To identify clinical indicators that assist in predicting acute abnormalities on head computed tomography (CT) scans in patients with altered mental status in the MICU.
This is a retrospective study of 100 patients admitted to the MICU between January 2001 and March 2002. Patients who developed altered mental status 48 hours or more after admission and subsequently had a head CT scan were reviewed. Data abstracted from the medical records were used to investigate the association between abnormal head CT scans and factors such as patients’ demographics, medical history, admitting diagnosis, length of stay, laboratory abnormalities (white blood cell count, coagulation profile, ammonia levels, blood urea nitrogen and creatinine), sedation, and focal neurological deficits.
Head CT scans were positive for acute abnormalities in 29% (29/100) of patients. Univariate analysis revealed age > 65 years (p=0.015), presence of a neurological deficit on physical examination (p<0.0001, and a history of myocardial infarction (p=0.030) as positive predictors for an abnormal head CT scan. Multivariate (Logistic Regression) analysis confirmed that age greater than 65 years (p=0.007; OR=9.9, 95% CI=1.9-52.2) and an abnormal neurological exam (p<0.0001; OR=21.0, 95% CI=4.1-106.6) as strong predictors for a positive head CT scan. The presence of a neurological deficit had a sensitivity of 59.7%, specificity of 87.9%, positive predictive value (PPV) of 66%, and a negative predictive value (NPV) of 84.9%.
In patients admitted to the MICU, who subsequently developed altered mental status, age greater than 65 years and a focal neurological deficit on physical examination were strong predictors for an abnormal head CT scan.
Older age and presence of a neurological exam are positive predictors of an abnormal head CT scan in critically ill patients.
A. Harandi, None.