824
survey2 lately showed no functional benefits 12 years after hip surgery in non-ambulant patients with whole body cerebral palsy and severe mental retardation by comparison with a similar group treated conservatively. Mean age at surgery was 13 years and all patients had dislocation of one or both hips before treatment. Troublesome hip pain occurred in only 4% of untreated cases. In earlier studies, pain from a dislocated hip was reported in 0-50% of patients.3-5 The frequency of scoliosis and hip dislocation depends on the severity of the cerebral palsy. There is little evidence that scoliosis is a consequence of hip dislocation.2,6 Orthotic management may be as successful as surgery in promoting the sitting posture. Surgery for dislocated hips in non-ambulant patients cannot be recommended except perhaps when severe symptoms are not controlled by medical treatment. If late surgery in severe cases does not achieve its aims early prophylactic surgery seems an attractive alternative. Close clinical monitoring and regular radiographs enable diagnosis of hip subluxation in young children with cerebral palsy. The aim of soft-tissue release surgery at this stage is to contain the femoral head and therefore allow normal acetabular development as proposed in congenital hip dislocation.7 Sadly the data available to test this hypothesis are inconclusive. The frequency and natural history of hip dislocation in cerebral palsy depend on the type and severity of the motor disorder and the ability to walk. Although population-based studies of incidence are not available, dislocation of the hip is commonly reported in severe quadriplegic cerebral palsy8 but rarely in patients who can walk independently or in children with hemiplegia or diplegia.6,9Against this background reports of successful prophylactic surgery are impossible to interpret.4,lo As Bleckll commented, "The controversy and confusion concerning prevention of the hip dislocation in cerebral palsy can be resolved only if the data include precisely the functional ambulatory status of the patient and the age". There is a continuing need to study the natural history of the conditions9 and intervention studies must contain a control group. Results of prophylactic surgery are poor in severely involved quadriplegic children, especially if subluxation or dislocation occur early in life .4,10,12 Since the unstable hip does not necessarily cause functional complications to many such patients, early surgery like late surgery has no proven value. Children with the potential for independent ambulation should be carefully monitored clinically and radiographically. Those who walk independently are unlikely to get hip problems, but what should one do about those who will walk late or walk with aids if hip subluxation shows signs of progressing? Surgery may be very successful in such patients/,12 but careful case selection, perhaps with gait analysis and vigorous postoperative therapy, 12 are
indispensable. MM, Abraham E, Nickel VL. Salvage surgery of the hip to improve sitting posture of mentally retarded severely disabled children with cerebral palsy. Dev Med Child Neurol 1972; 14: 51-55. Pritchet JW. Treated and untreated unstable hips in severe cerebral palsy.
1. Hoffer
2.
Dev Med Child Neurol 1990; 32: 3-6. 3. Moreau M, Drummond DS, Rogala E, Ashworth A, Porter P. Natural history of the dislocated hip in spastic cerebral palsy. Dev Med Child Neurol 1979; 21: 749-53. 4. Kalen V, Bleck EE. Prevention of spastic paralytic dislocation of the hip. Dev Med Child Neurol 1985; 27: 17-24. 5. Feldkamp M. Late results of hip and knee surgery in severely handicapped cerebral palsy patients. Arch Orthop Traum Surg 1982; 100: 217-24. 6. Cooke PH, Cole WG, Carey RPL. Dislocation of the hip in cerebral
palsy—natural history and predictability. J Bone Joint Surg 1989; 71B: 441-46. 7. Sherlock DA, Gibson PH, Benson MKD. Congenital subluxation of the hip: a long term review. J Bone Joint Surg 1985; 67B: 390-98. 8. Samilson RL, Tsou P, Aamoth G, Green WM. Dislocation and subluxation of the hip in cerebral palsy. J Bone Joint Surg 1972; 54A: 863-73. 9. Howard CB, McKibbin B, Williams LA, Mackie I. Factors affecting the incidence of hip dislocation in cerebral palsy. Bone J Joint Surg 1985; 67B: 530-32. 10. Sharrard WJW, Allen JMH, Heaney SH. Surgical prophylaxis of subluxation and dislocation of the hip in cerebral palsy. J Bone Joint Surg 1975; 57B: 160-66. 11. Bleck EE. Orthopaedic management in cerebral palsy. Clin Dev Med 1987; no 99-100. 12. Banks HH, Gren WJ. Adductor myotomy and obturator neurectomy for the correction of adduction contracture of the hip in cerebral palsy. J Bone Joint Surg 1960; 42A: 111-26.
MEDICAL INFORMATICS Medical informatics, according to two US researchers,1 "is emerging as a distinct academic entity". More cynically one could say that the academic world has realised that grants are to be had, jobs created, and money made from building databases of medical information. Commerce has already thought of this possibility, but will welcome the cachet of respectability bestowed by association with academics, the free training in the subject given to potential employees by academic institutions, and the cheap input of data (the most tedious part of information storage/retrieval) by academics looking for kudos. The bandwagon is about to roll, and there is a rush to climb aboard. For those not yet literate in this field, Greenes and Shortliffel point out that the name informatics has been anglicised from the French informatique, for which there is no English equivalent; whether this will please those in France who oppose the use of "franglais" remains to be seen. We learn from the US workers that "Medical Informatics is the field concerned with the cognitive, information processing, and communication tasks of medical practice, education and research, including the information science and technology to support these tasks. The methodologies for processing and communication of information may be viewed as both a science and a technology. This duality of information processing, in which computers are viewed as a tool for the science and as a vehicle for the technology, is connoted by the French term informatique". So, the storage of medical information in the form of computerised databases makes it possible to retrieve the information quickly, transmit it around the world (or even bounce it off the moon if so desired), sort it by various criteria, and display it in easily assimilable format. This is hardly news. The main reason that the predicted explosion in the use of computerised data has not yet happened is that few medical people can be bothered to learn how to use computers, and even the prospect of entering all the existing information, let alone new material, is daunting. The advent of the personal computer gave us all the opportunity to become computer literate, and thus to liberate ourselves from the tyranny of computer professionals. Few of us grasped this opportunity at the time, and computer technology has subsequently advanced at such a pace that the amateur has difficulty in keeping up. The professionals are back in power, and will once again control our access to computerised information. Although doctors may thump the keyboards, professionally prepared software packages will control how we use data, and the data available to us will be controlled by those who (selectively)
825
enter
it. Data will be
interpreted for
us
by informatics
professionals because these professionals will claim that only those who have been trained in information management will be capable of using information properly. Whoever coined the term job creation must have had an eye to the hospital service. Each new technological development has been taken up by specialist practitioners, who have recruited specialist technicians, who have then sought recognition, status, and more pay for what they do. Medical practitioners are outnumbered by the army of paramedical personnel. The National Health Service in the UK is the biggest employer in Europe outside the Red Army (and the Red Army is cutting staff). The bureaucratic masters seem happier to increase staff numbers than to finance equipment or new buildings which might reduce the need for personnel. To summarise what C. Northcote Parkinson said: Bureaucrats need secretaries Their writing skills to buck up. When these, in turn, need secretaries It’s asking for a--cock-up! The bureaucrats are already in love with the concept of informatics. In the next few years millions will be spent by health services worldwide on computers and specialist computer staff. Whether such activities will benefit mankind, or even the profession, remains to be seen. Now that academics are involved, the process will be unstoppable. How long will it be before we hear the cry that lives are being lost because a professor of medical informatics is not being funded to his entire satisfaction?
1. Greenes RA, Shortliffe EH. Medical informatics: an emerging academic discipline and institutional priority. JAMA 1990; 263: 1114-20.
SEVERE SYMPTOMATIC HYPONATRAEMIA: DANGERS IN LACK OF THERAPY What is the
appropriate treatment for severe symptomatic hyponatraemia? Until lately, this question most
elicited fierce debate. Some workers maintained that severe chronic hyponatraemia (serum sodium < 110 mmol/1) per se carried a grave prognosis, with mortality rates of 33-86% and required rapid correction.l-3 By contrast, Stern’s evaluation of the rate of correction of serum sodium suggested strongly that the morbidity and mortality associated with severe hyponatraemia, due particularly to central pontine myelinolysis (osmotic demyelination syndrome), were related more to the rapid rise in serum sodium concentration during therapy than to the degree of hyponatraemia.4,5 There is now widespread agreement that serum sodium should be increased slowly, 6-8 probably by no more than 0-5 mmol/1 per hour. But should such patients receive any specific treatment for their hyponatraemia? An emphatic response is given in a retrospective report by Fraser and Arieff,9 who describe the course of 11 women with profound postoperative hyponatraemia for which no specific treatment was given. The patients subsequently became grossly polyuric and hypernatraemic due to diabetes insipidus and diabetes mellitus and they died. These were healthy young women (aged 23-47 years) who had undergone minor surgical procedures. They had received large volumes of intravenous fluid, mainly 5 % dextrose (average 6-31) postoperatively. 32 hours after surgery, mean serum sodium concentration had fallen to 116 mmol/1, and
they had major neurological complications of fits, coma, and respiratory arrests. 18 hours later, on average, they were grossly polyuric with urine volumes of 0-4-1 0 1 per hour. During the next 2 days, while remaining polyuric, each became severely hypernatraemic (mean serum sodium concentration 167 mmol/1) and blood glucose rose from 511 mmol/1 in the immediate postoperative period to a maximum of 24mmol/1. Decorticate posturing and fixed dilated pupils developed in all patients and they died without regaining consciousness. At necropsy there was an increase in the mean brain weight of 12%, and evidence of tentorial herniation with grooving in the uncus and the cerebellum.
Ischaemic
infarcts
were
present in the
hypothalamus and pituitary of all patients examined (8 and 7, respectively), and 8 of the 11 had medullary ischaemic infarcts.
During surgery and the postoperative period many patients have raised plasma vasopressin concentrations,1O,11 which lead to antidiuresis. Infusion of large volumes of fluid, especially 5% dextrose, in conjunction with this antidiuresis will produce acute profound hyponatraemia. The severe neurological symptoms of this group of patients can be accounted for not only by the absolute degree of hyponatraemia but also by the rapid rate of fall of serum sodium. The
hypothalamo-pituitary infarcts seem to be a profound changes in serum sodium concentration and could readily explain the central diabetes insipidus. Since there was extensive pituitary damage it must be presumed that these patients also had anterior pituitary dysfunction, although this is not mentioned by
new
feature of
Fraser and Arieff. These researchers suggest that the cause of the diabetes mellitus in the terminal phase of the illness is a central cerebral lesion. Over a century ago Claude Bernard documented the development of central diabetes mellitus after experimental lesions in the region of the fourth cerebral ventricle.12,13Animal studies have lately indicated the existence of glucose-responsive areas in the lateral and ventromedial hypothalamus,14 and lesions in these regions can lead to hyperglycaemia.ls Whether Fraser and Arieffs patients had central diabetes mellitus or were hyperglycaemic due to massive release of catecholamines and other regulatory hormones is not at all clear. However, it is doubtful whether the clinical and laboratory features amount to a new syndrome of central diabetes insipidus and mellitus. This new report highlights the importance of administering fluids cautiously in the postoperative period and the necessity of specific therapy for severe symptomatic hyponatraemia. Slow rather than rapid correction of serum sodium is probably most appropriate in this group of patients whose hyponatraemia developed so quickly.16 1. Arieff AI. Hyponatremia, convulsions, respiratory arrest, and permanent brain damage after elective surgery in healthy women. N Engl J Med 1986; 314: 1529-35. 2. Ayus JC, Krothapalli RK, Arieff AI. Changing concepts in treatment of severe symptomatic hyponatremia: rapid correction and possible relation to central pontine myelinolysis. Am J Med 1985; 78: 897-902. 3. Dubois GK, Arieff AI. Symptomatic hyponatremia: the case for rapid correction. In: Naims RG, ed. Controversies in nephrology and hypertension. New York: Churchill Livingstone, 1984: 393-407. 4. Sterns RH, Riggs JE, Schochet SS. Osmotic demyelination syndrome following correction of hyponatremia. N Engl J Med 1986; 314: 1535-42. 5. Sterns RH. Severe symptomatic hyponatremia: treatment and outcome. Ann Intern Med 1987; 107: 656-64. 6. Swales JD. Dangers in treating hyponatraemia. Br Med J 1987; 294: 261-62.
survey2 lately showed no functional benefits 12 years after hip surgery in non-ambulant patients with whole body cerebral palsy and severe mental retardation by comparison with a similar group treated conservatively. Mean age at surgery was 13 years and all patients had dislocation of one or both hips before treatment. Troublesome hip pain occurred in only 4% of untreated cases. In earlier studies, pain from a dislocated hip was reported in 0-50% of patients.3-5 The frequency of scoliosis and hip dislocation depends on the severity of the cerebral palsy. There is little evidence that scoliosis is a consequence of hip dislocation.2,6 Orthotic management may be as successful as surgery in promoting the sitting posture. Surgery for dislocated hips in non-ambulant patients cannot be recommended except perhaps when severe symptoms are not controlled by medical treatment. If late surgery in severe cases does not achieve its aims early prophylactic surgery seems an attractive alternative. Close clinical monitoring and regular radiographs enable diagnosis of hip subluxation in young children with cerebral palsy. The aim of soft-tissue release surgery at this stage is to contain the femoral head and therefore allow normal acetabular development as proposed in congenital hip dislocation.7 Sadly the data available to test this hypothesis are inconclusive. The frequency and natural history of hip dislocation in cerebral palsy depend on the type and severity of the motor disorder and the ability to walk. Although population-based studies of incidence are not available, dislocation of the hip is commonly reported in severe quadriplegic cerebral palsy8 but rarely in patients who can walk independently or in children with hemiplegia or diplegia.6,9Against this background reports of successful prophylactic surgery are impossible to interpret.4,lo As Bleckll commented, "The controversy and confusion concerning prevention of the hip dislocation in cerebral palsy can be resolved only if the data include precisely the functional ambulatory status of the patient and the age". There is a continuing need to study the natural history of the conditions9 and intervention studies must contain a control group. Results of prophylactic surgery are poor in severely involved quadriplegic children, especially if subluxation or dislocation occur early in life .4,10,12 Since the unstable hip does not necessarily cause functional complications to many such patients, early surgery like late surgery has no proven value. Children with the potential for independent ambulation should be carefully monitored clinically and radiographically. Those who walk independently are unlikely to get hip problems, but what should one do about those who will walk late or walk with aids if hip subluxation shows signs of progressing? Surgery may be very successful in such patients/,12 but careful case selection, perhaps with gait analysis and vigorous postoperative therapy, 12 are
indispensable. MM, Abraham E, Nickel VL. Salvage surgery of the hip to improve sitting posture of mentally retarded severely disabled children with cerebral palsy. Dev Med Child Neurol 1972; 14: 51-55. Pritchet JW. Treated and untreated unstable hips in severe cerebral palsy.
1. Hoffer
2.
Dev Med Child Neurol 1990; 32: 3-6. 3. Moreau M, Drummond DS, Rogala E, Ashworth A, Porter P. Natural history of the dislocated hip in spastic cerebral palsy. Dev Med Child Neurol 1979; 21: 749-53. 4. Kalen V, Bleck EE. Prevention of spastic paralytic dislocation of the hip. Dev Med Child Neurol 1985; 27: 17-24. 5. Feldkamp M. Late results of hip and knee surgery in severely handicapped cerebral palsy patients. Arch Orthop Traum Surg 1982; 100: 217-24. 6. Cooke PH, Cole WG, Carey RPL. Dislocation of the hip in cerebral
palsy—natural history and predictability. J Bone Joint Surg 1989; 71B: 441-46. 7. Sherlock DA, Gibson PH, Benson MKD. Congenital subluxation of the hip: a long term review. J Bone Joint Surg 1985; 67B: 390-98. 8. Samilson RL, Tsou P, Aamoth G, Green WM. Dislocation and subluxation of the hip in cerebral palsy. J Bone Joint Surg 1972; 54A: 863-73. 9. Howard CB, McKibbin B, Williams LA, Mackie I. Factors affecting the incidence of hip dislocation in cerebral palsy. Bone J Joint Surg 1985; 67B: 530-32. 10. Sharrard WJW, Allen JMH, Heaney SH. Surgical prophylaxis of subluxation and dislocation of the hip in cerebral palsy. J Bone Joint Surg 1975; 57B: 160-66. 11. Bleck EE. Orthopaedic management in cerebral palsy. Clin Dev Med 1987; no 99-100. 12. Banks HH, Gren WJ. Adductor myotomy and obturator neurectomy for the correction of adduction contracture of the hip in cerebral palsy. J Bone Joint Surg 1960; 42A: 111-26.
MEDICAL INFORMATICS Medical informatics, according to two US researchers,1 "is emerging as a distinct academic entity". More cynically one could say that the academic world has realised that grants are to be had, jobs created, and money made from building databases of medical information. Commerce has already thought of this possibility, but will welcome the cachet of respectability bestowed by association with academics, the free training in the subject given to potential employees by academic institutions, and the cheap input of data (the most tedious part of information storage/retrieval) by academics looking for kudos. The bandwagon is about to roll, and there is a rush to climb aboard. For those not yet literate in this field, Greenes and Shortliffel point out that the name informatics has been anglicised from the French informatique, for which there is no English equivalent; whether this will please those in France who oppose the use of "franglais" remains to be seen. We learn from the US workers that "Medical Informatics is the field concerned with the cognitive, information processing, and communication tasks of medical practice, education and research, including the information science and technology to support these tasks. The methodologies for processing and communication of information may be viewed as both a science and a technology. This duality of information processing, in which computers are viewed as a tool for the science and as a vehicle for the technology, is connoted by the French term informatique". So, the storage of medical information in the form of computerised databases makes it possible to retrieve the information quickly, transmit it around the world (or even bounce it off the moon if so desired), sort it by various criteria, and display it in easily assimilable format. This is hardly news. The main reason that the predicted explosion in the use of computerised data has not yet happened is that few medical people can be bothered to learn how to use computers, and even the prospect of entering all the existing information, let alone new material, is daunting. The advent of the personal computer gave us all the opportunity to become computer literate, and thus to liberate ourselves from the tyranny of computer professionals. Few of us grasped this opportunity at the time, and computer technology has subsequently advanced at such a pace that the amateur has difficulty in keeping up. The professionals are back in power, and will once again control our access to computerised information. Although doctors may thump the keyboards, professionally prepared software packages will control how we use data, and the data available to us will be controlled by those who (selectively)
825
enter
it. Data will be
interpreted for
us
by informatics
professionals because these professionals will claim that only those who have been trained in information management will be capable of using information properly. Whoever coined the term job creation must have had an eye to the hospital service. Each new technological development has been taken up by specialist practitioners, who have recruited specialist technicians, who have then sought recognition, status, and more pay for what they do. Medical practitioners are outnumbered by the army of paramedical personnel. The National Health Service in the UK is the biggest employer in Europe outside the Red Army (and the Red Army is cutting staff). The bureaucratic masters seem happier to increase staff numbers than to finance equipment or new buildings which might reduce the need for personnel. To summarise what C. Northcote Parkinson said: Bureaucrats need secretaries Their writing skills to buck up. When these, in turn, need secretaries It’s asking for a--cock-up! The bureaucrats are already in love with the concept of informatics. In the next few years millions will be spent by health services worldwide on computers and specialist computer staff. Whether such activities will benefit mankind, or even the profession, remains to be seen. Now that academics are involved, the process will be unstoppable. How long will it be before we hear the cry that lives are being lost because a professor of medical informatics is not being funded to his entire satisfaction?
1. Greenes RA, Shortliffe EH. Medical informatics: an emerging academic discipline and institutional priority. JAMA 1990; 263: 1114-20.
SEVERE SYMPTOMATIC HYPONATRAEMIA: DANGERS IN LACK OF THERAPY What is the
appropriate treatment for severe symptomatic hyponatraemia? Until lately, this question most
elicited fierce debate. Some workers maintained that severe chronic hyponatraemia (serum sodium < 110 mmol/1) per se carried a grave prognosis, with mortality rates of 33-86% and required rapid correction.l-3 By contrast, Stern’s evaluation of the rate of correction of serum sodium suggested strongly that the morbidity and mortality associated with severe hyponatraemia, due particularly to central pontine myelinolysis (osmotic demyelination syndrome), were related more to the rapid rise in serum sodium concentration during therapy than to the degree of hyponatraemia.4,5 There is now widespread agreement that serum sodium should be increased slowly, 6-8 probably by no more than 0-5 mmol/1 per hour. But should such patients receive any specific treatment for their hyponatraemia? An emphatic response is given in a retrospective report by Fraser and Arieff,9 who describe the course of 11 women with profound postoperative hyponatraemia for which no specific treatment was given. The patients subsequently became grossly polyuric and hypernatraemic due to diabetes insipidus and diabetes mellitus and they died. These were healthy young women (aged 23-47 years) who had undergone minor surgical procedures. They had received large volumes of intravenous fluid, mainly 5 % dextrose (average 6-31) postoperatively. 32 hours after surgery, mean serum sodium concentration had fallen to 116 mmol/1, and
they had major neurological complications of fits, coma, and respiratory arrests. 18 hours later, on average, they were grossly polyuric with urine volumes of 0-4-1 0 1 per hour. During the next 2 days, while remaining polyuric, each became severely hypernatraemic (mean serum sodium concentration 167 mmol/1) and blood glucose rose from 511 mmol/1 in the immediate postoperative period to a maximum of 24mmol/1. Decorticate posturing and fixed dilated pupils developed in all patients and they died without regaining consciousness. At necropsy there was an increase in the mean brain weight of 12%, and evidence of tentorial herniation with grooving in the uncus and the cerebellum.
Ischaemic
infarcts
were
present in the
hypothalamus and pituitary of all patients examined (8 and 7, respectively), and 8 of the 11 had medullary ischaemic infarcts.
During surgery and the postoperative period many patients have raised plasma vasopressin concentrations,1O,11 which lead to antidiuresis. Infusion of large volumes of fluid, especially 5% dextrose, in conjunction with this antidiuresis will produce acute profound hyponatraemia. The severe neurological symptoms of this group of patients can be accounted for not only by the absolute degree of hyponatraemia but also by the rapid rate of fall of serum sodium. The
hypothalamo-pituitary infarcts seem to be a profound changes in serum sodium concentration and could readily explain the central diabetes insipidus. Since there was extensive pituitary damage it must be presumed that these patients also had anterior pituitary dysfunction, although this is not mentioned by
new
feature of
Fraser and Arieff. These researchers suggest that the cause of the diabetes mellitus in the terminal phase of the illness is a central cerebral lesion. Over a century ago Claude Bernard documented the development of central diabetes mellitus after experimental lesions in the region of the fourth cerebral ventricle.12,13Animal studies have lately indicated the existence of glucose-responsive areas in the lateral and ventromedial hypothalamus,14 and lesions in these regions can lead to hyperglycaemia.ls Whether Fraser and Arieffs patients had central diabetes mellitus or were hyperglycaemic due to massive release of catecholamines and other regulatory hormones is not at all clear. However, it is doubtful whether the clinical and laboratory features amount to a new syndrome of central diabetes insipidus and mellitus. This new report highlights the importance of administering fluids cautiously in the postoperative period and the necessity of specific therapy for severe symptomatic hyponatraemia. Slow rather than rapid correction of serum sodium is probably most appropriate in this group of patients whose hyponatraemia developed so quickly.16 1. Arieff AI. Hyponatremia, convulsions, respiratory arrest, and permanent brain damage after elective surgery in healthy women. N Engl J Med 1986; 314: 1529-35. 2. Ayus JC, Krothapalli RK, Arieff AI. Changing concepts in treatment of severe symptomatic hyponatremia: rapid correction and possible relation to central pontine myelinolysis. Am J Med 1985; 78: 897-902. 3. Dubois GK, Arieff AI. Symptomatic hyponatremia: the case for rapid correction. In: Naims RG, ed. Controversies in nephrology and hypertension. New York: Churchill Livingstone, 1984: 393-407. 4. Sterns RH, Riggs JE, Schochet SS. Osmotic demyelination syndrome following correction of hyponatremia. N Engl J Med 1986; 314: 1535-42. 5. Sterns RH. Severe symptomatic hyponatremia: treatment and outcome. Ann Intern Med 1987; 107: 656-64. 6. Swales JD. Dangers in treating hyponatraemia. Br Med J 1987; 294: 261-62.
