Dear Dr. Roach: Recent blood tests have left me perplexed. My hemoglobin, hematocrit and MCV were slightly high. What might be the underlying cause of these elevations? What do hemoglobin, hematocrit and MCV refer to? Also, my hematocrit and MCV levels were high on the previous blood test, about a year ago. Now the hemoglobin seems headed in the same direction. I am worried about cancer.
I have been healthy for most of my life, as a non-smoker, non-drug user. I do not live at high altitude.
R.Z.
Hemoglobin is the major protein in red blood cells, used to transport oxygen from the lungs to all the tissues and cells of the body that need it. Hematocrit is the proportion of blood comprised of red blood cells (the rest is plasma, with negligible contributions of white blood cells and platelets, normally). The mean corpuscular volume, MCV, is a measure of the average size of a red blood cell.
All of these are slightly above normal in you, which should raise the concern of polycythemia (rubra) vera (which literally means 鈥渢oo many red blood cells鈥�). Polycythemia vera is a myeloproliferative disorder, a disease of the bone marrow, but not a cancer. However, there are several other possibilities, which may need evaluation.
Your levels have been high twice, a year apart, so I do think you should be evaluated for the cause. Low blood oxygen from smoking or from altitude can be ruled out from the information you gave me. However, other heart or lung diseases, sleep apnea and carbon monoxide poisoning (much more common than you might think in winter months) can be quickly evaluated by a careful exam and by measuring blood oxygen and carbon monoxide levels. There are tumors that can secrete a hormone called erythropoietin, which increases bone marrow production of red blood cells, so that should be checked.
Polycythemia vera usually has high white blood cell and platelet cell counts and a low MCV, so it is less likely in you.
Given how well you feel, and how subtle the elevations are, I think it鈥檚 possible that you have no disease at all. These levels may be normal for you. However, get evaluated. A hematologist is the expert in these conditions.
Dear Dr. Roach: I am on a proton pump inhibitor, which was prescribed by my doctor several months ago after complaining of symptoms relating to GERD. While the medication has improved most of the symptoms, once in a while I still experience a slight burning sensation in my lower chest. Are PPIs designed to totally relieve the symptoms of GERD, or is it common to still have occasional chest discomfort? (I have had tests to rule out heart-related problems, which I am aware can cause the same sort of symptoms.) Also, if the problem is caused by the lower sphincter valve in the esophagus not functioning correctly, how does a PPI remedy that?
Anon.
Proton pump inhibitors do not stop gastroesophageal reflux, which literally means 鈥渢he backward passage of stomach contents into the esophagus.鈥� By reducing the ability of the stomach to make acid, the damage to the esophagus can be minimized and symptoms improved, though often not totally relieved.
Metoclopramide does reduce the actual reflux of material, but has such dangerous side effects that it is seldom used long term. PPIs have their own risk of long-term side effects, so I recommend trying to slowly taper off the medication after six weeks or so.
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Dear Dr. Roach: I understand that bile assists in the digestion and absorption of fats and is responsible for the elimination of certain waste products from our body. Could you please tell me what happens to a female who has had laparoscopic gallbladder surgery? I鈥檓 having a difficult time losing weight.
M.F.
Bile, which contains bile salts such as cholic acid, are secreted by the liver and stored in the gallbladder. They are essential in the digestion of fat, where they act chemically to emulsify fat (emulsification allows fat to dissolve in water, similar to soap breaking up fat when cleaning).
Ninety-five per cent of bile acids are reabsorbed, normally, in the intestine, allowing them to be reused. The gallbladder releases bile in response to a fatty meal (which is why people with gallstones develop pain after a fatty meal 鈥� the gallbladder constricts, causing pain if the duct is blocked by a stone).
Without bile, fat cannot be properly absorbed, leading to steatorrhea (鈥渟teato鈥� for 鈥渇at,鈥� and 鈥渞hea鈥� for 鈥渇low鈥�), a fatty diarrhea, and often weight loss.
However, after gallbladder surgery, in most cases the liver learns to release the bile appropriately in response to a meal within a few weeks of surgery. There are many reasons for inability to lose weight, but it shouldn鈥檛 be related to your gallbladder surgery. Thyroid disease may be the most common cause.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to [email protected].听听听
