Circulating antibodies to the neuritogenic myelin protein, P2, in neuritis of the cauda equina of the horse

Urinary Incontinence and Urinary Tract Infections

Urinary incontinence results from disorders of the lower urinary tract or neurologic diseases either of the nerve supply to the bladder/urethra or within the central nervous system. Congenital causes include patent urachus and ectopic ureter. Coordination of lower urinary tract function involves the interaction of both the sympathetic and parasympathetic system as well as somatic branches of the central nervous system. Well-recognized causes of incontinence include equine herpes virus 1 myeloencephalopathy, polyneuritis equi (neuritis of the cauda equina), and sacral/coccygeal trauma. Idiopathic bladder paralysis is characterized by bladder paralysis and sabulous cystitis in the absence of overt neurologic deficits.

Suspect Guillain-Barré syndrome in a male rhesus macaque (Macaca mulatta)

Guillain-Barré syndrome (GBS) is a rare, mainly acute inflammatory polyneuropathy in humans. It is frequently post-infectious with auto antibodies being formed against myelin sheaths, resulting in a progressive and more-or-less severe paralysis of the motor neuron and cranial nerves. Mortality is low and 60 % of the patients recover completely from the disease after intensive treatment. In animals, there are a few diseases that closely resemble GBS, but cases of GBS in monkeys seem to be scarce. In this case report, the clinical course of a progressive tetraplegia in a male rhesus macaque is described. Clinical, cerebrospinal fluid (CSF), electroneurography (ENG) and electromyography (EMG), and pathological findings revealed symptoms very similar to human GBS.

Miscellaneous neurologic or neuromuscular disorders in horses

NMD is an important cause of morbidity in horses. Signs of dysfunction could be variable depending on the specific area affected. NM disease can go unrecognized if a thorough evaluation is not performed in diseased horses. Electrodiagnostic testing is an area that has the potential to document and improve our understanding of NM disease yet is uncommonly performed. Keeping an open and observant mind will enhance our ability to search and find answers.

Hypersensitivity disorders in horses

Hypersensitivity is an exaggerated immunologic response to a foreign agent that results in inflammation and organ dysfunction. Hypersensitivity disorders are broadly divided into antibody-mediated and T-cell-mediated reactions. The inflammatory pathways that result in disease are initiated in an antigen-specific manner through Fab portions of antibodies or the T-cell receptor, causing the up-regulation of effector mechanisms designed to clear the offending agent. Effector mechanisms include the generation of inflammatory chemicals such as cytokines and chemokines and the attraction of leukocytes and potentiation of their function. This article reviews current concepts in the immunopathogenesis of hypersensitivity disorders and demonstrates these mechanisms as they apply to equine disease.

Seizures and other neurologic manifestations of allergy

Numerous disease entities affecting the nervous system can be attributed at least in part to immune responses. Neurons have been shown to have receptors from many of the vasoactive neurotransmitter and neuromodulator molecules first studied as mediators of inflammation and immediate hypersensitivity (Type 1 response). Immune responses have now been proven to affect CNS and peripheral neurons. In the diagnostic workup, consideration should be given to the possibility of immune-related causes for seizures and some other neurologic disorders.

Neuritis of the cauda equina in the horse

Ultrastructural lesions of the cranial nerves and their ganglia and the autonomic nervous system from 5 cases of neuritis of the cauda equina in the horse are described. They include lysosomal inclusions within the semilunar, geniculate and sympathetic chain ganglia, granulomatous involvement of the coeliaco-mesenteric ganglion and accumulation of axonal organelles in unmyelinated fibres of the great splanchnic nerve, sympathetic chain and oesophageal vagus.

Neuritis of the cauda equina

Although the specific etiology of NCE remains unknown, many advances have been made in recent years. It is hoped that we can expect continued success in this area. Etiologic and pathophysiologic determination of NCE is the key to developing an appropriate therapeutic regimen.

Use of an ELISA in the differential diagnosis of cauda equina neuritis and other equine neuropathies

In 27 potential neuropathies an enzyme-linked immunosorbent assay, using P2 preparations from either bovine or equine myelin, detected all cases of cauda equina neuritis in which there was caudal involvement. The test was of limited value in differentiating neuropathies involving only cranial or other peripheral nerves.

Spontaneous and experimental neuritis and the distribution of the myelin protein P2 in the nervous system

The P2 contents of nervous tissues from the human, rabbit, guinea pig, and Lewis rat were measured by radioimmunoassay. The ventral spinal roots contained more P2 than any other tissue. Human dorsal roots and peripheral nerves contained 41-65% of the amount in human ventral roots. Human olfactory and optic nerves and brain contained 1.1-2.7%, spinal cord, 2.8%, cranial nerve VIII, 11%, and cerebral grey matter, 0%. The relative amounts in the rabbit nervous system were similar except that the spinal cord contained 20% of the amount in the ventral roots. Qualitative estimates in the guinea pig showed that the spinal roots and peripheral nerves contained more P2 than the spinal cord, and that none was present in the brain. In the Lewis rat, P2 could be detected in the spinal roots and peripheral nerves but not in the CNS. The distribution of P2 in the human nervous system parallels the incidence and severity of lesions in acute polyradiculoneuritis. It also explains the absence of any lesions in the CNS when experimental allergic neuritis is induced in the Lewis rat.

Abnormal serum factors in Guillain-Barré syndrome

The Guillain-Barré Syndrome (GBS) is generally considered to be a cell-mediated immunopathologic disease of the peripheral nervous system (PNS), although the evidence for this is indirect. Both in vitro and in vivo studies of sera from experimental animals with autoimmune demyelinating neuropathies suggest that serum factors, including antibodies to PNS myelin and/or Schwann cells, may be important in the pathogenesis of some of these disorders. More recently, similar in vitro and in vivo techniques, including the production of demyelination following intraneural injection in the rat have been employed to study sera from patients with GBS. The results of these studies demonstrate the presence of factor(s), as yet not fully characterized, that may be important in mediating demyelination. Moreover, in some patients with chronic or relapsing demyelinative inflammatory neuropathies and monoclonal gammopathy, there is evidence of antimyelin antibodies to PNS myelin. Further studies of serum from patients with acute GBS and these other neuropathies may clarify the role of serum factors in acquired inflammatory diseases of the PNS.