BRITISH MEDICAL JOURNAL
24 SEPTEMBER 1977
might be there accidentally; even if they were found constantly they might be "merely parasitic evsen though constant elements of contagions, as some still say of the semenanimalcules, elements that develop in the fluid, and may even be of diagnostic significance, without being the active material of the fluid or of the semen." Henle then said that only by isolating semen-animalcules (Samienithierchleni) and seminal fluid, contagionorganisms (Conitagiwnoroganiismenl) and contagion fluid, could the power of each be separately observed. Such an experiment, added Henle, "must no doubt be renounced."2 As Koch himself recognised when he failed to produce experimental cholera infections in animals in 1883-4, the postulates attributed to him were an oversimplification, but to compare Henle's armchair speculations with the hard-won conclusions from Koch's careful experimental work is surely absurd. It is surprising that the scholarly William Bulloch should have adopted the Fildes-Mclntosh myth.' This question has been dealt with in more detail in a recent paper. NORMAN HOWARD-JONES Geneva, Switzerland Fildes, P, and McIntosh, J, British J7ournal of Experimental Pathology, 1920, 1, 119 and 159. Henle, J, Pathologische Untersuchungen,t p 43. Berlin, Hirschwald, 1840. Bulloch, W, History of Bacteriology, p 165. London, Oxford University Press, 1938. 'Howard-Jones, N, Medical History, 1977, 21, 61.
Safety and danger of piped gases SIR,-How encouraging to find Dr J V I Young (30 July, p 317) pointing out the dangers of piped nitrous oxide! Not only is it dangerous to have two gases piped to an operating theatre, it is surely quite unnecessary. Dr Young could in fact have drawn our attention to another nine reasons why, in 1977, we should dispense with the routine use of nitrous oxide in major surgery. (1) The risk of oxygen failure is minimised since if only one carrier gas is used the efforts of a patient to breathe on an empty bag, or a ventilator to work without a proper supply, are much more obvious than if another gas such as nitrous oxide carries on when oxygen has failed. (2) Nitrous oxide is produced chemically and therefore there is a risk of impurities. Oxygen is produced physically and any impurities present were presumably in the air from which the oxygen was produced. (3) All inhalational anaesthetics are more flammable in nitrous oxide than in oxygen. Even halothane will burn in nitrous oxide; it is non-flammable in pure oxygen. (4) Without nitrous oxide there is less danger from gut distension, air embolism, and bubbles in the middle ear, and the cuffs of endotracheal tubes are less liable to overdistension. Once the fact that good anaesthesia can be produced today without the use of nitrous oxide is accepted the way is clear for a real step forward in anaesthetic technique-the use of a totally closed system. The addition of a simple ultraviolet halothane meter is all that is required to be able to enjoy a greatly simplified anaesthetic technique, which has a further five advantages. (5) The problem of pollution is virtually eliminated. Apart from expense, present
scavenging systems have at least four risks of their own: (a) obstruction to free movement in the theatre; (b) risk of infection; (c) risk of misconnection; and (d) risks associated with the final disposal of waste gases. (6) With oxygen as the only carrier gas capital costs are greatly reduced. There is no need for a pipeline since nitrous oxide is not required and only about 250 ml of oxygen per minute is needed. (7) Running costs are greatly reduced. (8) Water vapour is saved. (9) Heat loss is reduced. T H S BURNS St Thomas's Hospital, London SEI
Prolonged remission maintenance in acute myeloid leukaemia SIR,-We were interested to read the account by Professor A S D Spiers and others (27 August, p 544) of their results in the treatment of acute myeloid leukaemia with three quadruple drug combinations in predetermined rotation: TRAP (thioguanine, daunorubicin, cytarabine, prednisolone); COAP (cyclophosphamide, vincristine, cytarabine, prednisolone); and POMP (prednisolone, vincristine, methotrexate, mercaptopurine). They state that "for maintenance, five-day courses of drugs were administered every 14-21 days and doses were increased to tolerance" (that is, if possible a 20 ",, dose increase of rubidomycin dosage was made on each course and a similar increase in that of some of the other drugs was also attempted at each course of treatment). Cardiotoxicity or fear of this complication made them discontinue rubidomycin when their patients had been in remission for 62-122 weeks. They treated a total of 25 patients according to this protocol between July 1970 and January 1976, and on 31 January 1977 only two of the 25 patients were still in complete remission. The remissions of these two patients had lasted for 119 and 134 weeks respectively, a relatively short time. They therefore came to the somewhat pessimistic conclusion that this protocol "must still be regarded as only palliative treatment for acute myeloid leukaemia." Since 1971 we have used a modification of Spiers et al TRAP-COAP-POMP rotation protocol. One of our modifications has been to keep the dosage of rubidomycin and other drugs at the original level (for example, 60 mg of rubidomycin for the average person for each course instead of the increases attempted by Spiers et al). During the first year we start treatment courses every two weeks, during the second year every three weeks, and during the third year every four weeks. (Two patients also received a fourth year of treatment, with courses starting every six weeks.) From August 1971 to December 1973 56 patients were started on this treatment. Our remission rate and median survival were similar to those of Spiers et al. However, with our modifications we encountered no cardiotoxicity and continued our treatment for three years (in two cases for four years). Seven of our 56 patients are still in full remission 4-6 years from the start of treatment, and 1-3 years after discontinuing all treatment. Of these seven long survivors one was 17 years old at the start of treatment, one was 57, and the other five were in their 40s. One of these was a 40-yearold farmer who had asymptomatic insufficiency of rheumatic aetiology when his acute
831
leukaemia was diagnosed six years ago. Three years ago he developed severe cardiac failure and a Bjork-Shiley disc valve prosthesis was inserted with dramatic improvement. Today his cardiac function is good and his bone marrow and peripheral blood counts are normal three years after discontinuing all leukaemia treatment. Another of our patients was a 17-year-old schoolgirl who was started on treatment six years ago. She was treated for four years and married at the time when the treatment was discontinued. One year after the treatment was discontinued a chromosome analysis showed normal findings with no chromosomal breakage. She then allowed herself to become pregnant and gave birth to a healthy daughter in August this year. We think that the results obtained with our modification of Spiers et al TRAP-COAPPOMP treatment permit us to be considerably more optimistic than to regard it as only palliative treatment. PER STAVEM TORBJORN GJEMDAL BERNT LY Section of Haematology, Medical Department A,
Rikshospitalet, Oslo, Norway
An epidural service
SIR,-In reply to Mr A F Pentecost's letter (3 September, p 644) about our epidural service at this hospital (6 August, p 370), our aim has not been to provide total relief of pain in labour but to allow midwives and patients to manage the epidural more flexibly, according to how much normal sensation the patient wishes to retain. A midwife might, for example, explain to a patient who requested a top-up close to full dilatation that she would deliver herself more readily without a top-up or with a half-volume top-up at that stage. However, if the patient wanted total sensory ablation she could have it but was more likely to require assistance with forceps. On this basis 80 ° of our patients were fully satisfied, and of the remaining 200%, who were not some were dissatisfied with the way their epidural was managed and a few had epidurals which were not working properly. In this latter group another epidural catheter which worked was usually inserted so that overall our records show that only 2",, of the total had a failed epidural which we could not correct. I do believe that the provision of epidural analgesia should be part of the in-service training of junior obstetric staff and that the acquisition of this skill is of greater value to overseas doctors returning home than some of the techniques we teach them. I also had difficulty in getting patients and midwives to accept the obvious benefits of this type of pain relief in labour. Resistance melted when our midwives, even some of the district midwives, realised how much more satisfying it was to manage a patient with adequate pain relief whose consciousness was not clouded with pethidine. Patients' attitudes have also changed because in a small town where the forum of communication is the local supermarket they quickly get to hear of each other's experiences in the maternity unit. I could not provide this service on my own with the help of a medical assistant as Mr Pentecost does, which is another reason why I have involved my junior staff.
BRITISH MEDICAL JOURNAL
832
In all previously reported cases,' as in that reported by Professor Bradley and his colleagues, full symptomatic recovery was generally apparent within four months of metronidazole withdrawal. This case is exceptional for the duration of symptoms in the lower limbs. Bowthorpe Maternity Hospital, Wisbech, Cambs The total amount of metronidazole in reported cases of neuropathy has ranged between 30 and 314 g. In this instance it was 78 g, implying SIR,-I have read the article by Mr A B W that duration and severity of symptoms in Taylor and others (6 August, p 370) with metronidazole neuropathy may not be strictly interest. However, I firmly believe that at the dose-related. present time an obstetric epidural service I J KARLSSON should be provided by anaesthetists and should ADRIAN N HAMLYN be available only when there is a resident Royal Victoria Infirmary, Newcastle upon Tyne anaesthetist on call in the hospital. The reason for this uncompromising attitude Ingham, H R, et al, 7ournal of Anitimnicrobial Chemiois that the greatest among the risks inherent therapy, 1975, 1, 355. Ursing, B, and Kamme, C, Lancet, 1975, 1, 775. in the procedure is the possibility of local I D, British Medical Journal, 1968, 4, 706. Ramsay, anaesthetic being introduced into the cerebroCoxon, A, and Pallis, C A, Jou4rnal of Neuirology, Neutrosuirgery and Psychiatry, 1976, 39, 403. The resultant "total spinal spinal fluid. anaesthesia" is a situation requiring resuscitation skills of the highest order, and when these are present a fatal outcome can be prevented. SIR,-Dr W G Bradley and his colleagues In this situation I think that anaesthetists, by (3 September, p 610) state that metronidazole virtue of their training and constant practice neuropathy is mild and recovery appears to be in this field, are much more likely to be complete. We strongly disagree. Although the successful than obstetricians. It is one thing patients described by Ursing and Kammel for the latter to be taught to pass an endo- indeed fared well, those described by Ramsay2 tracheal tube in the anaesthetic room under and by Coxon and Pallis' developed a severe ideal conditions but a totally different one for neuropathy which certainly did not regress them to cope with this and other aspects of completely on stopping the drug. We have a management in the acute state of chaos that further patient who developed a severe sensory would be precipitated by a "total spinal" neuropathy with intolerable dysaesthesiae four occurring in a labour ward. months after starting metronidazole for I was relieved to see that Mr Taylor's team Crohn's disease. Seven months after stopping did take steps to minimise the possibility of the drug there has been no improvement, high spinal anaesthesia. Unfortunately there either clinically or in nerve conduction is no way of ensuring it will not happen, nor studies. is it always a complication apparent with the In our view patients starting long-term first dose of local anaesthetic. Obstetric therapy with metronidazole should be specificepidurals have been a momentous step forward, ally warned about this complication and should but until we have accurate data on the incidence be told to stop the drug and report immediof complications and a realistic assessment of ately if any neurological symptoms occur. the procedures I do not think it is justified to relax the standards that have so far been S HISHON applied to its use in Britain. JOHN PILLING J M ANDERTON Norfolk and Norwich It took 50 years for midwives to administer nitrous oxide to patients in labour. I look forward to the day when they are trained to provide epidural analgesia. A B W TAYLOR
Royal Infirmary, Manchester
Metronidazole neuropathy SIR,-Further to the account of recovery in metronidazole neuropathy by Professor W G Bradley and others (3 September, p 610) we wish to report a case in which complete subjective recovery has not apparently resulted two years after discontinuing the drug. The patient is a 20-year-old girl with extensive Crohn's disease and episodes of bacteraemia and abscess formation. Prior to surgery she was treated with oral metronidazole 800 mg twice daily for seven weeks before developing numbness of the hands and feet. Examination then demonstrated diminished ankle jerks and reduced sensibility to pinprick and cotton wool below mid-calf. There was also apparent left calf muscle wasting, but weakness was not present. Fasting blood sugar, folate, and vitamin B12 levels were normal; other drugs currently taken were prednisone, folic acid, and ferrous sulphate. The metronidazole was discontinued and the hand numbness resolved over four weeks. Fourteen weeks after withdrawal of the drug the tendon reflexes were brisk and sensory testing revealed distal hyperaesthesia in the legs, more marked on the left. However, two years later she continues to be distressed by numbness in the feet, although objective signs are questionable. The patient has not consented to nerve conduction studies.
24 SEPTEMBER 1977
minutes to reach their full effect and so the administration of diazepam is stopped short of the desired point in the knowledge that sedation will deepen. The stage of ptosis where the upper eyelid droops to bisect the pupil has been found to be a reliable sign of adequate sedation. Using this method it is possible to perform a single dental extraction without further anaesthesia, and together with effective local anaesthesia the most complicated surgical extractions may be performed without disturbing the patient and without leaving any memory of the procedures. This would seem to equate with Mr Fowler's reduction of fractures and orthopaedic operations. It is also surprising how little diazepam is actually needed to eliminate distress and produce anterograde amnesia, and in dental operations I have never found any need for more than 20 mg of diazepam in combination with pentazocine. Readers will no doubt assess for themselves the degree of fear which is inspired by dental procedures as distinct from those on any other part of the body. Finally, although long-term medication with benzodiazepines may well lessen the effect of diazepam, in practice this does not so far seem to be much of a problem. Dosage may be increased, but since one is working with an "approach dose" technique the result is still effective. It would be interesting to know whether Mr Fowler has come across any grossly increased dosage-or, indeed, any failures of sedation-which might be attributed to benzodiazepine habituation. P SYKES Ampthill, Beds
Strawberry pickers' foot drop SIR,-In reply to recent letters concerning strawberry pickers' foot drop I write to inform you that this is a relatively common disorder in the Fenland area during the strawberry
season. I had been completely unaware of this conNorwich dition until I arrived here and was most alarmed at the first case that I saw but was Ursing, B, and Kamme, C, Lanicet, 1975, 1, 775. quickly reassured by one of my senior part2Ramsay, I D, British Medical J7ournal, 1968, 4, 706. Coxon, A, and Pallis, C A, J7o(rnal of Neu(rology, ners. Between us in this group practice of six Neuirosuirgery anid Psychiatry, 1976, 39, 403. we have seen five cases of this disorder this year and we feel that the majority of them tend to be in casual labourers who are less aware of Shortage of anaesthetists the consequences of continued crouching. It is a condition very rarely seen in the fenman. SIR,-Mr A W Fowler (27 August, p 576) makes a plea for the increasing use of local K E WARREN anaesthesia for surgical procedures and advocates a combination of diazepam and Cycli- Wisbech, Cambs morph. May I offer him an alternative tech- ***This correspondence is now closed.-ED, nique which is enjoying popularity in dental BMJ7. circles and which he might find of value ? Dentists are, for obvious reasons, very keen to avoid nauseating drugs. The combination Inhumanity to man of cyclizine and morphine in Cyclimorph seems designed to produce narcosis without SIR,-The title of your leading article (3 Septnausea but, as Mr Fowler admits, this may ember, p 591) makes your position clear, and only postpone the nausea so that it embar- many should agree with you that the increasing rasses the nursing staff rather than the failure of psychiatric hospitals to admit surgeon. An alternative which has been found patients who have committed offences is invirtually non-nauseating is to use pentazocine humane. Yet as the problem becomes inwith the diazepam. A standard dosage of creasingly acute, swelling the prison popula30 mg pentazocine intravenously will produce tion (at a cost of over £4000 a year per analgesia comparable with that produced by inmate), there seems to be no effort to solve it 10 mg morphine but without the nausea. This or at least ease it. The regional secure units, is then supplemented by diazepam given in the planning stage, will cope with only a intravenously at the rate of 2 5 mg/30 s until minute proportion of patients requiring hossedation is evident. Both drugs take some pital care, and none is yet established, but by Hospital,
24 SEPTEMBER 1977
might be there accidentally; even if they were found constantly they might be "merely parasitic evsen though constant elements of contagions, as some still say of the semenanimalcules, elements that develop in the fluid, and may even be of diagnostic significance, without being the active material of the fluid or of the semen." Henle then said that only by isolating semen-animalcules (Samienithierchleni) and seminal fluid, contagionorganisms (Conitagiwnoroganiismenl) and contagion fluid, could the power of each be separately observed. Such an experiment, added Henle, "must no doubt be renounced."2 As Koch himself recognised when he failed to produce experimental cholera infections in animals in 1883-4, the postulates attributed to him were an oversimplification, but to compare Henle's armchair speculations with the hard-won conclusions from Koch's careful experimental work is surely absurd. It is surprising that the scholarly William Bulloch should have adopted the Fildes-Mclntosh myth.' This question has been dealt with in more detail in a recent paper. NORMAN HOWARD-JONES Geneva, Switzerland Fildes, P, and McIntosh, J, British J7ournal of Experimental Pathology, 1920, 1, 119 and 159. Henle, J, Pathologische Untersuchungen,t p 43. Berlin, Hirschwald, 1840. Bulloch, W, History of Bacteriology, p 165. London, Oxford University Press, 1938. 'Howard-Jones, N, Medical History, 1977, 21, 61.
Safety and danger of piped gases SIR,-How encouraging to find Dr J V I Young (30 July, p 317) pointing out the dangers of piped nitrous oxide! Not only is it dangerous to have two gases piped to an operating theatre, it is surely quite unnecessary. Dr Young could in fact have drawn our attention to another nine reasons why, in 1977, we should dispense with the routine use of nitrous oxide in major surgery. (1) The risk of oxygen failure is minimised since if only one carrier gas is used the efforts of a patient to breathe on an empty bag, or a ventilator to work without a proper supply, are much more obvious than if another gas such as nitrous oxide carries on when oxygen has failed. (2) Nitrous oxide is produced chemically and therefore there is a risk of impurities. Oxygen is produced physically and any impurities present were presumably in the air from which the oxygen was produced. (3) All inhalational anaesthetics are more flammable in nitrous oxide than in oxygen. Even halothane will burn in nitrous oxide; it is non-flammable in pure oxygen. (4) Without nitrous oxide there is less danger from gut distension, air embolism, and bubbles in the middle ear, and the cuffs of endotracheal tubes are less liable to overdistension. Once the fact that good anaesthesia can be produced today without the use of nitrous oxide is accepted the way is clear for a real step forward in anaesthetic technique-the use of a totally closed system. The addition of a simple ultraviolet halothane meter is all that is required to be able to enjoy a greatly simplified anaesthetic technique, which has a further five advantages. (5) The problem of pollution is virtually eliminated. Apart from expense, present
scavenging systems have at least four risks of their own: (a) obstruction to free movement in the theatre; (b) risk of infection; (c) risk of misconnection; and (d) risks associated with the final disposal of waste gases. (6) With oxygen as the only carrier gas capital costs are greatly reduced. There is no need for a pipeline since nitrous oxide is not required and only about 250 ml of oxygen per minute is needed. (7) Running costs are greatly reduced. (8) Water vapour is saved. (9) Heat loss is reduced. T H S BURNS St Thomas's Hospital, London SEI
Prolonged remission maintenance in acute myeloid leukaemia SIR,-We were interested to read the account by Professor A S D Spiers and others (27 August, p 544) of their results in the treatment of acute myeloid leukaemia with three quadruple drug combinations in predetermined rotation: TRAP (thioguanine, daunorubicin, cytarabine, prednisolone); COAP (cyclophosphamide, vincristine, cytarabine, prednisolone); and POMP (prednisolone, vincristine, methotrexate, mercaptopurine). They state that "for maintenance, five-day courses of drugs were administered every 14-21 days and doses were increased to tolerance" (that is, if possible a 20 ",, dose increase of rubidomycin dosage was made on each course and a similar increase in that of some of the other drugs was also attempted at each course of treatment). Cardiotoxicity or fear of this complication made them discontinue rubidomycin when their patients had been in remission for 62-122 weeks. They treated a total of 25 patients according to this protocol between July 1970 and January 1976, and on 31 January 1977 only two of the 25 patients were still in complete remission. The remissions of these two patients had lasted for 119 and 134 weeks respectively, a relatively short time. They therefore came to the somewhat pessimistic conclusion that this protocol "must still be regarded as only palliative treatment for acute myeloid leukaemia." Since 1971 we have used a modification of Spiers et al TRAP-COAP-POMP rotation protocol. One of our modifications has been to keep the dosage of rubidomycin and other drugs at the original level (for example, 60 mg of rubidomycin for the average person for each course instead of the increases attempted by Spiers et al). During the first year we start treatment courses every two weeks, during the second year every three weeks, and during the third year every four weeks. (Two patients also received a fourth year of treatment, with courses starting every six weeks.) From August 1971 to December 1973 56 patients were started on this treatment. Our remission rate and median survival were similar to those of Spiers et al. However, with our modifications we encountered no cardiotoxicity and continued our treatment for three years (in two cases for four years). Seven of our 56 patients are still in full remission 4-6 years from the start of treatment, and 1-3 years after discontinuing all treatment. Of these seven long survivors one was 17 years old at the start of treatment, one was 57, and the other five were in their 40s. One of these was a 40-yearold farmer who had asymptomatic insufficiency of rheumatic aetiology when his acute
831
leukaemia was diagnosed six years ago. Three years ago he developed severe cardiac failure and a Bjork-Shiley disc valve prosthesis was inserted with dramatic improvement. Today his cardiac function is good and his bone marrow and peripheral blood counts are normal three years after discontinuing all leukaemia treatment. Another of our patients was a 17-year-old schoolgirl who was started on treatment six years ago. She was treated for four years and married at the time when the treatment was discontinued. One year after the treatment was discontinued a chromosome analysis showed normal findings with no chromosomal breakage. She then allowed herself to become pregnant and gave birth to a healthy daughter in August this year. We think that the results obtained with our modification of Spiers et al TRAP-COAPPOMP treatment permit us to be considerably more optimistic than to regard it as only palliative treatment. PER STAVEM TORBJORN GJEMDAL BERNT LY Section of Haematology, Medical Department A,
Rikshospitalet, Oslo, Norway
An epidural service
SIR,-In reply to Mr A F Pentecost's letter (3 September, p 644) about our epidural service at this hospital (6 August, p 370), our aim has not been to provide total relief of pain in labour but to allow midwives and patients to manage the epidural more flexibly, according to how much normal sensation the patient wishes to retain. A midwife might, for example, explain to a patient who requested a top-up close to full dilatation that she would deliver herself more readily without a top-up or with a half-volume top-up at that stage. However, if the patient wanted total sensory ablation she could have it but was more likely to require assistance with forceps. On this basis 80 ° of our patients were fully satisfied, and of the remaining 200%, who were not some were dissatisfied with the way their epidural was managed and a few had epidurals which were not working properly. In this latter group another epidural catheter which worked was usually inserted so that overall our records show that only 2",, of the total had a failed epidural which we could not correct. I do believe that the provision of epidural analgesia should be part of the in-service training of junior obstetric staff and that the acquisition of this skill is of greater value to overseas doctors returning home than some of the techniques we teach them. I also had difficulty in getting patients and midwives to accept the obvious benefits of this type of pain relief in labour. Resistance melted when our midwives, even some of the district midwives, realised how much more satisfying it was to manage a patient with adequate pain relief whose consciousness was not clouded with pethidine. Patients' attitudes have also changed because in a small town where the forum of communication is the local supermarket they quickly get to hear of each other's experiences in the maternity unit. I could not provide this service on my own with the help of a medical assistant as Mr Pentecost does, which is another reason why I have involved my junior staff.
BRITISH MEDICAL JOURNAL
832
In all previously reported cases,' as in that reported by Professor Bradley and his colleagues, full symptomatic recovery was generally apparent within four months of metronidazole withdrawal. This case is exceptional for the duration of symptoms in the lower limbs. Bowthorpe Maternity Hospital, Wisbech, Cambs The total amount of metronidazole in reported cases of neuropathy has ranged between 30 and 314 g. In this instance it was 78 g, implying SIR,-I have read the article by Mr A B W that duration and severity of symptoms in Taylor and others (6 August, p 370) with metronidazole neuropathy may not be strictly interest. However, I firmly believe that at the dose-related. present time an obstetric epidural service I J KARLSSON should be provided by anaesthetists and should ADRIAN N HAMLYN be available only when there is a resident Royal Victoria Infirmary, Newcastle upon Tyne anaesthetist on call in the hospital. The reason for this uncompromising attitude Ingham, H R, et al, 7ournal of Anitimnicrobial Chemiois that the greatest among the risks inherent therapy, 1975, 1, 355. Ursing, B, and Kamme, C, Lancet, 1975, 1, 775. in the procedure is the possibility of local I D, British Medical Journal, 1968, 4, 706. Ramsay, anaesthetic being introduced into the cerebroCoxon, A, and Pallis, C A, Jou4rnal of Neuirology, Neutrosuirgery and Psychiatry, 1976, 39, 403. The resultant "total spinal spinal fluid. anaesthesia" is a situation requiring resuscitation skills of the highest order, and when these are present a fatal outcome can be prevented. SIR,-Dr W G Bradley and his colleagues In this situation I think that anaesthetists, by (3 September, p 610) state that metronidazole virtue of their training and constant practice neuropathy is mild and recovery appears to be in this field, are much more likely to be complete. We strongly disagree. Although the successful than obstetricians. It is one thing patients described by Ursing and Kammel for the latter to be taught to pass an endo- indeed fared well, those described by Ramsay2 tracheal tube in the anaesthetic room under and by Coxon and Pallis' developed a severe ideal conditions but a totally different one for neuropathy which certainly did not regress them to cope with this and other aspects of completely on stopping the drug. We have a management in the acute state of chaos that further patient who developed a severe sensory would be precipitated by a "total spinal" neuropathy with intolerable dysaesthesiae four occurring in a labour ward. months after starting metronidazole for I was relieved to see that Mr Taylor's team Crohn's disease. Seven months after stopping did take steps to minimise the possibility of the drug there has been no improvement, high spinal anaesthesia. Unfortunately there either clinically or in nerve conduction is no way of ensuring it will not happen, nor studies. is it always a complication apparent with the In our view patients starting long-term first dose of local anaesthetic. Obstetric therapy with metronidazole should be specificepidurals have been a momentous step forward, ally warned about this complication and should but until we have accurate data on the incidence be told to stop the drug and report immediof complications and a realistic assessment of ately if any neurological symptoms occur. the procedures I do not think it is justified to relax the standards that have so far been S HISHON applied to its use in Britain. JOHN PILLING J M ANDERTON Norfolk and Norwich It took 50 years for midwives to administer nitrous oxide to patients in labour. I look forward to the day when they are trained to provide epidural analgesia. A B W TAYLOR
Royal Infirmary, Manchester
Metronidazole neuropathy SIR,-Further to the account of recovery in metronidazole neuropathy by Professor W G Bradley and others (3 September, p 610) we wish to report a case in which complete subjective recovery has not apparently resulted two years after discontinuing the drug. The patient is a 20-year-old girl with extensive Crohn's disease and episodes of bacteraemia and abscess formation. Prior to surgery she was treated with oral metronidazole 800 mg twice daily for seven weeks before developing numbness of the hands and feet. Examination then demonstrated diminished ankle jerks and reduced sensibility to pinprick and cotton wool below mid-calf. There was also apparent left calf muscle wasting, but weakness was not present. Fasting blood sugar, folate, and vitamin B12 levels were normal; other drugs currently taken were prednisone, folic acid, and ferrous sulphate. The metronidazole was discontinued and the hand numbness resolved over four weeks. Fourteen weeks after withdrawal of the drug the tendon reflexes were brisk and sensory testing revealed distal hyperaesthesia in the legs, more marked on the left. However, two years later she continues to be distressed by numbness in the feet, although objective signs are questionable. The patient has not consented to nerve conduction studies.
24 SEPTEMBER 1977
minutes to reach their full effect and so the administration of diazepam is stopped short of the desired point in the knowledge that sedation will deepen. The stage of ptosis where the upper eyelid droops to bisect the pupil has been found to be a reliable sign of adequate sedation. Using this method it is possible to perform a single dental extraction without further anaesthesia, and together with effective local anaesthesia the most complicated surgical extractions may be performed without disturbing the patient and without leaving any memory of the procedures. This would seem to equate with Mr Fowler's reduction of fractures and orthopaedic operations. It is also surprising how little diazepam is actually needed to eliminate distress and produce anterograde amnesia, and in dental operations I have never found any need for more than 20 mg of diazepam in combination with pentazocine. Readers will no doubt assess for themselves the degree of fear which is inspired by dental procedures as distinct from those on any other part of the body. Finally, although long-term medication with benzodiazepines may well lessen the effect of diazepam, in practice this does not so far seem to be much of a problem. Dosage may be increased, but since one is working with an "approach dose" technique the result is still effective. It would be interesting to know whether Mr Fowler has come across any grossly increased dosage-or, indeed, any failures of sedation-which might be attributed to benzodiazepine habituation. P SYKES Ampthill, Beds
Strawberry pickers' foot drop SIR,-In reply to recent letters concerning strawberry pickers' foot drop I write to inform you that this is a relatively common disorder in the Fenland area during the strawberry
season. I had been completely unaware of this conNorwich dition until I arrived here and was most alarmed at the first case that I saw but was Ursing, B, and Kamme, C, Lanicet, 1975, 1, 775. quickly reassured by one of my senior part2Ramsay, I D, British Medical J7ournal, 1968, 4, 706. Coxon, A, and Pallis, C A, J7o(rnal of Neu(rology, ners. Between us in this group practice of six Neuirosuirgery anid Psychiatry, 1976, 39, 403. we have seen five cases of this disorder this year and we feel that the majority of them tend to be in casual labourers who are less aware of Shortage of anaesthetists the consequences of continued crouching. It is a condition very rarely seen in the fenman. SIR,-Mr A W Fowler (27 August, p 576) makes a plea for the increasing use of local K E WARREN anaesthesia for surgical procedures and advocates a combination of diazepam and Cycli- Wisbech, Cambs morph. May I offer him an alternative tech- ***This correspondence is now closed.-ED, nique which is enjoying popularity in dental BMJ7. circles and which he might find of value ? Dentists are, for obvious reasons, very keen to avoid nauseating drugs. The combination Inhumanity to man of cyclizine and morphine in Cyclimorph seems designed to produce narcosis without SIR,-The title of your leading article (3 Septnausea but, as Mr Fowler admits, this may ember, p 591) makes your position clear, and only postpone the nausea so that it embar- many should agree with you that the increasing rasses the nursing staff rather than the failure of psychiatric hospitals to admit surgeon. An alternative which has been found patients who have committed offences is invirtually non-nauseating is to use pentazocine humane. Yet as the problem becomes inwith the diazepam. A standard dosage of creasingly acute, swelling the prison popula30 mg pentazocine intravenously will produce tion (at a cost of over £4000 a year per analgesia comparable with that produced by inmate), there seems to be no effort to solve it 10 mg morphine but without the nausea. This or at least ease it. The regional secure units, is then supplemented by diazepam given in the planning stage, will cope with only a intravenously at the rate of 2 5 mg/30 s until minute proportion of patients requiring hossedation is evident. Both drugs take some pital care, and none is yet established, but by Hospital,
