Blood has been a subject of religious worship, superstition, magic, fear and pride since man evolved. Blood sacrifice was an Aztec rutual in which the conscious victim’s heart was cut out. Blood’s function was unknown until its oxygen-carrying capacity was discovered in the nineteenth century. Before, weakness and death were seen with prolonged blood loss.
Families prided their ‘bloodlines’ which conferred royal status. Anemia was observed and eventually associated with iron deficiency, low vitamin levels and infectious disease. The discovery of syphilis infection led to anti-biotic treatment, mainly penicillin. Before, mercurial Salversan was moderately effective, but syphilis killed or crippled about one third of those infected.
Blood typing, A, B, ABO, O, was discovered around 1910. There are over thirty large molecules which attach to cell walls, but are not used for typing.
Typing enabled accurate transfusions; unmatched types were incompatible, possibly resulting in massive clotting. The O type is a universal donar.
Blood is roughly half hemoglobin, half water. Blood volume in dehydrated patients may be restored by oral fluids (Beer is good.)
As an intern, I saw many‘milk babies’, pale little pishers whose ignorant or indifferent mothers had fed them only milk. Milk has little iron. The babies were anemic with low hemoglobin levels and red cell counts. Iron shots and transfusions were curative. You could diagnose them as they came in by their pale ivory skin. It is amazing and tragic that any mother could could be unaware of the need for iron.
The table at right shows circulating blood volumes, given as volume per kilogram, for healthy adults of a selection of animals. However, it can be 15% less in obese and old animals.
The usual blood volume is about 5 litres in men, four in women. Red cell counts are stable, about 5 millon/cubic millimeter. White cell counts rise during infection from a normal 7-8 thousand to 12,000 or more, the polymorph leucocytes increasing to kill and engulf invading bacteria.
Blood cells are produced in the bone marrow — 3 million per second! Red cells have a life span of 120 days, then are metabolized in the liver to bilirubin which colors the liver a reddish- brown. Elevated bilirubin may be a sign of illness such as hepatitis or gall bladder disease. Pale stools may indicate gall stones blocking the normal secretion of bilirubin in bile. Elevated liver enzymes indicate liver damage and are often associated with alcoholism, as well as the trendy Hepatitis C.
The liver is a forgiving organ which continues to function when damaged by alcohol, illicit drugs, infection–up to a point. But when damaged beyond repair liver damage may be fatal. Treatment has come a long way; liver transplants are common. If an alcoholic can stop drinking, the liver will often heal if not too scarred.
When I was a junior year med student, we admitted an alcoholic in liver failure. No transplants then. Next morning, he vomited his breakfast. When asked how he felt, he said, “Not so good.”
With third-year optimism, I said, “Don’t worry, you’ll be all right.”
That was the last he ever heard.
William Goldsmith, M.D.
23 DEC 2014