Hemoglobinemia

Hemoglobinemia can be caused by intrinsic or extrinsic factors. When hemoglobinemia is internally caused, it is a result of recessive genetic defects that cause the red blood cells to lyse, letting the hemoglobin spill out of the cell into the blood plasma.

In intravascular hemolysis, hemoglobin is released and binds with haptoglobin. This causes haptoglobin levels to decrease. Once haptoglobin is saturated, free hemoglobin readily distributes to tissues where it might be exposed to oxidative conditions. In such conditions, heme can be released from ferric hemoglobin. The free heme can then accelerate tissue damage by promoting peroxidative reactions and activation of inflammatory cascades. Hemopexin (Hx) is another plasma glycoprotein able to bind heme with high affinity. Hx sequesters heme in an inert, non-toxic form and transports it to the liver for catabolism and excretion. As long as both haptoglobin and hemopexin are saturated, the remaining free hemoglobins are filtered in the kidney and some of them will be reabsorbed by way of proximal tubules.

In externally caused hemoglobinemia, an outside attacker acts as an antibody against the red blood cells. This can cause the cells to be destroyed and their hemoglobin released. In extravascular hemolysis, red blood cells are phagocytized by macrophages in the spleen and liver.

Abnormal value of hemoglobin does not necessarily indicate a medical problem needing treatment. Diet, activity level, medications, a women's menstrual cycle, and other considerations can affect the results. Additionally to these, one may have higher than normal hemoglobin if they live in a high altitude area.

Causes

There are other causes besides what happens within the body in the blood cells. Other factors that can cause an excess amount of hemoglobin are:

• Smoking (which may result in low blood oxygen levels)
• Higher altitudes where your red blood cell production naturally increases to compensate for the lower oxygen supply there

Specific disorders or other factors that may cause a high hemoglobin count include:

• Lung disease
• Heart disease
• COPD (chronic obstructive pulmonary disease)
• Dehydration
• Emphysema
• Heart failure
• Kidney cancer
• Liver cancer
• Other types of heart disease
• Other types of lung disease
• Polycythemia vera, a disorder in which your body makes too many red blood cells. It can cause headaches, fatigue, and shortness of breath.