primary-care clinician in Canada. * Priority should be given to evaluations of the usefulness of treating hypertension at the worksite or in other nontraditional settings. DAVID L. SACKETT, MD, M Sc Departments of clinical epidemiology and biostatistics, and medicine McMaster University Hamilton, Ont.
References 1. American Medical Association, committee on hypertension: Drug treatment of ambulatory patients with hypertension. JAMA 225: '1647, 1973 2. Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. A cooperative study. JAMA 237: 255, 1977 3. WRIGHT JM, MCLEOD PJ, MCCULLOUGH W: Antihypertensive efficacy of a single bedtime dose of methyldopa. Clin Pharmacol Ther 20: 733, 1976
The Canada Health Survey - can we get along without it? In 1974, the year in which health professionals all method of the survey have already been described;3'4 over the world began to read "A New Perspective on however, an answer to these questions should include the Health of Canadians",1 a group of federal health consideration of the purpose of surveys and of the scientists developed a proposal for an ongoing survey important questions that this survey might answer. of the health of Canadians. After approval by the Data on the health of populations are gathered in Cabinet in 1975, a joint team from Statistics Canada three ways: from rates of use of treatment facilities, and the Department of National Health and Welfare by analysis of vital statistics and through community developed a system for annually interviewing 12 000 surveys. The study of rates of treatment alone is very families; one third of the 12 000 would also undergo useful in the analysis of the medical care system and selected physical tests. After a successful pretest the in the planning for allocation of resources; however, survey was launched, in May 1978. Four months it cannot give an unbiased picture of the true rates later both agencies were notified that budget cuts of disease or disability, especially for asymptomatic necessitated the cancellation of the survey, and that or self-limiting conditions, in the population as a no funds would be forthcoming for analysis of the whole. Vital statistics are highly accurate and furnish data already gathered. a base for following trends such as birth and death In these days of lacerating budgetary sacrifices, one rates, which have a general significance for health; always hopes that a cut has found its mark, dismem- however, they offer no details on the causes and bering a superfluous program or exsanguinating a courses of disease and disability. Surveys, although nonproductive agency. Indeed, some of my colleagues dependent in part on the difficult art of interviewing,3 have pointed out that starting the Canada Health give a broad view of the distribution and determinants Survey would have committed the government to the of health and disease, and are the only means by cost of continuing a valueless long-term project. Some which health problems that fall outside the medical potential users initially questioned the content and care network can be studied. At present in Canada method of the survey; health care planners with a such data come from localized surveys and epidephilosophic orientation moaned that Canada is a small, miologic studies of limited scope: there has been no diverse and diffuse country that cannot know, or national view of health since the almost-forgotten does not need to know, more about the health of its Canadian sickness survey of 1950-51 *6 people; and some epidemiologists cited the apparent The overall objective of the Canada Health Survey uselessness of the proliferation of surveys sponsored was to gather data on health status that would be by the National Center for Health Statistics in the useful in evaluating and planning health care services, United States. However, the years of planning that health promotion activities and protective measures went into the Canada Health Survey, the relevance of for the population as a whole. An integral part of its objectives to the "Spirit of Lalonde",2 and its en- this approach was the relatively new view that health dorsement by the Canadian Public Health Association, status has both positive and negative measurable comthe Canadian Medical Association, professors of med- ponents.7 Knowledge of the causes and consequences icine and public health, provincial health agencies and of risk factors is also important in the planning of health interest groups suggest that the survey may preventive programs. The survey's data bank would not have been given a fair trial before it was dragged allow the testing of hypotheses and the examination of to the altar last September to have its heart cut out. associations so necessary in epidemiologic research What could the Canada Health Survey have done relevant to the study of the detection, distribution and for the people of Canada, and what, in fact, have we causes of disease. lost with its demise? The objectives, content and The working paper by the Canada Health Survey8 148 CMA JOURNAL/JULY 21, 1979/VOL. 121
illustrates the wide scope of the survey, with questions ever, we would certainly be wiser, and probably on lifestyle, physical and recreational activities, driving healthier, if we knew. habits, preventive practices, self-reported health status P.P. MORGAN, MD, DPH, D EPID (including contacts with any type of health care proAssociate scientific editor vider), self-medication, emotional health, life satisfacCanadian Medical Association Journal tion, and physical measures, including those of blood pressure, aerobic fitness, concentrations of trace ele- References ments in the blood and immunization status. The pilot studies showed that these data could be collected 1. LALONDE M: A New Perspective on the Health of Canadians. A Working Document, Govt of Canada, Ottawa, economically by part-time local field workers, and 1974 that the survey was well accepted by most respondents. 2. MCEWAN ED: Whatever happened to the Lalonde report? The usual safeguards to protect the identity of inCan J Public Health 70: 13, 1979 dividuals were set up. Also, the survey was very flex- 3. Woors D: Canada Health Survey should provide useful information if carefully used. Can Med Assoc J 116: 1302, ible; questions could be changed and new problems 1977 identified and followed. 4. MUIZNIECKS VE: A review of the Canada Health Survey. Recently, the director of the Canada Health Survey Can J Public Health 69: 204, 1978 has indicated that very limited funds will be available 5. CANNELL CF, MARQUIS KH, LAURENT A: A Summary of Studies of Interviewing Methodology, National Center for for analysis of the data already gathered. If this is a Health Statistics, Rockville, Md, DHEW publ no (HRA) governmental response to pressures from the health 77-1343, 1977 community, more pressure should be applied to restore 6. Statistics Canada: Illness and Health Care in Canada, the survey to a useful form. It is true that Canada Canadian sickness survey, 1950-Si, Queen's Printer, Otwill continue to unfold without the knowledge of tawa, 1960 why people self-medicate and do not go to doctors 7. BRUHN JG, CORDOvA FD, WILLIAM JA, et al: The wellness J Comm Health 2: 209, 1977 when they are sick, of how persons with unreported 8. process. Output Variables and Proposed Tables, selected comments disabilities cope, of which communities are furthest from professional associations and university researchers behind in immunization procedures, and of the possible on working paper 78-1, Canada Health Survey, Ottawa, Sept 1978 causes and certain effects of healthful lifestyles; how-
Computed tomography and the early diagnostic lumbar puncture Computed tomographic head scans have greatly influenced the diagnosis of neurologic illness. It is a marvellous accomplishment that this technique, which is far safer, easier to perform and less threatening to the patient than the older investigative measures, should provide such improved and astonishing neuroanatomic detail. The computed tomographic image of traditional lesions of the central nervous system is now familiar to neuroradiologists, neurologists and neurosurgeons. At last we have a neurologic nostrum to unlock mysteries of the central nervous system. But are the traditional methods of neurologic diagnosis now rendered obsolete? Specifically, is diagnostic lumbar puncture required anymore? The indications for early diagnostic lumbar puncture performed by the primary-care physician are the same as they always have been, and, except for certain types of cerebrovascular disease, remain uninfluenced by the availability of computed tomography.1 Although there are a few indications for early diagnostic lumbar puncture, there are even more contraindications for its use. One should not expect more of early diagnostic lumbar puncture than it is capable of providing, for, as Craigmile and Welch2 state, "there is a trend in . . . medicine in general, to employ special diagnostic procedures excessively. While in some situations lumbar puncture is a necessary initial step, in others the in150 CMA JOURNAL/JULY 21, 1979/VOL 121
dications should be weighed in the light of the development of other planned investigations; in yet others, it is unnecessary or contraindicated." When is early diagnostic lumbar puncture required? The medical student's answer expresses the colloquialism "to diagnose pus or blood". In other words, lumbar puncture discloses bacterial meningitis or subarachnoid hemorrhage. Early lumbar puncture is indicated in the following instances: * When the history of the present illness is brief, and the disease is acute in onset and associated with recent malaise, lethargy, a febrile episode (as in meningitis or viral encephalitis), severe headache (as in subarachnoid hemorrhage) or, particularly, neck stiffness. * When a "septic work-up" is performed in an infant, or in a child with an atypical febrile convulsion - a focal or asymmetric seizure in a child less than 6 months or more than 4 years of age. In both instances the patient presents with an acute illness of short duration and usually of sudden onset. In patients with meningitis or encephalitis the current medical history will suggest a possible infection of the central nervous system; however, lumbar puncture is mandatory not only to determine which of the two is present, but also to provide microbiologic and therapeutic information. The same sort of information
References 1. American Medical Association, committee on hypertension: Drug treatment of ambulatory patients with hypertension. JAMA 225: '1647, 1973 2. Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. A cooperative study. JAMA 237: 255, 1977 3. WRIGHT JM, MCLEOD PJ, MCCULLOUGH W: Antihypertensive efficacy of a single bedtime dose of methyldopa. Clin Pharmacol Ther 20: 733, 1976
The Canada Health Survey - can we get along without it? In 1974, the year in which health professionals all method of the survey have already been described;3'4 over the world began to read "A New Perspective on however, an answer to these questions should include the Health of Canadians",1 a group of federal health consideration of the purpose of surveys and of the scientists developed a proposal for an ongoing survey important questions that this survey might answer. of the health of Canadians. After approval by the Data on the health of populations are gathered in Cabinet in 1975, a joint team from Statistics Canada three ways: from rates of use of treatment facilities, and the Department of National Health and Welfare by analysis of vital statistics and through community developed a system for annually interviewing 12 000 surveys. The study of rates of treatment alone is very families; one third of the 12 000 would also undergo useful in the analysis of the medical care system and selected physical tests. After a successful pretest the in the planning for allocation of resources; however, survey was launched, in May 1978. Four months it cannot give an unbiased picture of the true rates later both agencies were notified that budget cuts of disease or disability, especially for asymptomatic necessitated the cancellation of the survey, and that or self-limiting conditions, in the population as a no funds would be forthcoming for analysis of the whole. Vital statistics are highly accurate and furnish data already gathered. a base for following trends such as birth and death In these days of lacerating budgetary sacrifices, one rates, which have a general significance for health; always hopes that a cut has found its mark, dismem- however, they offer no details on the causes and bering a superfluous program or exsanguinating a courses of disease and disability. Surveys, although nonproductive agency. Indeed, some of my colleagues dependent in part on the difficult art of interviewing,3 have pointed out that starting the Canada Health give a broad view of the distribution and determinants Survey would have committed the government to the of health and disease, and are the only means by cost of continuing a valueless long-term project. Some which health problems that fall outside the medical potential users initially questioned the content and care network can be studied. At present in Canada method of the survey; health care planners with a such data come from localized surveys and epidephilosophic orientation moaned that Canada is a small, miologic studies of limited scope: there has been no diverse and diffuse country that cannot know, or national view of health since the almost-forgotten does not need to know, more about the health of its Canadian sickness survey of 1950-51 *6 people; and some epidemiologists cited the apparent The overall objective of the Canada Health Survey uselessness of the proliferation of surveys sponsored was to gather data on health status that would be by the National Center for Health Statistics in the useful in evaluating and planning health care services, United States. However, the years of planning that health promotion activities and protective measures went into the Canada Health Survey, the relevance of for the population as a whole. An integral part of its objectives to the "Spirit of Lalonde",2 and its en- this approach was the relatively new view that health dorsement by the Canadian Public Health Association, status has both positive and negative measurable comthe Canadian Medical Association, professors of med- ponents.7 Knowledge of the causes and consequences icine and public health, provincial health agencies and of risk factors is also important in the planning of health interest groups suggest that the survey may preventive programs. The survey's data bank would not have been given a fair trial before it was dragged allow the testing of hypotheses and the examination of to the altar last September to have its heart cut out. associations so necessary in epidemiologic research What could the Canada Health Survey have done relevant to the study of the detection, distribution and for the people of Canada, and what, in fact, have we causes of disease. lost with its demise? The objectives, content and The working paper by the Canada Health Survey8 148 CMA JOURNAL/JULY 21, 1979/VOL. 121
illustrates the wide scope of the survey, with questions ever, we would certainly be wiser, and probably on lifestyle, physical and recreational activities, driving healthier, if we knew. habits, preventive practices, self-reported health status P.P. MORGAN, MD, DPH, D EPID (including contacts with any type of health care proAssociate scientific editor vider), self-medication, emotional health, life satisfacCanadian Medical Association Journal tion, and physical measures, including those of blood pressure, aerobic fitness, concentrations of trace ele- References ments in the blood and immunization status. The pilot studies showed that these data could be collected 1. LALONDE M: A New Perspective on the Health of Canadians. A Working Document, Govt of Canada, Ottawa, economically by part-time local field workers, and 1974 that the survey was well accepted by most respondents. 2. MCEWAN ED: Whatever happened to the Lalonde report? The usual safeguards to protect the identity of inCan J Public Health 70: 13, 1979 dividuals were set up. Also, the survey was very flex- 3. Woors D: Canada Health Survey should provide useful information if carefully used. Can Med Assoc J 116: 1302, ible; questions could be changed and new problems 1977 identified and followed. 4. MUIZNIECKS VE: A review of the Canada Health Survey. Recently, the director of the Canada Health Survey Can J Public Health 69: 204, 1978 has indicated that very limited funds will be available 5. CANNELL CF, MARQUIS KH, LAURENT A: A Summary of Studies of Interviewing Methodology, National Center for for analysis of the data already gathered. If this is a Health Statistics, Rockville, Md, DHEW publ no (HRA) governmental response to pressures from the health 77-1343, 1977 community, more pressure should be applied to restore 6. Statistics Canada: Illness and Health Care in Canada, the survey to a useful form. It is true that Canada Canadian sickness survey, 1950-Si, Queen's Printer, Otwill continue to unfold without the knowledge of tawa, 1960 why people self-medicate and do not go to doctors 7. BRUHN JG, CORDOvA FD, WILLIAM JA, et al: The wellness J Comm Health 2: 209, 1977 when they are sick, of how persons with unreported 8. process. Output Variables and Proposed Tables, selected comments disabilities cope, of which communities are furthest from professional associations and university researchers behind in immunization procedures, and of the possible on working paper 78-1, Canada Health Survey, Ottawa, Sept 1978 causes and certain effects of healthful lifestyles; how-
Computed tomography and the early diagnostic lumbar puncture Computed tomographic head scans have greatly influenced the diagnosis of neurologic illness. It is a marvellous accomplishment that this technique, which is far safer, easier to perform and less threatening to the patient than the older investigative measures, should provide such improved and astonishing neuroanatomic detail. The computed tomographic image of traditional lesions of the central nervous system is now familiar to neuroradiologists, neurologists and neurosurgeons. At last we have a neurologic nostrum to unlock mysteries of the central nervous system. But are the traditional methods of neurologic diagnosis now rendered obsolete? Specifically, is diagnostic lumbar puncture required anymore? The indications for early diagnostic lumbar puncture performed by the primary-care physician are the same as they always have been, and, except for certain types of cerebrovascular disease, remain uninfluenced by the availability of computed tomography.1 Although there are a few indications for early diagnostic lumbar puncture, there are even more contraindications for its use. One should not expect more of early diagnostic lumbar puncture than it is capable of providing, for, as Craigmile and Welch2 state, "there is a trend in . . . medicine in general, to employ special diagnostic procedures excessively. While in some situations lumbar puncture is a necessary initial step, in others the in150 CMA JOURNAL/JULY 21, 1979/VOL 121
dications should be weighed in the light of the development of other planned investigations; in yet others, it is unnecessary or contraindicated." When is early diagnostic lumbar puncture required? The medical student's answer expresses the colloquialism "to diagnose pus or blood". In other words, lumbar puncture discloses bacterial meningitis or subarachnoid hemorrhage. Early lumbar puncture is indicated in the following instances: * When the history of the present illness is brief, and the disease is acute in onset and associated with recent malaise, lethargy, a febrile episode (as in meningitis or viral encephalitis), severe headache (as in subarachnoid hemorrhage) or, particularly, neck stiffness. * When a "septic work-up" is performed in an infant, or in a child with an atypical febrile convulsion - a focal or asymmetric seizure in a child less than 6 months or more than 4 years of age. In both instances the patient presents with an acute illness of short duration and usually of sudden onset. In patients with meningitis or encephalitis the current medical history will suggest a possible infection of the central nervous system; however, lumbar puncture is mandatory not only to determine which of the two is present, but also to provide microbiologic and therapeutic information. The same sort of information
