Intended for healthcare professionals

Minerva

High frequency hearing . . . and other stories

BMJ 2018; 361 doi: https://doi.org/10.1136/bmj.k1649 (Published 18 April 2018) Cite this as: BMJ 2018;361:k1649

Presbyacusis

Hearing, especially of high frequencies, tends to deteriorate with increasing age—but not as much as it did in previous generations. That’s the finding of a comparison of four cohorts of people born in 1901-02, 1906-07, 1922, and 1944 in Sweden (Age Ageing doi:10.1093/ageing/afy002). Tested at age 70, pure tone thresholds were lower and hearing loss was less prevalent in the more recent cohorts. Hearing in men improved more than hearing in women, which the investigators think points to decreasing occupational noise exposure as part of the explanation.

Atrial septal defects

Along with persistent ductus arteriosus, atrial septal defect is among the more benign congenital heart defects. Even so, the results of a population based study show that it needs to be taken seriously (Eur Heart J doi:10.1093/eurheartj/ehx687). After excluding those with patent foramen ovale, more than 2000 people were born with an atrial septal defect in Denmark between 1959 and 2013. Over a median follow-up of 18 years, their mortality was around 70% higher than that of an age matched and gender matched comparison group from the general population. Long term mortality was reduced in people whose defect had been closed either surgically or by catheter.

Deciding when to treat hypertension

It is axiomatic that people at highest risk have the most to gain from preventative interventions. And a re-analysis of data from a large trial of blood pressure lowering emphasises this point (BMJ Open doi:10.1136/bmjopen-2017-017723). When participants were grouped into thirds by their five year cardiovascular risk at entry to the trial, only those in the highest risk category derived any worthwhile clinical benefit in terms of decreased mortality or reduction in numbers of cardiovascular events. The conclusion is that decisions to treat blood pressure shouldn’t be made according to a numerical threshold but be taken in the context of overall risk.

Antibiotic resistance

Eight per cent of E coli positive cultures from children being investigated for urinary tract infections at an Australian hospital were resistant to multiple antibiotics. Rather disappointingly, a case-control study failed to identify any strong risk factors except for exposure to an antibiotic in the previous month. No statistically significant associations were found with previous hospital admission, being an inpatient at the time of diagnosis, or a history of instrumentation of the urinary tract (Arch Dis Child doi:10.1136/archdischild-2017-312831).

Man’s best friend?

A community survey in England finds that dog bites are commoner than one might guess. Over a quarter of participants had been bitten at some point during their lives and about a third of these bites had been severe enough to require medical attention. Although dog owners were more likely to have been bitten than people who didn’t own a dog, most bites weren’t from people’s own pets but from dogs that they hadn’t encountered before (J Epidemiol Community doi:10.1136/jech-2017-209330).

Seeing double

Intractable diplopia—a condition in which symptoms can be eliminated only by occluding one eye—is uncommon but disabling. A prospective survey in the UK finds that unsuccessful surgery for strabismus is the commonest cause, although it can also occur after cataract removal, vitrectomy, and head trauma (Br J Ophthalmol doi:10.1136/bjophthalmol-2017-310454). In a quarter of cases, no preceding event was identified. Treatment involves rendering the patient mono-ocular, either with an opaque contact lens or with an opaque intraocular lens.

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