Posterior Cerebral Artery Stroke

Clinical Presentation

A stroke affecting the blood supply from the posterior cerebral artery (PCA) most characteristically causes a contralateral homonymous hemianopia, which occurs due to damage to the visual cortex in the occipital lobe, which receives its blood supply primarily from the PCA 1
Complete homonymous hemianopia is the most common pattern with extensive PCA territory involvement 1
Automated perimetry is more sensitive than confrontation testing at the bedside for visual field testing in PCA stroke 1
Patients with homonymous hemianopia may experience difficulty seeing objects in the affected visual field, bumping into objects, and reading problems, and may be unaware of their visual field defect, which can lead to safety concerns, as recommended by the American Academy of Ophthalmology 2

MRI of the brain is the gold standard for confirming the diagnosis and determining the extent of the infarct in PCA stroke 3
Rapid neurological assessment using the National Institutes of Health Stroke Scale (NIHSS) and assessment of time of symptom onset are critical for treatment decisions, as recommended by the American Academy of Neurology 4
Urgent brain imaging with non-contrast CT or MRI to rule out hemorrhage, CT angiography (CTA) or MR angiography (MRA) from aortic arch to vertex, and diffusion-weighted imaging (DWI) if available to assess early infarct, are essential for diagnosis, according to the American Heart Association 5 and the International Stroke Society 6
The NIHSS may underestimate posterior circulation strokes, and patients may present with non-specific symptoms such as headache and dizziness, leading to potential delays in diagnosis 7

Acute stroke management for patients with homonymous hemianopia from PCA stroke should follow standard protocols, as recommended by the American Heart Association 1, 7
Consider intravenous thrombolysis with IV tPA if within 4.5 hours of symptom onset, with contraindications including recent surgery, bleeding disorders, or evidence of hemorrhage on imaging, as recommended by the American Heart Association 4
Endovascular therapy with mechanical thrombectomy may be considered if large vessel occlusion (LVO) is identified on CTA/MRA, within 24 hours of symptom onset with salvageable penumbra, particularly beneficial for proximal MCA occlusions, as stated by the American Stroke Association
Antiplatelet therapy with aspirin initially, followed by consideration of dual antiplatelet therapy or alternative agents based on stroke etiology, is essential for secondary prevention, according to the American College of Cardiology
Risk factor modification with hypertension management, lipid-lowering therapy, diabetes management, and smoking cessation, is crucial for reducing the risk of future strokes, as recommended by the American Heart Association

Early rehabilitation focusing on motor recovery, language therapy for aphasia if present, cognitive rehabilitation, and functional independence training, is crucial for optimal outcomes, as stated by the American Academy of Physical Medicine and Rehabilitation
Scanning training, which involves teaching patients to make larger eye movements into the affected field, has moderate quality evidence and is a discretionary recommendation to improve quality of life compared to placebo or control, as supported by the American Academy of Neurology 2
Peripheral prism glasses may be useful for some patients but requires careful fitting and training, with low quality evidence of minor, frequent adverse events, according to the American Heart Association 2
Recovery depends on the cause and severity of the brain injury, time since onset, patient's age and cognitive status, consistency with rehabilitation exercises, and associated neurological deficits, according to the American Heart Association 2
Avoid medications that may impair recovery, such as neuroleptics, benzodiazepines, phenobarbital, and phenytoin, as recommended by the American Heart Association 8

Homonymous hemianopia can be caused by various conditions, including stroke (69.7%), traumatic brain injury, brain tumors, neurosurgical procedures, and demyelinating diseases like multiple sclerosis, as noted by the American Academy of Ophthalmology and the American Academy of Neurology 2
Cognitive assessment is essential to identify post-stroke cognitive impairment, which may be overlooked if formal assessment is not performed, as recommended by the American Stroke Association 9
Language assessment should include comprehension, fluency, repetition, and naming abilities, as stated by the American Speech-Language-Hearing Association 5
Left hemisphere strokes may cause language deficits, right-sided neglect, and cognitive impairment, according to the American Academy of Neurology 9

Marking the margin of text can help locate the beginning of each line 2
Tilt text vertically to aid in line tracking 2
Practicing with laterally scrolling text may improve reading ability 2
Using a guide to aid reading from line to line can be helpful, as recommended by the American Academy of Physical Medicine and Rehabilitation 2