All of the following are causes of microvesicular fatty liver except –
**Core Concept**
Microvesicular fatty liver is characterized by the accumulation of small lipid droplets in hepatocytes, leading to liver dysfunction. This condition is often associated with mitochondrial dysfunction, impaired fatty acid oxidation, and accumulation of long-chain fatty acyl-CoA esters.
**Why the Correct Answer is Right**
The correct answer is **B** (Reye's syndrome) because it is a cause of macrovesicular fatty liver, not microvesicular. Reye's syndrome is a rare but serious condition that affects the liver and brain, typically occurring in children and adolescents recovering from a viral infection. It is characterized by the accumulation of large lipid droplets in hepatocytes, leading to liver dysfunction.
**Why Each Wrong Option is Incorrect**
**Option A:** **Toxicity to valproic acid** can cause microvesicular fatty liver due to its inhibitory effect on mitochondrial fatty acid oxidation, leading to the accumulation of long-chain fatty acyl-CoA esters.
**Option C:** **Acute fatty liver of pregnancy** is a cause of microvesicular fatty liver, resulting from the accumulation of long-chain fatty acyl-CoA esters due to impaired fatty acid oxidation.
**Option D:** **Phospholipid storage disorders** such as Niemann-Pick disease can cause microvesicular fatty liver by impairing phospholipid metabolism and leading to the accumulation of lipid droplets in hepatocytes.
**Clinical Pearl / High-Yield Fact**
It's essential to differentiate between microvesicular and macrovesicular fatty liver, as the former is often associated with mitochondrial dysfunction and impaired fatty acid oxidation, while the latter is typically seen in conditions like Reye's syndrome.
**Correct Answer: B. Reye's syndrome**