What does a "nutmeg" appearance of the liver indicate?

A "nutmeg" appearance of the liver is characteristic of chronic passive congestion, most commonly associated with right heart failure. This appearance results from the accumulation of blood in the hepatic sinusoids due to impaired venous outflow, leading to areas of congestion within the liver. The congested areas appear dark and red, resembling a nutmeg seed when cut in cross-section, while the surrounding liver tissue remains relatively normal.

This condition highlights the consequences of heart failure on the liver and underscores the interconnectedness of the cardiovascular and hepatic systems. In chronic passive congestion, the liver can exhibit signs of edema and can even lead to hepatocyte dysfunction and potentially further complications such as fibrosis and cirrhosis if the underlying cardiac condition is not managed.

Other conditions, such as fatty liver disease, hepatitis B infection, or liver cirrhosis, present with different histological and clinical features that do not exhibit the distinct nutmeg appearance characteristic of chronic passive congestion. Thus, recognizing the nutmeg pattern is essential for diagnosing the underlying issue of right heart failure and its effects on the liver.