Although one of Vincent van Gogh's most famous paintings, Starry Night, might have a peaceful and familiar air to it, the starry sky pattern seen on some equine hepatic (liver) ultrasounds is everything but van Gogh. It's more obscure and less preferred because it often points to a horse health problem.
To help equine practitioners gain a better understanding of this uncommon finding, Kelly Carlson, DVM, Dipl. ACVIM, presented a review of this pattern and associated findings at the 2011 American Association of Equine Practitioners convention, held Nov. 18-22 in San Antonio, Texas.
"The starry sky pattern is an unusual and dramatic ultrasonographic appearance of the equine liver characterized by numerous small hyperechoic foci, some of which cast an acoustic shadow," explained Carlson, of Rood & Riddle Equine Hospital, in Lexington, Ky.
In their retrospective review, Carlson and her colleagues aimed to better characterize all aspects of the ultrasonographic pattern. They reviewed the case records and ultrasonographic images of 18 adult horses (of mixed ages and breeds) in which the starry sky pattern was found.
Key findings included:
- Weight loss and anorexia were the most common associated clinical signs;
- The size of the liver and the echogenicity (solid matter visible as white; fluid appears black) were normal in most horses;
- The patterns resulted from hepatic granulomas (chronic inflammatory lesions), of unknown cause; and
- Fifteen of the 18 horses evaluated were diagnosed with additional ailments believed to be the primary cause of the clinical signs horses were exhibiting.
"Practitioners should recognize this dramatic ultrasonographic pattern and its association with hepatic granulomas," Carlson concluded, adding that the pattern seems to be associated with an additional disease process in most cases.
Additionally, she noted, a growing body of recent research from Texas A&M University indicates that the hepatic granulomas might be due to infection with ¬Heterobilharzia americana. In dogs, raccoons, and other mammals in the Southeast, migration of H. americana eggs into the liver results in parasitic granulomas.
More research is needed to further the understanding of the starry sky ultrasound pattern and H. americana infection in horses.
Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.