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| − | {{review}}
| + | #redirect[[:Category: Central Nervous System - Idiopathic Pathology]] |
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| − | {{toplink
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| − | |backcolour = E0EEEE
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| − | |linkpage = Nervous System - Pathology
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| − | |linktext =Nervous System
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| − | |maplink = Nervous System (Content Map) - Pathology
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| − | |pagetype =Pathology
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| − | }}
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| − | <br>
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| − | ==Idiopathic Epilepsy==
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| − | * A seizure is a brain disorder which manifests as paroxysmal cerebral dysrhythmia.
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| − | ** The episode has a sudden onset and ceases spontaneously.
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| − | ** Seizures tend to recur.
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| − | * In epilepsy, individuals appear to have a low seizure threshold.
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| − | ** This predisposes their neurons to depolarize of their own volition.
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| − | * "Idiopathic epilepsy" is said to occur when no other cause of seizuring is apparent.
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| − | ===Pathogenesis===
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| − | * All seizures arise from a small group of neurons that periodically and spontaneously depolarize.
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| − | * In addition to being idiopathic (i.e. low seizure threshold), this sudden, uncontrolled neuronal discharge can occur due to:
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| − | ** Structural causes
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| − | *** Neoplasms
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| − | *** Inflammation
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| − | *** Trauma
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| − | ** Biochemical causes
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| − | *** Hypocalcaemia
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| − | *** hypoglycaemia
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| − | *** Hepatic encephalopathy.
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| − | ==Pug Dog Encephalitis==
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| − | * A non-infectious [[CNS Inflammation - Pathology|central nervous inflammatory disease]]
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| − | * Affects pugs.
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| − | ** Similar conditions are seen in yorkshire and maltese terriers.
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| − | * Officially known as necrotising meningoencephalitis of small dogs.
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| − | * Characterised by histological forebrain inflammation and necrosis.
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| − | * The disease is uniformly fatal.
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| − | ** Corticosterid treatment has no effect.
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| − | ==Granulomatous Meningoencephalitis==
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| − | * A non-infectious [[CNS Inflammation - Pathology|central nervous inflammatory disease]]
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| − | * May occur as:
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| − | ** A disseminated disease
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| − | ** A focal mass lesion
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| − | ** A primary occular disease
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| − | * Brainstem signs are common, although the forebrain is primarily affected.
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| − | * May be incorrectly diagnosed as lymphoma.
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| − | * Changes are apparent in the CSF.
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| − | ** There is usually a mononucloear pleocytosis.
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| − | ** Sometimes only protein is elveated.
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| − | * Diffuse inflammatory changes or a mass lesion will be seen by advanced imaging.
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| − | ** However, biopsy is required for a definative diagnosis.
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| − | * Life span is between 6 months and 1 year from diagnosis.
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| − | ==Polyneuritis equi==
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| − | * A non-infectious [[CNS Inflammation - Pathology|central nervous inflammatory disease]]
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| − | * Polyneuritis equi (PNE) is an uncommon disease which affects mature horses
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| − | * Formerly known as 'cauda equina syndrome' or 'cauda equine neuritis'
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| − | * May occur as:
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| − | ** A disease effecting the spinal nerve roots and ganglia of the cauda equina.
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| − | ** A disease effecting the cranial nerves.
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| − | * Cauda equina disease is characterised by progressive loss of anal tone, tail paralysis, urinary and/or faecal incontinence, urine scalding of the hindlimbs, hyperaesthesia and muscle fasciculations over hindquarters.
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| − | * If the pelvic nerve roots are also involved, there may be changes in hindlimb gait.
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| − | * Cranial nerve signs may be apparent, including signs associated with facial nerve paralysis.
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| − | * Changes in the CSF are often non-specific.
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| − | ** There is usually a moderate mononucloear pleocytosis.
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| − | ** Protein is usually elveated.
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| − | * Histologically, the disease presents as a severe, chronic, destructive lymphocytic and histiocytic polyradiculoneuritis.
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| − | * Considered to be caused by a T-lymphocyte mediated response to myelin, followed by destruction of myelin and axons by macrophages
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| − | * Disease appears similar to:
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| − | ** Guillain-Barré Syndrome (GBS), an autoimmune demyelinating diease in humans
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| − | ** Experimental allergic neuritis (EAN) in laboratory animals
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| − | * Important differential diagnoses for progressive neurologic signs effecting the bladder, rectum, perineum, tail, penis and hindlimbs in horses include:
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| − | ** Equine herpesvirus-1 myeloencephalopathy
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| − | ** Sacral/coccygeal trauma
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| − | ** Equine motor neuron disease
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| − | ** Abberant parasite migration (e.g. ''Strongylus'')
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| − | ** In endemic areas, ''Sarcocystis neurona'' myelitis (equine protozoal myelitis), rabies and ''rhodococcus equi'' myeloencepahlitis should also be considered.
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