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Présentation atypique d’une dissection de l’artère carotide interne: à propos d’un cas

Internal carotid artery dissection can manifest in various ways and is important to diagnose in order to prevent its morbidity. The classic triad of symptoms consists of headaches, Horner syndrome, and cerebral or retinal ischemia but is only found in one third of cases. We report a case with an atypical presentation and we highlight suggestive ophthalmologic findings to avoid diagnostic delays.

A 41 years old woman without any medical history complained of colored photopsia in the right eye with occipital headaches 4 days after she ran a half-marathon.

The ophthalmologic examination revealed a right central and paracentral scotoma and a small right relative afferent pupillary defect. The visual acuity, color perception, anterior segment examination and eye fundus were normal and symmetrical. A right retro-orbital optic neuropathy was initially suspected. Brain magnetic resonance imaging with injection and lumbar puncture were normal, and visual evoked potential revealed a discrete pre-chiasmatic prolonged latency from paramacular afferents in the right eye. Five days later, a macular spectral domain optical coherence tomography showed hyper-reflective lesions in the inner part of the retina in the right eye. We concluded to a paracentral acute middle maculopathy. A few days later, she came back with a right pulsatile tinnitus and left hand paresthesia. An emergency computed tomography angiography showed a dissection of the intrapetrous part of the right internal carotid artery. A fluorescein angiography confirmed a perfusion delay both in the choroidal and retinal circulation in the right eye.

The diagnosis of internal carotid artery dissection can be a real challenge. Eye manifestations can vary from Horner syndrome, oculomotor nerve palsy or ischemic disorders like central or branch retinal artery occlusion, ischemic optic neuropathy, ischemic ocular syndrome, paracentral acute middle maculopathy, and transient monocular visual loss. Among these, scintillating or colored photopsia may suggest acute choroidal hypoperfusion.

Paracentral acute middle maculopathy lesions are associated with ischemia in capillary plexus and choriocapillaris. It may be idiopathic, or secondary to a vasculopathy or a systemic condition like internal carotid artery dissection. Fluorescein angiogram, which is most often normal in idiopathic cases, can be useful to rule out secondary etiologies.

Paracentral acute middle maculopathy associated with neurological symptoms should lead to internal carotid artery dissection exclusion.