Thrombocytosis is defined as a circulating condition in which platelet count in adults is greater than the upper limit of normal, i.e., 450 × 109/L, which is broadly classified as reactive (secondary), essential (clonal or primary), or inherited [1]. At least 90% of patients with thrombocytosis have reactive thrombocytosis (RT) seen in infections, inflammatory disorders, malignant diseases, or after splenectomy. Thrombocytosis is caused by cytokines and other acute-phase response mediators active in these circumstances; most important being interleukin-6 (IL-6) and thrombopoietin (TPO).

Due to advancements in early diagnosis and treatment of both primary and secondary causes of thrombocytosis, the role of thrombocytapheresis is, though limited but a valuable, temporizing intervention. Here, the role of thrombocytapheresis is discussed to reduce platelet count in a case of cerebral venous thrombosis where platelet reduction was urgently needed because of a reactive thrombocytosis.

A 42-year-old female was admitted with a history of sudden loss of consciousness followed by generalized tonic-clonic seizures (GTCS) and in a critical general condition. The patient was referred from another healthcare facility in intubated state and on manual ventilation. At the time of admission, routine investigations revealed all hematological and biochemical tests including platelet count (384 × 10⁹/L) within normal limits, except a low hemoglobin. Non-contrast computed tomography (NCCT) revealed a large hemorrhagic venous infarct in the left frontal lobe with subarachnoid and intraventricular bleeding. Magnetic resonance angiogram (MRA) did not show any significant vascular abnormality but magnetic resonance venogram (MRV) showed venous sinus thrombosis in the superior sagittal sinus. The patient was immediately taken for surgery (left decompressive craniotomy with duraplasty). Post-operatively, the patient was put on ventilator support along with antibiotics, anti-epileptics, anti-platelet (aspirin), cerebral decongestants, diuretics, and symptomatic treatment. After a week’s time, platelet count started to increase and on 15th day of admission and surgery, increased to 1,195 × 10⁹/L (Figure 1) when it was decided to therapeutic platelet reduction through thrombocytapheresis. Two therapeutic platelet reduction procedures were done using Amicus blood cell separator (Fresenius-Kabi), four days apart, using dedicated closed system disposable sets, acid citrate dextrose-A (ACD-A) as an anticoagulant and physiologic saline as replacement fluid as per manufacturer’s instructions. According to ASFA recommendations, 1.5–2 total blood volume (TBV) were processed using ACD-A in a 1:6–12 whole blood:anticoagulant ratio without any adverse effects (Table 1) [2]. At the end of two procedures, platelet count was reduced to 441 × 10⁹/L with aggregate reduction of 63% between pre-and post-apheresis platelet count (48% and 46.7% respectively in two procedures). Procedures finished in 97 minutes and 84 minutes, respectively.

Gradually, the patient was weaned off from the ventilator, extubated, and discharged on 22nd day of admission in a satisfactory stable condition. The patient was followed up for 12 months by hospital visits and telephone follow-up with no rebound of symptoms or increased platelet count.

Thrombocytosis, defined as increased circulating platelet count >450 × 10⁹/L, is seen reactive more commonly to bleeding, hemolysis, infection, inflammation, asplenia, or cancer [3],[4]. Normally, increased platelet counts being functionally normal, do not predispose to thrombosis or bleeding while in myeloproliferative neoplasms (MPN), which include essential thrombocythemia (ET), polycythemia vera, etc., platelets are functionally abnormal and thrombocytosis is associated with thrombo-hemorrhagic events [2].

In low-risk patients, thromboprophylaxis is done with low-dose aspirin while in high-risk patients, hydroxyurea and interferon-α are given as platelet-normalizing therapy. Since this patient was unresponsive to other first-line therapies (anti-platelet) and platelet count was increasing to extreme thrombocytosis levels, urgent cell reduction was considered to avoid thrombotic/hemorrhagic complications.

In a case-based review on the role of thrombocytapheresis in the management of hyperthrombocytosis, Boddu et al. have recommended that plateletapheresis should be considered with relative urgency when platelet counts are above 1,500 × 10⁹/L with increased risk of major hemorrhage and when cytoreductive agents are contraindicated or less desirable [3], whereas ASFA has recommended thrombocytapheresis in essential thrombocythemia with Grade recommendation of 2C signifying that thrombocytapheresis is accepted as second-line therapy, either as a stand-alone treatment or in conjunction with other modes of treatment, under category II for indication of symptomatic relief [2]. In this case of cerebral venous thrombosis and cerebral infarct, an acute thrombo-hemorrhagic event, the primary goal was normalization of platelet count and maintenance of a normal platelet count to help improve the patient. Few cases are reported in the literature where thrombocytapheresis has been used in different indications like myelofibrosis, post-splenectomy, essential thrombocytosis, chronic myeloid leukemia (CML) [3],[4],[5],[6],[7]. Thrombocytapheresis has been utilized to prevent or treat acute thromboembolism or hemorrhage in selected patients [2]. Various case reports have shown improvements of symptoms of thrombotic/hemorrhagic complications which are not responding to other first-line therapies [3].

To the best of our knowledge, there are no studies in the literature comparing various cell separators used for platelet reduction. Thrombocytapheresis procedures in this case were done on Amicus cell separator (Fresenius-Kabi) and were able to achieve 63% platelet count reduction in just two procedures while the Haemonetics MCS + cell separator used by other authors, showed 60% and 47% platelet reduction respectively indicating that Amicus cell separator has a better efficiency in platelet reduction leading to better management and quick recovery of the patient [5],[6].

To conclude, therapeutic thrombocytapheresis is found to be a useful measure of platelet reduction in severe thrombocytosis to relieve the patient of debilitating complications in a case of cerebral venous thrombosis. Elective thrombocytapheresis should be considered for cytoreduction in patients at increased risk of major hemorrhage where rapid platelet count reduction is urgently required to avoid further deterioration in patient’s condition. Thrombocytapheresis is a bridging therapy to maintain cytoreduction with anti-platelet drugs. In this case also, no rebound thrombocytosis was seen with good recovery during 12 month follow-up.