuse causes damage to the GI system by slowing down normal functioning leading to symptoms of constipation and bloating. Short-term laxative abuse can be overcome fairly easily, but long-term abuse can cause permanent damage. The colon sometimes cannot resume normal function and is damaged by the constant trauma of these medications. The effect is colonic inertia or very slowed processing of foods and waste, constipation and constant bloating.
After years of laxative abuse, the body becomes used to losing significant amount of fluid through multiple episodes of diarrhea per day. The human body is constantly working towards a way to survive any change in circumstances. Thus, it will adapt to the daily loss of fluid by retaining fluid in another ways. Once laxative use is stopped, people often experience fluid retention since the adaptation of holding onto fluid continues. Most often, the body adapts back to its typical way of managing fluid, but years of abuse can damage the system of maintaining normal fluid levels and it can take months or years to adapt back again. In this situation, fluid retention and swelling are common symptoms until the body resumes normal fluid management.
These last two posts highlight how anorexia and bulimia are medical as well as psychiatric diseases. Sufferers need to understand that medical evaluation and care are important parts of treatment and clinicians need to be sure all patients have regular medical follow-up.