Okay, let's tackle this question. The patient is a chronic alcoholic with altered sensorium and normal blood sugar. Hmm, what conditions are common in alcoholics that could cause altered mental status without hypoglycemia? Well, thiamine deficiency comes to mind. Chronic alcoholics often have poor nutrition and thiamine deficiency can lead to Wernicke's encephalopathy. The classic triad is confusion, ataxia, and ophthalmoplegia. But even if they don't have all three, treatment is still thiamine.

Wait, the blood sugar is normal, so hypoglycemia is ruled out. Other possibilities could include ethanol toxicity itself, but that's less likely if he's a chronic user. Maybe hepatic encephalopathy? But that's more associated with liver failure. Or maybe another vitamin deficiency? Thiamine is the key here. The treatment would be thiamine, so the correct answer is probably thiamine. Let me check the options again. The options aren't listed, but the correct answer is likely thiamine. The other options might be glucose, folic acid, or something else. Glucose is incorrect here because blood sugar is normal. Folic acid deficiency can occur in alcoholics but isn't the immediate treatment for altered sensorium. So the answer is thiamine.

**Core Concept**
Chronic alcoholism is associated with thiamine (vitamin B1) deficiency due to poor dietary intake, malabsorption, and increased metabolic demand. Thiamine deficiency can lead to **Wernicke’s encephalopathy**, a neurologic emergency characterized by altered mental status, ophthalmoplegia, and ataxia. Immediate thiamine administration is critical to prevent irreversible brain damage.

**Why the Correct Answer is Right**
Thiamine (option C, likely) is the correct treatment because the patient’s altered sensorium is most consistent with Wernicke’s encephalopathy. Thiamine deficiency impairs glucose metabolism via the **pyruvate dehydrogenase** complex, leading to energy depletion in the brain. Intravenous thiamine reverses this by restoring enzymatic function and preventing neuronal injury. Even if blood sugar is normal, thiamine deficiency must be addressed first to avoid precipitating lactic acidosis in a glucose-treated patient.

**Why Each Wrong Option is Incorrect**
**Option A:** Glucose may worsen thiamine deficiency by increasing glucose metabolism without adequate thiamine, risking lactic acidosis.
**Option B:** Folic acid deficiency is common in alcoholics but does not cause acute altered sensorium.
**Option D:** Naloxone is used for opioid overdose, which is not indicated here.

**Clinical Pearl / High-Yield Fact**
**"Thiamine before glucose"** is a critical rule in alcoholics with altered mental status. Administering glucose without thiamine can exacerbate Wernicke’s encephalopathy and lead to irreversible neurological damage. Always prioritize thiamine in this clinical scenario.

**Correct Answer: C. Thiamine**

✓ Correct Answer: A. Inj . Vitamin B1