CT and MR perfusion imaging viability thresholds in stroke are derived from small numbers of patients, variable perfusion analysis methods and definitions of tissue states. Greater consistency of methods would help determine reliable perfusion viability values for wider clinical use of perfusion imaging.

Introduction Key populations at elevated risk to contract or transmit HIV may also be at higher risk of COVID‐19 complications and adverse outcomes associated with public health prevention measures. However, the conditions faced by specific populations vary according to social, structural and environmental factors, including stigma and discrimination, criminalization, social and economic safety nets and the local epidemiology of HIV and COVID‐19, which determine risk of exposure and vulnerability to adverse health outcomes, as well as the ability to comply with measures such as physical distancing. This commentary identifies common vulnerabilities and cross‐cutting themes in terms of the impacts of COVID‐19 on key populations before addressing issues and concerns specific to particular populations. Discussion Cross‐cutting themes include direct impacts such as disrupted access to essential medicines, commodities and services such as anti‐retroviral treatment, HIV pre‐exposure prophylaxis, opioid agonist treatment, viral load monitoring, HIV and sexually transmitted infections testing, condoms and syringes. Indirect impacts include significant collateral damage arising from prevention measures which restrict human rights, increase or impose criminal penalties, and expand police powers to target vulnerable and criminalized populations. Significant heterogeneity in the COVID‐19 pandemic, the underlying HIV epidemic and the ability of key populations to protect themselves means that people who inject drugs and sex workers face particular challenges, including indirect impacts as a result of police targeting, loss of income and sometimes both. Geographical variations mean that transgender people and men who have sex with men in regions like Africa and the middle east remain criminalized, as well as stigmatized and discriminated against, increasing their vulnerability to adverse outcomes in relation to COVID‐19. Conclusions Disruptions to both licit and illicit supply chains, loss of income and livelihoods and changes in behaviour as a result of lockdowns and physical distancing have the potential to exacerbate the impacts of the COVID‐19 pandemic on key populations. While these impacts will vary significantly, human‐rights approaches to COVID‐19 emergency laws and public health prevention measures that are population‐specific and sensitive, will be key to reducing adverse health outcomes and ensuring that no one is left behind.

Striae gravidarum are a common finding in the abdominal skin of pregnant women. This study of 128 pregnant women examined factors which are associated with their occurrence. It is clear that women with higher body mass indices have more striae and that striae are also more common in younger women. These findings may be explained by the greater degrees of stretch applied to the skin in obese women with larger babies, and by changes in skin collagen and connective tissue that are age-related and affect its tendency to tear.

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using 1H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17 hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P=0.03) but both were equally elevated by 5 days; both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome; in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature; that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes.

BackgroundPyrexia after stroke (temperature ≥37.5°C) is associated with poor prognosis, but information on timing of body temperature changes and relationship to stroke severity and subtypes varies.MethodsWe recruited patients with acute ischemic stroke, measured stroke severity, stroke subtype and recorded four-hourly tympanic (body) temperature readings from admission to 120 hours after stroke. We sought causes of pyrexia and measured functional outcome at 90 days. We systematically summarised all relevant previous studies.ResultsAmongst 44 patients (21 males, mean age 72 years SD 11) with median National Institute of Health Stroke Score (NIHSS) 7 (range 0–28), 14 had total anterior circulation strokes (TACS). On admission all patients, both TACS and non-TACS, were normothermic (median 36.3°C vs 36.5°C, p=0.382 respectively) at median 4 hours (interquartile range, IQR, 2–8) after stroke; admission temperature and NIHSS were not associated (r2=0.0, p=0.353). Peak temperature, occurring at 35.5 (IQR 19.0 to 53.8) hours after stroke, was higher in TACS (37.7°C) than non-TACS (37.1°C, p<0.001) and was associated with admission NIHSS (r2=0.20, p=0.002). Poor outcome (modified Rankin Scale ≥3) at 90 days was associated with higher admission (36.6°C vs. 36.2°C p=0.031) and peak (37.4°C vs. 37.0°C, p=0.016) temperatures. Sixteen (36%) patients became pyrexial, in seven (44%) of whom we found no cause other than the stroke.ConclusionsNormothermia is usual within the first 4 hours of stroke. Peak temperature occurs at 1.5 to 2 days after stroke, and is related to stroke severity/subtype and more closely associated with poor outcome than admission temperature. Temperature-outcome associations after stroke are complex, but normothermia on admission should not preclude randomisation of patients into trials of therapeutic hypothermia.