AFTER THE HISTORY AND EXAMINATION, WHAT NEXT?

chapter 6


After the History and Examination, What Next?


Upon completing the history and examination, the next step is determined by the following factors:



This chapter will discuss each of these aspects and how they influence the course of action.



LEVEL OF CERTAINTY OF DIAGNOSIS


There are three possible scenarios:




A particular diagnosis seems certain


In most instances the diagnosis is apparent. In the general practice setting almost 90% of diagnoses are established at the completion of the history and examination [1]. In one outpatient clinic this figure was 73% (history 56% and examination 17%) in patients with cardiovascular, neurological, respiratory, urinary and other miscellaneous problems [2]. In patients with neurological problems the initial diagnosis is less obvious and was correct in only 60% of patients presenting to an emergency department [3]. In this setting the appropriate course of action is to initiate investigations that can confirm the diagnosis, exclude alternative diagnoses with potentially more severe adverse outcomes and institute a plan of management taking into account factors in the past, social and medical drug history that would influence management in this particular patient.


A word of caution: being absolutely certain is potentially the most dangerous scenario. Doctors are strongly anchored by their initial diagnoses [4] (see Case 6.1) and are at risk of closing their minds to possible alternatives, often in the presence of clinical features or results from investigations that should raise doubt about the diagnosis.



Doctors recognise patterns of familiar problems with respect to critical cues [6]. Doctors who are more experienced appear to weigh their first impressions more heavily than those who are less experienced and at risk of closing their minds early on in the diagnostic process [7]. Even experienced clinicians may be unaware of the correctness of their diagnoses when they initially make them [8].


If there are tests to confirm the diagnosis, it is appropriate to perform those tests, provided the patient is informed of the risks associated with them. When ordering tests and reviewing the results, it is most important to be aware of the sensitivity and specificity and the influence of the prevalence of the disease on the positive predictive value and the negative predictive value of those tests [9] (for a discussion of these concepts, refer to the section ‘Understanding and interpreting test results’ below).


If there are no tests, one can proceed cautiously with management, but it is most important to review the response to therapy. A lack of response to therapy or the emergence of unexpected side effects (the latter is a personal observation) is often a clue that the diagnosis is incorrect. Conversely, a response to a therapy does not prove the diagnosis. This author has seen patients with vertebral artery dissection, viral meningitis and pituitary cysts ‘respond’ to treatment for migraine. This is discussed in more detail below.



There are several possible diagnoses


It is imperative to keep the diagnostic options open by making provisional diagnoses while keeping alternatives in mind. Be circumspect and take action to minimise the possibility of missing other critical diagnoses [10]. Once again, if there are tests that can differentiate one particular diagnosis from another, it would be most appropriate to perform those tests. If a specific diagnosis cannot be made following the investigations, the approach is similar to that discussed in the following section.



You have no idea what is wrong


In the setting of uncertainty there are several possible courses of action. A particularly useful strategy is to start again: take a more detailed history and repeat the examination.1 This is the approach recommended when you have absolutely no idea what the diagnosis is. In this situation performing many tests is often misleading because of the sensitivity and specificity of tests.


If you have elicited a detailed history, but still have no idea what is wrong with the patient, there are several options including:



These various approaches will be discussed in terms of their relative merits and deficiencies.



WAIT AND SEE


In resolving uncertainty, time is a very powerful diagnostic tool. The idea is to wait for a period of time in the hope that the diagnosis becomes clear or the patient gets better [10], [11]. The effective use of this approach requires considerable skill, however. Often in this situation a doctor may order unnecessary tests in the hope that a diagnosis may be established; most often it is not. If the ‘wait and see’ approach is adopted, it is important to:



Shared medical decision making is a process in which patients and providers consider outcome probabilities and patient preferences and reach a healthcare decision based on mutual agreement. Shared decision making is best employed for problems involving medical uncertainty [12]. However, it is important to consider the fact that not all patients wish to be involved in shared medical decisions [13].



UNDERTAKE INVESTIGATIONS


In most cases there are tests that can confirm or exclude a particular disease. In this situation it is important to understand the concepts of the sensitivity and specificity of tests and the importance of prevalence of the disease. The essential questions to ask when considering investigations include:



There is a more detailed discussion of investigations later in this chapter.


There are no tests for some diseases and the diagnosis is based entirely on the clinical features. When there are several possible diagnoses or when one has absolutely no idea what the diagnosis might be, performing numerous tests in the hope of making a diagnosis is a wonderful way of giving the illusion that something useful is being done when often all that may be achieved is stalling or buying time. It is a tactic that is used by a number of clinicians in the hope that a diagnosis will be made by a test result (unlikely), the illness will progress so that the diagnosis will become apparent or the patient’s problem will resolve. A reasonable approach is to think of the worst case scenario (the most serious diagnosis that the symptoms could represent, a diagnosis that if missed could result in an adverse outcome) and proceed accordingly.



OBTAIN A SECOND OPINION


Although doctors prefer to obtain information from journals and books, they often consult colleagues to get answers to clinical and research questions [14], [15]. Even for doctors whose first choice of information source was the medical literature – either books or journals – the most frequent second choice was consultations [14].


In a study of 254 referrals seen by a neurologist there was a significant change in diagnosis in 55%, and in management in nearly 70% [16].


There are several ways of obtaining a second opinion:





Corridor or curbside consultation: ‘Corridor or curbside consultation’ is another approach used often [17]. Unfortunately, and sometimes with dire consequences, this is used by medical practitioners to seek informal advice about their own medical problems. The model of a good curbside consultation ‘is to say what you know and what you don’t know. Then you hope the person you are consulting with will treat you with respect’ [17]. Requesting doctors who could not present relevant information, frame a clear question or answer consultant questions in a well-informed manner were generally asked to formally refer the patient [17]. Perley et al [17] commented that tacit rules govern curbside consultation interactions, and negative consequences result when the rules are misunderstood or not observed.


Once again, the correct advice very much depends on being given the correct information. The neurologist providing advice will want to know the mode of onset and progression of the symptoms of the current illness together with the EXACT nature and distribution of the symptoms and the abnormal neurological signs, if present. It is difficult for inexperienced clinicians to perform detailed neurological examinations but there should be no reason why, as outlined in Chapter 2, ‘The neurological history’, an inexperienced clinician cannot obtain a detailed history. Finally, the neurologist would want information about the social, past and drug history that may influence any subsequent course of action.






SEARCH THE INTERNET


An increasingly popular and useful strategy is to search the Internet3 [1820]. Patients frequently look for answers on the internet [21]. In the author’s own experience many patients bring the results of their searches to the consultation. In one study [19] Google was able to make the correct diagnosis in 58% of the cases in the New England Journal of Medicine clinical-pathological conferences. In a comparison of PubMed, Scopus, Web of Science and Google Scholar, the keyword search function of PubMed was superior. While Google Scholar could retrieve the most obscure of information, its use was marred by inadequate and less frequently updated citation information [22]. Searching in Google Scholar can be refined by adding + emedicine to the search [23]. For example, ‘trigeminal neuralgia’ yields 48,000 ‘hits’ while ‘trigeminal neuralgia + emedicine’ retrieves 478 references. Many remain skeptical [24] and, as recently as 2 years ago, Twisselmann stated that the jury is still out on whether searching for symptoms on the Internet is the way forward for doctors and consumers [25].


The author has adopted the practice of frequently consulting the Internet even in the midst of a formal consultation.4 It is a useful way to look for any new advances in therapy, to provide information to the patient or referring practitioner by adding the abstracts and references to the letter or even to search for an obscure diagnosis (see Case 6.2).


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Jun 19, 2016 | Posted by in NEUROLOGY | Comments Off on AFTER THE HISTORY AND EXAMINATION, WHAT NEXT?

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