Case report and literature review: Misdiagnoses of contrast encephalopathy as stroke

Abstract

Rationale: Contrast-induced encephalopathy (CIE) is a rare complication following carotid artery stenting, often mimicking stroke symptoms such as focal neurological deficits. Its transient nature and reversibility necessitate differentiation from critical complications like cerebral hemorrhage or infarction, as management strategies differ substantially. This case underscores the diagnostic challenges and clinical implications of CIE in endovascular procedures.

Patient concerns: A 65-year-old woman with a history of cerebral infarction and prior carotid artery stenting presented with persistent numbness in her extremities for over 1 month. Post-carotid artery stenting, she developed acute slurred speech and right-sided limb weakness within 1 hour, raising concerns for stroke or procedural complications.

Diagnoses: Emergency cranial computed tomography revealed left cerebral hemisphere swelling and linear hyperdensities, while magnetic resonance imaging demonstrated punctate diffusion-weighted imaging hyperintensities in the left parietal lobe. Temporal correlation of symptoms with iodixanol contrast administration (150 mL) supported a diagnosis of CIE, excluding acute infarction or hemorrhage.

Interventions: Immediate management included antiplatelet therapy (tirofiban), thrombolysis (urokinase), corticosteroids (methylprednisolone), and antiedema agents (mannitol and albumin). Supportive care emphasized hydration and neurological monitoring.

Outcomes: The patient exhibited progressive improvement, with complete resolution of speech and motor deficits by postoperative day 3. Neuroimaging abnormalities regressed, aligning with the transient nature of CIE.

Lessons: This case highlights the critical role of prompt neuroimaging to exclude life-threatening differentials and confirms CIE's reversibility with supportive care. Risk factors such as contrast volume and cerebral circulation dynamics warrant attention. Clinicians should exercise caution in readministering iodinated contrast to patients with prior CIE episodes.

Figure 1.

Comparison of patients with carotid artery stenting before and after implantation. (A) The last left general carotid artery stenosis in the DSA. The yellow arrow is the stent shadow of the last general carotid artery stent implantation. (B and C) Unobstructed stent insertion lumen in the DSA. DSA = digital subtraction angiography.

Figure 2.

CT scan of the brain immediately after stenting when the patient developed symptoms. (A–I) Multiple high-density strips were observed in the left cerebral hemisphere, part of the right frontal sulcus, cerebral falx, and cerebellar curtain. Edema of brain tissue was also observed. CT = computed tomography.

Figure 3.

Follow-up cranial MRI after CAS. (A) Magnetic resonance DWI imaging after CAS, DWI point-like high signal in the left parietal lobe, with possible acute/subacute cerebral infarction. (B) Magnetic resonance ADC imaging after CAS. ADC = apparent diffusion coefficient, CAS = carotid artery stenting, DWI = diffusion-weighted imaging.