Dangerously Low Hemoglobin Levels - Low Hemoglobin

Our blood is fluid for a reason. Its fluidity allows for cells swimming in the circulation to move quickly throughout the body. The main cells of our blood are called red blood cells and they are the ones that give the blood its red color.

What are red blood cells

First off, red blood cells is a common misnomer and the “c” in RBCs is referring to corpuscles not cells, since red blood corpuscles don’t have a nucleus and they are mostly a biconcave red disc that is formed mainly of hemoglobin. Hemoglobin in RBCs is a protein that contains iron ions. Its function is to carry oxygen from the lungs to various body organs. Oxygen is essential for the production of energy from food and without energy, body organs can’t function especially the brain and death results. RBCs are produced in the bone marrow through the division and differentiation of their mother cells called hematopoietic stem cells.

The normal level of RBCs in the circulation is 4.7-6.1 million cells per cubic microliter for males and 4.2-5.4 million cells per cubic milliliter in females. Each liter has a million microliters and our body has an average of 5 liters of blood. This difference in count between males and females can be attributed to the effect of testosterone in males which increases the production of RBCs from the bone marrow as well as the monthly loss of red cells by women in the form of menses. Normal hemoglobin level is 13.5-17.5 grams per deciliter for males and 12-15.5 grams per deciliter in females. A fall in the level of hemoglobin is called anemia.

What does it mean if I have low hemoglobin?

Low hemoglobin levels can be seen in a large number of medical conditions. Generally speaking, this can result from decreased production by the bone marrow, increased loss in the form of bleeding or increased destruction inside the body. A fourth cause would be wrong lab numbers and that can be suspected if your general condition doesn’t correlate with the lab findings.

A) Decreased formation of red cells is termed aplastic anemia and is seen in the following conditions:

1) Congenital causes

Congenital anemia means that you are born with a condition that affected the production of RBCs. This cause can be hereditary or acquired during intrauterine life. They include:

Fanconi’s anemia: This is a complex disease involving many associated conditions such as short stature, increased risk of cancer and decreased production of all blood elements due to bone marrow failure.
Familial aplastic anemia: This is an inherited condition which presents solely by anemia due to a mutation of a certain gene increasing the risk of bone marrow failure.
Diamond-Blackfan syndroms: This is another disease resulting from multiple gene mutations. It manifests in the form of many anomalies including the heart, the limbs and the genital system. Aplastic anemia is found in a minority of cases.

2) Acquired causes

Acquired causes of aplastic anemia include:

Infections: Infections are one of the most important causes of aplastic anemias. Some infections directly act on the bone marrow causing its suppression such as parvovirus b19 infection while others mostly damage the bone marrow indirectly via the body’s immune response. Common infections that cause aplastic anemia include: Viral hepatitis, Epstein-Barr virus, HIV and tuberculosis.
Drugs: Some medications can suppress the bone marrow via various mechanisms. Some drugs directly damage stem cells such as chemotherapeutic agents in cancers, some act through inducing an immune reaction in the patient and others may act due to a rare genetic anomaly in some patients. The most known drugs with that side effect are: chloramphenicol, carbamazepine, phenytoin and quinine.
Exposure to some chemicals: Some chemicals are known to have a negative effect on the bone marrow and their toxicity can result in aplastic anemia especially petrochemical products, pesticides and fertilizers.
Radiation: Ionizing radiation exposure can have a serious effect on the bone marrow. This is usually seen in people exposed to large amounts of radiation such as cancer patients, radiologists and those working in nuclear plants.
Cancer: Some cancers invade the bone marrow extensively enough that they encroach on the normal stem cells and decrease their capacity to produce new cells. This can be seen in acute leukemias and multiple myeloma.
No known cause: Despite advances in modern medicine and hematology, a significant number of cases of aplastic anemia remain without a known cause.

Some anemias can result from nutritional deficiencies. This type ,however, rarely produces significant anemia unless the deficiency is severe. The main deficiencies responsible for anemia are iron deficiency anemia -which is by far the most common cause of anemia worldwide-, B12 deficiency, folate deficiency and starvation or severe protein deficiency.

Blood loss is a common cause of anemia, it can be acute or chronic. Acute loss of blood can be severe that it also produces hypovolemia and shock which puts the life of the patient in danger or it may be severe enough to cause anemia but not severe enough to cause hypovolemia. Chronic blood loss is mostly incriminated in anemia when it occurs in the gastrointestinal tract. The GIT ends in the colon which produces feces. Any source of bleeding above the colon can be completely obscured because the blood is exposed to gastric acid for long periods of time and becomes altered, causing it to be brown or tarry in color. If bleeding, however, occurs in the colon or rectum, blood will appear in stool as fresh red or dark red in color. This chronic loss of blood will produce iron deficiency which will in turn cause the anemia. Another important cause of anemia in females is the monthly menses in a female who doesn’t compensate with iron-rich food.

Causes of bleeding in the gastrointestinal tract include:

Esophageal varices: They can be the result of end stage liver disease or bilharziasis.
Esophageal tear: This can be the result of trauma or rupture of the esophagus (Boerhaave syndrome)
Esophageal cancer
Stomach ulcer: Which is a common cause of chronic blood loss.
Stomach cancer
Duodenal ulcer
Duodenal cancer
Diverticular disease: Which is an outpouching of the wall of any part of the GIT. It can get inflamed and bleeding may also occur in a minority of cases.
Polyps: They occur in the colon or the small intestines. They are usually harmless, but can be the precursor of colon cancer.
Inflammatory bowel disease: Both ulcerative colitis and Crohn’s disease can result in chronic loss of blood.
Colon and rectal cancer: Colon cancer is the 2^nd commonest cancer in males after lung cancer -or 3^rd if we count prostate cancer-. There is a general clinical rule that any iron deficiency anemia in a male aged 40 or more is due to colon cancer until otherwise proven.

B) Increased destruction of red cells in the body is called hemolysis and is seen in the following conditions :

Enzyme defects in RBCs: Red cells have different enzymes that help the cell deal with oxidative stress. The 2 most common forms of enzyme deficiencies produce a condition called favism whether due to glucose 6 phosphate dehydrogenase deficiency or pyruvate kinase deficiency.
Structural abnormalities in RBCs: RBCs are biconcave structures that can fold into themselves on passing through narrow capillaries. If the structure is disturbed due to defects in hemoglobin synthesis, they become rigid and their passage becomes difficult. This causes the corpuscles to be destroyed in the narrow sinusoids of the spleen. This is seen in the following conditions:
- Thalassemia Both alpha and beta thalassemia patients suffer from various degrees of anemia. The disease is prevalent in the Mediterranean region.
- Sickle cell anemia: This condition is prevalent in patients from African ancestry.
- Spherocytosis: In this condition, the red corpuscles become spheres rather than biconcave discs. It rarely causes significant anemia.
Autoimmune diseases: In many patients with autoimmune diseases, antibodies develop against blood elements whether red corpuscles, white blood cells or platelets. The most common autoimmune disease that can cause significant anemia is systemic lupus, but it can also be found in rheumatoid arthritis. Autoimmune hemolytic anemia is another disease that can result from viral infections or some blood cancers or lymphomas.
Infections: Some infections can cause destruction of RBCs. The most famous and common of which is malaria.
Drugs: Some drugs can cause anemia by inducing the destruction or RBCs. They include antibiotics such as ceftriaxone, antipyretics such as diclofenac and even the antiparkinsonian drug levodopa. Some cause the destruction of RBCs via the formation of antibodies while others cause non-antibody mediated mechanisms.
Hypersplenism: Due to some of the above causes such as thalassemia, the spleen may enlarge and at a certain point, this enlargement can cause the development of a condition known as hypersplenism. In this condition, the spleen becomes “aggressive” towards all types of cells whether healthy or deformed which can cause one or more types of blood cells to be destroyed in excess and their numbers to fall. Severe anemia and platelet deficiencies may result.

Symptoms of anemia

Anemia is mostly a laboratory term and its expression varies widely according to the person affected, the severity of the anemia and the onset by which it started. Symptoms of anemia include:

Fatigue, feeling of unwellness and inability to perform daily tasks: This is usually felt when anemia develops somehow quickly -within weeks to a few months-. This is due to the inability of the blood to deliver oxygen to tissues at the required rate leading to decreased metabolism.
Breathlessness: This is quite a common complaint among anemics, and it results from the same reason: the body sense that not enough oxygen is delivered to its cells.
Chest pain: This pain is like that felt in angina and results from the heart muscle not receiving enough oxygen. It is felt more like a tightening or choking sensation. It is usually exacerbated by effort and relieved by rest.
Fast heartbeats: The body compensates for the low oxygen delivery by increasing the rate of delivery of that oxygen through increasing heartbeats. This can cause much discomfort to the patient who becomes aware of their heartbeat. This is termed palpitations.
Lightheadedness and loss of consciousness: Our brains are very sensitive to decreased oxygen delivery and anemic patients frequently complain of headaches and lightheadedness. This can be further complicated by attacks of fainting -which is a good indicator of the severity of the anemia-.
Cold hands and feet: Since oxygen is delivered sub optimally to the tissues, the rate of metabolism is reduced, which is the greatest contributor to the production of body heat. To preserve its heat, the body constricts its peripheral vessels to reduce the loss of heat and concentrate warmth at its core leading to cold extremities.
Paleness of the face, palms and lips: Since the level of hemoglobin is low, the level of redness of the blood is reduced. This is especially seen in the lips, gums and conjunctiva of the eye because their blood vessels are not blocked by skin or pigmentation.

These symptoms are generally seen in all types of anemias and regardless of the cause, but they are usually associated with other manifestations of the cause for example:

Iron deficiency anemia is usually associated with brittle nails, a desire to eat strange substances such as ice, wood and mud, a condition called pica or geophagia and inflammation surrounding the mouth.
Thalassemia is associated with jaundice, enlarged spleen with abdominal pain and some endocrinal abnormalities such as delayed puberty.
Autoimmune disease will present by their prevalent symptoms. Lupus, for example, can present by joint pain and facial rash.
Hemolytic anemias in general present by jaundice with change in stool and urine color.
Chronic loss of blood due to cancer colon is also associated with loss of weight, abdominal pain and change of bowel habits.

Complications of dangerously low hemoglobin level

If hemoglobin falls low enough, the body won’t be able to function with such low oxygen delivery, which will lead to it pushing the heart too hard to pump more blood. This, however, comes with a downside, since the heart fills in between heartbeats. When it beats fast enough, it can no longer fill with blood leading to heart failure and death.

Chronically low hemoglobin in children can also delay their growth and development and is considered a common cause of stunted growth in many developing countries. Constriction of blood vessels can also leave those tissues susceptible to infections leading to their death in severe cases “gangrene”.