Sudden-onset anisocoria in a patient with upper respiratory tract infection

• Published in: Canadian Medical Association journal (CMAJ) 2014-01, Vol.186 (1), p.57-61
• Main Authors: Furlan, Julio C, Sundaram, Arun N E
• Format: Article
• Language: English
• Subjects: Adult; Anisocoria - diagnosis; Anisocoria - etiology; Antiplatyhelmintic Agents - therapeutic use; Carotid Artery, Internal, Dissection - complications; Carotid Artery, Internal, Dissection - diagnosis; Carotid Artery, Internal, Dissection - drug therapy; Carotid Artery, Internal, Dissection - etiology; Diagnosis, Differential; Diagnostic tests; Female; Horner Syndrome - diagnosis; Horner Syndrome - etiology; Humans; Medical diagnosis; Medical treatment; Neurological disorders; Practice; Prognosis; Respiratory Tract Infections - complications; Systematic review
• ISSN: 0820-3946; 1488-2329
• DOI: 10.1503/cmaj.130581

With acute Horner syndrome, an urgent imaging study is required to rule in or out the suspected diagnosis of carotid artery dissection. Although all of the above imaging techniques could be used to investigate carotid artery dissection, CT angiography (a), MR angiography (b) or Doppler ultrasonography (c) is traditionally chosen.3,4 The first 2 are more sensitive diagnostic tools than Doppler ultrasonography and can also be used to detect intracranial extension of the carotid artery dissection, an important piece of information for planning further interventions.3,4 Given its high sensitivity and its ready availability in emer- gency care settings, CT angiography (a) is the most commonly used investigation in patients with suspected acute carotid artery dissection.3,4 Transoral carotid ultrasonography (e) is a rela- tively novel diagnostic tool that has been used to investigate distal flow in the extracranial internal carotid artery.5 In our p atient , an urgent CT angiogram showed eccentric luminal narrowing of the distal cervical and petrous segments of the right carotid artery at the skull base, consistent with carotid artery dissection (Figure 1A). Because the dis- section extended intracranially, involving the petrous portion, we started antiplatelet therapy with acetylsalicylic acid (ASA) 81 mg/d. Mag- netic resonance imaging and MR angiography of the brain and neck were done the following day to rule out progression of the arterial dissection and embolic stroke. These investigations showed an intramural hematoma compatible with the diagnosis of right internal carotid artery dissec- tion, with extension into the cranial portion of that artery but no further extension of the dissec- tion or ischemic stroke (Figures 1B and 1C). Despite the lack of evidence from randomized clinical trials, current guidelines suggest that use of either an anticoagulant (heparin, low-molecular- weight heparin or warfarin) or an antiplatelet (ASA, clopidogrel or a combination of extended- release dipyridamole plus ASA) for at least 3-6 months is reasonable to treat acute extracranial carotid or vertebral arterial dissection associated with ischemic stroke or transient ischemic attack.10 Typically, pharmacologic treatment is started as soon as possible in the acute phase of the dissec- tio n. The most rec ent Cochr ane review o f antithrombotic drugs for extracranial carotid artery dissection found no randomized trials comparing either anticoagulants or antiplatelet drugs w