Understanding jump in platelet levels

[Imkerin]

Advice Please!

After two years of PV being managed with venesections and aspirin, I moved into the high risk category by virtue of age and six weeks ago started on Hydroxy, 500mg Mon-Fri.

Blood tests after two weeks showed a rather dramatic decrease in platelets 480 – 336, RBC no change at 6 and WBC nudged down into normal range. HCT .43 I was hugely relieved to see this positive response with minimal Hydroxy side effects.

At the blood test yesterday (six weeks since starting Hydroxy), platelets had almost doubled to 622!

RBC and WBC counts down a few notches. HCT up slightly to .45 The only time in the last two years that platelets have been higher was following thoracic surgery last year; they then quickly settled down to bump along the top range of normal.

The only advice via a telephone call with the MPN clinic this morning is to increase the Hydroxy ‘as you are on a relatively low dose’. I’m left unable to understand the logic of this advice.

Has anyone on the Forum had a similar experience or information on how to understand this jump in platelet levels? And any advice regards next steps gratefully received.

After some quick research I see that ‘infection’ and low iron are also common reasons for platelets to rise. I have now arranged to go in for another blood test next week to include an iron profile (it was 4.4 in Feb) and to check for inflammatory markers

[hunter5582]

There are a number of factors that influence platelet levels. It is normal for platelets to vary by as much as 100K in a single day based on what is going on in your body. infection, inflammation, injury, surgery, bleeding, and iron deficiency can all cause reactive thrombocytosis. Venesection is on the list since it is a bleeding event and it is intended to induce iron deficiency. Treatment decisions should not be made based on a single lab. It is the trend over time that matters.

I did find that venesection induced iron deficiency caused reactive thrombocytosis. it increased my PLT levels by about 200K. Hydroxy did an adequate job of controlling the thrombocytosis, but was ineffective at controlling erythrocytosis at a dose I could tolerate. I experienced toxicity even at very low doses of hydroxy, I had to discontinue the hydroxy as I was intolerant and refractory to it. After a period of venesection-only, i started on Pegasys, then switched to Besremi. The interferons have been much more effective and easier to tolerate for me.

You are currently on a low dose of hydroxy. Increasing the dose would most likely reduce the thrombocytosis and other blood cell counts. The issue would be whether you tolerate the higher dose as adverse effects are dose dependant.

It is worth noting that the risk of thrombosis is more closely associated with erythrocytosis than thrombocytosis. There is no linear correlation between thrombosis risk and platelet levels like there is with erythrocytosis for PV. That is why HCT is used as the primary treatment target for PV. The usual treatment goal is HCT<45% for males, HCT<42 /43% for females. With your HCT at 45%, it would be time to consider either a venesection or an increase in the hydroxy dose.

The other option would be to consider the alternatives to hydroxy. The interferons (Pegasys/Besremi) are preferred by some MPN Specialists and MPN patients. Jakavi is also an option in some ciremunstances. This would be a conversation to have with a MPN Specialist. Suggest consulting with your care team if you wish to pursue a different treatment plan.

You are asking very reasonable questions that deserve an answer. It is important that you understand the rationale for all aspects of your treatment plan. Reviewing all of your treatment options and the risk/benefit if each choice is part of the process for making decisions. If you are not clear on the current recommendation, then it would be prudent to call back and seek a more detailed explanation.

All the best moving forward.

[Imkerin in reply to hunter5582]

Thank you Hunter, a very thorough answer, as usual.

[Imkerin in reply to Imkerin]

And I take on board your comment regards the HCT level and will follow up - not sure why that wasn't flagged in the consultation this morning.

[saltmarsh]

As indicated in Hunter's reply, a number of things can drive the platelets. In my case a year ago an infection unrelated to PV was the cause. It resolved itself. Personally I'd give it a little time before changing medications but also consider the other things Hunter mentioned. Good luck

[Imkerin in reply to saltmarsh]

Thank you saltmarsh, my inclination is to not rush to change the dosage on the strength of a single blood test.

[Solyesh]

I think your intuition is correct - to change a medication based upon a single blood test, especially when platelets can cycle naturally around 100K any given day, would also give me pause. Your levels, to my unprofessional eye, at 622 are higher the reference range but not dangerously so...sometimes doctors react in a "textbook" manner rather than thinking about the individual patient in front of them. I would ask to wait for another reading before considering upping a medication which i had only recently started.

[Imkerin in reply to Solyesh]

Thank you Solyesh for your thoughts