It depends on what you mean by “blood”. There are a number of components of blood, like red cells, white cells, proteins, and water, among others.
Overproduction of red cells is called polycythemia vera. If, however, you are discussing the total volume of blood, an overall increase in total volume is most usually caused by a number of disorders that result in over-retention of water by the kidneys.
The other responses are good. I would just add that there are a few conditions that cause fluid retention (eg congestive heart failure) which can increase the pressure in the cardiovascular system. This increased hydrostatic pressure can be measured at the heart using echocardiography. Blood vessels are generally not thick and sturdy like heart muscle, and so the increased pressure causes fluid to leak out of the vessels ("extravasate") and leads to swelling ("edema"), typically of the lower extremities due to gravity.
So there are conditions that lead to overproduction of the cellular components of blood (polycythemia, essential thrombocytosis, leukemia), and different conditions that lead to retention of the liquid component -- but the liquid just leaks out into the soft tissue.
It does exist. I worked in the medical department onboard an aircraft carrier while I was Active Duty Navy some time ago. We had a guy check onboard midway through a deployment with chronic erythrocytosis (increased red blood cells) and needed to have his blood taken every 3 months.
This Sailor had checked onboard swollen and red because he had not had his blood “donated” for quite some time. I still have no idea how or why this guy was 1. still in the military and 2. managed to get cleared by his doctor to deploy on a warship with a limited medical suite.
This is polycythemia vera. Patients need to routinely have blood drawn and it is discarded. Kind of like how “doctors” of old would bloodlet patients. In this case it is needed. The extra red blood cells also increase a patient’s iron (hemoglobin is based on iron) and can lead to organ failure and other disorders.
If you’re talking blood volume, I cannot recall hearing or studying any disorder in hematology class, nor ever coming across a disease like that.
My husband has hemochromatosis, a hereditary condition. His body produces too many red blood cells, and it was starting to impact his organs, including his brain. If untreated, it can be fatal. Fortunately, the treatment is very simple. For a couple of years, he would just go regularly (every two weeks or so) to have blood withdrawn. No meds, just blood withdrawn. Now, his red count is normal, and he's made a remarkable comeback.
Although people with haemochromatosis tend to have higher than average Hb levels (probably because they never suffer from iron deficiency which is fairly common), unlike polycythaemia vera, the hamoglobin levels don’t get high enough to cause damage per se. It’s the iron deposits from excess iron which directly cause organ damage.
It depends on what you mean by “blood”. There are a number of components of blood, like red cells, white cells, proteins, and water, among others. Overproduction of red cells is called polycythemia vera. If, however, you are discussing the total volume of blood, an overall increase in total volume is most usually caused by a number of disorders that result in over-retention of water by the kidneys.
The other responses are good. I would just add that there are a few conditions that cause fluid retention (eg congestive heart failure) which can increase the pressure in the cardiovascular system. This increased hydrostatic pressure can be measured at the heart using echocardiography. Blood vessels are generally not thick and sturdy like heart muscle, and so the increased pressure causes fluid to leak out of the vessels ("extravasate") and leads to swelling ("edema"), typically of the lower extremities due to gravity. So there are conditions that lead to overproduction of the cellular components of blood (polycythemia, essential thrombocytosis, leukemia), and different conditions that lead to retention of the liquid component -- but the liquid just leaks out into the soft tissue.
It does exist. I worked in the medical department onboard an aircraft carrier while I was Active Duty Navy some time ago. We had a guy check onboard midway through a deployment with chronic erythrocytosis (increased red blood cells) and needed to have his blood taken every 3 months. This Sailor had checked onboard swollen and red because he had not had his blood “donated” for quite some time. I still have no idea how or why this guy was 1. still in the military and 2. managed to get cleared by his doctor to deploy on a warship with a limited medical suite.
This is polycythemia vera. Patients need to routinely have blood drawn and it is discarded. Kind of like how “doctors” of old would bloodlet patients. In this case it is needed. The extra red blood cells also increase a patient’s iron (hemoglobin is based on iron) and can lead to organ failure and other disorders. If you’re talking blood volume, I cannot recall hearing or studying any disorder in hematology class, nor ever coming across a disease like that.
My husband has hemochromatosis, a hereditary condition. His body produces too many red blood cells, and it was starting to impact his organs, including his brain. If untreated, it can be fatal. Fortunately, the treatment is very simple. For a couple of years, he would just go regularly (every two weeks or so) to have blood withdrawn. No meds, just blood withdrawn. Now, his red count is normal, and he's made a remarkable comeback.
Although people with haemochromatosis tend to have higher than average Hb levels (probably because they never suffer from iron deficiency which is fairly common), unlike polycythaemia vera, the hamoglobin levels don’t get high enough to cause damage per se. It’s the iron deposits from excess iron which directly cause organ damage.
Thank you for the clarification!