Delirium and severe illness: Etiologies, severity of delirium and phenomenological differences

Our aim was to examine the characteristics of delirium in the severely medically ill cancer population on the basis of sociodemographic and medical variables, delirium severity, and phenomenology, as well as severity of medical illness.

All subjects in the database were recruited from psychiatric referrals at Memorial Sloan Kettering Cancer Center (MSKCC). Sociodemographic and medical variables, as well as the Karnofsky Performance Status (KPS) scale and Memorial Delirium Assessment Scale (MDAS) scores were recorded at baseline. Subsequently, these variables were analyzed with respect to the severity of the medical illness.

Out of 111 patients, 67 qualified as severely medically ill. KPS scores were 19.7 and 30.7 in less severe illness. There were no significant differences with respect to age, history of dementia, and MDAS scores. Although the severity of delirium did not differ, an increased frequency and severity of consciousness disturbance, disorientation, and inability to maintain and shift attention did exist. With respect to etiologies contributing to delirium, hypoxia and infection were commonly associated with severe illness. In contrast, corticosteroid administration was more often associated with less severe illness. There were no differences with respect to opiate administration, dehydration, and CNS disease, including brain metastasis.

Delirium in the severely medically ill cancer population has been characterized by an increased disturbance of consciousness, disorientation, and an inability to maintain and shift attention. However, the severity of illness did not predict severity of delirium. Furthermore, hypoxia and infection were etiologies more commonly associated with delirium in severe illness, whereas the administration of corticosteroids was associated with less severe illness.