Prednisolone-responsive neuropathy in a cat

Clinical Course and Diagnostic Findings of Biopsy Controlled Presumed Immune-Mediated Polyneuropathy in 70 European Cats

There is a paucity of information on the clinical course and outcome of young cats with polyneuropathy. The aim of the study was to describe the clinical features, diagnostic investigations, and outcome of a large cohort of cats with inflammatory polyneuropathy from several European countries. Seventy cats with inflammatory infiltrates in intramuscular nerves and/or peripheral nerve biopsies were retrospectively included. Information from medical records and follow up were acquired via questionnaires filled by veterinary neurologists who had submitted muscle and nerve biopsies (2011-2019). Median age at onset was 10 months (range: 4-120 months). The most common breed was British short hair (25.7%), followed by Domestic short hair (24.3%), Bengal cat (11.4%), Maine Coon (8.6%) and Persian cat (5.7%), and 14 other breeds. Male cats were predominantly affected (64.3%). Clinical signs were weakness (98.6%) and tetraparesis (75.7%) in association with decreased withdrawal reflexes (83.6%) and, less commonly, cranial nerve signs (17.1%), spinal pain/hyperesthesia (12.9%), and micturition/defecation problems (14.3%). Onset was sudden (30.1%) or insidious (69.1%), and an initial progressive phase was reported in 74.3%. Characteristic findings on electrodiagnostic examination were presence of generalized spontaneous electric muscle activity (89.6%), decreased motor nerve conduction velocity (52.3%), abnormal F-wave studies (72.4%), pattern of temporal dispersion (26.1%) and unremarkable sensory tests. The clinical course was mainly described as remittent (49.2%) or remittent-relapsing (34.9%), while stagnation, progressive course or waxing and waning were less frequently reported. Relapses were common and occurred in 35.7% of the cats' population. An overall favorable outcome was reported in 79.4% of patients. In conclusion, young age at the time of diagnosis and sudden onset of clinical signs were significantly associated with recovery (p < 0.05). Clinical and electrodiagnostic features and the remittent-relapsing clinical course resembles juvenile chronic inflammatory demyelinating polyneuropathy (CIDP), as seen in human (children/adolescents), in many aspects.

Nodo-paranodopathy, internodopathy and cleftopathy: Target-based reclassification of Guillain-Barré-like immune-mediated polyradiculoneuropathies in dogs and cats

Recent views on Guillain-Barré syndrome (GBS) question the accuracy of classification into axonal and demyelinating subtypes that represent convergent neurophysiological phenotypes rather than immunological targets. Instead it has been proposed to clarify the primarily affected fibre subunit in nerve biopsies. As nerve biopsies rarely are part of routine work-up in human patients we evaluated tissues taken from companion animals affected by GBS-like polyradiculoneuropathy to screen for distribution of immune cells, targeted fibre components and segregating non-inflammatory lesions. We identified that immune responses were directed either at Schmidt-Lanterman clefts, the paranode-node complex or both. Based on infiltrative and non-inflammatory changes, four subtypes and/or stages were distinguished, some of which indicate localisation of primary target antigens while others represent convergent late stage pictures, as a consequence to epitope spreading. The impact of histological subtyping onto clinical management and prognosis remains to be evaluated in future clinical trials. Natural development and clinical manifestation of large animal dysimmune neuropathy may reflect human Guillain-Barré syndrome more accurately than experimental models and therefore provide complementary clues for translational research.

Distal polyneuropathy in an adult Birman cat with toxoplasmosis

Case summary

A 6-year-old female spayed Birman cat presented with a history of weight loss, stiff and short-strided gait in the pelvic limbs and reluctance to jump, progressing to non-ambulatory tetraparesis over 6 weeks. Poor body condition, dehydration and generalised muscle wastage were evident on general examination. Neurological examination revealed mildly depressed mental status, non-ambulatory flaccid tetraparesis and severely decreased proprioception and spinal reflexes in all four limbs. The neuroanatomical localisation was to the peripheral nervous system. Haematology, feline immunodeficiency virus/feline leukaemia virus serology, serum biochemistry, including creatine kinase and thyroxine, thoracic radiographs and abdominal ultrasound did not reveal significant abnormalities. Electromyography revealed fibrillation potentials and positive sharp waves in axial and appendicular muscles. Decreased motor conduction velocities and compound muscle action potential amplitudes were detected in ulnar and sciatic–tibial nerves. Residual latency was increased in the sciatic–tibial nerve. Histologically, several intramuscular nerve branches were depleted of myelinated fibres and a few showed mononuclear infiltrations. Toxoplasma gondii serology titres were compatible with active toxoplasmosis. Four days after treatment initiation with oral clindamycin the cat recovered the ability to walk. T gondii serology titres and neurological examination were normal after 11 and 16 weeks, respectively. Clindamycin was discontinued after 16 weeks. One year after presentation the cat showed mild relapse of clinical signs and seroconversion, which again resolved following treatment with clindamycin.

Relevance and novel information

To our knowledge, this is the first report of distal polyneuropathy associated with toxoplasmosis in a cat. This case suggests the inclusion of toxoplasmosis as a possible differential diagnosis for acquired polyneuropathies in cats.

Idiopathic polyradiculoneuropathy in a Bengal cat: electrophysiological findings and 1 year follow-up

This report describes a rapidly progressive loss of motor function in a 16-month-old male neutered Bengal cat, beginning in the pelvic limbs and progressing to involve all limbs and rendering the cat non-ambulatory. The neurological examination revealed flaccid tetraparesis with decreased spinal reflexes but preserved conscious proprioception and skin sensation. Extensive electrophysiological tests were conducted including electromyography, motor and sensory peripheral nerves potential recordings and 'late' potentials, defining the electrodiagnostic characteristics of this disease. Based on the electrophysiological findings, a generalised proximal and predominantly axonal neuropathy affecting the ventral (motor) nerve roots was suspected. As no aetiology was identified, this disease was classified as idiopathic polyradiculoneuropathy. Over a year, the cat presented three separate episodes of tetraparesis, each with a spontaneous complete recovery, consistent with the reportedly good prognosis for this disease.

Polyneuropathies of cats

Polyneuropathies of cats have a variety of clinical presentations. Areflexic flaccid quadriparesis, or quadriplegia, progressing over a 24- to 48-hour period, may be associated with polyneuropathies, as can chronic insidiously progressive tremors and muscle weakness that wax and wane or progress slowly over weeks or months, and which can go undiagnosed for years. In addition, these neurological signs may be due to spinal cord, neuromuscular junction or muscle disorders, so the diagnosis of polyneuropathy can be a challenge even for the most astute of clinicians. Polyneuropathies may have congenital, inherited, inflammatory, metabolic and toxic causes. Sometimes the underlying aetiology is not found and a diagnosis of idiopathic polyneuropathy is made. Since the treatment and prognosis of polyneuropathies in cats vary, the purpose of this review is to assist the veterinary practitioner to recognise, appropriately manage and provide an accurate prognosis for these challenging cases.

Salinomycin-induced polyneuropathy in cats: morphologic and epidemiologic data

In April 1996, an outbreak of toxic polyneuropathy in cats occurred in the Netherlands. All cats had been fed one of two brands of dry cat food from one manufacturer. Chemical analyses of these foods, stomach contents, and liver and kidney of affected cats revealed contamination with the ionophor salinomycin. Epidemiologic and clinical data were collected from 823 cats, or about 1% of the cats at risk. In 21 affected cats, postmortem examination was performed. The affected cats had acute onset of lameness and paralysis of the hindlimbs followed by the forelimbs. Clinical and pathologic examination indicated a distal polyneuropathy involving both the sensory and motor nerves.

Acute idiopathic polyneuropathy in nine cats

This report describes nine unrelated cats with acute idiopathic polyneuropathy. All cats presented with acutely developing tetraparesis or tetraparalysis and loss of spinal reflexes. Seven cats recovered completely within 4 to 6 weeks, without any medication. Two years after complete recovery, none of these cats had had a relapse. In the acute stage, two cats were euthanized because of respiratory complications. Postmortem examination was performed on one of these cats and revealed generalized peripheral motor polyneuropathy. The clinical signs in these cats were identical to those of the Guillain-Barré syndrome in humans.