Investigations for a Low Platelet Count

Dear Ask The Doctor: I am a 39 year old male, I recently received care for strep throat and found out I had a low platelet count. I have done a fair bit of research and am currently working on this with my family doctor, but was hoping for more advice. A recent blood test shows my number on the rise (currently 90, up from 45 I believe) and am scheduled for another to see if it was temporary. I understand treatment for this is based on the underlying cause. I recently had some vaccinations (including MMR and Hep B among others) and understand this may be a reason. I am scheduled for an HIV test because I am really scared. Is the rise a good sign that it is temporary or do I need to keep it an ongoing concern if my count reaches normal levels soon? I also see nothing that I, personally, can do to help production of platelets--save maybe avoiding alcohol and aspirin. I was on Bupropion to help in smoking cessation but have switched to a NRT patch. That all said, I also recently had some polyps removed after a colonoscopy and had continued bleeding in my stool afterwards. Would this be a cause or a symptom of low platelets?

Dear Drew: Your platelet count may have doubled from the original number of 45 but is still low at 90. The persistent bleeding in your stool post colonoscopy and polyp removal is more than likely due to the fact your platelet count remains low. There are a variety of causes of a low platelet count. These can be generally grouped into three categories: Reduced production of platelets; increased destruction of platelets and; concealment in an enlarged spleen. If your spleen is not enlarged; the causes may range from nutritional deficiencies to auto-immune diseases, drug-induced, infection, or malignancy invading the bone marrow. Thrombocytopenia may be the initial disease manifestation in as many as 10 percent of patients with HIV infection; therefore I would recommend this test if you have potentially been exposed to the virus. The initial investigations required are a complete blood count, with white cell count differential and a blood film. Bone marrow investigation is not always necessary in platelet disorders. However if your family doctor has carried out the initial blood work and still found no obvious cause, it would be advisable to proceed with bone marrow investigation and HIV test to reveal the underlying diagnosis