A 26 years old man came with complaints of pain in abdomen with few episodes of haematuria. On examination, patient’s BP is 160/100 mm of Hg. Patient is refractory to standard antihypeensive drugs. On renal Doppler, parvus tardus pattern was seen. Subsequently, CT renal angiogram was done. This condition as shown below may occur in all of the following except?

**Core Concept**
The question describes a patient with hypertension and renal involvement, leading to a parvus tardus pattern on renal Doppler, which suggests a potential obstruction to blood flow in the renal arteries. This condition can be due to various underlying causes, including fibromuscular dysplasia, atherosclerosis, or other vascular anomalies.

**Why the Correct Answer is Right**
The parvus tardus pattern on renal Doppler is a characteristic finding in conditions that cause a significant reduction in blood flow to the kidney, such as renal artery stenosis. This condition can lead to a decrease in renal function and may result in hypertension that is refractory to standard antihypertensive drugs. The CT renal angiogram is a diagnostic tool used to visualize the renal arteries and identify any potential obstructions or anomalies.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because fibromuscular dysplasia is a common cause of renal artery stenosis, which can lead to a parvus tardus pattern on renal Doppler.
**Option B:** This option is incorrect because atherosclerosis is a common cause of renal artery stenosis, especially in older patients.
**Option C:** This option is incorrect because Takayasu arteritis is a large vessel vasculitis that can affect the renal arteries and cause renal artery stenosis, leading to a parvus tardus pattern on renal Doppler.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that a parvus tardus pattern on renal Doppler can be an indicator of renal artery stenosis, which requires further investigation with imaging studies like CT renal angiogram to identify the underlying cause.

**Correct Answer: D.**

✓ Correct Answer: D. PAN