Causal reasoning and the diagnostic process.

BACKGROUND: Causal reasoning as a way to make a diagnosis seems convincing. Modern medicine depends on the search for causes of disease and it seems fair to assert that such knowledge is employed in diagnosis. Causal reasoning as it has been presented neglects to some extent the conception of multifactorial disease causes. GOAL: The purpose of this paper is to analyze aspects of causation relevant for discussing causal reasoning in a diagnostic context. PROCEDURES: The analysis will discuss different conceptions of causal reasoning in medical diagnosis, discriminating primarily between narrow causal diagnosis and more thorough causal explanation. The theory of causes as non-redundant factors in effective causal complexes is used as an analytical background. Causal explanations are performed according to different causal models. Such models of diagnosis are assumptions concerning structure and mechanisms, which cannot be directly or immediately observed. Conceptions and results of causal search strategies differ, according to the focus of the searcher. Causal reasoning is also seen in diagnosis in a more extensive meaning: the pin-pointing of factors responsible for the condition of the patient at any time during the course of disease. CONCLUSION: Causal reasoning and diagnosis go well in hand, especially if both concepts are widened. The theory of causes as non-redundant components in effective causal complexes, modulated by what is referred to as the stop problem and causal fields, is valuable for explaining the many aspects of causal reasoning in medical diagnosis.

Medical prognosis--some fundamentals.

BACKGROUND: The concept of prognosis as a prediction concerning the probable outcome of an attack of disease shows some severe contextual drawbacks in the everyday clinical sense. It is often used to describe possible outcomes of the disease in general, or the progression of a disease course, not the expected course in a particular case. GOAL: To render more discriminating uses of the term prognosis, in order to provide the prognosticating physician with a valid tool, comparable to the theoretical basis of diagnostic and therapeutic actions. PROCEDURES: Analysis and discussion of etymology, definition and practical usage. CONCLUSION: Prognosis is not to be considered soothsaying, but forecasting on qualified grounds. Prognostic statements are announcements containing prognostic information. Prognostic factors are pieces of information associated with a specific outcome of disease, which can be utilized in the formulation of the prognosis. Prognostic estimates involve subjective probability and can be formulated by using frequencies along with (clinical) experience. A prognosis is a prediction of a particular future stage of disease, considering a single case--the prognosis is neither part of the patient, nor part of the disease.

Causality in medicine: towards a theory and terminology.

One of the cornerstones of modern medicine is the search for what causes diseases to develop. A conception of multifactorial disease causes has emerged over the years. Theories of disease causation, however, have not quite been developed in accordance with this view. It is the purpose of this paper to provide a fundamental explication of aspects of causation relevant for discussing causes of disease. The first part of the analysis will discuss discrimination between singular and general causality. Singular causality, as in the specific patient, is a relation between a concrete sequence of causally linked events. General causation, e.g. as in disease etiology, means various categories of causal relations between event types. The paper introduces the concept of a reference case serving as a source for causal inference, reaching beyond the concept of general causality. The second part of the analysis provides exemplification of a theory of causation suitable for discussing singular causation. The chain of events that induce a disease state can be identified as effective causal complexes, each complex composed of non-redundant components, which separately contribute to the effect of the complex, without the individual component being necessary or sufficient in itself to produce the effect. In the third part of the analysis the theory is elaborated further. Causes, defined as non-redundant components, can furthermore be differentiated according to their avoidability, according to theories about human error or by the potential of eradication. Multifactorial models of disease creates a need for systematic approaches to causal factors. The paper proposes a taxonomical terminology that serves this purpose.

[Causes of death in patients with cerebral neoplasms]. / Dødsårsagen ved neoplasma cerebri.

The case records of 41 patients with cerebral cancer and their death certificates were reviewed with the object of investigating clinicians' causal reasoning. No really clear impression could be obtained. The case records did not contain any reflections about clinical or paraclinical conditions which might be related to conceptions of causality. The death certificates contained errors and deficits which were so serious in 44% of the cases that the death certificate presented an erroneous picture of the cause or causes of death. Minor errors were encountered in further 19% of the death certificates. These involved logically untenable statements of causes in 11 certificates (27%), statements about conditions which were not in agreement with the reports in 13 cases (32%) and errors in the statements about duration in ten cases (24%). These results scarcely express doctors' causal reasoning but rather that there is no uniform conception of how death certificates should be completed.

[Medical diagnosis]. / Medicinsk diagnostik.

The diagnostic process holds a firm position in medical practice, but is often claimed to be part of the "art of medicine", partially beyond reach of rational and logical analysis. Research in clinical cognition, decision analysis and artificial intelligence have, however, elucidated essential parts of medical diagnosis. A characteristic feature of diagnosis is the manner in which uncertainties are handled. Early generation of hypotheses about the nature of the condition present seems to be useful method. Similarly, probabilistic, causal and deterministic reasoning can be illustrated by diagnostic models which have found favor during recent years. A certain type of cognitive process (heuristic) is employed when assessing information of probabilistic nature. The diagnostic models are partial and concern the parts of the process, which may be represented verbally and consciously. This raises the question of how the clinician actually draws upon experience (background knowledge), which preconditions shape the generation of applicable diagnostic hypotheses and how the diagnostic capability of the individual physician can be facilitated.

[Classification of diseases--is a systematic approach only possible at the expense of applicability?]. / Klassifikation af sygdomme--kan systematik kun opnås på bekostning af anvendelighed?

Classification of diseases is a practical tool in clinical and scientific medicine, but it is not free of problems. Using for example WHO's classification of diseases as a starting point, an example of the problems is given in the article, with reference to both methodological and philosophical points of view. It is suggested that pragmatic taxonomies with several dimensions, which would be useful for more than just a handful of clinicians, should be created. Subsequently, this type of classification can be revised in accordance with theoretical ideal requirements and considerations.

Sexual dysfunction in male and female patients with epilepsy: a study of 86 outpatients.

Sexual dysfunction is a well-known complication of chronic somatic illness. Eighty-six consecutive epileptic outpatients, 38 men and 48 women, without accompanying disorders, were studied. The frequency and symptoms of sexual dysfunction were compared with results from previous studies using identical sexological methodology. The previous studies were of diabetic patients and healthy controls. Eight percent of the epileptic men reported a sexual dysfunction compared to 44% of the diabetics and 13% of the controls. Epileptic women, diabetic women, and controls showed no significant differences in sexual dysfunction (29%, 28%, and 25%, respectively). In both sexes, the sexual function measured by frequencies of coitus and masturbation was normal. Most patients had good control of epileptic attacks on a treatment of monotherapy. Hormonal status was generally within normal limits in both men and women; only a few minor differences were found and they showed no correlation with sexual dysfunction. Psychologically and socially the patients did not differ appreciably from normals, and they exhibited a high degree of disease acceptance. This study, using a biopsychosocial approach in understanding sexual dysfunctions, is in contrast with previous, mainly uncontrolled, studies of epileptic patients that reported high frequencies of "hyposexuality" in males. We conclude that epilepsy does not necessarily increase the risk of sexual dysfunction in male or female.

[Altitude sickness]. / Bjergsyge.

The interest in mountain tracking and climbing has increased and there is a need for knowledge of altitude-related diseases. About one million non-acclimatized individuals annually frequent areas around 2,000 to 3,000 m above sea level and incur unpleasant symptoms in the form of acute altitude sickness or potentially fatal conditions such as pulmonary and/or cerebral oedema. Headache is the most prominent sign of acute altitude sickness but fainting fits, loss of appetite, hesitant gait, euphoria, or confusion also occur. Dyspnoea, cyanosis at rest, and a dry cough are signs of pulmonary oedema. Cerebral oedema may be feared when inexperienced climbers are afflicted by severe headaches, vomiting, and hesitant gait. Coma ensues relatively soon. Treatment consisting in descent to lower altitude, administration of oxygen, and possible medicinal therapy is effective if immediately introduced.

The frenulum labii inferioris laterale.

A lateral counterpart to the frenulum of the lower lip, located between the dens caninus and the area of the angle of the mouth is reviewed. Anatomical considerations are discussed and the term frenulum labii inferioris laterale is suggested.