MRI Head Without IV Contrast There may be unique instances where a brain MRI examination may be useful in confirming a suspected clinical diagnosis responsible for AMS, such as carbon monoxide poisoning, Wernicke encephalopathy (thiamine deficiency) [40], drug toxicity including medications (eg, methotrexate, metronidazole) and illegal drug use, central pontine myelinolysis, or additional metabolic disorders. However, the literature search did not identify any studies regarding the use of MRI relevant to this variant. Altered Mental Status, Coma, Delirium, and Psychosis Variant 4: Adult. Altered mental status despite clinical management of known medical illness or toxic- metabolic cause. Initial imaging. This is a challenging clinical scenario in which common and treatable causes of AMS have been deemed unlikely, and a more exhaustive evaluation is required to find the precipitating cause of AMS. Clinical suspicion for a neurologic cause of AMS may be in an intermediate category. CT Head With IV Contrast Contrast-enhanced CT examinations are usually not performed as a first-line test in this setting but may be considered as a second-line test to assess abnormalities found on the screening head CT and for patients unable or unwilling to have MRI [28]. Evidence guiding appropriate imaging recommendations in this variant is limited because most studies in the literature search sampled undifferentiated patient populations with a broad range of risk factors and are not directly applicable to this variant [2,29,31-33]. CT Head Without and With IV Contrast A common practice is to perform a noncontrast screening head CT followed by a more sensitive MRI brain examination performed with and without IV contrast in the setting of AMS. There is no relevant literature to support the use of CT head without and with IV contrast in the initial imaging of this clinical scenario.
Altered Mental Status Coma Delirium and Psychosis. MRI Head Without IV Contrast There may be unique instances where a brain MRI examination may be useful in confirming a suspected clinical diagnosis responsible for AMS, such as carbon monoxide poisoning, Wernicke encephalopathy (thiamine deficiency) [40], drug toxicity including medications (eg, methotrexate, metronidazole) and illegal drug use, central pontine myelinolysis, or additional metabolic disorders. However, the literature search did not identify any studies regarding the use of MRI relevant to this variant. Altered Mental Status, Coma, Delirium, and Psychosis Variant 4: Adult. Altered mental status despite clinical management of known medical illness or toxic- metabolic cause. Initial imaging. This is a challenging clinical scenario in which common and treatable causes of AMS have been deemed unlikely, and a more exhaustive evaluation is required to find the precipitating cause of AMS. Clinical suspicion for a neurologic cause of AMS may be in an intermediate category. CT Head With IV Contrast Contrast-enhanced CT examinations are usually not performed as a first-line test in this setting but may be considered as a second-line test to assess abnormalities found on the screening head CT and for patients unable or unwilling to have MRI [28]. Evidence guiding appropriate imaging recommendations in this variant is limited because most studies in the literature search sampled undifferentiated patient populations with a broad range of risk factors and are not directly applicable to this variant [2,29,31-33]. CT Head Without and With IV Contrast A common practice is to perform a noncontrast screening head CT followed by a more sensitive MRI brain examination performed with and without IV contrast in the setting of AMS. There is no relevant literature to support the use of CT head without and with IV contrast in the initial imaging of this clinical scenario.