Left heart catheterization may cause cerebral microemboli leading to acute ischemic stroke with morphological changes in a brain and acute cognitive impairment [5]. However, cognitive abnormalities can be also related to the use of contrast dye and its influence on central nervous system function. The present case report describes a unique presentation of CIE with concomitant visual and auditory hallucinations. To the best of our knowledge, this is the first case of a patient with such a manifestation of CIE triggered by coronary angiography.

The underlying pathomechanism of CIE still remains a matter of debate. The most plausible one is a “disruption” of BBB integrity caused by a contrast agent and its direct neurotoxic effect [1, 4]. The overwhelming majority of CIE cases are reversible and have no significant long-term effects. Patients spontaneously recover within hours or days (as presented in this case); however, more severe and fatal cases have also been reported [6, 7]. Interestingly, the present patient started having visual and auditory hallucinations lasting for 5 days. While the formers have been reported (two cases to date), the latters have never been documented in the course of CIE [8].

CIE may present with a variety of symptoms (confusion, headache, seizures and rarely focal neurological deficits), but the most common manifestation is transient cortical blindness, presumably due to higher occipital BBB permeability [1, 4]. We posit that this mechanism was responsible for visual hallucinations in the presented case. The auditory hallucinations are a completely novel finding requiring further investigation.

From clinical standpoint, the key issue is to identify patients at risk, and to establish preventive and therapeutic strategies. Hypertension, diabetes, renal impairment, impaired cerebral autoregulation and male gender are among risk factors for CIE [1]. A type of a contrast agent is also of vital importance. Iodixanol which was used in the present case is a nonionic iso-osmolar agent, less neurotoxic compared to older hypertonic contrast media. However, even a low volume of this agent may potentially cause a devastating CIE [7]. Interestingly, post-CIE patients do not necessarily develop this complication again upon reexposure to contrast dye [9]. The above-mentioned findings imply that CIE occurs in a sporadic fashion at any dosage, and with all types of contrast agents. As a consequence, the unpredictability of CIE recurrence may prevent health professionals from referring post-CIE patients for coronary procedures, even when they are strongly indicated, which might be one of the underestimated and detrimental effects of CIE.

Currently, no specific preventive measure or treatment is available. The use of the lowest possible volume of less neurotoxic contrast agents is recommended. Steroids and mannitol are anecdotally used, but no reliable data on this have been provided to date [1, 6]. Finally, and perhaps most importantly, given the self-limiting nature of CIE in vast majority of cases, it is crucial to exclude more deleterious clinical conditions and prevent a patient from receiving a potentially harmful treatment (e.g., thrombolytic therapy).