**Core Concept**
Microvesicular fatty liver is a severe form of hepatic steatosis characterized by small, uniform lipid droplets within hepatocytes, often indicating toxic injury or metabolic disruption. It differs from macrovesicular steatosis and is associated with specific drug-induced or metabolic insults.

**Why the Correct Answer is Right**
Valproate, a sodium channel blocker used in epilepsy and bipolar disorder, is a well-known cause of microvesicular steatosis. It inhibits mitochondrial β-oxidation and disrupts fatty acid metabolism by interfering with the carnitine palmitoyltransferase system. This leads to intracellular accumulation of fatty acids and microvesicular lipid droplets. The toxicity is dose-dependent and more common in children and patients with underlying metabolic disorders.

**Why Each Wrong Option is Incorrect**
Option A: DM (Diabetes Mellitus) primarily causes macrovesicular steatosis due to insulin resistance and hyperglycemia, not microvesicular changes.
Option C: Starvation leads to microvesicular steatosis in severe cases, but it is a rare and transient condition, not a classic cause.
Option D: IBD is associated with cholestatic or inflammatory liver injury, not microvesicular fatty change.

**Clinical Pearl / High-Yield Fact**
Valproate-induced microvesicular steatosis can present as acute liver failure and is a key warning sign of drug-induced hepatotoxicity—prompt discontinuation and monitoring are essential.

✓ Correct Answer: B. Valproate