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Bilateral thalamic infarction caused by artery of Percheron obstruction
  1. Marco Lizwan1 and
  2. Sumit Kumar Sonu2
  1. 1Duke-NUS Medical School, Singapore
  2. 2Department of Neurology, National Neuroscience Institute - Singapore General Hospital Campus, Singapore
  1. Correspondence to Dr Sumit Kumar Sonu; maithalimunda{at}

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A man in his 90s with atrial fibrillation presented with a 4-day history of increasing drowsiness associated with decreased oral intake. On arrival, his Glasgow Coma Scale score was 7 (E1V2M4). On examination, there was no eye tracking, reflexes were diminished globally and patient was unable to cooperate with motor examination. At that point of time, differential diagnoses include bilateral thalamus lesion, basilar syndrome, deep cerebral venous thrombosis, metabolic and toxic processes, infection as well as neoplasm. Initial CT of the brain showed interval development of acute non-haemorrhagic infarcts in the medial aspect of the right occipital lobe, adjoining aspects of both thalami and possible right cerebral peduncle (posterior circulation artery (PCA) territory). MRI of the brain (figure 1) revealed acute non-haemorrhagic infarct in the right PCA and artery of Percheron (AOP) territories with involvement of posteromedial right temporo-occipital lobes, para-median thalami and anteromedial cerebral peduncles. The AOP is a rare variant of arterial supply to the thalamus that arises from segment one of the PCAs. Four major variants were previously described1 (figure 2), and our patient likely has a type II variant. Infarct of AOP can affect bilateral structures with varying clinical presentations.2 Diagnosis of AOP infarct is often missed due to the unusual presentation, and it may not be visualised on primary imaging.

Figure 1

Symmetrical areas of restricted diffusion (A) with corresponding apparent diffusion coefficient (ADC) (B) and fluid attenuated inversion recovery (FLAIR) (C) changes noted compatible with acute infarcts in the territory of artery of Percheron. Time of flight (D) shows absent flow signal in proximal right P1 segment. Magnetic resonance angiography (MRA) (E) shows subtotal occlusion of the right posterior cerebral artery.

Figure 2

Classification of the artery of Percheron by Marco Lizwan.

Learning points

  • Artery of Percheron (AOP) infarct should be considered in a patient presenting with altered consciousness and changing neurology once other causes, including seizures, drug toxicity, infection and multiple sclerosis, have been excluded.

  • Diffusion-weighted MRI is the best modality for diagnosing acute AOP infarcts, and a high index of suspicion is required.

  • Early thrombolysis in patients with no contraindications offers the best prognosis.

Ethics statements

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  • Contributors ML wrote the manuscript and SKS supervised the writing of the manuscript. All authors read and approved the final manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.