Dr. Nabili received his undergraduate degree from the University of California, San Diego (UCSD), majoring in chemistry and biochemistry. He then completed his graduate degree at the University of California, Los Angeles (UCLA). His graduate training included a specialized fellowship in public health where his research focused on environmental health and health-care delivery and management.
Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Polycythemia is normally reported in terms of increased
hematocrit or hemoglobin.
Hematocrit (HCT): Polycythemia is considered when
the hematocrit is greater than 48% in women and 52% in men.
Hemoglobin (HGB): Polycythemia is considered when a hemoglobin level of greater than 16.5g/dL in women or
hemoglobin level greater
than18.5 g/dL in men.
Polycythemia can be divided into two categories; primary and secondary.
Primary polycythemia: In primary polycythemia the increase in red blood cells is due to inherent
problems in the process of red blood cell production.
Secondary polycythemia: Secondary polycythemia generally occurs as a response to other factors or underlying conditions that
promote red blood cell production.
Red cell production (erythropoiesis) takes place in the bone marrow through a
complex sequence of tightly regulated steps. The main regulator of the red cell
production is the hormone erythropoietin (EPO). This hormone is largely
secreted by the kidneys, although, about 10% may be produced and secreted by the
Erythropoietin secretion is up-regulated in response to
low oxygen levels
(hypoxia) in the blood.
More oxygen can be carried to tissues when erythropoietin stimulates red blood cell
production in the bone marrow to compensate for the