Risk of cerebrovascular adverse events and death in elderly patients with dementia when treated with antipsychotic medications: a literature review of evidence

Behavioral and Psychological Symptoms of Dementia (BPSD) are increasingly recognized as a major risk factor for caregiver burden, institutionalization, greater impairment in activities of daily living (ADLs), more rapid cognitive decline, and a poorer quality of life. BPSD contribute significantly to the direct and indirect costs of caring for patients with dementia even after adjusting for the severity of cognitive impairment and other co-morbidities. Research on these symptoms has indicated a complex interplay between the biological, psychological and social factors involved in the disease process. Although some psychotropic medications have shown modest efficacy in the treatment of these behaviors, their use has generated controversy due to increasing recognition of the side effects of these medications especially the antipsychotic medications. In this review, we examine the risk of cerebrovascular adverse events (CVAEs) and death with antipsychotic medications when used to treat elderly patients with dementia.     

The Imperial Stress Assessment Tool (ISAT): A Feasible, Reliable and Valid Approach to Measuring Stress in the Operating Room

Background  

Stress can impair surgical performance and may compromise patient safety. This prospective, cross-sectional study describes the feasibility, reliability, and validity of the Imperial Stress Assessment Tool (ISAT) as an approach to measuring stress during surgery.     

Rupture of the ilio-psoas tendon after a total hip arthroplasty: an unusual cause of radio-lucency of the lesser trochanter simulating a malignancy

Avulsion fracture or progressive radiolucency of lesser trochanter is considered a pathognomic finding in patients with malignancies. Although surgical release of the iliopsoas tendon may be required during a total hip arthroplasty (THA), there is no literature on spontaneous rupture of the ilio-psoas tendon after a THA causing significant functional impairment. We report here such a case, which developed progressive radiolucency of the lesser trochanter over six years after a THA, simulating a malignancy. The diagnosis was confirmed by MRI. Because of the chronic nature of the lesion, gross retraction of the tendon into the pelvis, and low demand of our patient, he was treated by physiotherapy and gait training. Injury to the ilio-psoas tendon can occur in various steps of the THA and extreme care should be taken to avoid this injury. Prevention during surgery is better, although there are no reports of repair in the THA setting. This condition should be considered in patients who present with progressive radioluceny of the lesser trochanter, especially in the setting of a hip/pelvic surgery. Awareness and earlier recognition of the signs and symptoms of this condition will aid in diagnosis and will direct appropriate management.     

The effect of bone strontium on BMD is different for different manufacturers' DXA Systems

Osteoporotic patients treated with strontium ranelate show relatively large increases in bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) due to the replacement of some of the calcium atoms in bone by strontium. A study published by Pors Nielsen and colleagues reported that replacement of 1% of calcium atoms by strontium causes a 10% increase in BMD. We refer to the ratio of the percentage increase in BMD to the molar percentage of strontium in bone as the strontium ratio. Theoretically it is expected that the strontium ratio should vary between different manufacturers' DXA equipment depending on the effective photon energy of the device, an effect that arises because of the proximity of the X-ray energies produced by lower energy devices to the strontium K-edge at 16 keV. In this study we report theoretical estimates of the strontium ratio for two axial DXA systems and two peripheral DXA devices based on their broad spectrum X-ray emission. The theoretical figures were verified in an experimental study in which the strontium ratio for each device was measured using phantoms containing mixtures of hydroxyapatite and strontium hydrogen-phosphate. The theoretical values of the strontium ratio were 11.0 for the Hologic Discovery, 9.9 for the GE-Lunar Prodigy, 9.1 for the Demetech Calscan, and 8.5 for the Osteometer Dexacare G4. Experimental results were 11.2 for the Discovery, 9.9 for the Prodigy, 8.6 for the Calscan and 6.3 for the Dexacare G4. The results confirm both theoretically and experimentally that the effect of bone strontium on BMD measurements is different for different DXA systems. In the future it might be possible to exploit this effect to make a non-invasive estimate of average bone strontium content in groups of patients receiving strontium medication for osteoporosis.     

Percutaneous coronary intervention for acute myocardial infarction in a patient with dextrocardia

Situs inversus with dextrocardia is a rare congenital anomaly. There are limited published case reports of successful percutaneous coronary intervention (PCI) in these patients who have atherosclerotic coronary artery disease, especially when presenting with acute myocardial infarction. PCI is technically difficult because of mirror image dextrocardia. We hereby describe a 48-yr-old female, who had acute inferior wall myocardial infarction and underwent successful emergency primary coronary angioplasty and stenting of a proximally occluded right coronary artery. Technical details about PCI are discussed.     

Update on Obstructive Sleep Apnea and Its Associated Metabolic Abnormalities: Insulin Resistance,Metabolic Syndrome,and Type 2 Diabetes Mellitus

Obstructive sleep apnea is characterized by repeated episodes of upper airway collapse during sleep, leading to apneic and hypopneic episodes, oxygen desaturation, and sleep fragmentation. This condition is closely associated with features of “metabolic syndrome” as well as overt diabetes. Although the association of metabolic abnormalities clearly portend increased cardiovascular risk, it remains unclear to what extent obesity confounds these associations. Attempts to demonstrate a causal relationship between obstructive sleep apnea and insulin resistance have yielded conflicting results. Although several recent studies have demonstrated a relationship between obstructive sleep apnea and diabetes mellitus independent of obesity, there are currently limited data demonstrating a strong causative link. The currently proposed pathophysiology involves intermittent hypoxia, sleep fragmentation, sympathetic activation, oxidative stress, an increase in proinflammatory adipocytokines, and hyperleptinemia and leptin resistance. Although continuous positive airway pressure has shown promise in treating obstructive sleep apnea and its associated metabolic derangements, two recent large, randomized controlled trials have redoubled the emphasis on weight loss in treating the triad of metabolic syndrome, diabetes, and obstructive sleep apnea. Weight loss and aggressive lifestyle intervention remain a common treatment modality for all of these conditions and should always be considered first-line treatment for this clinical construct.     

Subthalamic nucleus deep brain stimulation changes speech respiratory and laryngeal control in Parkinson’s disease

Adequate respiratory and laryngeal motor control are essential for speech, but may be impaired in Parkinson’s disease (PD). Bilateral subthalamic nucleus deep brain stimulation (STN DBS) improves limb function in PD, but the effects on respiratory and laryngeal control remain unknown. We tested whether STN DBS would change aerodynamic measures of respiratory and laryngeal control, and whether these changes were correlated with limb function and stimulation parameters. Eighteen PD participants with bilateral STN DBS were tested within a morning session after a minimum of 12 h since their most recent dose of anti-PD medication. Testing occurred when DBS was on, and again 1 h after DBS was turned off, and included aerodynamic measures during syllable production, and standard clinical ratings of limb function. We found that PD participants exhibited changes with DBS, consistent with increased respiratory driving pressure (n = 9) and increased vocal fold closure (n = 9). However, most participants exceeded a typical operating range for these respiratory and laryngeal control variables with DBS. Changes were uncorrelated with limb function, but showed some correlation with stimulation frequency and pulse width, suggesting that speech may benefit more from low-frequency stimulation and shorter pulse width. Therefore, high-frequency STN DBS may be less beneficial for speech-related respiratory and laryngeal control than for limb motor control. It is important to consider these distinctions and their underlying mechanisms when assessing the impact of STN DBS on PD.     

Characterisation and reproducibility of a human ex vivo model of thrombosis

Background

The Badimon chamber is a clinical ex vivo model of thrombosis that mimics flow conditions within the coronary circulation of man. The aims of this study were to characterise thrombus formation in the chamber and evaluate its reproducibility.

Methods

Using blood from 24 healthy human volunteers, thrombus formation was assessed at low and high shear rates with porcine aortic tunica media as the thrombogenic substrate. Thrombus area was measured histomorphometrically. Reproducibility was assessed by paired measurements made both within and between days. Platelet activation was assessed before and at selected points within the extracorporeal circuit using flow cytometry, and fibrin content and distribution within the thrombus were assessed by immunohistochemistry.

Results

Total thrombus area was highly reproducible within and between days in the low shear ([mean thrombus area, mean difference ± SEM] 8,018 μm², 58 ± 204 μm² and 8,177 μm², -154 ± 168 μm² respectively) and high shear chambers (11,802 μm², -52 ± 175 μm² and 11,877 μm², 220 ± 181 μm² respectively). Total thrombus area was greater in the high compared to the low shear chamber (11,970 ± 285 μm²versus 7,892 ± 298 μm²; P < 0.0001). Transit through the extracorporeal circuit did not result in platelet activation which was only detected after blood passed across the perfusion chambers (P = 0.02 for platelet-monocyte aggregate formation and P = 0.05 for P-selectin expression). Thrombus in the low shear chamber contained a greater proportion of fibrin (25.0 ± 6.0% versus 8.3 ± 1.6%, P < 0.001).

Conclusions

The Badimon chamber provides a highly reproducible technique for the assessment of ex vivo platelet-rich thrombus formation in man.