Immune Thrombocytopenia Defined

2020-11-18 12:00:00
Tags: Immune Thrombocytopenia,oncology



A description of what immune thrombocytopenia is and presenting factors that prompt providers to refer patients to be assessed by a specialist for the condition.


Bhavesh Shah, RPh, BCOP: Hello, and welcome to this Directions in Pharmacy® Peer Exchange® on “Advancements in the Management of Immune Thrombocytopenia.” I’m Bhavesh Shah from Boston Medical Center Health System, and I’m joined by Ali McBride from the University of Arizona Cancer Center and David Hughes from Boston Medical Center Health System.

Today we’re going to discuss a number of topics pertaining to ITP [immune thrombocytopenia], including the diagnosis, clinical manifestations, traditional treatment options, and the advances we’ve seen in the past few years. Let’s get started on our first topic. Ali, would you walk us through the diagnosis and pathophysiology of ITP?

Ali McBride, PharmD, MS, BCOP, FASHP, FAzPA: The baseline of ITP has been characterized over the last few years. We know some of the initial discussions. I know we’ve talked before, Bhavesh, about that first study done many years ago where someone took someone else’s blood, put it into their own system, and had an ITP diagnosis.

ITP is a blood disorder characterized by a decreased number of platelets in the blood. These platelets are essential because they stop bleeding. Any decrease can cause issues of bruising, bleeding gums, internal bleeding, etc. Therefore, it affects the patient, but it can also affect other issues in terms of a patient’s normal daily life.

When we’re looking at a patient’s normal platelet level, we’re looking at 400, 500,000 per mm3, depending on our patients. Because we work in oncology, our bias is 100,000 per mm3 at baseline, where everyone else is around 400,000 per mm3. These are distinguishing factors when we look at a normal baseline platelet count. But in the ITP situation, this is clearly a different setting. For ITP, these patients often have low-level platelets, 25,000, 15,000, 10,000s per mm3. It’s not uncommon—albeit rare—where we see patients with 5000, 3000, or 2000 per mm3, when they are not on treatment or are refractory treatment. The ITP level is stark compared with the normal baseline level.

As such, we have to make sure we address what those platelets look like: the thrombocytopenia effect but also the purpura effect, when we’re looking at the disease state or coloring of skin, which is often 1 of those actual facts of purpura. That discoloration of the skin can also occur because of easy bruising.

Bhavesh Shah, RPh, BCOP: How do these patients usually present into the clinic? How do you get the referrals for these patients?
 
Ali McBride, PharmD, MS, BCOP, FASHP, FAzPA: This is a great point. Referrals usually come from primary care physicians. You go for your normal physical. The patient complains. This example occurs more in our older-patient population; pediatrics is a very different story. In the adult-patient population, the patient comes in and often has a warfarin-like petechiae in some cases. The physician says, “Well, you’re not on warfarin. What’s going on here?” The physician does a follow-up with the patient’s blood count and sees that it’s low. If it’s precipitously low, they refer the patient directly to a benign hematologist. That’s really where we get those initial diagnoses from.

We also see some follow-up for patients gradually over time, which we’ll get to that autoimmune-based effect for these ITP-based situations. From that immune reaction—that gradual change over time—we may see the patient’s platelet count go from 500,000 mm3 down to 400,000 or 300,000 mm3, and then they just drop to less than 100,000 mm3. In those cases, under a normal physical, that may be hard to find. But if there’s a physician, a family physician, a primary care physician seeing that patient, they may catch that a little earlier on to get those lab levels in place.

We’ve also had referrals for bleeding without stopping. That’s where the patient goes to the ER [emergency department]. In that case, that ER situation provides a consult to the benign hematology team. Then they’ll do a follow-up work-up to that patient as well.