**Question:** A 50-year old female presents with sudden blindness .There is Scalp tenderness. There is history of pain while combing the hair. Temporal artery biopsy shows intimal thickening with granulomatous inflammation. Diagnosis is

A. Tuberculosis
B. Giant Cell Arteritis
C. Rheumatoid Arthritis
D. Psoriasis

**Correct Answer:** B. Giant Cell Arteritis

**Core Concept:**
Giant Cell Arteritis (GCA) is a common vasculitis affecting the medium and large-sized arteries, primarily in older adults. It is characterized by the presence of granulomatous inflammation in the arterial walls, leading to ischemic complications and nonspecific systemic symptoms. Temporal artery biopsy is a diagnostic gold standard for GCA.

**Why the Correct Answer is Right:**
In this case, the patient presents with sudden blindness, scalp tenderness, and pain while combing the hair. These symptoms are strongly indicative of GCA. Additionally, the temporal artery biopsy shows intimal thickening with granulomatous inflammation, which is consistent with the pathological findings in GCA. This makes option B the correct answer.

**Why Each Wrong Option is Incorrect:**
A. Tuberculosis (TB) is a common infectious condition, usually involving pulmonary and lymphatic systems. While it can rarely affect the temporal artery, it is less likely than GCA due to the absence of certain clinical features.
C. Rheumatoid Arthritis (RA) is an autoimmune disorder affecting multiple joints, while GCA primarily affects the temporal and other large arteries. The absence of joint involvement and the presence of visual symptoms make RA an unlikely diagnosis.
D. Psoriasis is an autoimmune disorder affecting the skin, with no association with temporal artery inflammation or visual symptoms.

**Clinical Pearl:**
Giant Cell Arteritis can present with non-specific symptoms, making diagnosis challenging. A high index of suspicion and thorough history taking, physical examination, and appropriate investigations (like temporal artery biopsy) are essential for its diagnosis. Prompt treatment with corticosteroids is crucial to prevent irreversible visual loss caused by ischemia in the optic nerve head due to arterial occlusion.