Asymmetric Boreal Summer Intraseasonal Oscillation Events Over the Western North Pacific and Their Impacts on East Asian Precipitation

The boreal summer intraseasonal oscillation (BSISO) is the most prominent tropical subseasonal signature especially over the western North Pacific (WNP). Due to restrictions of methodology in extracting BSISO with band-pass filtering or EOF decomposition, most of the previous studies ignored the asymmetry of BSISO. This study reexamines the BSISO events over WNP and their impacts on the East Asian precipitation. With a hierarchical cluster analysis, the BSISO events over WNP during the summers of 1985-2010 are classified into two categories, the long-period (30-60 day) and short-period (10-20 day) events. The long-period BSISO events manifest as a northward propagating mode with a significant phase asymmetry characterized by a fast development, but a slow decay of the intraseasonal convection. The fast development tends to cause a rapid reversal of the atmospheric anomalies over WNP from an anomalous anticyclone induced by the preceding slow convection suppression to an anomalous cyclone, leading to a fast northeastward retreat of the preceding enhanced western North Pacific subtropical high. Accordingly, the middle and lower reaches of Yangtze River valley experience a rapid reversal from the increased precipitation to the decreased, while the precipitation in coastal South China keeps decreased. The short-period BSISO events which are symmetric in phase act as a northwestward propagating mode, mainly affecting East Asian precipitation in an oblique belt extending from southwest China to southern Japan and southern Korean Peninsula. Therefore, the two types of the BSISO events especially the asymmetric long-period BSISO events over WNP and their impacts on the East Asian precipitation revealed in this study would provide a new potential for subseasonal-to-seasonal forecast of the East Asian summer monsoon precipitation.

Opioid-Free Naloxone Emergence Under Dexmedetomidine: A Case Report

This report describes a case in which naloxone appeared to expedite emergence from general anesthesia in a patient who underwent an opioid-free anesthetic that included dexmedetomidine. After administration of naloxone, the patient progressed rapidly from general anesthesia to alert and oriented in approximately two minutes. Additionally, the patient demonstrated rapid reversal of miosis. He also reported adequate analgesia in the PACU, requiring no opioids and denied any recall of events that occurred prior to the administration of naloxone. Keywords: Naloxone, Dexmedetomidine, Delayed emergence.

McKenzie Mobilisation on Acute Lumbar Lateral Shift in Patients with Low Back Pain: A Narrative Review

Low back pain is often associated with a lateral shift in the lumbar spine. McKenzie mobilisation produces a rapid reversal of the deformity and reduction in pain. The purpose of this review is to present an overview of the effects of McKenzie exercises in reducing pain and disability in individuals with an acute lumbar shift. A literature review was performed using four databases. All studies comprising the McKenzie method of treatment in the lateral lumbar shift were included. In total 18 articles were retrieved from the databases, of which six articles were finally selected to be included in this review. Six studies reported a reduction in pain, improvement in range of motion and reduction in disability. The present review identified supportive research for McKenzie treatment in individuals with an acute lumbar shift. However, more robust interventional trials are required to conclude the effectiveness of the McKenzie method in the acute lumbar list.

Metformin-associated lactic acidosis: reinforcing learning points

Metformin-associated lactic acidosis (MALA) carries a high mortality rate. It is seen in patients with type 2 diabetes on metformin or patients who attempt suicide with metformin overdose. We present the case of a man in his early 20s with type 2 diabetes, hypertension and hypothyroidism who presented with agitation, abdominal pain and vomiting after ingesting 50–60 g of metformin; he developed severe lactic acidosis (blood pH 6.93, bicarbonate 7.8 mEq/L, lactate 28.0 mEq/L). He was managed with intravenous 8.4% bicarbonate infusion and continuous venovenous haemodiafiltration. He also developed acute renal failure (ARF) requiring intermittent haemodialysis and continuous haemodiafiltration. MALA is uncommon and causes changes in different vital organs and even death. The primary goals of therapy are restoration of acid-base status and removal of metformin. Early renal replacement therapy for ARF can result in rapid reversal of the acidosis and good recovery, even with levels of lactate normally considered to be incompatible with survival.

A review of optic perineuritis

Optic perineuritis (OPN) refers to a spectrum of conditions involving pathologic inflammation of the optic nerve sheath. The classic triad of OPN consists of unilateral optic neuropathy associated with pain and/or disc oedema, but the condition often mimics other optic neuropathies, resulting in delayed diagnosis and suboptimal treatment. We performed a database search of Medline and Ovid in January 2016 for articles published in any language with the keywords ‘optic perineuritis’. Sixty articles were found, published from 1956 to 2015. Two reviewers (Tai ELM and Tevaraj JMP) performed an independent screening of abstracts. Articles of interest were subsequently examined. In this review, we highlight the salient features of OPN, with particular emphasis on the clinical differences between OPN and optic neuritis. Although the majority of cases of OPN are idiopathic, investigations are required to rule out specific infectious and inflammatory causes of secondary OPN. MRI is an invaluable component of the workup, as radiographic demonstration of peri-neural inflammation is diagnostic of OPN. Corticosteroid therapy results in dramatic and rapid reversal of the signs and symptoms, but prolonged therapy with slow tapering of oral corticosteroids may be necessary to reduce the risk of relapses.