What produces the neurologic symptoms in acute fatty liver of pregnancy?

Acute fatty liver of pregnancy (AFLP) is a serious condition typically occurring in the third trimester that can lead to hepatic failure and various systemic symptoms, including neurologic manifestations. The neurologic symptoms in AFLP are mainly attributed to elevated ammonia levels that result from liver dysfunction.

In a state of hepatic failure, the liver is unable to efficiently convert ammonia, a toxic byproduct of protein metabolism, into urea for excretion. As a result, ammonia accumulates in the bloodstream, leading to hyperammonemia. Elevated ammonia levels can significantly impact the central nervous system, resulting in symptoms such as confusion, lethargy, and, in severe cases, hepatic encephalopathy.

Other factors, while they may be present in the context of AFLP, do not directly cause the neurologic symptoms associated with the condition. Elevated bilirubin levels and increased liver enzymes indicate hepatic injury but do not sufficiently explain the specific neurologic manifestations. Decreased fetal movement may be a concerning clinical sign but is not related to the mechanism of neurologic symptoms stemming from liver dysfunction.