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Wong C.W.,Caritas Medical Center
Hong Kong Medical Journal

Vitamin B12 deficiency is common among the elderly. Elderly people are particularly at risk of vitamin B12 deficiency because of the high prevalence of atrophic gastritis–associated food-cobalamin (vitamin B12) malabsorption, and the increasing prevalence of pernicious anaemia with advancing age. The deficiency most often goes unrecognised because the clinical manifestations are highly variable, often subtle and non-specific, but if left undiagnosed the consequences can be serious. Diagnosis of vitamin B12 deficiency, however, is not straightforward as laboratory tests have certain limitations. Setting a cut-off level to define serum vitamin B12 deficiency is difficult; though homocysteine and methylmalonic acid are more sensitive for vitamin B12deficiency, it may give false result in some conditions and the reference intervals are not standardised. At present, there is no consensus or guideline for diagnosis of this deficiency. It is most often based on the clinical symptoms together with laboratory assessment (low serum vitamin B12 level and elevated serum homocysteine or methylmalonic acid level) and the response to treatment to make definitive diagnosis. Treatment and replacement with oral vitamin B12 can be as effective as parenteral administration even in patients with pernicious anaemia. The suggested oral vitamin B12 dose is 1 mg daily for a month, and then maintenance dose of 125 to 250 μg for patients with dietary insufficiency and 1 mg daily for those with pernicious anaemia. Vitamin B12 replacement is safe and without side-effects, but prompt treatment is required to reverse the damage before it becomes extensive or irreversible. At present, there is no recommendation for mass screening for vitamin B12 in the elderly. Nevertheless, the higher prevalence with age, increasing risk of vitamin B12 deficiency in the elderly, symptoms being difficult to recognise, and availability of safe treatment options make screening a favourable option. However, the unavailability of reliable diagnostic tool or gold standard test makes screening difficult to carry out. © 2015, Hong Kong Academy of Medicine Press. All rights reserved. Source

Wong C.W.,Caritas Medical Center
Asian Journal of Gerontology and Geriatrics

Both cholinergic deficit and glutamatergic dysfunction contribute to the pathophysiology of Alzheimer’s disease (AD) and are the rationale for the use of cholinesterase inhibitor (ChEI) and memantine for AD. Donepezil, rivastigmine, and galantamine are the 3 common ChEIs available in the market. Although they have slightly different modes of action, their primary action is to prevent the breakdown of acetylcholine and their clinical efficacies are similar. ChEIs are widely used for mild-to- moderate AD and other types of dementia; however, their clinical efficacy is modest and only a subset of AD patients shows significant clinical benefits. Memantine is an N-methyl-D-aspartate (NMDA) receptor blocker approved for moderate-to-severe AD. Although its clinical efficacy is also modest, it has additional behavioural benefits. The combination of ChEI and memantine is possibly not superior to ChEI monotherapy. The evidence supporting ChEI and memantine use in other types of dementia is limited. © 2015, Hong Kong Academy of Medicine Press. All rights reserved. Source

Wong M.O.M.,Queen Mary Hospital | Lee J.W.Y.,Caritas Medical Center | Choy B.N.K.,University of Hong Kong | Chan J.C.H.,Queen Mary Hospital | Lai J.S.M.,University of Hong Kong
Survey of Ophthalmology

Selective laser trabeculoplasty (SLT) is a relatively new type of laser used in treating open-angle glaucoma (OAG) and is reported to be equally efficacious to a first-line medication and argon laser trabeculoplasty (ALT). We summarize available evidence for considering SLT as an alternative treatment in OAG through systematic review and meta-analysis. Among OAG patients who range from newly diagnosed to those on maximally tolerated medical therapy, SLT results in a 6.9-35.9% intraocular pressure (IOP) reduction. Complications are rare and include an IOP spike requiring surgery, persistent macular edema, and corneal haze and thinning. Meta-analysis of randomized, controlled trials shows that SLT is non-inferior to ALT and medication in IOP reduction and also in achieving treatment success. Number of medications reduction is similar between SLT and ALT. More robust evidence is needed to determine its efficacy as a repeated procedure. © 2015 Elsevier Inc. Source

Wong C.W.,Caritas Medical Center
Hong Kong Medical Journal

Optimising glycaemic control to prevent diabetesassociated complications has received much attention. The associated risk of iatrogenic hypoglycaemia, however, is inevitable and can have a significant impact on health. The prevalence of iatrogenic hypoglycaemia tends to increase with advancing age. Elderly people are intrinsically prone to hypoglycaemia. Ageing attenuates the glucose counter-regulatory and symptomatic response to hypoglycaemia, particularly in the presence of a longer duration of diabetes. Multiple co-morbidities and polypharmacy correlated with advancing age also increase the hypoglycaemic risk. In addition to the acute adverse effects of hypoglycaemia, such as fall with injury, cardiovascular events and mortality, a hypoglycaemic episode can have longterm consequences. Repeated episodes may have a significant psychological impact and are also a risk factor for dementia. Because of the heterogeneous health status of the elderly, not all will benefit from optimal glycaemic control. Setting an individual glycaemic target and formulating a management plan that takes account of the patient’s circumstances combined with balancing the benefit and risk of diabetes intervention to avoid hypoglycaemia is a more practical approach to the management of elderly diabetic patients. © 2015, Hong Kong Academy of Medicine Press. All Rights Reserved. Source

Cholinesterase inhibitors and memantine are the only classes of drugs approved for the treatment of dementia due to Alzheimer’s disease. This article provides evidence-based recommendations to address the issues regarding the use of cholinesterase inhibitors and memantine in clinical practice. It includes their efficacy, timing, assessment, use in institutionalized patients, combined use, and use in other dementia types. However, most of the studies are of short duration (<1 year) and are mainly focused on cognitive and global improvement, whereas the practical issue of their use in daily practice such as optimal duration of treatment, long-term efficacy and delaying institutionalization are limited. © 2016, Springer International Publishing Switzerland. Source

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