Cervical extradural haematoma in an ataxic horse

As neurological diseases in horses share many overlapping clinical signs, the veterinarian is required to know how to perform a focused evaluation of this system as well as how to carry out complementary examinations to establish an aetiological diagnosis. This is a case report of an ataxic horse presenting with an extradural haematoma in the region of the 7th cervical vertebra. The 7‐year‐old Criollo mare presented with clinical signs of ataxia grade 3 (scale 1–5) in all limbs and a proprioceptive deficit. Radiological evaluation did not show bone changes or narrowing of the cervical canal. Samples of blood, serum and cerebrospinal fluid were collected and tested negative for antibodies to equine herpes virus type 1–4, Trypanosoma evansi and Sarcocystis neurona. The disease evolution was followed over a 4‐week period, after which the animal showed worsening overall clinical signs, and thus euthanasia was performed. A necropsy did not reveal macroscopic changes in any organs, except for an extradural haematoma in the region of the 7th cervical vertebra causing spinal cord compression. Histological examinations showed that the nodular lesion consisted of fibrovascular tissue, granulation tissue at different stages of maturation, red blood cells, cellular debris, fibrin and macrophages. The white matter of the ventral horn of the spinal cord contained degenerative lesions. In addition, the brain tested negative for rabies virus encephalitis. Based on the history, the laboratory test results, anamnesis and the lesion observed at necropsy, it was concluded that the ataxia was due to spinal cord compression, which was caused by an extradural haematoma in the region of the 7th cervical vertebra. Evaluation of the equine neurological system is highly important in localising the area of lesions, and complementary examinations are useful in differentiating between diseases affecting this system. Spinal cord compression injuries, such as extradural haematomas, are rarely reported in the literature, and their pathophysiology is difficult to understand. Nevertheless, they should be included in the differential diagnosis of ataxia in horses.