Delirious after undergoing workup for stroke
Ms. L, age 91, experiences acute altered mental status after undergoing routine evaluation of an episode of left-sided weakness. What could be causing her symptoms?
Routine EEG was clinically inconclusive. Diffusion-weighted MRI may have been helpful to identify ischemic strokes that a CT scan of the head might miss,1 but we were unable to conduct this test because Ms. L had a pacemaker. Barber et al2 suggested that in the setting of acute stroke, the use of MRI may not have an added advantage over the CT scan of the head.
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TREATMENT Rapid improvement with supportive therapy
Intravenous fluids are administered as supportive therapy to Ms. L for suspected contrast-induced encephalopathy (CIE). The next day, Ms. L experiences a notable improvement in cognition, beyond that attributed to IV hydration. By 3 days post-contrast injection, her SLUMS score increases to 15. By 72 hours after contrast administration, Ms. L’s cognition returns to baseline. She is monitored for 24 hours after returning to baseline cognitive functioning. After observing her to be in no physical or medical distress and at baseline functioning, she is discharged home under the care of her son with outpatient follow-up and rehab services.
The authors’ observations
For Ms. L, the differential diagnosis included post-ictal phenomenon, new-onset ischemic or hemorrhagic changes, hyperperfusion syndrome, and CIE.
Seizures were ruled out because EEG was inconclusive, and Ms. L did not have the clinical features one would expect in an ictal episode. Transient ischemic attack is, by definition, an ischemic event with clinical return to baseline within 24 hours. Although a CT scan of the head may not be the most sensitive way to detect early ischemic changes and small ischemic zones, the self-limiting course and complete resolution of Ms. L’s symptoms with return to baseline is indicative of a more benign pathology, such as CIE. New hemorrhagic conversions have a dramatic presentation on radiologic studies. Historically, CIE presentations on imaging have been closely associated with the hyperattentuation seen in subarachnoid hemorrhage (SAH). The absence of typical radiologic and clinical findings in our case ruled out SAH.
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