Psychological versus biological clinical interpretation: a patient with prion disease.

Abstract

Conversion disorder is a diagnosis based on a psychological construct that currently has no known neurobiologic substrate (1). This diagnosis is intended to be reserved for individuals who show deficits that do not conform to known neuroanatomy or neurophysiology. Conversion disorder is usually thought to relate to “secondary gain,” a remnant of a hypothesis that conversion symptoms were the result of the primitive resolution of unconscious conflicts, also known as “primary gain.” Today, secondary gain is used more as a psychosocial assessment and attempts to take into account how illness behavior, or the “sick role,” may be used to focus family, medical, and societal resources. Conversion symptoms are also considered by most clinicians to be an expression of intense distress, resulting from trauma that the emotionally fragile individual can only express somatically. Thus, along with the diagnosis of conversion disorder is the search for the insult or trauma precipitating the expression of the somatic symptoms. Prion diseases are a heterogeneous group of neurologic disorders that occur in familial forms affecting animals and humans. This can be through iatrogenic transmission or after ingestion of or exposure to affected tissues, or it can occur sporadically. These disorders are characterized by a confusing and invariably fatal array of clinical manifestations, including relatively rapid and progressive dementia, cerebellar ataxia, as well as the speech and visual abnormalities (2) seen in the most common form of human prion disease, Creutzfeldt-Jakob disease (3). Additionally, early in the disease course, nonspecific diffuse EEG abnormalities are found in most patients; later, diagnostic sharp-wave patterns are observed in 75%–85% of the patients with Creutzfeldt-Jakob disease. Finally, diagnostic confirmation relies on the neuropathologic examination of brain tissue obtained by biopsy or at autopsy, with demonstration of characteristic spongiform changes in the parenchyma. This case reflects the continuing dilemma within psychiatry to reconcile confusing clinical presentations and resolve discordant psychological and neurobiological constructs of axis I diagnoses. In retrospect, it also outlines the interaction of neuropathologic lesions, symptom profiles, and personality, and highlights the level of difficulty discerning the underlying etiology of complex clinical presentations.