that the patient's own lens capsule or cortex is as important a ... has occurred after a penetrating eye injury with ... vitrectomy and intraocular antibiotics and may ... risk of inner ear damage is not present if aluminium ... irradiated simply because of defensive medicine, ... side effects, and was preferred by most volunteers" may ...
tion of a polymethylmethacrylate lens, and it seems that the patient's own lens capsule or cortex is as important a reservoir of infection as the prosthetic lens. This type of endophthalmitis has not been reported after intracapsular surgery, where the patient's own lens is removed completely, but has occurred after a penetrating eye injury with damage to the patient's lens.3 Presumably the lens capsule offers some protection to the bacteria from the aerobic environment of the anterior segment of the eye until the organism can invade the vitreous cavity, which has a low oxygen concentration. The management of these cases usually entails vitrectomy and intraocular antibiotics and may require removal of the implant and the patient's residual lens capsule. All tie cases reported so far have been from the United States, but this probably represents a greater awareness of the possibility of an anaerobic infection rather than any geographical difference. P acnes occurs in 30% of adult conjunctival sacs,4 and undoubtedly this is the source of infection with bacteria adhering to the implant or instruments during surgery. A M GLENN C M WOOD Department of Ophthalmology, Royal Victoria Infirmary, Newcastle upon Tyne NEI 4LP I Ormerod LD, Paton BG, Haaf J, I opping TM, Baker J.
Anaerobic bacterial endophthalmitis. Ophthalmology 1987;94: 799. 2 Meister DM, Palestine AG, Vastine DW, et al. Chronic propionibacterium endophthalmitis after extracapsular cataract extraction and intra-ocular lens implantation. Am J Ophthalmol
1986;102:733-9. 3 Fish LA, Ragen TM, Smith RE, Lean J. Propionibacterium acnes lens abscess after traumatic implantation of intralenticular cilia. Am7 Ophthalmol 1988;105:423-4. 4 Singer TR, Isenberg SJ, Apt L. Conjunctival anaerobic and aerobic flora in paediatric versus adult subjects. Br7 Ophthalmol 1988;72:448-51.
Discharging ears Messrs R C Bickerton and others ( 1 June, p 1649) highlight an important area of confusion in the treatment of discharging ears and must be congratulated on the high response to their questionnaire. We found, however, that their article contained some inaccuracies and omissions and did not mention the value of cheaper and theoretically less dangerous topical antiseptic preparations. They state that "the standard medical treatment recommended by all recognised textbooks of otolaryngology is adequate aural toilet and periodically instilling a topical preparation containing an antibiotic and steroid solution." In fact the reference that they quote points out that there is no difference in the results of treatment with aural toilet alone, antibiotic drops, or systemic antibiotics.' A large series has shown that systemic antibiotics are as effective as topical preparations in the treatment of actively discharging ears.2 The rationale of treatment for otitis externa and discharging ears caused by chronic suppurative otitis media is to clear the debris from the ear canal and provide an environment hostile to the pathogenic bacteria. We agree that aural toilet and a topical agent is the simplest and most rational approach, but the authors do not mention aluminium acetate drops. Boric acid and iodine are discussed and the authors state that these have been replaced over the years by newer aminoglycoside preparations. Aluminium acetate drops provide an acid environment hostile to the pathogens and are also hygroscopic, so reducing oedema and inflammation. They are as effective as drops containing gentamicin in the treatment of discharging ears.3 There are many advantages in using aluminium acetate drops instead of those containing aminoglycosides. Resistant strains of organisms may
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appear with indiscriminate use of aminoglycosides. Skin sensitisation can occur with topical aminoglycosides, and this may preclude their use systemically in life threatening infection. The theoretical risk of inner ear damage is not present ifaluminium acetate drops are used. Aluminium acetate drops cost substantially less than proprietary preparations containing antibiotics and steroids. We propose that the use of cheaper, safer, and equally efficacious aluminium acetate drops, in conjunction with aural toilet, should be the first line treatment of discharging ears. HAMISH G THOMSON MICHAEL J BROCKBANK Royal National T hroat, Nose and Ear Hospital, London WC1X 8DA I Kerr AG, Booth JB. Scott Brown's otolarvngology. 5th ed. London: Butterworth, 1987:215-37. 2 Browning GG, Picozzi GL, Calder IT, Sweeney G. Controlled trial of medical treatment of active otitis media. Br Med J 1983;287: 1024. 3 Claytonn MI, Osborne JE, Rutherford D, Rivion RP. A double blind randomised prospective trial of a topical antiseptic versus a topical antibiotic in the treatment of otorrhoea. Clin Otolarvngol (in press).
for only 24 hours and, as a result, the effect of each treatment is probably less evident. Had the period of urine collection been extended to 48 hours salicylate recovery in control subjects would have been approximately 96%, rather than 60%, and greater differences between each treatment group would have been observed. ' Moreover, the analytical method used quantitatively underestimates some of the aspirin metabolites. We are surprised that the authors did not also measure plasma salicylate concentrations and so determine peak concentrations and the area under the plasma drug concentration-time curve so that the relative efficacy of each treatment could be assessed further. Like similar volunteer studies this investigation does not predict accurately the effect of the treatment regimens in poisoned patients. For example, nausea and vomiting make activated charcoal difficult to give to a patient poisoned with aspirin, except by a lavage or nasogastric tube. Once given it is often vomited. The authors' statement that "charcoal was easiest to administer, had fewest side effects, and was preferred by most volunteers" may not, therefore, be relevant to the intoxicated patient. J A VALE West Midlands Poisons Unit, Dudley Road Hospital, Birmingham B18 7QH
Imaging for prostatism
ANDREW J HEATH
Dr David Southcott (14 May, p 1402) states that the British Association of Urological Surgeons recommends that an intravenous urogram should at times be taken for "defensive" purposes. A letter published in the Daily Telegraph on 30 November 1987 quoted the Medical and Dental Defence Union of Scotland recommending that in all cases in which there is doubt doctors should take x ray films. These statements indicate a reprehensible approach to radiological investigation. The Royal College of Radiologists has supported studies on the effective use of radiological investigations to enforce the maxim that these investigations should be based on sound clinical judgment arrived at by good medical history taking and clinical examination. No patient should be irradiated simply because of defensive medicine, and fortunately in Britain the judiciary would not support unnecessary investigations simply to cover the doctor for possible litigation. Paramount to this problem is that to irradiate a patient without good clinical reason is contrary to the patient's interests, which must be central to any doctor's actions. It is with good sense that the European Community's regulations on ionising radiation state that all radiological investigations must be based on clinical judgment. We must continue to educate doctors to depend on the skills of history taking and examination before requesting expensive technological aids. If not indicated these add an unnecessary burden to legitimately overworked departments of diagnostic radiology, needlessly irradiate patients, and increase the financial burden on the NHS. JO M C CRAIG E R DAVIES G DE LACEY
Department of Diagnostic Radiology, St Marv's Hospital, London W2 I NY
Treating aspirin overdose The report by Dr V Danel and others (28 May, p 1507) on the relative efficacy of activated charcoal, syrup of ipecacuanha, and gastric lavage in reducing the absorption of 1-5 g aspirin given one hour previously to healthy volunteers has several shortcomings which make extrapolation to poisoned patients difficult. Salicylate elimination in the urine was followed
Middle Tennessee Regional Poison and Clinical Toxicology Center, Nashville, Tennessee, United States I Curtis RA, Barone J, Giacona N. Efficacy of ipecac and activated charcoal/cathartic: prevention of salicylate absorption in a simulated overdose. Arch Intern Med 1984;144:48-52.
Babywalkers Dr M A Birchall and Mr H P Henderson discuss the most serious examples of injuries associated with babywalkers (11 June, p 1641) which require specialist hospital treatment. The volume of less serious illness associated with babywalkers is considerable and is unnecessary. The home accident surveillance system of the Department of Trade and Industry recorded 258 babywalker injuries in 1984, making babywalkers the largest single cause of injuries in the category of baby transport. ' An estimated 2500 children attend accident departments each year with babywalker injuries. In the United States there were an estimated 8000 babywalker injuries in 1978. These estimates cover only injuries treated in hospital and are likely to be underestimates. Some further case histories from my experience in Coventry and Warwickshire Hospital accident department in 1986 illustrate these less serious injuries which cause much needless suffering. An 11 month old girl fell from a babywalker on to her outstretched right hand in a "tipping" accident. She sustained a fracture of the distal radius which healed uneventfully over three weeks. An 8 month old girl sustained a minor frontal head injury when her babywalker fell down a step. A child sustained minor finger injuries from their entrapment between the babywalker's rim and a wall. The home accident surveillance system and its American equivalent, the national electronic surveillance system, aim primarily to enable design and safety standards to be devised. They are concerned with the safety of a product rather than the need for it. Doctors need to be aware of the weight of data collected routinely by the home accident surveillance system which they can tap into. Cooperation would speed up the identification of dangerous products and give impetus to policy review. Collaboration between accident doctors
BMJ
VOLUME
297
16 JULY 1988
