Intended for healthcare professionals

Minerva Minerva

Minerva

BMJ 2000; 321 doi: https://doi.org/10.1136/bmj.321.7253.124 (Published 08 July 2000) Cite this as: BMJ 2000;321:124

Acute appendicitis is the commonest extrauterine indication for laparotomy in pregnancy, and it can occur in any trimester. Diagnosis can be difficult, not least because conventional wisdom has been that the site of the pain migrates upwards with the growing uterus. A case series in the American Journal of Obstetrics and Gynecology (2000;182:1027-9) refutes this belief: right lower quadrant pain was the commonest presenting symptom in all trimesters.

Class differences in health status are well recognised and, although many explanatory variables (such as differing rates of smoking) are well understood, they by no means explain all observed differences. Lack of job control is a principal suspect, and a recent study (Journal of Epidemiology and Community Health 2000;54:484-93) reports a natural experiment that occurred when cutbacks changed the nature of Finnish local authority workers' jobs. The results show that reducing job control increases time lost to sickness by a factor of around 1.3.

Anticonvulsants of all types are known to influence visual function, presumably through their direct effects on GABAergic neurons of retinal cells. However, a study that compared the effects of carbamazepine and vigabatrin found that carbamazepine had no effect on contrast sensitivity but vigabatrin did (British Journal of Ophthalmology 2000;84:622-5). Contrast sensitivity is measured with the Pelli-Robson letter chart, by the way, in which successively greyer letters of equal size fade mysteriously into a grey background.

Although there has been considerable discussion in the media directed at underperforming doctors, actually calculating underperformance can be quite a tricky business. Is a run of poor results a statistical blip or a deeper problem? A paper in Heart (2000;84:79-82) attempts to provide a predictor for managers: it uses a mathematical model to compare a surgeon's performance with the average and presents the results as a graphical comparison with the expected performance of 90% of average surgeons.

More and more projects are using standard software tools to forward clinical images over the internet for interpretation by experts at a remote site. Compressing images saves bandwidth, although the more efficient methods trade some information loss for speed. A study comparing the accuracy of interpretation of digital angiograms after such compression (Journal of the American College of Cardiology 2000;35:1370-9) found that the losses start to be clinically important at a “jpeg” compression ratio of around 10:1. The authors recommend caution in interpreting images compressed at greater than 6:1.

Acupuncture is an increasingly popular treatment for chronic pain, but its effectiveness remains questionable. A recent systematic review of randomised trials (Pain 2000;86:217-25) found that six or more acupuncture treatments are associated with a positive outcome at least as good as placebo. Most studies were dogged with methodological problems, not least of which is that the sham acupuncture used as a placebo in the best studies may not in fact be physiologically inert. More trials are needed.

The duration of oral anticoagulation after venous thromboembolism remains contentious, although recent practice has been guided by considering whether the risk factors for the episode were short lived or permanent. A meta-analysis of results from 936 patients in seven trials shows that the balance favours longer anticoagulation (3-6 months), although it had inadequate power to exclude the possibility that the risk of haemorrhagic complications might be higher. For that, the authors calculate, a study with 16 200 patients in each arm would be needed.

The team that brought you Dolly, the sheep cloned from a somatic cell, has succeeded in breeding lambs from a fibroblast with a transgene containing human α1 antitrypsin (Nature 2000;405:1066-9). Milk from the lambs had high levels of α1 antitrypsin, which will presumably be useful in α1 antitrypsin deficiency in future. Nowhere in the paper are costs mentioned, but these will presumably be even greater than those of producing that long established ovine delicacy, Roquefort cheese.

The existing live measles vaccine is not perfect. Although safe, it cannot be given to infants younger than 9 months and must be refrigerated, which makes it less useful in the developing world. Killed measles vaccine has more severe problems: an imbalance in the antibody response it induced led to atypical measles. It looks as though a DNA vaccine will be effective at bypassing lingering maternal antibody, and be heat stable to boot, although so far it has been tested only in macaques (Nature Medicine 2000;6:776-81).

Gulf war veterans have poorer reported health than colleagues who were not deployed in the conflict, and they also seem to have a different pattern of mortality. A case-control study reported in the Lancet (2000;356:17-21) found a somewhat higher rate of death due to external causes (principally accidents, but not suicide) than in a matched cohort, but a lower risk of death from disease. This is a similar pattern to that already observed in US veterans and those from other conflicts.

Figure1

This 61 year old smoker presented with breathlessness and haemoptysis. His chest radiograph was striking, the cardiac silhouette being invisible in the standard postero-anterior view. The features were, in fact, those of left upper lobe collapse with a veil-like shadow obscuring the left hemithorax. He had a squamous carcinoma completely occluding the left upper lobe orifice. He had already had radical radiotherapy for a right sided squamous carcinoma two years before, so was treated with endobronchial radiotherapy for this second tumour. His left upper lobe reopened, and his quality of life improved. He died 18 months later.

M K Sridhar, consultant thoracic physician, Staffordshire General Hospital, Stafford ST16 3SA

Gastrointestinal infection with enterohaemorrhagic Escherichia coli O157:H7 is the chief cause of the haemolytic uraemic syndrome in children, and a study in the New England Journal of Medicine (2000;342:1930-6) shows that the syndrome is more common if children receive treatment with antibiotics at any stage in their illness. The reason for this is not certain, although it may be because the drugs induce the gene for the characteristic Shiga toxin of the disease. More reason, if any were needed, to avoid indiscriminate prescribing of antibiotics for any intestinal infection.

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