## **Core Concept**
The patient's symptoms, including headaches, scalp tenderness, arthralgias, fatigue, jaw discomfort during chewing (jaw claudication), and elevated ESR, are highly suggestive of **Giant Cell Arteritis (GCA)**, also known as Temporal Arteritis. This condition is a form of large vessel vasculitis that predominantly affects the aorta and its major branches, particularly the temporal arteries.

## **Why the Correct Answer is Right**
The clinical presentation and laboratory findings in this case are classic for GCA. The immediate concern in GCA is the risk of **visual loss**, which can occur due to involvement of the ophthalmic arteries. Therefore, prompt initiation of treatment is crucial, even before the biopsy results are available, given the high risk of complications such as irreversible vision loss. The standard treatment for GCA is **high-dose corticosteroids**, which are effective in reducing inflammation and preventing complications.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While a temporal artery biopsy is considered the gold standard for diagnosing GCA, treatment should not be delayed pending biopsy results due to the risk of visual complications.
- **Option B:** Although **low-dose aspirin** may be considered for patients with GCA for its potential antiplatelet effects, it does not address the acute inflammatory process and is not the immediate next step in management.
- **Option C:** **Methotrexate** and other immunosuppressive agents may be used as steroid-sparing agents in the long-term management of GCA but are not the initial treatment.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that **Giant Cell Arteritis is a medical emergency** due to the risk of sudden and irreversible vision loss. Therefore, once the clinical suspicion is high, as in this case, **treatment with corticosteroids should be initiated immediately**, without waiting for biopsy confirmation.

## **Correct Answer:** D. Initiate high-dose corticosteroids.