Nadir and Chemotherapy

What is Nadir?

Nadir is term that refers to the lowest point of anything. But when used in reference to chemotherapy, it describes the point when blood cell counts are at their lowest after a chemotherapy treatment. It is commonly referred as the "nadir period" or simply "nadir" among healthcare workers and patients.

Why Does Nadir Occur

While chemotherapy directly targets cancer cells, it also affects our blood cells in the process -- red blood cells, white blood cells, and platelets. These cells are manufactured in the bone marrow. During chemotherapy, bone marrow activity may be decreased, resulting in lowered blood cell counts within the body.

Each Blood Cell Type Reaches Nadir at Different Times

White blood cells (WBC) generally drop to their lowest count at about 7 to 14 days following a chemotherapy treatment. When WBC are at their lowest count, people are at a heightened risk of developing infections. White blood cells are a vital component of the immune system and keep invading bacteria at bay. When the white cell count is too low, the immune system is compromised and cannot effectively fight infections.

Red blood cells (RBC) generally live longer than white blood cells and reach a nadir period weeks after treatment. Their job in the body is to carry oxygen to the body's tissues from the lungs. RBC contain hemoglobin, a iron rich protein that transports oxygen and also gives blood it's red color. When red blood cells counts are too low, the result is called anemia.

Platelets also serve an important function by helping to clot the blood, which prevents bleeding. When the amount of platelets in the body fall too low, then condition is called thrombocytopenia. It is marked by bruising, nosebleeds, excessive bleeding from cuts, and fatigue. A reddish-purple skin rash that looks like small dots also is a symptom of a low platelet count. Platelets generally reach their nadir period at about the same time as white blood cells.

Lowered Blood Cell Counts Can Be Managed

Gradually, blood cells counts do return to normal. But, with each treatment comes a nadir period, so people who have more frequent chemotherapy treatments may experience lowered counts more often than someone whose treatments are spaced further apart.

When blood cell counts become too low, they can be managed through drugs the boost cell production and also through transfusions. Lowered counts may also merit delaying chemotherapy treatments.

_Source:

American Cancer Society. How Will Chemotherapy Affect My Blood Cell Count? 09/11/2008.
http://www.cancer.org/docroot/ETO/content/ETO_1_7X_How_Will_Chemotherapy_Affect_My_Blood_Cell_Count.asp