Bleeding in the subarachnoid space: a possible complication during laser therapy for equine progressive ethmoid haematoma.

The research article discusses a case where a gelding horse had to be put down after developing serious neurological symptoms following a laser treatment for a progressive ethmoid haematoma, a blood-filled swelling in its nasal cavity. In this case, the laser treatment likely caused hemorrhages which led to sharp neurological symptoms and subsequent euthanasia.

Case Synopsis

• The subject of the study was a 10-year-old gelding from the Royal Warmblood Studbook of the Netherlands (KWPN).
• The horse was euthanized due to severe neurological symptoms. These symptoms were preceded by grave nosebleeds (epistaxis) during a laser therapy meant to treat progressive ethmoid haematoma (PEH) in the right nasal cavity.
• PEH is a common equine condition characterized by a benign mass or swelling that slowly develops within the ethmoid labyrinth, a complex structure in the nasal cavity, and eventually protrudes through the nostril.

Postmortem Findings

• Following euthanasia, a postmortem examination of the gelding’s head was conducted.
• The examination revealed a substantial amount of clotted blood among the right ventral and dorsal conchae in the nasal cavity, showing evidence of a recent bleeding.
• Additionally, there was acute haemorrhage (bleeding) in the right subarachnoid space. The subarachnoid space is the area between the brain and the thin membrane that covers the brain. Bleeding in this space is a serious condition associated with neurological symptoms.

Neuropathological Findings

• Further microscopic examination (histology) indicated moderate, acute polioencephalomalacia in the neuropil adjacent to the haemorrhage. Polioencephalomalacia is a neurological condition characterized by softening of the grey matter in the brain.
• This condition was also likely triggered by the haemorrhages.

Implications of the Findings

• The haemorrhages, and subsequent neurological symptoms, were likely caused by the laser treatment for PEH.
• This suggests that such complications should be considered possible side-effects of laser treatments for PEH in equine patients.
• The findings highlight the importance of carefully evaluating potential risks before undergoing such therapeutic procedures.