Up to 10% of pregnant women will develop low platelet counts during their pregnancy.61,62 The most common etiology is gestational thrombocytopenia, which is an exaggeration of the lowered platelet count seen in pregnancy. Counts may fall as low as 50 × 103/µL at the time of delivery. No therapy is required as the fetus is not affected and the mother does not have an increased risk of bleeding. Pregnancy complications such as HELLP syndrome and thrombotic microangiopathies also present with low platelet counts, but these can be diagnosed by history.61,63
Women with ITP can either develop the disease during pregnancy or have a worsening of the symptoms.64 Counts often drop dramatically during the first trimester. Early management should be conservative with low doses of prednisone to keep the count above 10 × 103/µL.21 Immunoglobulin is also effective,65 but there are rare reports of pulmonary edema. Rarely patients who are refractory will require splenectomy, which may be safely performed in the second trimester. For delivery the count should be greater than 30 × 103/µL and for an epidural greater than 50 × 103/µL.64 There are reports of the use of TPO-RAs in pregnancy, and this can be considered for refractory cases.66
Most controversy centers on management of the delivery. In the past it was feared that fetal thrombocytopenia could lead to intracranial hemorrhage, and Caesarean section was always recommended. It now appears that most cases of intracranial hemorrhage were due to alloimmune thrombocytopenia and not ITP. Furthermore, the nadir of the baby’s platelet count is not at birth but several days after. It appears the safest course is to proceed with a vaginal or C-section delivery determined by obstetrical indications and then immediately check the baby’s platelet count. If the platelet count is low in the neonate, immunoglobulin will raise the count. Since the neonatal thrombocytopenia is due to passive transfer of maternal antibody, the platelet destruction will abate in 4 to 6 weeks.
Pediatric Patients
The incidence of ITP in children is 2.2 to 5.3 per 100,000 children.1 There are several distinct differences in pediatric ITP. Most cases will resolve in weeks, with only a minority of patients transforming into chronic ITP (5%–10%). Also, the rates of serious bleeding are lower in children than in adults, with intracranial hemorrhage rates of 0.1% to 0.5% being seen.67 For most patients with no or mild bleeding, management now is observation alone regardless of platelet count because it is felt that the risks of therapies are higher than the risk of bleeding.21 For patients with bleeding, IVIG, anti-D, or a short course of steroids can be used. Given the risk of overwhelming sepsis, splenectomy is often deferred as long as possible. Rituximab is increasingly being used in children due to concerns about use of agents such a cyclophosphamide or azathioprine in children.68 Abundant data on use of TPO-RAs in children showing high response rates and safety support their use, and these should be considered in refractory ITP before any cytotoxic agent.69–71
Helicobacter PyloriInfection
There has been much interest in the relationship between H. pylori and ITP.16,72,73H. pylori infections have been associated with a variety of autoimmune diseases, and there is a confusing literature on this infection and ITP. Several meta-analyses have shown that eradication of H. pylori will result in an ITP response rate of 20% to 30%, but responses curiously appear to be limited to certain geographic areas such as Japan and Italy but not the United States. In patients with recalcitrant ITP, especially in geographic areas with high incidence, it may be worthwhile to check for H. pylori infection and treat accordingly if positive.
Drug-Induced Thrombocytopenia
Patients with drug-induced thrombocytopenia present with very low (< 10 × 103/µL) platelet counts 1 to 3 weeks after starting a new medication.74–76 In patients with a possible drug-induced thrombocytopenia, the primary therapy is to stop the suspect drug.77 If there are multiple new medications, the best approach is to stop any drug that has been strongly associated with thrombocytopenia (Table 3).74,78,79
Immune globulin, corticosteroids, or intravenous anti‑D have been suggested as useful in drug‑related thrombocytopenia. However, since most of these thrombocytopenic patients recover when the agent is cleared from the body, this therapy is probably not necessary and withholding treatment avoids exposing the patients to the adverse events associated with further therapy.
