Platelet E-News – January 16, 2004

Contents:

  • Inherited Thrombocytopenia: when a low platelet count does not mean ITP
  • Injured Megakaryocytes in ITP
  • Increased Prevalence of Heart Attacks in Lupus Patients
  • Thrombic Complications in ITP
  • Becoming a Partner in Your Healthcare
  • ITP and Pregnancy: A retrospective analysis

 

INHERITED THROMBOCYTOPENIA: when a low platelet count does not mean ITP

“Congenital thrombocytopenias, once considered rare and obscure conditions, are today recognized with increasing frequency….”. It is especially important to distinguish low platelets due to inherited genetic abnormalities from ITP. The treatments used for ITP will be ineffective if the cause of low platelets is genetic reports Dr. Jonathan Drachman in his review article in the journal “Blood.”

Many of the congenital thrombocytopenias have platelet abnormalities that can be recognized by a careful review of a blood smear. In adults, congenital thrombocytopenias are usually mild or moderate with platelet counts above 20,000. Factors such as family history, and tendencies toward easy bruising, prolonged bleeding, or petechiae are important considerations in diagnosis.

If congenital thrombocytopenia is suspected, it is important for the patient to see a hematologist who specializes in inherited platelet disorders.

“Inherited thrombocytopenia: when a low platelet count does not mean ITP” by Jonathan G. Drachman, Blood, 15 January 2004, Vol. 103, No. 2 http://www.bloodjournal.org/
Note that this article contains a long list and description of various inherited thrombocytopenias. See www.itppeople.com/lowplate.htm for a partial list.

See also http://www.familygenetics.net/

INJURED MEGAKARYOCYTES IN ITP

Megakaryocytes are bone marrow cells that produce platelets and other blood cells. In the past, studies have shown that 30% to 50% of patients with ITP have a reduced rate of platelet production. Now scientists in the Netherlands have found evidence that the reduced platelet production may be associated with injured megakaryocytes. They found that the megakaryocytes of ITP patients had extensive abnormalities. These megakaryocytes were surrounded by neutrophils and macrophages (types of white blood cells) indicating an inflammatory response against the megakaryocytes. The megakaryocytes also displayed characteristic signals that cells display when they are dying. The authors concluded that the release of platelets into circulation was depressed in some cases of active ITP possibly due to the action of autoantibodies against the megakaryocytes.

INCREASED PREVALENCE OF HEART ATTACKS IN LUPUS PATIENTS

Patients with systemic lupus erythematosus (SLE) have an increased prevalence of heart attacks according to studies in the New England Journal of Medicine. In one study 40% of lupus patients had atherosclerotic plaques, a precursor of heart problems. This could be due to the chronic activation of the immune system. Possible SLE-related risk factors include systemic inflammation, autoantibodies to endothelium cells that make up the inside of blood vessels, HDL, phospholipids, circulating immune complexes, activated complement products, nephritis (kidney disease), and dyslipidemia (disorders of HDL and LDL metabolism).

“Systemic Lupus Erythematosus and Accelerated Atherosclerosis”, Bevra Hannahs Hahn, MD, NEJM 349:25, December 18, 2003, P. 2379

“Prevalence and Correlates of Accelerated Atherosclerosis in Systemic Lupus Erythematosus

THROMBIC COMPLICATIONS IN ITP

Platelet microparticles, a marker of platelet activation, are often elevated in ITP patients according to Yeon S. Ahn, MD. In his 2002 study of twenty ITP patients who experience cognitive problems, he observed evidence consistent with small vessel disease. He concluded that thrombic complications can occur in ITP. This could lead to gradual memory loss and vascular dementia. The progression was faster in those with splenectomy and higher platelet counts. At the 2003 American Society of Hematology conference he presented research showing that ITP patients who experienced the dementia had plasma that activated the endothelial cells lining the walls of the blood vessels. This could lead to thrombosis and cause small stroke-like reactions in the brain.

ASH Abstract [1052] Plasma from Patients with ITP-Associated Dementia (ITPAD) Activates Endothelial Cells (EC) and Enhances Transendothelial Migration of Leukocytes (TEML). Session Type: Poster Session 164-I www.hematology.org

“Vascular dementia in patients with immune thrombocytopenic purpura” J Clin Lab Med 119:334,1992; Throm Res 107:337,2002

BECOMING A PARTNER IN YOUR HEALTHCARE

“People who become partners in their care and view the receipt and delivery of healthcare as a service wherein they are the consumer and the doctor or clinician is the provider, will feel more in control and will likely have better outcomes than people who assume the more traditional role of ‘patient’.” In the past the physician/patient model was considered one of compliance and patients who found it difficult to follow physician directive were considered non-compliant. Now it is recognized that the more active a role a person takes in deciding their treatment protocol, the more likely that the decisions will be carried out.

“Becoming a partner in your healthcare” R. Paper, RN, Haemophilia (2002), 8, 447-449

ITP AND PREGNANCY: a retrospective analysis

In most studies of ITP and pregnancy, the focus has been on the infant. In a new retrospective study at McMaster University in Hamilton, Ontario, the records of 119 pregnancies over an 11-year period were reviewed. They revealed that for most women, the pregnancies were uneventful. However 21.5% of the women had moderate to severe bleeding. Most deliveries (82%) were vaginal. The authors concluded that “ITP in pregnancy carries a low risk, but mothers and infants may require therapy to raise their platelet counts.”

“A retrospective 11-year analysis of obstetric patients with idiopathic thrombocytopenic purpura” Blood, 15 December 2003, Vol. 102, No. 13. www.bloodjournal.org

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