Episodic blindness and ataxia in a horse with cholesterinic granulomas.

The research presents a case of intermittent blindness and uncoordinated movements in an 11-year-old horse that had developed cholesterinic granulomas, which are mass formations of cholesterol clefts, leukocytes, minerals, and connective tissues in the brain. Despite treatment with corticosteroids, the horse’s condition worsened, leading to its euthanasia.

Patients and Episodes

• The patient was an 11-year-old Oldenburg mare.
• This mare had suffered from three episodes of sudden, temporary blindness, lack of coordination (ataxia), and confusion over the past 7 months.
• Each time, the mare experienced a clinical improvement, including the restoration of vision, within a week of starting treatment with corticosteroids.
• However, even after treatment, a mild squeeze on the right side (miosis) kept showing up in eye examinations.

Diagnostic Process

• The horse underwent routine clinical and laboratory testing, but no significant anomalies were observed to explain the mare’s symptoms.
• The medical team analysed the cerebrospinal fluid, but this did not lead to a conclusion either.
• Finally, computed tomography (CT) scan of the horse’s brain showed a high-density mass with outer accumulation of minerals (peripheral mineralization) in the frontal part of each of the side cavities of the brain (lateral ventricles).

Treatment and Outcome

• Based on the severity of the condition, the experts decided to euthanize the horse since the prognosis was considered to be between guarded to poor.
• Upon studying the tissue after euthanasia (histopathology), the masses were indeed found to be composed of cholesterol clefts, white blood cells (leukocytes), mineral deposits, and connective tissues, diagnosing them as cholesterinic granulomas.
• The diagnosis also included an accumulation of cerebrospinal fluid within the brain (hydrocephaly).

Conclusions and Implications

• The study concludes by stating that cholesterinic granulomas should be considered as a possible cause in horses presenting with intermittent blindness.
• This demonstrates that routine clinical and laboratory tests may not be sufficient to diagnose such conditions, highlighting the importance of advanced diagnostic techniques like CT scans.