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Tuesday, September 07, 2004
To scan or not to scan in headache
An editorial by Peter J Goadsby, professor of clinical neurology, Institute of Neurology, University College London, which appeared in British Medical Journal recently (1) had the above title.Though it looks like a medical issue, it is a general issue too, which every body should be aware of, since all of us ( not only doctors, nurses and health managers) are potential patients and demystification of medicine is the need of the hour. Hence this becomes my topic this week.
To introduce the topic, I have to quote excerpts from the editorial rather liberally, taking the liberty to demystify wherever deemed necessary . Peter J Goadsby says " Some life threatening brain disorders present with secondary headache, where the headache is caused by the disease. A brain tumour, for example, is best diagnosed by brain imaging( means scans, commonly a CT scan or an MRI scan ) early in the course of the disease, which is essential for optimal management of this and other secondary headache disorders. However, brain tumours, as an example, account for less than 0.1% of the lifetime prevalence of headache.This contrasts with the fact that most headaches in the community are either associated with mild systemic infection or are due to primary headache, where the headache is itself the disorder. Dissecting primary from secondary headache is the problem, since, by definition, primary headache does not need brain imaging ,because no disease process exists that leads to macroscopic change in general terms(and therefore vsible with scans).
Prof. Goadsby continues-" How does one dissect primary from secondary headache?...... In clinical practice we generally accept that the so called red flags of headache should trigger a search for secondary headache.Thus,change in the pattern of headache; new onset of headache in people older than 50; onset of seizures ( fits ) or headache associated with systemic illness, including fever; personality change; or with symptoms suggestive of raised intracranial pressure, such as new onset headache in the early morning; or headache that is worsening with coughing, sneezing, or straining should each be viewed with concern. Acute onset of the worst headache of the patient's life should trigger immediate referral for consideration as a sentinel headache of an intracranial aneurysm. An abnormal neurological finding is a clear indication to investigate, unless the finding is longstanding." Prof. Goadsby quotes data from a published study of The American academy of neurology to support his statements which shows that the yield from scans were extremely low when patients with obviously primary headaches like migraine were scanned, compared to the significant yield when patients with clinically diagnosed secondary headaches ( those presenting with red flag symptoms) were subjected to scans.
If that is the case, why should we do so many scans for patients with headaches and are specialists justified in asking for scans for most of the patients with headache. Prof. Goadsby states " Ultimately this is a public health question, perhaps a medicolegal question: how many potentially normal scans would society wish to pay for to diagnose treatable brain disease— 98 in every 100? What is reasonable in terms of missing a reversible cause, such as a meningioma, which can do exceedingly well in the hands of the neurosurgeons? Unfortunately, properly done controlled studies are unavailable, and the lowest common denominator is what a convincing expert might tell a court".The situation of society paying for scans is confined only to few countries,where the Government runs health services. Even in other situations where health care is totally in private hands, the fact is that money is being expended unneccessarily,though met by patients themselves.The situation becomes worse, when the normal scans require to be reinforced with contrast studies ( which are extraneous substances injected into body to make scans more informative and light up certain findings), because contrast medium, a costly chemical, not only makes the scan more expensive , but leads to doubling of radiation dose , as the scan has to be done a second time after administering contrast. The chemical is not entirely not without side effects and research which has made it less toxic has further lead to an increase in the cost of the chemical and thereby the scan itself.It is worthy to note here that a study done by this author and colleague (2) has shown a strange paradox - negativity in a CT scan is more, when contrast study is done.This is because the contrast study is done to reconfirm normalcy in normal plain scans, whereas in head injury cases and stroke cases,it is customary to do only plain scans ( without a repeat contrast study) where chance of positivity is high.
Is it justifiable to do a scan just to reassure all parties concerned including the patient.To this question Prof. Goadsby answers "i have scanned patients for reasons of reassurance: for the patients, for their relatives—spouses or parents—and because they perturbed me. So it seems unrealistic and elitist of me to suggest no one ever be scanned for reassurance." . He suggests two solutions. One is something which everybody says - that we should explain to the patient why this is being done and why this can be normal etc , as otherwise patient is still back to you or another specialist with added anxiety and a normal scan report.But that does not reduce a single unwanted scan. Nobody wants to take a risk in these days of unjustifiably high litigations against doctors.
Second solution which prof. Goadsby suggests is that general practitioners who know patients personally for a longer time and better than the specialists should be extremely sensible about scanning. He quotes some Australian experience as well.As an Indian Radiologist who has some experience with patterns of scans being done for patients with headaches, I feel the issue can not be that easily resolved. In countries or set ups where public is funding the scans ( as in free Government run hospitals of various developing countries and set ups like those of NHS in UK and some other well off economies) the public funding itself is the cause of unnecessary scans. " Why should I take a risk of a one in thousand miss of a sinister diagnosis ?" philosophy will dictate the decision. Suppose it is a scenario where spending is private. Scanning is not only a high tech imaging modality, it is also a business. The business managers will do all that is possible to raise the number of scans to make the scanning machine and business a viable project, before the machine gets out dated or becomes less suitable or efficient for the meant purposes. All that is possible means giving cuts and kickbacks to doctors who ask for more scans, needed or not.Doctors thus become party to promoting unwanted scans and occasionally comes to the open against it. It is a catch - 22 situation. It is a vicious circle . Even honest and ethical business managers and doctor business men have to fall prey to it. Otherwise they will face closure of their medical businesses for which banks have no special low interest rates . In India, which is home to the largest medical association of the world called Indian Medical Association with a member ship of over 150,000 , a small state branch of Kerala with just 10,000 members have tried very sincerely to put an end to this kick back practice, with no convincing results.In other words, the issue is not medical, but social and ethical and political ( remember, Rudolf Virchow's words " medicine is nothing but politics writ large".)
Surely, the suggestion of Prof. Goadsby has to be heeded to , not only by health managers , but public too. A conscientious general practitioner or a family medicine practitioner will often be in a much better position to judge whether his patient with headaches needs a scan or not. In countries like India, a new breed of highly qualified general or family practitioners have come up in recent years. They are actually fully trained and qualified internal medicine specialists who reach out to the masses just because they can not remain confined to big cities and big hospitals,due to the sheer increase in number of them. Their higher performance rates compared to the general practitioners who only have a primary medical qualification, has also lead to a corrective influence on the sub specialists who have to maintain their credibility with reference to cases referred to them for opinion. So long as scan is not an inexpensive investigation like a chest x ray, restraint has to be exerted on the number of likely negative scans. Probably more important is the radiation risks from a CT scan which is not justifiable, especially when it is not a clinically indicated scan. Not only patients , but some times doctors also tend to forget or underestimate this point as I have seen many do not want to believe that a CTscan of Chest will give a patient a radiation exposure equivalent to 400 chest X rays.
References:
1.To scan or not to scan in headache Peter J Goadsby http://bmj.com/cgi/content/full/329/7464/469?ecoll
2.Ramachandran PV, Nandakumar A et.al. Positivity in Computerised Tomographic Imaging-A Retrospective Analysis of 5000
cases.Calicut Medical Journal 2004;2(2):e6. URL: http://www.calicutmedicaljournal.org/2004/2/2/e6
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