White matter tracts characteristics in habitual decision-making circuit underlie ritual behaviors in anorexia nervosa

Anorexia nervosa (AN) is a difficult to treat, pernicious psychiatric disorder that has been linked to decision-making abnormalities. We examined the structural characteristics of habitual and goal-directed decision-making circuits and their connecting white matter tracts in 32 AN and 43 healthy controls across two independent data sets of adults and adolescents as an explanatory sub-study. Total bilateral premotor/supplementary motor area-putamen tracts in the habit circuit had a significantly higher volume in adults with AN, relative to controls. Positive correlations were found between both the number of tracts and white matter volume (WMV) in the habit circuit, and the severity of ritualistic/compulsive behaviors in adults and adolescents with AN. Moreover, we found a significant influence of the habit circuit WMV on AN ritualistic/compulsive symptom severity, depending on the preoccupations symptom severity levels. These findings suggest that AN is associated with white matter plasticity alterations in the habit circuit. The association between characteristics of habit circuit white matter tracts and AN behavioral symptoms provides support for a circuit based neurobiological model of AN, and identifies the habit circuit as a focus for further investigation to aid in development of novel and more effective treatments based on brain-behavior relationships

Characterizing the delays in adequate thromboprophylaxis after TBI

Background We sought to compare enoxaparin dosing for venous thromboembolism (VTE) prophylaxis in trauma patients with and without traumatic brain injury (TBI) to better understand the time and dose required to reach target anti-Xa levels. Our hypothesis was that patients with TBI have significant delays in the initiation of adequate pharmacological prophylaxis and require a higher enoxaparin dose than currently recommended.Methods The medical records of trauma patients who received enoxaparin dosing based on anti-Xa trough levels between August 2014 and October 2016 were reviewed. Patients were included if their anti-Xa trough level reached the target range (0.1 IU/mL to 0.2 IU/mL).Results A total of 163 patients had anti-Xa levels within the target range of which 41 (25.2%) had TBI. Patients with TBI had longer delays before initiating enoxaparin (7.5 days vs. 1.5 days after admission, p<0.01) and were more likely to receive unfractionated heparin prior to enoxaparin (46.3% vs. 11.5%, p<0.01). Anti-Xa levels reached the target range later in patients with TBI (11 days vs. 5 days after admission, p<0.01). Enoxaparin 40 mg two times per day was the median dose required to reach the target anti-Xa levels for both cohorts. VTE rates were higher among patients with TBI (22.0% vs. 9.0%, p=0.03). Four patients (9.8%) had progression of their intracranial hemorrhage prior to receiving enoxaparin, although none progressed during enoxaparin administration.Conclusion Among patients with TBI who reached target anti-Xa levels, 11 days after admission were required to reach a median enoxaparin dose of 40 mg two times per day. Unfractionated heparin was used as pharmacological prophylaxis in about half of these patients. The delay in reaching the target anti-Xa levels and the use of unfractionated heparin likely contribute to the higher VTE rate in patients with TBI.Level of evidence Level III, therapeutic