Postanaesthetic spinal cord myelopathy in a Welsh section D pony

Abstract

A healthy two-year-old, male entire Welsh section D pony presenting for cryptorchid castration failed to recover from an uneventful anaesthetic. Clinical signs classical of spinal cord myelopathy were evident in recovery. Despite supportive therapy and an initial improvement in clinical signs, the pony deteriorated and was euthanased the following day.

Suspected severe post‐anaesthetic myopathy or myelopathy in a Clydesdale horse resulting in euthanasia

“…5 Myelopathy following general anaesthesia in the horse has been documented in case reports and series. 5,[7][8][9][10][11][12][13] The underlying pathology is ischaemic damage to the spinal cord and its blood vessels. There is a tendency for 'large-framed' breeds to be affected.…”

“…There is a tendency for ‘large‐framed’ breeds to be affected 5 . Dorsal recumbency is also a common feature in horses with suspected spinal cord pathology or bilateral neuropathy 8–13 . Subclinical hypovitaminosis E and selenium deficiency may also be implicated 5 .…”

“…5 Dorsal recumbency is also a common feature in horses with suspected spinal cord pathology or bilateral neuropathy. [8][9][10][11][12][13] Subclinical hypovitaminosis E and selenium deficiency may also be implicated. 5 Measurement of vitamin E levels could be considered on an individual basis in horses that may be predisposed to myelopathy.…”

Mortality and morbidity in equine anaesthesia

“…Spinal cord myelopathy has been reported in 33 cases since 1979 (Schatzmann et al 1979;Blakemore et al 1984;Zink 1985;Brearley et al 1986;Yovich et al 1986;Stolk et al 1991;Lerche et al 1993;Wan et al 1994;Lam et al 1995;Raidal et al 1997;Joubert et al 2005;van Loon et al 2010;Ragle et al 2011;Patschova et al 2014;K€ uls and Rocchi 2017;Hughes et al 2019) and has occasionally been recorded in equine mortality investigations (Johnston et al 2002;Jago et al 2015;. The aetiology of SCM remains unknown; reduced perfusion and ischaemia of the spinal cord in dorsal recumbency (Schatzmann et al 1979), reduced venous return due to compression of the vena cava by abdominal contents (Blakemore et al 1984;Yovich et al 1986;Wan et al 1994), vitamin E deficiency destabilising spinal cord membranes (Stolk et al 1991), stretch ischaemia of the spinal cord, verminous arteritis and embolism (Dugdale and Taylor 2016) have all been suggested.…”

“…However, SCM also has been described in mares (Schatzmann et al 1979;Blakemore et al 1984;Brearley et al 1986;Ragle et al 2011;K€ uls and Rocchi 2017). Positioning in dorsal recumbency and heavier breeds were associated with SCM, but cases are also reported after lateral recumbency (Raidal et al 1997;Ragle et al 2011), in lighter horses (Zink 1985;Yovich et al 1986;Wan et al 1994;Lam et al 1995) and in a pony (Hughes et al 2019). Various anaesthetic protocols were used, including halothane, isoflurane and sevoflurane as well as TIVA (Raidal et al 1997).…”