Digestive Problems
Common Symptoms: Anemia
Anemia is a condition defined by deficiency of Hemoglobin in your blood. Hemoglobin is contained in the red blood cells and is responsible for carrying oxygen. The normal level of Hemoglobin in the blood is approximately 12-14 in men and 11-13 in women.
Anemia can occur rapidly when there is a sudden loss of blood. Often, the source of this blood loss can be from your esophagus, stomach, or lower (or small) intestines. This is often seen as vomiting blood or passing red blood or black, sticky blood in your stool. Patients usually feel dizzy because the blood pressure drops, especially when standing up. Anemia occurs more chronically when the body does not produce enough Hemoglobin or red blood cells to maintain the normal level.
By far, the most common cause of anemia is shortage of iron. Iron is essential to make new red blood cells. In women, this is usually due to menstrual loss of blood. In anyone, it could be due to poor iron intake or a slow loss of blood in your GI tract that cannot be seen in your stool. The lack of iron can be recognized easily on a blood smear, and the levels can be measured. Iron deficiency anemia responds rapidly to treatment with iron, usually given by mouth. In severe cases, iron can be given by injection.
Anemias can also occur because of deficiencies of vitamin B12 and folic acid. Vitamin B12 needs a special substance in the stomach to be absorbed from the food; this "intrinsic factor" is missing in patients with pernicious anemia, and others who have had major stomach operations. Vitamin B12 can be replaced by injections (usually monthly). Folic acid deficiency used to be common in pregnancy (before routine supplements were given). It can occur in anyone with a poor diet, or a "malabsorption syndrome" in which there is damage to the lining of the upper small intestine and poor absorption of folic acid and other vitamins.
There are other less common causes of anemia. It can be seen in patients with a "chronic disease" (such as severe arthritis, inflammation, etc.), in which the red blood-forming tissues (blood marrow) become sluggish. There are specific diseases of the bone marrow such as leukemia and aplastic anemia, in which all of the main blood cells are not made efficiently or adequately.
Anemia can occur also if the red blood cells are broken down too quickly. Normally they last for about 120 days in the circulation. In conditions of "hemolysis" the life span may be reduced to a matter of days so that the blood forming tissues cannot keep up. Common causes of hemolysis include reactions to drugs, congenital conditions such as hereditary spherocytosis and sickle cell disease, and infections such as malaria.
Mild chronic anemia (Hemoglobin greater than 10 gm%) does not usually cause significant symptoms. More severe anemia, however, will result in pallor, tiredness, and (eventually) shortness of breath. Other symptoms may be present according to the cause of the anemia. Thus, patients with bone marrow problems may have inadequate white blood cells and platelets (causing infections and bleeding). Patients with hemolysis may develop yellow jaundice of the skin and eyes.
Tests for anemia are simple and logical. We measure the blood levels of Hemoglobin (and hematocrit), and look at the red blood cells under the microscope to assess the likely cause. Red cells have characteristic appearances according to the specific deficiency. It is possible to recognize very "young" red blood cells (reticulocytes). More than the usual number of these in the blood indicates a rapid turnover of red blood cells in response to hemolysis or blood loss. Assessment of the other blood constituents (white cells and platelets) will demonstrate whether the problem is solely due to Hemoglobin development, or a more diffuse bone marrow disease.
Blood levels of iron, folate, and B12 are measured as appropriate. When they are discovered, further investigations can determine the precise cause of any deficiency. The finding of iron deficiency anemia, particularly in men and in women who are not menstruating, should prompt the investigation for chronic bleeding into the bowel. This bleeding may not be obvious to the patient, and is then called "occult." It can be detected by tests on the stool (occult blood tests). These then lead logically to examination of the lining of the intestine to seek a source for the bleeding. These are most commonly found in the stomach and colon, using standard endoscopic techniques (upper endoscopy and colonoscopy). These investigations are particularly important in older patients, since occult bleeding is an important early sign of gastrointestinal cancer.
In some people, a source of bleeding can not be found in the esophagus, stomach or colon. These people may need further evaluation of their small intestines for bleeding. This can now be accomplished by swallowing a small capsule with a camera in it that can take pictures of the small intestines and transmit them to a recorder that the patient wears on a belt. These pictures can then be reviewed by a physician for areas of bleeding that can not be reached by standard endoscopes.