Page 1133 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

1108 CHAPTER 10

VetBooks.ir SPINAL ABSCESSATION AND 10.60
VERTEBRAL OSTEOMYELITIS

Definition/overview
Spinal abscessation is very rare in horses and is
usually associated with vertebral osteomyelitis or
discospondylitis (an infectious or inflammatory
degenerative disease of one or more vertebrae and
associated disc[s]).

Aetiology/pathophysiology
Vertebral osteomyelitis has been related to haematog-
enous spread of infectious agents in the newborn Fig. 10.60 Vertebral osteomyelitis causing spinal
and extension from local wounds. Progression of the cord compression. Streptococcus equi was isolated from
vertebral infection leads to paravertebral abscess, the bone.
meningitis, vertebral collapse and spinal cord com-
pression. Many pathogens have been isolated includ-
ing Streptococcus equi subsp. equi and Rhodococcus equi compression. Blood culture may be useful for iden-
in foals (Fig. 10.60). In foals, aetiological agents tifying the offending pathogen. Repeated blood
tend to be those associated with septicaemia, includ- cultures may be required and, ideally, taken during
ing Actinobacillus equuli, Escherichia coli and Klebsiella periods of pyrexia. Culture of possible septic foci
spp. The unique vasculature of the vertebrae con- should also be attempted, ideally prior to initiation
tributes to the development of disease. Blood vessels of antimicrobial therapy. Possible useful tests should
take a tortuous route through the metaphyseal arter- be borne in mind in animals with other clinical
ies, and as blood flow slows by the vertebral physis, signs, for example tracheal wash cultures and cytol-
an ideal environment for the embolisation of septic ogy in foals suspected of Rhodococcus equi infections.
thrombi is created. Abscessation following CSF col- Nuclear scintigraphy or myelography may be use-
lection from the lumbosacral site has been reported. ful in some cases to identify a lesion or evaluate the
degree of spinal cord compression.
Clinical presentation
The initial signs of localised spinal pain usually go Management
unnoticed. Fever, stiffness and sensory deficits with Long-term (3–6 months) antibiotic therapy is
variable paresis are the signs that are noted. There required and relapses are common. In the absence of
may be rapid progress to recumbency. The pres- culture and sensitivity data, broad-spectrum antimi-
ence of neurological signs depends on the presence crobial therapy is required.
of spinal cord compression, which is not a feature
of every case. Prognosis
The prognosis is poor if neurological abnormalities
Differential diagnosis are present. The success of treatment depends on the
Spinal trauma or neoplasia, meningitis and arboviral severity of signs at presentation and the presence and
encephalitis should be considered. severity of concurrent disease.

Diagnosis POLYNEURITIS EQUI (NEURITIS
Diagnosis is based on clinical signs, history and OF THE CAUDA EQUINA)
positive findings on radiography, scintigraphy, CT
or ultrasonography. Haematology findings are usu- Definition/overview
ally consistent with inflammation, and CSF analy- Polyneuritis equi refers to a condition of neuritis
sis may be normal or consistent with spinal cord of the cauda equina with, in addition, CN deficits.