Background: Contrast induced encephalopathy (CIE) following radiographic procedures, though a well-recognized complication, occurs sporadically enough that its diagnosis, prognosis, and treatment remain undefined and varied.
Objective: We sought to identify clinical and radiographic criteria as well as treatment experience vis a vis reported outcomes.
Methods: We identified case reports in PUBMED using search terms “contrast induced encephalopathy/neurotoxicity” from which we collected clinical and radiographic variables.
Results: Among 52 reports (total 79 patients, including our own unpublished 3 cases) the mean age was 60±16 years, with similar gender distribution. Multiple different contrast media were used (mean dose, 207 ±158 mL). Onset was typically immediate, though delayed cases up to 39 days later occurred. There were 3 confirmed cases (n=2, direct evidence of contrast in cerebrospinal fluid; n=1, autopsy excluded other cause of abnormality) which we classified as ‘definite CIE’. No imaging hallmark features were described in 30 patients, whom we classified as ‘possible CIE.’ The remaining 47, ‘probable CIE,’ demonstrated either diffuse edema or enhancement, with the latter being a more common finding (enhancement=33, 42% vs 11, 14%). Administered treatments included: hydration (n=31), steroids (n=10), hyperosmolar agents (n=4), anti-hypertensives (n=3), anti-convulsants (n=3), thrombolytics (n=3), hemodialysis (n=2), hemicraniectomy (n=1), and n-acetylcysteine. (n=1). There was no correlation between imaging features nor treatment modality and final outcome. Resolution occurred within 5 ±9 days. While most patients improved, 9 (11%) had no/incomplete improvement including 2 (2.5%) who expired. The 2 fatal cases occurred among the only 2 children in the entire series, p<0.001.
Conclusion: The diagnostic approach to CIE may be systemized based on the identification of hallmark radiologic findings, which, whether present or absent, do not appear to affect outcome. Though hydration and supportive remedies are most common, other treatments were not associated with hastened or worsened symptom resolution. And while the outcome of CIE among adults is generally benign, it may be fatal in children.