Monday, March 13, 2006

Polycythema vera

A man with mild COPD (FEV1 69%, DLCO 88%) who still smokes was found to have a hematocrit of 51. His hematologist has been subjecting him to phlebotomies. Here is the data:
1. The patient is not hypoxic. A 6 minute walk on RA also did not show hypoxia. A blood gas shows: PaO2 mmHg 94.5, PaCO2 mmHg 35.0.
2. The patient's red blood cell mass was normal.
3.His erythropoietin level was 19, which was normal (the hct was 43.5 that day).
4. His Hct was once 55, but usually lower. He gets frequent phlebotomies when it goes to about 50, but they have neveer seen if it would go any higher.

Umm, with the above, my take is that this is NEITHER primary or secondary polycythemia. The quesitonthough, is, can smoking cause secondary PV without hypoxia? (if that were the case he shouldn't be getting phlebotomies anyway)

3 comments - CLICK HERE to read & add your own!:

Baleeiro said...

Very cool question. I have also been taught that we shouldn't see much erythrocytosis without hypoxemia so I checked MedLine and found a few papers on carboxyhemoglobin (related to TOB) without hypoxia leading to erythrocytosis. There was also an older paper from the Blue journal when it was the American Review showing that in hypoxic smokers with COPD, higher levels of COHgb also correlated with more erythrocytosis and that improved if they quit.
Aitchison R, Russell N.
Smoking--a major cause of polycythaemia J R Soc Med. 1988 Feb;81(2):89-91.
Calverley PM, Leggett RJ, McElderry L, Flenley DC.Cigarette smoking and secondary polycythemia in hypoxic cor pulmonale. Am Rev Respir Dis. 1982 May;125(5):507-10.

Mike L said...

Another thing you might think about is obstructive sleep apnea or nocturnal hypoxemia.

If your patient desaturates at night, you may have your answer as to why he has polycythemia.

You can study this in 1 of 2 ways:
1. Do a polysomnogram if you have any suspicion that he has OSA.
2. Do an overnight oximetry study (any oxygen supply company can arrange for this) to see if he desaturates at night

Anonymous said...

i have copd and polycythemia vera secondary..i am on co2, and undergo phlebotomies, as well as take oral chemo, uric acid reducers. the amount of phlebotmies are reduced since chemo has been added. i still maintain a low dlco and have moderate lung obstruction..but the feeling of suffocation has been eliminated between the phlebotomy and oxygen...yes phlebotomies do work when the wbc,rbc,platets are too high...and when introduced to oral chemo and is is the cells that the bone marrow produce because of lack of oxygen...but not the extra lliquid..the cell are mutant and do cause the spleen to enlarge thus causing possible splenectomy..thus this condition shows a risk factor of 50% with or without chemo of developing luekemia, and left untreated thrombotic is not to be taken lightly and still this desease is not throughly understood, but more studies are being done to improve future patients results.