Pathophysiology of Anorexia Nervosa

Pathophysiology Of Anorexia Nervosa
Most of the medical complications of anorexia nervosa result from starvation. Few organs are spared the progressive deterioration brought about by anorexia.
Cardiovascular Changes
People who suffer from Anorexia Nervosa severely restrict the amount of calories they consume, which means the body is not getting adequate nutrients. The body then slows down all bodily processes. Eventually, it will begin to consume itself, leading to muscle and bone loss. Most of those die from heart disease, as the heart especially suffers from the effects of anorexia. The heart muscles as well act as a source of energy for the body and the muscles undergo atrophy. Muscle mass of the heart decreases until that it cannot generate enough force to pump blood adequately to other parts of the body. This results in heart failure, hypotension, fatal heart arrhythmias and heart rate could be as low as 50 beats/min (sinus bradycardia). A reduction in the work capacity of the heart is associated with severe weight loss and starvation.
Gastrointestinal Changes
Constipation is a common complication of anorexia. In fact, many cases of anorexia come to the attention of doctors when anorexics seek out treatment for constipation. Dehydration can arise with severe weight loss, starvation, and abuse of laxatives, so it is not surprising that it is such a common complaint among anorexics. As anorexia progresses and starvation complications become more pronounced, a number of gastrointestinal problems may develop, both in combination with or independent from constipation. Normal movement in intestinal tract often slows down with very restricted eating and severe weight loss. Gaining weight and some medications help to restore normal intestinal motility. Gastrointestinal mobility slows, and it takes longer for the gastric system to empty. Some anorexics also develop abnormal muscle activity in the esophagus. Gastric problems such as constipation, bloating, and a sensation of early fullness all tend to suppress the urge to eat, thus speeding up the process of weight loss and starvation.
Endocrine Abnormalities (The Glandular System)
Disturbances in the menstrual cycle are frequent and can affect not only fertility but also bone density, which is very important to a woman's health as she ages. Hormonal imbalances are found in men with anorexia as well. Continual restrictive eating can trick the thyroid into thinking that the body is starving, causing it to slow down in an attempt to preserve calories.
Amenorrhea (cessation of the menstrual cycle) is one of the hallmark symptoms of anorexia, when a menstrual period is missed for three or more months without any other underlying cause. Amenorrhea often precedes severe weight loss and continues after normal weight is restored. Reduced levels of growth hormones are sometimes found on anorexic patients and may explain growth retardation sometimes seen in anorexic patients. Normal nutrition usually restores normal growth.

Bone Changes
Persons with anorexia are at an increased risk for skeletal fractures (broken bones). When the onset of anorexic symptoms occurs before peak bone formation has been attained (usually mid to late teens), a greater risk of osteopenia (decreased bone tissue) or osteoporosis (bone loss) exists. Bone density is often found to be low in females with anorexia, and low calcium intake and absorption is common. An 18-year-old high school student can have bones as fragile as those of her 84-year-old grandmother.
Other Changes
Kidney (renal) function may appear normal. However, there are significant changes in kidney function in many people with anorexia, resulting in potassium deficiency, increased urination, or decreased urination.
Anorexics who use a large quantity of laxatives or who frequently vomit are at great risk for electrolyte imbalance, which can have life-threatening consequences.
Anemia is frequently found in anorexic patients. Suppressed immunity and a high risk for infection are suspected, but not clinically proven.
Physical Symptoms
Physical symptoms, other than the obvious loss of weight, can be seen. Anorexia can cause dry, flaky skin that takes on a yellow tinge. Fine, downy hair grows on the face, back, arms, and legs. Despite this new hair growth, loss of hair on the head is not uncommon. Nails can become brittle. Frequent vomiting can erode dental enamel and eventually lead to tooth loss.