Non-organic neurological diseases

Published on 12/04/2015 by admin

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Last modified 12/04/2015

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5 Non-organic neurological diseases

Introduction

Many believe that the diagnosis of functional, and for that read non-organic or psychological, disease should be a diagnosis of last resort. Those advocating this approach adopt the view that one should never have functional illness as the number one diagnosis. They believe one should only entertain the possibility after all other potential diagnoses have been excluded. The problem with this concept is that it has the capacity to encourage ‘sick’ behaviour. It reinforces that there is something seriously wrong.

The need for an exhaustive list of investigations before broaching the topic of psychological illness suggests that the true diagnosis is beyond the doctor’s capacity to discern. It suggests that the label of ‘functional illness’ is a euphemism for medical ignorance or incompetence. This may be more worrying to the anxious patient than would be an early identification of the probable diagnosis of psychological illness.

It does not mean that the provisional diagnosis of non-organic disease should exclude investigation for alternative differential diagnoses. While a provisional diagnosis is the most likely answer, it is not the only possibility. The same applies to the provisional diagnosis of functional illness. Nevertheless, an early acknowledgement that the most likely diagnosis is non-organic serves to reinforce that the doctor retains clinical acumen, assuming that there are valid reasons for placing the ‘functional’ label as the most likely diagnosis.

To consider what some claim a diagnosis of last resort necessitates the clinician appreciating those features of non-organic diseases that justify placing them at the top of the diagnostic ladder. What follows in this chapter is the evidence upon which a diagnosis of non-organic disease can be suspected as the principal diagnosis.

Observation

In earlier chapters it was proposed that an astute receptionist may be invaluable in suspecting psychological illness. A patient may display a range of behaviours that lead to the suspicion of non-organic disease. A receptionist may note how the behaviour changes when the attending doctor is, or is not, in the waiting room. The way the patient walks into the room or excessive complaint of pain without attendant signs may raise suspicion. These features suggest malingering and patient complicity in the claim of symptoms and signs. The patient may benefit from a fraudulent claim, as might occur following an accident. An experienced general practitioner will be atuned to such behaviour, which will not be discussed further in this chapter.

History

As was stated earlier, the taking of an accurate medical history remains a fundamental tool of the neurological consultation. Within the context of functional illness, other than the case of a malingerer who wilfully aims to confound the picture, the patient usually is unaware of the possibility of a non-organic diagnosis. As with so many neurological diagnoses, including non-organic neurological presentations, the doctor must maintain a high index of suspicion. This is imperative if the diagnosis is to be identified as early as possible. Often the diagnosis of non-organic disease emerges because the history in these cases makes little sense, does not suggest a diagnostic label and confuses, rather than assists, the clinician.

Whenever the history fails to offer clinical diagnostic direction, the possibility of functional illness should arise. In these circumstances functional illness should not climb the diagnostic ladder, but merely be included among the potential diagnoses. It is part of the differential options but lacks credibility to be a principal choice. The provisional diagnosis should be based on positive factors, and confusion is far from positive, but may provide an important clue.

Having made the distinction, history is the tool that differentiates tension-type headache from migraine. Tension-type headache may well be a ‘front’ for non-organic disease. Particularly in societies in which physical fitness is a primary requirement, as is the case for members of the armed forces, patients often find it unacceptable to present with complaints of a psychological nature. Once tension-type headache becomes apparent, then the general practitioner is in an ideal position to seek and deal with the cause of the tension. The same applies to various complaints of pain. An example of this is the chest pain that accompanies da Costa’s syndrome, which is a left inframammary pain attached to stressful situations. It is unlike the pain that reflects ischaemic heart disease or chest infection. This should raise the red flag of probable psychological illness but this warning does not negate the need to investigate for both cardiac and pulmonary disease. An early suggestion that the primary diagnosis is most likely non-organic, allows a strengthening of the doctor–patient relationship and potential for mutual respect while the auxiliary investigations proceed.

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