Introduction

• One of most common polyneuropathies.
• Signs: similar to distal denervating disease Distal denervating disease, an acute rapidly progressive generalized lower motor neuron flaccid paresis to paralysis with stabilization of signs after 10 days.
• Diagnosis:
  • Acute progressive flaccid tetraparesis to tetraplegia with normal bladder and tail function and normal pain sensation.
  • Electrophysiology and lumbar CSF analysis aid in diagnosis.
• Treatment: supportive care, intense physical rehabilitation.
• Prognosis: often recover within 3-5 weeks with adequate supportive care.

Pathogenesis

Etiology

• Strong association with contact with raccoon saliva in some cases.
• Raw chicken meat consumption is a risk factor in dogs for the development of acute polyradiculoneuritis which potentially is mediated by infection with Campylobacter spp Campylobacter jejuni.
• Possibly related as well to upper respiratory infections. 
• Possibly associated with modified live rabies vaccine and distemper-hepatitis-parvovirus-leptospirosis combination vaccine.
• Dogs with acute polyradiculoneuritis have significantly lower serum 25-hydroxy vitamin D3 concentration compared to a control group. The cause and significance of this altered vitamin D status in dogs with polyradiculoneuritis are unclear and require further investigations.

Specific

• Possibly vaccination.
• Contact with raccoons and raccoon saliva.
• Possibly upper respiratory or gastrointestinal infections.
• Consumption of raw chicken.
• Odds of developing acute idiopathic polyradiculoneuritis possibly greater in the autumn and winter compared to spring in one study.

Pathophysiology

• Disease affects ventral spinal nerve roots more severely with minimal dorsal nerve root involvement.
• Immune response directed against proteins or lipids in raccoon saliva, bacteria or viruses → immune response cross reaction with similar proteins or lipids found in canine peripheral nerves → axonal degeneration with some demyelination → impaired nerve impulse → decreased muscle tone and tendon reflex → muscular atrophy.
• Lipopolysaccharides from Campylobacter contain a ganglioside-like epitope that resembles elements of peripheral nerve gangliosides. Molecular minicry and a cross-reactive immune-response may play a role in the pathogenesis.
• Anti-GM2 ganglioside antibodies in dogs affected with acute polyradiculoneuritis has been demonstrated, reinforcing the hypothesis that this condition is the canine counterpart of Guillain-Barre syndrome in humans.
• Immune responses directed either at Schmidt-Lanterman clefts, the paranode-node complex or both.
• Based on infiltrative and non-inflammatory changes, 4 subtypes and/or stages are distinguished, some of which indicate localization of primary target antigens while others represent convergent late stage pictures, as a consequence to epitope spreading.

Timecourse

• Duration of neurologic dysfunction ranges from several weeks to 4 months and depends on initial severity of neurologic involvement.
• Histopathological changes in nerves seen within 7-10 days of onset of signs.
• Signs appear 7-14 days after initiating incident.
• Paralysis lasts several weeks to 4 months.
• Incomplete recovery and lack of improvement have been observed.
• Tetraparesis occurs 24-48 hours after neurological signs first develop.
• Initial progression of signs occurs over 4-5 days <10 days.

Diagnosis

Treatment

Prevention

Outcomes