Unintentional cetirizine overdose causing anticholinergic syndrome.

The incidence of anticholinergic syndrome due to second generation antihistamines is infrequently reported. Largely due to their decreased affinity for central nervous system (CNS) receptors, second generation antihistamines are rarely associated with anticholinergic symptoms, though toxicity is still possible particularly when taken in excess. We report a case of a six year old boy who presented with agitation, hallucinations, fixed and dilated pupils, tachycardia, and hyperthermia consistent with anticholinergic toxicity several hours after accidental overdose of a second generation antihistamine, cetirizine. Early identification of this rare phenomenon is important not only for appropriate emergency management but also for avoidance of potentially invasive and unnecessary tests which may further increase patient morbidity.

Effects of PaCO2 derangements on clinical outcomes after cerebral injury: A systematic review.

OBJECTIVE: Partial pressure of arterial carbon dioxide (PaCO2) is a major regulator of cerebral blood flow (CBF). Derangements in PaCO2 have been thought to worsen clinical outcomes after many forms of cerebral injury by altering CBF. Our aim was to systematically analyze the biomedical literature to determine the effects of PaCO2 derangements on clinical outcomes after cerebral injury. METHODS: We performed a search of Cochrane Library, PUBMED, CINHAL, conference proceedings, and other sources using a comprehensive strategy. Study inclusion criteria were (1) human subjects; (2) cerebral injury; (3) mechanical ventilation post-injury; (4) measurement of PaCO2; and (5) comparison of a clinical outcome measure (e.g. mortality) between different PaCO2 exposures. We performed a qualitative analysis to collate and summarize effects of PaCO2 derangements according to the recommended methodology from the Cochrane Handbook. RESULTS: Seventeen studies involving different etiologies of cerebral injury (six traumatic brain injury, six post-cardiac arrest syndrome, two cerebral vascular accident, three neonatal ischemic encephalopathy) met all inclusion and no exclusion criteria. Three randomized control trials were identified and only one was considered a high quality study as per the Cochrane criteria for assessing risk of bias. In 13/17 (76%) studies examining hypocapnia, and 7/10 (70%) studies examining hypercapnia, the exposed group (hypercapnia or hypocapnia) was associated with poor clinical outcome. CONCLUSION: The majority of studies in this report found exposure to hypocapnia and hypercapnia after cerebral injury to be associated with poor clinical outcome. However, the optimal PaCO2 range associated with good clinical outcome remains unclear.

Outcomes of secondary hyperparathyroidism in chronic kidney disease and the direct costs of treatment.

BACKGROUND: There has been an emphasis over the last several years to identify and treat chronic kidney disease (CKD) and its complications as they evolve rather than waiting until the patient reaches end-stage renal disease (ESRD), also known as CKD stage 5. The number of patients who will be identified and prescribed therapies for complications such as secondary hyperparathyroidism (SHPT) is greater than initially proposed. OBJECTIVE: To review the pathways, complications, management, and estimated treatment costs of CKD-related SHPT. METHODS: An electronic literature search of MEDLINE (January 1980 through January 2007) was conducted for English-language publications using the base search term secondary hyperparathyroidism. To refine subsequent searches, the authors added Boolean operators to the following secondary and tertiary search terms: parathyroid hormone, chronic kidney disease, renal osteodystrophy, adynamic bone disease, vascular calcification, cardiovascular disease, vitamin D, vitamin D analogs, hypercalcemia, hyperphosphatemia, calcimimetics, costs, prevalence, and economics. RESULTS: The initial MEDLINE search produced 278 relevant articles. After refining the search terms, the authors triaged the results for English-language publications relevant to the discussion of SHPT and its complications in CKD, eliminating 149 publications. The remaining 129 publications were accepted for review. These articles represent a growing body of primarily observational evidence that demonstrates that elevated intact parathyroid hormone (PTH) levels cause deleterious physiological results across a variety of organ systems, including the cardiovascular and skeletal systems. Specific complications associated with SHPT are left ventricular hypertrophy (LVH), renal osteodystrophy (ROD), and extraskeletal calcification. Medical management of the PTH/vitamin D/calcium and phosphorus imbalances in SHPT focus on regulating PTH levels via vitamin D therapy. The class of calcimimetics is a newer treatment modality that has favorable effects on biochemical laboratory values, such as serum calcium and phosphorus levels, but current data do not show differences on hard endpoint patient-oriented outcomes compared with standard generic agents. The direct drug costs in April 2007 U.S. dollars of treating CKD-associated elevations in PTH in predialysis patients range from $8.40 per patient per week ($437 per year) for oral generic calcitriol to $88.90 per patient per week ($4,623 per year) for oral paricalcitol (expressed as 85% of average wholesale price [AWP] for brand drugs or 70% of AWP for generic drugs). The direct drug costs of treating SHPT in hemodialysis patients range from $80.20 per patient per week ($4,170 per year) for generic calcitriol (IV) to $278.46 per patient per week ($14,480 per year) for oral cinacalcet. CONCLUSIONS: SHPT causes skeletal and cardiovascular complications in CKD patients. Calcitriol therapy is effective in managing PTH levels, but efforts to reduce the associated hypercalcemia and hyperphosphatemia have led to the development of newer, yet more expensive, vitamin D analogs. With the lack of evidence to support comparative superior outcomes in end-organ disease among SHPT therapy alternatives, future research is still needed to clearly identify which newer agents are most competitive with the historical gold standard of calcitriol therapy.

Solvent dependent photocyclization and photophysics of some 2-ethynylbiphenyls.

The spectroscopic properties and photochemical behavior of molecules having 2-ethynylbiphenyl or 2-phenyldiphenylacetylene structures are reported. These molecules undergo photocyclization reactions to yield phenanthrene and dihydrophenanthrene products via putative isophenanthrene (cyclic allene) intermediates. Phenanthrene formation from the isophenanthrene intermediates does not occur via a unimolecular sigmatropic hydrogen shift, but rather by protonation or hydrogen abstraction mechanisms involving the solvent. Cyclization efficiencies are much lower than is the case for previously-investigated 2-vinylbiphenyl systems. The 2-phenyldiphenylacetylenes have high fluorescence quantum yields and long singlet lifetimes when compared to diphenylacetylene. The 2-ethynylbiphenyls decay via a combination of fluorescence and intersystem crossing.