Examination of the central nervous system in the critically ill patient: Important clinical signs and diagnoses

Curiously, there are wide differences in the admission rates to intensive care units (ICU) due to neurological illness. For example the Intensive Care Society's study of 26 units in the UK and Ireland reported an admission rate for neurological illness of between 2.9 and 23.1% (mean 9.4%) for all ICU admissions. Another study, of a single ICU in Chicago, reported that only 4.9% of 1850 admissions were due to neurological illness. This lower incidence probably reflects the exclusion of patients with drug overdose from the diagnostic category. Importantly, these authors went on to demonstrate that among the remaining patients (95.1%), 12.3% developed one or more neurological complications while in the ICU. Moreover the development of neurological complications worsened the patient's prognosis in terms of mortality and duration of ICU stay. This background of neurological morbidity in the ICU emphasises the importance of the neurological examination of critically ill patients; without such an examination, diagnoses will be missed, treatment inadequate and estimates of prognosis inaccurate.