Okay, let's tackle this question about the most common feature of essential hypertension from the September 2005 exam. First, I need to recall what essential hypertension is. It's the most common type of hypertension, right? Unlike secondary hypertension, which has a clear cause like kidney disease or tumors, essential hypertension is idiopathic, meaning the exact cause isn't known. But the question is about its most common feature.

The options aren't provided, but from the correct answer line, I can infer that the correct answer is likely option C. Now, common features of essential hypertension include things like elevated blood pressure, maybe left ventricular hypertrophy, or retinal changes. But which is the most common?

Wait, the most common feature would be something that's present in the majority of patients. Let's think. Elevated blood pressure is the definition, but maybe the question is looking for a clinical manifestation. Left ventricular hypertrophy is a complication that develops over time. Retinal changes, like arteriolar narrowing, can occur. Headaches and dizziness are symptoms, but not all patients have them.

Wait, the question specifies "most common feature," so it's probably a physical finding that's routinely observed. Left ventricular hypertrophy is a common finding on ECG or echocardiogram in patients with long-standing hypertension. But is that the most common? Alternatively, maybe it's retinal changes. Or perhaps the correct answer is something else.

Wait, I remember that in essential hypertension, the most common physical finding is elevated blood pressure. But since that's the defining feature, maybe the question is looking for a secondary feature. Alternatively, maybe the most common feature is left ventricular hypertrophy. Wait, not sure. Let me check my notes.

Another angle: Essential hypertension is often asymptomatic in early stages. So the most common feature might be asymptomatic until complications arise. But the question is about a feature observed in the condition, so maybe the answer is left ventricular hypertrophy. Alternatively, maybe the answer is retinal changes. Or maybe it's the absence of symptoms.

Wait, the correct answer here is likely to be left ventricular hypertrophy. Because in the majority of patients with essential hypertension, over time, the heart has to work harder, leading to increased left ventricular mass. So, on ECG, LVH is a common finding. So the answer is option C. But I need to make sure. Let me structure the explanation accordingly.

So, the core concept is that essential hypertension leads to certain structural and functional changes in the body. The most common feature would be left ventricular hypertrophy (LVH) due to increased afterload. The other options might include symptoms like headaches, which are less common, or retinal changes, which are a later complication. The clinical pearl would be that LVH is a key finding in essential hypertension and is a marker of end-organ damage. So the correct answer is C.

**Core Concept**
Essential hypertension is characterized by chronic elevation of blood pressure without an identifiable secondary cause. Over time, it leads to structural and functional adaptations in target organs, with **left ventricular hypertrophy (LVH)** being a hallmark due to increased afterload on the heart.

**Why the Correct Answer is Right**
Left ventricular hypertrophy (LVH) develops as a compensatory response to the increased workload caused by elevated systemic vascular resistance in

✓ Correct Answer: B. Headache