Evidence before this study: Acute appendicitis is the most common general surgical emergency in children. Its diagnosis remains challenging and children presenting with acute right iliac fossa (RIF) pain may be admitted for clinical observation or undergo normal appendicectomy (removal of a histologically normal appendix). A search for external validation studies of risk prediction models for acute appendicitis in children was performed on MEDLINE and Web of Science on 12 January 2017 using the search terms ["appendicitis" OR "appendectomy" OR "appendicectomy"] AND ["score" OR "model" OR "nomogram" OR "scoring"]. Studies validating prediction models aimed at differentiating acute appendicitis from all other causes of RIF pain were included. No date restrictions were applied. Validation studies were most commonly performed for the Alvarado, Appendicitis Inflammatory Response Score (AIRS), and Paediatric Appendicitis Score (PAS) models. Most validation studies were based on retrospective, single centre, or small cohorts, and findings regarding model performance were inconsistent. There was no high quality evidence to guide selection of the optimum model and threshold cutoff for identification of low-risk children in the UK and Ireland. Added value of this study: Most children admitted to hospital with RIF pain do not undergo surgery. When children do undergo appendicectomy, removal of a normal appendix (normal appendicectomy) is common, occurring in around 1 in 6 children. The Shera score is able to identify a large low-risk group of children who present with acute RIF pain but do not have acute appendicitis (specificity 44%). This low-risk group has an overall 1 in 30 risk of acute appendicitis and a 1 in 270 risk of perforated appendicitis. The Shera score is unable to achieve a sufficiently high positive predictive value to select a high-risk group who should proceed directly to surgery. Current diagnostic performance of ultrasound is also too poor to select children for surgery. Implications of all the available evidence: Routine pre-operative risk scoring could inform shared decision making by doctors, children, and parents by supporting safe selection of lowrisk patients for ambulatory management, reducing unnecessary admissions and normal appendicectomy. Hospitals should ensure seven-day-a-week availability of ultrasound for medium and high-risk patients. Ultrasound should be performed by operators trained to assess for acute appendicitis in children. For children in whom diagnostic uncertainty remains following ultrasound, magnetic resonance imaging (MRI) or low-dose computed tomography (CT) are second-line investigations.

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Greenstein et al 1 report a signi®cant correlation between the number of coronary vessels occluded on angiography and erectile dysfunction (ED). This is an important ®nding because previous links between ischaemic heart disease (IHD) and ED have been largely restricted to demonstrating that these conditions share common risk factors (for example, smoking, dyslipidaemia, diabetes and hypertension). 2 ± 4 In addition, some of the drugs (for example anti-hypertensives) used to treat IHD can cause ED. If the pathogenesis of IHD and ED is similar, then other predictors of vascular events should be shared by both these conditions. We therefore assessed plasma ®brinogen concentrations in men with ED and in matched controls. Our results reveal higher levels of this coagulation factor in those with ED. 4 We are currently evaluating lipoprotein (a) levels in men with ED. This lipoprotein is another predictor of a variety of vascular events (for example, myocardial infarction and stroke). These studies would support the routine screening of patients with vasculogenic ED for cardiovascular risk factors.Good diabetic and blood pressure control are well recognised therapies, but current evidence also raises the question of early intervention with lipidlowering agents (some of which are known to reduce ®brinogen levels). Support for such an approach comes from several studies, 5,6 which showed a signi®cant reduction in cardiovascular events and a reduction in the progression of coronary atheromatous lesions in patients with hypercholesterolaemia taking lipid-lowering therapy (for example 4S 5 and MAAS 6 ).Finally, medical practitioners who treat patients with ED should be aware of potential underlying IHD and its clinical relevance in terms of`whole patient management.' References

CR BELL, HB SPECHT, BA CooMBs. T he search f or Ixodes dammini and Borre lia burgdoife ri i n Nova Scotia. Can J Infect Dis 1992;3(5): 224·230.1\venty-four Ixodes dammini ticks (23 adu lts and one nymph) have been recovered in Nova Scotia since 1984. There has not been a systematic search for larvae and none has been identified. The recovery of the nymph from a road-killed yellow U1roat bird. Geothypis trichas. in late May 1990 supports U1e contention U1at migrating birds are bringing deer ticks into U1e province every spring. In March and April 1991 . four adult deer ticks were identified. suggesting U1al these ticks had overwintered. These deer Lick specimens indicate U1at il is possible that I dammini is becoming established in Nova Scotia. if il is not already established. There has been no evidence for the existence of Borrelia burgdorjeri in U1e province. The spirochete was not cultured from 650 Dermacentor variabilis ticks. nor were antibodies detected in a small san1ple of feral rodents using an indirect fluorescent antibody lesl. A survey of 137 dog sera san1ples. analyzed by enzyme-linked immunosorbent assay. a lso proved negative . There has been no confirmed indigenous case of Lyme disease in Nova Scotia to dale. Fi e ld site 6Field site 3.. T ICK-BORNE LYME DISEASE WAS RECOGNIZED AND C HARACterized in North America in the early 1970s (1 .2). There have now been thousands of cases reported throughout the contiguous United Stales which have contributed to the presen t awareness of the e tiology and epidemiology of the d isease in the United Stales (3.4). Information on the disease in Canada is nol as complete.The first case of Lyme disease in Canada was diagnosed in 1977 (5), and at a sympos ium on Lyme d isease in Canada conducted at the Un iversity of Guelph in January 1991 (6). it was revealed U1al 65 indigenous cases of th e d isease had been reported to the Laboratory Centre for Disease Control in the previous seven years (personal communication). Fifty-four of U1ese cases were limited to Ontario. with only one case occurring in the Maritimes, in New Bru nswick (7). However. there has been some concern expressed by health professionals about the potential for the disease in Nova Scotia largely because of the proximity to disease foci in the state of Maine (8) dammini ticks into the province each spring (9). Certainly because of the very la rge numbers of Dermacen· tor variabiLis ticks in Nova Scotia (10). introduced at the turn of the century. U1ere is palpable concern an1ong the general public. These factors p rovided the impetus in 1984 for this continuing search for the Lyme disease agent. BorreLia burgdor:feri. and the vector. I dammini. in Nova Scotia. MATERIALS AND METHODS Collection of D variabilis:In the summer of 1988 licks were collected from seven field sites within the area endemic forD var iab ilis in south western Nova Scotia. Adults were collected using a 0 .5 nlllag dragged over vegetation along roadsides and clearings near woods. The boundaries of the area sampled were establish...