Piscator's disposition is sorely affected by climatic considerations. A certain greyness and lowness of mood has descended despite the thermometer registering double figures – just! The Everest Expedition jacket referred to in July's column will however get scant use. Rather the current posting has necessitated the purchase of an oilcloth jacket, sou'wester and gumboots – not forgetting personal protection in the form of a Kevlar jacket. … … … … … .

The effects of climatic considerations are explored further in this column's perorations. We all know that during cold weather potassium leaches out of cells – in my last posting close to 57°N, primary care practitioners were provided with their own centrifuges. This was to minimize the occurrence of pseudohyperkalaemia in that remote and rural environment particularly during the winter months. But does the converse apply? In another city on the western seaboard (with a similar illustrious maritime history to the one in which I now find myself) the seasonality of pseudohypokalaemia in samples received from primary care was explored in some detail (Clin Biochem 2009;42:813–8). Given the inverse relationship between daily temperature and mean potassium concentrations, higher summer temperatures should stimulate cellular glucose metabolism and potassium uptake. Over a 12-month period, 1110 specimens yielding a potassium result of less than 2.8 mmol/L were identified by interrogating the laboratory database. After eliminating those specimens from acute medical units and renal units, there were approximately 400 from primary care. The mean monthly temperatures were provided by the local meteorological office. An increased incidence of hypokalaemia in the summer months in samples received from primary care was confirmed but with no real demonstrable temperature-related association in samples obtained from hospital inpatients. Furthermore, 33 patients attending primary care were recalled to hospital for repeat blood tests – 90% of whom demonstrated an increase in plasma potassium in the samples that were separated and analysed promptly. Further experimental data confirmed that the hypokalaemia is an in vitro pseudophenomenon, which is mediated by sodium–potassium exchanging ATP-ase. Addition of the selective inhibitor ouabain completely attenuated the potassium decrease at 37°C. The authors of the paper noted that reference range data provided by labs in the rather idyllic settings of Barbados have a lower limit for potassium of 2.8 mmol/L compared with those in northern Europe (how do you get the funding to repeat this field study?).

Another climatic phenomena is discussed in a case report in which diabetic ketoacidosis was precipitated by exposure of an insulin pump to heat and sunlight (BMJ 2009;338:1077–78). Needless to say the incident happened in Australia!

An 11-year-old girl with diabetes presented to the emergency department with vomiting and abdominal pain. Her blood glucose was 20.6 mmol/L and she had a pH of 7.14. She had been diagnosed with diabetes four years previously and had been managed by use of an insulin pump for the preceding year. Her diabetic ketoacidosis was managed in hospital by intravenous insulin and fluids, but on reconnecting her own insulin pump there was a complete failure to maintain euglycaemia. Careful questioning elicited the information that prior to a swimming pool party, the pump had been disconnected and left in the lovely warm Eastern Seaboard sunshine. Scrutiny of the manufacturer's advice on storage of insulin shows some tolerance for exposure to high temperature. The authors are of the opinion that it was heat exposure rather than sunshine that caused the degradation of insulin.

For those of us for whom the long winter evenings may see a return to the couch with the TV remote readily to hand, a recent article explores the impact of media violence on aggressive behaviour – perhaps too many episodes of Taggart or The Wire being bad for one? (J Pediatrics 2009;154:759–63). For the purposes of the study, media includes not only the revered box, but also video, computer games, movies (obviously an American study) and music. There is recent concern that the potential health risks of media violence are on a par with cigarette smoking. This study effectively refutes this through a meta-analytical review. The authors are concerned that methodological weaknesses may account for unreliable conclusions and data. In a thought provoking summary, the ideological impetus for proving that media violence damages society is explored. The authors discuss the likelihood of a ‘perfect storm’ of opportunism, which allies the social agendas of both the far-right and far-left. Scientific dogmatism may also prevent a more critical examination of the data. This study cannot find the evidence from the meta-analysis to confirm that media violence is a significant public health concern. ‘If it is the goal of society to reduce violence, scientific, political, and economic efforts would likely bear more fruit in other realms’ – thought provoking stuff.