A 66-year-old woman presents with a unilateral headache and transient visual loss. What should be included in the next step of her evaluation?

In this clinical scenario involving a 66-year-old woman with unilateral headache and transient visual loss, the next step in evaluation should include an erythrocyte sedimentation rate (ESR). This is particularly relevant in the context of suspicion for giant cell arteritis (GCA), also known as temporal arteritis, which is more common in older individuals and can lead to serious complications such as permanent vision loss if not diagnosed and treated promptly.

An elevated ESR indicates inflammation and is a key laboratory test used in the assessment of conditions like GCA. It helps to support the diagnosis when a patient presents with symptoms like those described. Early detection of this condition is critical for initiating corticosteroid treatment to prevent vision complications.

Other evaluation steps, while potentially relevant in different contexts, are not as immediately pertinent in this scenario. For instance, a lumbar puncture would be indicated if there were concerns for conditions like meningitis or other central nervous system pathologies, while a complete blood count may provide general health information but would not be specific for the condition in question. A CT scan of the head could be useful in ruling out other intracranial abnormalities but does not directly assess for temporal arteritis or its inflammatory process.

In summary, ordering an erythrocy