Page 80 - JSOM Summer 2022

an effective, expeditious treatment plan if thrombocytopenia is Treatments
suspected.
Treatments for thrombocytopenia vary depending on the or-
igin and severity of symptoms. Without proper intervention,
Thromboelastography (TEG), if available, can also be used
(often in the trauma setting) to assess coagulation. This di- death can occur from active bleeding. Thus, timely blood
agnostic test is a noninvasive method to quantitatively mea- or platelet transfusions, if available in real-time and in most
sure the ability of the blood to coagulate and, by analyzing cases, are the most effective means to treat patients with a low
the various phases of coagulation, identify which part of the platelet count with active bleeding. This is an emergency treat-
clotting process to target in therapy. When obtaining a throm- ment administered via an intravenous needle or, in some cases,
boelastograph, two different chambers are used to examine intraosseous needle.
a whole blood sample to reduce the risk of measurement er-
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ror. Each chamber consists of a platform with a disposable As previously noted, one of the most likely causes of throm-
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cup and a detection pin suspended in the middle. The cup bocytopenia to be expected in the SOF environment, is dilu-
is then rotated with a transducer such that the blood makes tion following large transfusions of blood or administration
a hemostatic plug. As the cup oscillates around the detection of other less efficacious fluid therapies for hemorrhagic shock.
pin, it is possible to detect and quantify the viscoelastic prop- The logistical constraints of a field environment mean that it
erties of the blood sample during clotting as a measure of pin is likely that the only immediate treatment available will be
movement versus time. This reveals the blood’s efficacy in platelet replacement. However, when available and generally
coagulation. in a more definitive setting of care, other treatment regimens
may be used that will depend on the type of thrombocytopenia
that is diagnosed. Some medications, specifically corticoste-
When to Intervene roids (administered orally or intravenously) slow the destruc-
tion of platelets in the blood. In some cases, immunoglobulins
It is important to identify the appropriate actions for patients
with serious thrombocytopenia that may require medical inter- such as rituximab can be utilized to block the immune system
vention and hospitalization. As we have discussed, prolonged from destroying platelets in the circulation. Other medications
active bleeding and excessive bruising is often indicative of a can assist with increasing platelet production; eltrombopag
low platelet count. Furthermore, superficial bleeding, bleeding and romiplostim are notable in treating low platelet counts.
in the gums or nose, blood in urine or stools, unusually heavy Other etiologies of thrombocytopenia, such as inherited
menstrual bleeding, fatigue, and an enlarged spleen are all crit- thrombocytopenia, will typically not require treatment in the
ical signs of an abnormally low platelet count. Rapidly identi- absence of active bleeding requiring platelet support.
fying these signs and symptoms in the prehospital setting, and
moving toward rapid treatment, is critical. It is important to note that platelet transfusion is avoided in
certain situations in which transfusing platelets may have little
effect or even worsen the patient’s condition, such as in HIT,
Expeditiously acquiring a patient’s blood platelet count is
important. Typically, a normal platelet count is 150,000– TTP, ITP, or DIC.
400,000/μL; a count below 150,000/μL is indicative of throm-
bocytopenia. Sometimes labs drawn during a routine physical A strong suspicion for HIT should trigger a move toward im-
or preventative care visit lead to an incidental discovery of a mediate treatment even before confirmatory laboratory tests
low platelet count. Patients with platelet counts greater than have resulted. This clinical suspicion should be based upon an
50,000/μL rarely have symptoms and indications of less than intermediate or higher probability from the 4 Ts score (or sim-
30,000/μL is usually when purpura appears on the skin. Plate- ilar validated decisionmaking tool) as proposed by Lo, et al.
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let counts of 10,000–30,000/μL may cause bleeding with min- in 2006. The factors considered in this score are 1) thrombo-
imal trauma. A hematological emergency is clearly present cytopenia (the platelet count), 2) timing of platelet count fall,
when the platelet count is less than 5,000/μL, which is typi- 3) thrombosis or other sequelae, and 4) other causes of throm-
cally when spontaneous bleeding occurs. Nonetheless, when bocytopenia. If a high enough score is met then all heparin
the platelet count is less than 50,000/μL, treatment may in- products should be discontinued, warfarin should be reversed,
clude a platelet transfusion to correct coagulopathy depending and a non-heparin anticoagulant should be started (i.e., arg-
on the specific patient case. In some cases, such as in high-risk atroban, bivalirudin, etc.). The decision should be made with
surgery where bleeding is anticipated, the threshold to trans- careful consideration of the risk of thrombosis, likelihood of
fuse may even be higher (i.e., 100,000/μL). bleeding, potential need for rapid reversal, cost, renal and he-
patic function, and other factors. When making the clinical
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decision to treat a patient for presumed HIT, it is important to
There are some cases where HIT can be anticipated in a con-
trolled hospital environment. For instance, patients undergo- remember that it can occur from several sources and the risk
ing cardiopulmonary bypass surgeries are exposed to heparin remains the same whether that source is low-molecular-weight
2
and experience a decreased platelet count postsurgery. If HIT heparin or unfractionated heparin.
is expected, physicians must first determine how low the plate-
let count has dropped. For instance, a platelet decrease of 50% The treatment of ITP often does not include an immediate
or more after initial heparin therapies and the timing of this platelet transfusion because the immune system is poised to
decrease is critical. With regard to timing, 5–10 days after ini- attack the platelets that are transfused. A decision to treat for
tial heparin therapies or within 2 days of a second therapy this condition includes a clinical assessment of bleeding (and
after 3 months of previous use is telling. Physical examination severity, if present), platelet count, other bleeding risk factors,
of the heparin injection site is also required to assess any le- what treatments have been completed in the past and their
sions or the onset of thrombosis. A HIT antibody test should efficacy, and review of any treatments given for the current
be ordered if any of these findings are encountered. episode. If bleeding is minor or not present the patient may not

78 | JSOM Volume 22, Edition 2 / Summer 2022