2 Diagnosis: the process and the result
It is assumed that at this stage you will have knowledge/competencies in the following areas:
If you think that you are not competent in these areas, revise them before reading this chapter or cross-check with relevant texts as you read.
In courses in oral surgery and oral medicine undergraduates come face to face with disorders, which they need to unravel, using a range of interview and examination techniques, before treatment planning. It is worth thinking in some detail about how to get the maximum benefit from the process and the best understanding of the result. A comprehensive evaluation of a patient’s problem involves history taking and physical examination.
Over many years a standard method of performing and recording the history and examination has evolved. This is useful, both for communication with colleagues and for structuring clinical practice. Because this examination is a significant event for most patients, the examiner must display a professional attitude in order to develop the patient’s trust. Ensuring the patient’s cooperation is an important part of achieving the correct diagnosis.
The scene must be set carefully, and the examination carried out in privacy with a chaperone if necessary. The clinician should exhibit appropriate body language to encourage the patient’s confidence. For example, sitting face to face at the same level as the patient is more reassuring than standing over a patient reclined in a dental chair.
The written medical notes are a record of the course of the patient’s care and may have to be submitted in evidence in a case of litigation. Therefore, use of humorous remarks and unusual abbreviations is inappropriate in the notes.
Diagnosis may reflect a clinical picture, histological features, tissues involved, microbial cause, or other perceived mechanisms of disease and is not drawn from a unified taxonomic system. It is common to find variation in disease naming because of dispute over the nature of a condition or the particular impact that one name or another may have on those using it. Names of some disorders may also change under the influence of national or international organizations. For example, some previously common diagnoses such as ‘dropsy’ or ‘scrofula’ have disappeared as medicine has advanced.
You should not think of diagnosis as absolute, for you are not uncovering a predetermined truth. Rather you are measuring, comparing and estimating to move towards a functional grasp of your patient’s problem.
A systematic approach helps. Many clinicians begin with a conversation with the patient and work stepwise through examination until eventually they reach a diagnosis. In theory, this ensures that all questions that might be asked are asked, and that no points are missed.
We will start by describing how you can make the best of this style, but will follow up with additional material that more accurately reflects what experienced practitioners actually do.
The following sections are divided according to commonly used subdivisions in a patient record. The concept of this progression and the written record certainly help to keep one’s thoughts in a logical order.
The patient’s full name, address, date of birth, gender, ethnic origin and marital status should be recorded. Include the sources of information used in ascertaining the history. These may include the patient, relations and friends, an interpreter and any referral letters.
This is usually written as an abbreviation: C.O. (‘complaining of’). If you wish to write the complaint in the patient’s own words, ensure you put it in inverted commas’for example, ‘I’ve been in agony for ages with neuralgia’. Complaints can be multiple and should be dealt with one at a time.
This is usually written as H.P.C. Record the history chronologically, beginning with the onset and detailing the progress of the complaint to the present day.
In oral surgery the common complaints are of pain, swelling or lump, or ulcer. Allow the patient to tell the story in her or his own way and do not ask leading questions. Main points to cover include:
It is important to note recurrence of problems. For example, wisdom tooth infections may settle spontaneously, but tend to recur at intervals of weeks to months, whereas malignant tumours tend to be relentlessly progressive.
This is often written as P.M.H. A medical history is essential in order to assess the fitness of the patient for any potential procedure. The history will also help to warn you of any emergencies that could arise and any possible contribution to the diagnosis of the presenting complaint.
The medical history should be reviewed systematically.
In physical medicine it is common, after initial open questions about the patient’s general health, to ask questions in relation to each body system in turn: cardiovascular, respiratory, CNS, gastrointestinal tract (including the liver), genitourinary tract (including the kidneys), etc. It is essential also to ask specific questions about drug therapy, allergies and abnormal bleeding.
However, any system that ensures that all relevant questions are asked is satisfactory. It is equally important to follow up any positive responses to determine the full extent and implications of the condition. The patient’s general medical practitioner may provide additional necessary information or examine the patient afresh if appropriate.
It is important to record negative as well as positive findings in a patient’s dental history.
If a general anaesthetic or intravenous sedation might be considered, the American Society of Anesthesiologists Classification of Physical Status is useful (see Ch. 3, p. 19, Table 3.1).
Occupation, home circumstances and travelling arrangements should be reviewed so they can be used to help formulate the details of the treatment plan. For example, planning third molar surgery as an outpatient, for a parent with small children, with a one-hour journey to the surgery by public transport, returning to an empty house would be unsympathetic and unwise as the patient would have difficulty in dealing with postoperative complications such as haemorrhage or fainting.
Smoking and alcohol consumption should also be considered under this heading.
If the patient is new to your practice then you should note details of previous attendance and treatment. This would include the name and address of their previous practitioner, frequency of attendance and any problems relevant to the presenting complaint. The reason for discontinuing attendance at that practice should also be noted.
There are two ways of approaching the examination. You may look at the site of complaint first and subsequently carry out extraoral and intraoral examination. Alternatively you may do a systematic extraoral examination followed by a systematic intraoral examination, which will encompass the area of complaint. The patient might expect you to examine the site of complaint first and may be puzzled if your routine does not allow this.
The author favours extraoral examination followed by intraoral examination because, if a system is adhered to time after time, then no area is neglected in the enthusiasm of looking at the site of complaint. A colleague appointed to oversee primary oral health care receiving casual patients diagnosed nine new primary squamous cell carcinomas in the first six months, probably because of adherence to this system.
Be systematic in examination; start by inspecting the area of concern, then if appropriate, palpate it. In a full medical examination you might proceed to auscultation and percussion.
The general appearance of the patient should be considered. Do they look ill or well; are they anxious? Look for obvious upper respiratory tract infection. Note the skin complexion and mucosal colour for signs of anaemia or jaundice. Assess the body in general and the head and neck for signs of deformity or asymmetry. In trauma cases look carefully for lacerations and abrasions.
Look systematically at, or for:
The size of the oral cavity and the distensibility of the soft tissues should be noted. The soft tissues should then be examined in sequence, and this sequence should always be used by that clinician, so no area is omitted. A suggested sequence is:
Next, the teeth may be examined and charted using a conventional system to identify the number present and their distribution; noting dentures, crowns, bridges, implants, partial eruption of teeth and coronal disease. The periodontal condition should be noted.
The surgical or problem area should now be examined. Redness or swelling or inflammation should be noted, as should any discharge of pus. Look specifically for ulceration, erosion or keratosis of mucosal surfaces and for any lumps or deformity.
Consider which teeth may be involved in the disease process and whether any are in abnormal position.
When many diagnoses might explain the signs and symptoms of the chief complaint, a differential diagnosis is made. This is a list of possible diagnoses written in order of probability. It is unhelpful to arrange special tests unless there is a list of different possible diagnoses that must be distinguished.
Differential diagnosis initially involves the consideration and comparison of groups of diseases, but ultimately of perhaps two or three individual conditions with various clinical and pathological features in common. Whole groups of conditions, and then individual diseases, can be eliminated because certain features are unlike those of the patient’s illness. Ultimately a single condition is chosen on a ‘best-fit’ basis.
A diagnosis, therefore, involves the recognition of a specific pattern in the available data. Even in straightforward cases, alternative diagnoses should be considered, although they may rapidly be dismissed if they are clearly incorrect. This way any feature that may be inconsistent with the obvious solution and which suggests the possibility of some alternative explanation is not overlooked.
Dealing successfully with the variability of the disease and of the patient in whom it manifests is part of the intellectual pleasure to be gained from surgical practice. Here lies the value of clinical experience. No clinician has seen it all, but the more he or she has seen, the more likely he or she is to have seen a patient with a condition similar to the one being examined.
Often the history and clinical examination are not sufficient to clarify the diagnosis and enable a sound treatment plan to be drawn up. Further investigation might involve a wide range of measures, such as:
These investigations are key to reaching a sound diagnosis, but you should resist the common temptation to make the diagnosis solely on the basis of a radiograph (or any other individual investigation). This risks undervaluing clinical information.
The outcome of the history and examination should be a definitive diagnosis and a treatment plan, both of which should be recorded fully. The diagnosis can be multiple, in which case the treatment plan should relate to each complaint.
Before any treatment is carried out, it must be explained to the patient, other options discussed and possible complications explained.
All patients must be fully informed before any decision concerning treatment is made and no treatment should be performed without a patient’s full consent. Surgery is regarded as an assault on the body. Adults may give consent to such a process, but cannot be regarded as having consented if they do not fully understand the implications.
What a patient should be told should be influenced by what a reasonable patient could be expected to want to know. This is difficult to judge, so it is proper to offer more rather than less information. For example, surgery for an impacted wisdom tooth has potential complications of pain, swelling, trismus, altered sensibility of the lip and/or tongue. Patients should also be advised as to the likelihood of incidence, the approximate extent and probable duration of each of the problems.
The UK Department of Health provides extensive advice on consent on its website (DoH 2005). For patients under 16 years of age it is generally accepted that a parent or legal guardian will give consent on the child’s behalf. However, it is important to remember that a minor may withhold consent, if they are able to understand the issues involved: this must also be respected. For adults who are not competent to give consent it is appropriate to involve close family members or legal guardians and another non-involved individual, such as the medical practitioner, in determining whether the patient would consent to the procedure if they were able. Note: this is a rather different concept from the patient actually agreeing to the procedure!
The process of obtaining consent should include making a written record of the advice given to the patient and may require their signature to indicate consent, but the essential processes are the giving of information, the response to the patient’s additional enquiries and their indication of a willingness to proceed.
Consent may be withdrawn at any time. The patient’s wishes must be respected.
The process of diagnosis, as described earlier, tends to gather a great deal of information, much of which is not directly relevant to the specific condition from which the patient suffers. The process is complete, but inefficient.
Diagnosis for the expert is often a combination of:
Formation of questions in taking the history is in the form of a dialogue. It is an iterative process in which the result of one question or finding may reduce the search field or suggest a further question. The examination is also guided by the findings during the history and may prompt further questions. There is also a strong component of the ‘hypothetico-deductive’ reasoning recommended for scientific endeavour, by which a likely diagnosis (or list of diagnoses) is tested against the results found thus far. If the proposed diagnosis is not excluded, further evidence may be sought to support or refute the proposal. For example, if a patient volunteered that pain was centred in a particular tooth, was worsened by cold stimulation and had been present for a few days, the practitioner might ask specifically about any observed swelling or about pain in the tooth on pressure, to exclude periapical inflammation. It would still be necessary to examine lymph nodes and the oral mucosa as routine screening, but not because malignancy is anticipated as the cause of the pain. Failure to find caries or a large restoration in the tooth indicated by the patient would make you redouble your efforts to find a cause of pulpitis in an adjacent or opposing tooth.
What is not so clear is how, and to what degree, experienced clinicians place weight on particular clues, such as the change in a disease process over time. Some of this can be learned from books, some by asking more experienced colleagues, but sadly some must come from personal experience.
It still seems that, to arrive at a diagnosis and a treatment plan, you are going to have to remember the whole of medicine and dentistry all at one time, but fortunately the process can be eased somewhat by aides-mémoire and guidelines.
A surgical sieve is an aide-mémoire which cross-references disease processes and tissues involved.
Disease processes may be listed as:
Some lists will also include ‘vascular’ (e.g. stroke), ‘haematological’ (e.g. anaemias) or ‘cystic’ (particularly in relation to the jaws), all of which tend to cut across the other categories. However, as this is only an aid to memory, you may include whatever categories you find helpful.
The anatomical classification might include:
You may find it helpful to think which tissue plane is involved as well as the tissue type.
In this process you aim to link together knowledge of anatomy, physiology, pathology and human disease. But remember: a surgical sieve is not an end in itself. It is merely a tool to help you think about the range of possible diagnoses.
These may take the form of written texts or computer-based, interactive schemes. The latter have been shown markedly to improve the diagnostic accuracy of junior surgeons dealing with acute abdominal pain. Simple algorithms of the type ‘If A is true then branch right, then if B is true branch right again, etc.’ do not work well because there is rarely sufficient information at all of the required steps. However, systems that allow for missing data and place weighting on particular factors, shown by research to be indicative of specific conditions, can be very powerful.
At present, little of this sort of system is available for clinical decision-making in dentistry. Clinical guidelines on treatment planning, based on published evidence of efficacy, are, however, now becoming available for much of the subject.
It is said that ‘common things occur commonly’. This means that you should take some note of the likelihood of particular diagnoses before deciding what is wrong with your patient; however, you must do so with care. Toothache as pain referred from myocardial ischaemia is exceptionally unusual, but in a patient with pain in the left lower jaw which is worse on exercise and with no local dental disease in the upper or lower jaw on that side, it should be considered. If, on the other hand (as is much more likely), the pain becomes worse with local thermal stimulation and the lower first molar shows extensive caries, pulpitis should be considered. Similarly, just because oral carcinoma is rare in people under 40 years of age, you should not ignore the possible diagnosis in a 25-year-old patient.
If you are struggling with a diagnosis, it is more likely that your patient’s disorder is an unusual form of something common than an entirely new disease.
UK Department of Health (DoH). Consent key documents. [Online]. 2005 [cited 2005 September]. Available from: URL: http://www.dh.gov.uk/PolicyAndGuidance/HealthAndSocialCareTopics/Consent/ConsentGeneralInformation/fs/en.
Answers on page 262.