Leucoencephalopathy with Pigmented Glia in a Horse with Recurrent Convulsive Seizures.

The research tries to understand the first reported case of leucoencephalopathy with pigmented glia in a horse which showed recurrent seizures. Despite attempts to control the seizures with medication, unsuccessful control led to the euthanization of the horse. Post-death examination revealed specifc lesions in the brain and a form of degeneration within cells.

Clinical Observations and Diagnosis

• The researchers studied a 7-year-old male Thoroughbred horse which experienced recurrent seizures leading to physical falls.
• The horse was diagnosed with epilepsy and was put on phenobarbital treatment, a common medication used to control seizures.
• Due to unsuccessful control of seizures, ensuing trauma to the animal resulted in it being euthanized.

Necropsy Findings

• The research team discovered yellow-brown linear lesions extensively at the U-fibres and cingulate gyrus within the cerebral white matter-levels of the brain upon necropsy. This indicates a high degree of brain tissue damage.
• Under histopathological examination, these lesions showed linear demyelination and occasional cavitation, offering further evidence of brain damage, specifically in the protective myelin sheath surrounding neurons.
• Glial cells containing yellow-brown pigment granules were found within these demyelinating lesions. These cells showed autofluorescence and reacted positively to several staining techniques, including periodic acid-Schiff reaction, Masson-Fontana, and Schmorl’s stains.
• The pigment granules didn’t react to Berlin blue, Luxol fast blue or Sudan III stains.

Detailed Findings and Final Diagnosis

• Following haematoxylin and eosin staining techniques along with immunohistochemistry on serial brain sections, the researchers identified that these pigmented glial cells were derived from astrocytes. Astrocytes are a type of glial cell that provide support and nutrients to the nervous system.
• Based on the findings, the disease of the subject horse was diagnosed with a rare neurological condition known as leucoencephalopathy with pigmented glia. Leucoencephalopathy refers to a condition where white matter in the brain becomes diseased or damaged.
• This research represents the first reported case of leucoencephalopathy with pigmented glia in any animal species.