Equis ISSN 2398-2977

Bladder: paralysis

Contributor(s): Graham Munroe, Sarah Stoneham

Introduction

  • Bladder paralysis usually occurs with other neurologic deficits.
  • Cause: cauda equina neuritis, equine herpesvirus-1 myeloencephalitis, sorghum toxicity, spinal disease, iatrogenic.
  • Signs: urinary incontinence, other neurologic signs.
  • Diagnosis: clinical signs, history, detect underlying cause.
  • Treatment: specific therapy rarely available, supportive therapy may allow resolution.
  • Prognosis: depends on cause.

Pathogenesis

Etiology

  • Severe UMN spinal cord disease, eg transverse thoracolumbar spinal cord lesions.
  • LMN lesions.
  • Neuritis of the cauda equina (equine polyradiculoneuritis, polyneuritis equi)   Polyneuritis equi  .
  • Equine herpesvirus-1 myeloencephalitis.
  • Sorghum or sudangrass ataxia-cystitis (enzootic equine ataxia-cystitis) .
  • Lower lumbar, sacral, or upper coccygeal vertebral fractures   Spine: fracture  .
  • Lower lumbar, sacral, or upper coccygeal vertebral osteomyelitis .
  • Lower lumbar, sacral, or upper coccygeal vertebral neoplasia .
  • Iatrogenic alcohol "tail blocks".
  • Protozoal myelitis .

Predisposing factors

General
  • Neurologic disease.

Pathophysiology

  • Control of bladder function is complex and there are many sites where this can be disrupted.
  • Several basic dysfunctions of equine bladder control are recognized:
    • Reflex or upper motor neuron (UMN) bladder control.
    • Paralytic or lower motor neuron (LMN) bladder control.
    • Myogenic or non-neurogenic bladder control.
  • Whatever the cause the condition manifests itself as enlargement of the bladder and incontinence.
Lower motor neurone disease
  • Disease   Neurology: motor neuron disease  interfering with lower motor neurone pathway in sacral spinal cord and sacral spinal nerves   →   complete atonia of smooth muscle of bladder and urethralis muscle   →   bladder paralysis   →   incontinence: easy to empty bladder by pressure.
    • Injury to sacral segments of spinal cord or sacral nerves.
    • Protozoal myelitis in grey matter of sacral segments.
    • Cauda equina neuritis   →   insidious progressive inflammatory reaction of unknown etiology   →   affects sacral as well as caudal nerves   →   paralysis of tail, anus, rectum and bladder; may show cranial nerve deficits.
    • Abscesses or neoplasia of sacral segments or vertebrae.
    • Vertebral fractures involving pelvic limb paralysis.
    • Equine herpesvirus-1 infection   →   ischemic myelopathy   →   weakness/ataxia of hindlimbs, full bladder, incontinence, weakness of tail, normal anal tone.
    • Sorghum or sudangrass (hyocyanic acid) poisoning   →   focal degenerative, mild white matter (axonic) lesions   →   bladder paralysis and cystitis.

    Upper motor neurone disease
  • Less common.
  • Upper motor neurone pathway in reticulospinal tracts of white matter of spinal cord   →   urethralis muscle may be spastic   →   no voluntary contraction of bladder muscle, but difficult to evacuate manually   →   usually associated with weakness, paralysis or ataxia of hindlimbs.

Timecourse

  • Chronic, progressive or acute onset.

Epidemiology

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Holt P Eet al(1990)Ten cases of bladder paralysis associated with sabulous urolithiasis in horses.Vet Rec127(5), 108-110 PubMed.


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