Screening for Platelet Dysfunction and Use of Prophylactic Tranexamic Acid in Patients Undergoing Deep Brain Stimulation: A Retrospective Analysis of Incidence and Outcome of Intracranial Hemorrhage.

INTRODUCTION: The rate of intracranial hemorrhage (ICH) after deep brain stimulation (DBS) is between 1.5 and 6.1%, with prolonged deficits occurring in 0.4-2.5% of the patients. This retrospective study investigates whether the prophylactic administration of tranexamic acid (TA) to patients with abnormal platelet function detected preoperatively by platelet function analyzer (PFA) lowered the risk for an ICH event. METHODS: We performed a systematic review of the medical records of 485 consecutively admitted patients who underwent bilateral DBS surgery in a single-center university hospital setting between 2009 and 2018. The cohort was split into two groups. In one group, preoperative PFA screening was performed (n = 156, patients recruited from 2014 to 2018), and TA was administered if platelet function was abnormal. No preoperative PFA was performed in the second group (n = 359, patients recruited from 2009 to 2013). Both cohorts were analyzed for the occurrence of ICH, defined by (i) detection of ICH in routine postoperative magnetic resonance/computed tomography imaging or (ii) in non-routine imaging for the onset of new neurological symptoms. RESULTS: Fourteen of the 156 screened patients (9%) showed reproducible PFA-100 closure abnormalities (3 with von Willebrand disease, 11 with no identifiable cause of platelet dysfunction). Two of the 156 patients (1.3%) in this cohort revealed an ICH on imaging, 1 of whom (0.6%) exhibited a prolonged neurological deficit as a result of ICH. In the cohort without platelet testing, 11 of the 329 patients (3.3%) demonstrated ICH on imaging, of whom 5 (1.5%) suffered from a prolonged neurological deficit. CONCLUSION: In this retrospective study, the screening and the administration of TA appeared to lower the risk of an ICH by 1.8%. One patient with von Willebrand disease suffered an ICH despite TA treatment. A prospective study is needed to clarify the impact of platelet testing and TA administration on the of incidence ICH.

A 40-Year-Old Man With Albinism and Progressive Dyspnea.

CASE PRESENTATION: A 40-year-old male subject employed as a grocery store manager presented to a pulmonary clinic with a dry cough and progressive dyspnea of 1 year duration. The patient was previously an avid cyclist and first noted his dyspnea when he was unable to bike as far as before. Bilateral interstitial lung infiltrates were recently noted on chest radiography. At the time of presentation, he could no longer cycle due to dyspnea. The patient's medical history was significant for albinism and severe visual impairment. He had no family history of albinism or pulmonary disorders. He had never smoked, drank alcohol only occasionally, and had no significant environmental exposures.

Electron microscopy examination of platelet whole mount preparations to quantitate platelet dense granule numbers: Implications for diagnosing suspected platelet function disorders due to dense granule deficiency.

INTRODUCTION: Dense granule (DG) deficiency (DGD) is a feature of some platelet function disorders (PFD) with a prevalence similar to von Willebrand disease. Most laboratories assess for DGD using whole mount platelet preparations and electron microscopy (EM). We evaluated our experiences with this test and associations between DGD and bleeding. METHODS: Dense granule EM records for 2006-2017 were examined for patients and simultaneously tested controls, and for an overlapping PFD study cohort to evaluate findings and their relationship to bleeding. RESULTS: More patient than control samples had reduced DG counts (6.5% vs 0.3%, P < .01). DG counts showed no relationship to age or mean platelet volume and had acceptable within-subject variability that was higher for DGD than control participants (28% vs 12%). Repeat tests confirmed DGD in all persons with initial DG counts <4.0/platelet, but not in those with less severe reductions (4.0-4.8 DG/platelet) or normal DG counts (≥4.9 DG/platelet). Aggregometry and adenosine triphosphate release tests, respectively, had only ~52% and 70% sensitivity for DGD. Confirmed DGD by EM was associated with higher bleeding scores and a bleeding disorder. CONCLUSION: Whole mount EM is useful for the evaluation of suspected PFD due to DGD and detects abnormalities associated with bleeding.

Platelet Dysfunction and Intracerebral Hemorrhage in a Patient Treated with Empiric Piperacillin-Tazobactam in the Neurocritical Care Unit.

BACKGROUND: Piperacillin-tazobactam is common empiric antibiotic therapy. Hematologic laboratory test abnormalities were documented but rare in premarketing studies, and whether these alterations are of clinical significance has been studied little. Very few cases of piperacillin-induced bleeding, thrombocytopenia, or both have been reported; aberrations in platelet function have not been implicated. CASE DESCRIPTION: A 55-year old Vietnamese man with hypertension presented for treatment of an Intracranial hemorrhage. Platelet function assays (PFAs) at the time of external ventricular drain and quad-lumen bolt placement were normal, and imaging showed no hemorrhage after placement. The patient was later started on empiric piperacillin-tazobactam due to high suspicion for aspiration pneumonia. After removal of the quad-lumen bolt and external ventricular drain on separate days, both follow-up computed tomography scans showed new hematomas in the devices' tracts, with significant intraventricular hemorrhage. Repeat PFAs were abnormally prolonged, representing a distinct change from baseline. A trend toward normalization of PFAs was observed 6 hours after discontinuation of piperacillin-tazobactam with progression toward baseline thereafter. CONCLUSIONS: This is unique in that the significant bleeding that occurred was attributable to platelet dysfunction rather than thrombocytopenia. This is the first reported case of intracranial (periprocedural) hemorrhage potentially related to piperacillin-tazobactam; further research into this drug's impact upon qualitative platelet function is needed.

Slippery platelet syndromes in subdural hematoma.

BACKGROUND: This study investigates platelet dysfunction in patients with subdural hematomas (SDH) using platelet function analysis (PFA). METHODS: PFA using the PFA-100 (Dade International Inc., Miami, FL) was performed at admission using the collagen-epinephrine and collagen-ADP assays in 58 SDH patients. Clinical and radiologic information was collected. RESULTS: Normal PFA results were present in 36 patients (62%; PFA collagen:epinephrine assay (s) 118 ave; PFA collagen:adenosine diphosphate assay (s) ave 75) and abnormal platelet function in 22 patients (38%; PFA collagen:epinephrine assay (s) 231 average; PFA collagen:adenosine diphosphate assay (s) 124 average). Compared to patients with normal PFA results, patients with abnormal PFA results were more likely to have hypertension (22 vs. 55%; P = 0.01), take clopidogrel (3 vs. 32%; P = 0.001), and use anti-platelet medications and non-steroidal anti-inflammatory agents (22 vs. 59%; P = 0.004). Measurements of baseline CT for midline shift, maximum thickness, presence of blood/fluid levels in the hematoma, and presence of additional sites of intracranial bleeding did not reveal significant differences based on PFA testing. Platelet dysfunction improved after platelet transfusions (PFA collagen:epinephrine assay: baseline 270 s, CI 61 s; after transfusion 124 s, CI 50 s, P < 0.001). CONCLUSION: Platelet dysfunction was found in 38% of SDH patients. This finding adds to our understanding of the pathophysiology of SDH. Since platelet transfusions are indicated for platelet dysfunction accompanied by major bleeding or need for surgery, these results impact peri-operative management.

The Hermansky-Pudlak syndrome: radiographic features.

We present the radiologic features of four patients proven to have Hermansky-Pudlak syndrome. All four patients had evidence of pulmonary involvement characterized by a progressive, diffuse, bilateral interstitial fibrosis. Extensive bullous changes were seen in one patient. Two patients with evidence of diffuse colitis exhibited an asymmetrical pattern of focal, superficial, and deep ulcerations similar to that of Crohn's disease. The association of these radiographic abnormalities with albinism, ocular abnormalities, bleeding diathesis, and Puerto Rican ancestry establishes the diagnosis.

Spleen function and platelet kinetics.

In patients suffering from various platelet abnormalities, quantitative scanning after injection of indium-111 (111In) labelled platelets showed three different patterns of platelet destruction and distribution. In patients with a normal platelet life span but with evidence of increased splenic pooling, the spleen tended to be the main site of destruction. In patients with a moderately reduced platelet life span, the distribution of destruction in the system and variable destruction in the marrow. However, because of its rapidity this destruction was difficult to quantify, and it was difficult in these cases to distinguish reliably between spleen pool, sequestration, and destruction. Destruction of platelets on the liver appeared to be unimportant in all three groups. 111In, because of its physical characteristics, is preferable to chromium-51 as a platelet label in the assessment of abnormal platelet kinetics.