The Paralysed dog - Differentials for Paraparesis and Paraplegia

 

Dogs and Cats with pelvic limb neurological deficits and a completely functional pectoral limb will have a neurological lesion caudal to the cervical intumescence, i.e., caudal to T3 segment. Lesions in T3-L3 segments result in general proprioceptive ataxia and UMN signs in the pelvic limbs. The segments caudal to L3 remain functional and hence can elicit the reflex motor activity although conscious control is lost, therefore voluntary visceral functions like micturition may also be lost. Lesions involving the L4-S3 segments produce LMN signs in the pelvic limb as they injure the motor neurons in the lumbosacral intumescence. This can hamper the functioning of the femoral, sciatic, pudendal, and pelvic nerves. The femoral nerve function is spared when the lesion is present in the caudal segments or in the cauda equina which means that the animal will be able to bear weight and elicit a normal patellar reflex (L4-L6 segments functional).   

Although there is no correct or wrong way of classifying these diseases, the various diseases reported to cause either solely pelvic limb neurological signs or involving the other body segments can be classified into three divisions based on their speed of onset and progression.

 a) Acute Progressive Diseases

b) Chronic Progressive Diseases

c) Acute non-progressive Diseases

The neurological diseases causing paraplegia/paresis or tetraplegia/paresis can also be classified based on etiology into the following

1)      a) Degenerative

2)      b) Anomalous

3)      c) Neoplastic

4)      d) Nutritional

5)      e) Inflammatory

6)      f) Traumatic

7)      g) Vascular

 

Below listed is a set of differentials commonly reported in the literature. Most of them require expensive neuroimaging techniques for diagnosis and is practically difficult to diagnose some or most of these diseases. Sound theoretical knowledge of many reported anomalies in small animal practice helps to narrow down our spectrum of thoughts and leads us toward the right diagnosis. The below list covers some commonly reported anomalies and is not complete by any means. Some aren’t as well described to completely limit them to the table. Anomalous disorders of the spine and neoplastic conditions are beyond the scope of this article although the latter is often encountered in small animal practice. The differential list below includes some diseases which can affect the forelimbs or all four limbs depending on the location and severity of the lesion in the spinal cord.

 

Acute Progressive Neurologic Diseases of the Pelvic Limb

	Signalment	Clinical Signs	Diagnosis	Conservative Treatment	Surgical treatment	Prognosis
Thoracolumbar intervertebral disc disease Hansen Type 1	Chondrodystrophic breeds, young onset (<3-4 years) >65% occur in the thoracolumbar junction (small breeds) and L1-L2 in large breeds.	Paresis, paralysis, pain, hyperaesthesia, kyphosis, loss of general proprioception> loss of voluntary limb function>loss of pain perception>= loss of bladder function. Per acute cases – SS posture	Signalment, Myelography, CT, MRI	Cage rest, anti-inflammatory, Success -50-100% 30-50% recurrence rates within 6-12 months	Indications – relapses, refractory to medical therapy, progression, paraplegia with intact pain perception, or without pain perception for<24hrs	Mainly depends on chronicity. The success rate of decompressive surgery in ambulatory dogs – 60- 95%. Paraplegic with intact pain perception – 79-96%. Residual signs of fecal and urinary incontinence may remain. Recovery to ambulation – 10-52 days.
Thoracolumbar intervertebral disc disease Hansen Type 2	Non Chondrodystrophic, Old age onset > 5-6 years,
Spinal Epidural Empyema	Hematogenous spread or direct local extension to epidural space			Culture and long-term antibiotics	Spinal decompression

 

 Acute Nonprogressive Disease, Pelvic Limb

	Signalment	Clinical Signs	Diagnosis	Conservative Treatment	Surgical treatment	Prognosis
Acute Spinal Cord Trauma (Fracture/ Luxation)		Schiff Sherrington syndrome,	Physical examination, history and Radiography is often convincing	Fluid therapy to maintain spinal perfusion, prevent hypotension, Methylprednisolone, sodium succinate – 30mg/kg, repeat after 4 & 6 hours (if injury less than 8 hours old). Cage rest	Fracture repair considering the neurologic status	Good / guarded depending on chronicity and method of fixation
Fibro-cartilagenous Embolic Myelopathy and Spinal Cord Infarction	Can affect any segment but is more common in the caudal lumbar and sacral segments. Fibrocartilage emboli in artery and veins > causes ischemic necrotizing myelopathy. More common in non-chondrodystrophic breeds	Has a brief progressive course (hours) and then becomes non-progressive. Non-painful asymmetric paresis classical sign but can be bilateral. Paraspinal hyperaesthesia is absent, no traumatic history	History, findings, disease of exclusion. Rule out spinal cord compression Radiographs – NAD Contrast MRI – choice.	Steroids are considered controversial. Neurologic improvement maybe noticed earlier but functional recovery may take time.		Depends on severity. Animals with upper motor neuron damage more likely to recover. 2-3 weeks’ time for functional recovery
Aortic Thromboembolism	In cats with cardiomyopathy. Acute onset with little progression – pelvic limb	Weak femoral pulse. Cold distal extremities	Signalment with a history of heart disease and unilateral neurologic signs, elevated CPK	Primary cardiac treatment		Good but relapses are common

 

 

Chronic Progressive Diseases, Pelvic Limb

	Signalment	Clinical Signs	Diagnosis	Conservative Treatment	Surgical treatment	Prognosis
Degenerative myelopathy	Non-inflammatory axonal degeneration. Usually UMN damage. >6 years onset	Progressive UMN paraparesis, spastic pelvic limbs, pelvic limb GP ataxia. Dogs become non-ambulatory in about 6-9 months	Neurodiagnostics. MRI to rule out other compressive diseases. Disease of exclusion. Biopsy	Steroids unlikely to help	NA	Unfavourable.
Spondylosis Deformans	Noninfectious, non-neoplastic. Boxers overpresented Lesions are often incidental findings. Osteophyte formation very rarely compresses nerve roots- search for other causes concurrently	UMN signs, signs similar to that seen in intervertebral disease.	Radiography, MRI, and CT	Palliative care including Pain management, Neutraceuticals (GAG, hyaluronic acid etc.) and class IV LASER.	Spinal decompression	Long-term prognosis - poor
Solitary or Multiple Cartilaginous Exostoses	Benign proliferation of Bone and cartilage of the spine, rib. Inherited. Pain or loss of function develop when adjacent structures are compressed.		Radiopaque masses on the vertebra/ribs. Neuro-diagnostics.   Definitive diagnosis – biopsy to differentiate from tumor
Spinal Synovial Cysts	Young large breed dogs – cervical spine. Old large breed dogs – thoracolumbar spine.	Extradural synovial cysts arise from articular facets – excessive motion and biomechanical stress
Degenerative lumbosacral stenosis	Compression of cauda equina. The L7 spinal nerve is usually impinged at lumbosacral transition. GSD, Retrievers	Caudal lumbar pain, difficulty rising, recurrent lameness, difficulty in jumping, climbing stairs. Pelvic limb paresis is unusual initially. Often confused with HD and arthritis. Altered tail carriage. Urine, fecal incontinence. < anal sphincter reflex.	Radiography and Myelography to rule out compressive spine diseases. CT – IVD bulging, spondylosis, narrowed vertebral canal, osteophyte formation, thickened articular process MRI – IVD degeneration, neural and ligamentous tissue	Confined rest for 4-8 weeks. Pain management. (25-50% response) Epidural MPSS (improvement in 79%)	Decompressive procedures – Dorsal laminectomy. Foraminotomy, facetectomy	Recurrence is usual.   Prognosis fair to good if improvement seen after surgery.
Spinal Arachnoid Cysts	Cysts or Diverticulum consisting of CSF within a focal area of subarachnoid space. Rottweilers	Syringomyelia	MRI > more sensitive than CT, Myelography		Decompressive surgery	Good in young dogs

 

Neurologic Diseases causing Tetraparesis /Tetraplegia

 

	Signalment	Clinical Signs	Diagnosis	Conservative Treatment	Surgical treatment	Prognosis
Cervical intervertebral disc disease (Acute progressive)	Hansen type 1, in chondrodystrophic breeds. Spinal compression causes severe pain but is not always sufficient to cause paresis	Cervical spinal pain, low head and neck carriage, intermittent thoracic limb lameness. Tetraparesis.	Radiography (mineralized disc), CT, and MRI (method of choice)	Avoid collars, opioid analgesics, NSAIDs, and steroids. Confinement. Consider surgery when refractory for > 2 weeks	Ventral slot technique, dorsal laminectomy	Good after surgery. Recurrence rates of 10-33% after surgery
Cervical meningomyelitis (Bacterial)	Not very common. Occurs in association with bacteremia and toxemia secondary to UTI, pneumonia, or direct penetrative wounds. P. multocida, Staph. Pseudointermedius, Streptococcus and E. coli	Usually, acute course but can be chronic. Fever and Leucocytosis need not be noticed	Isolation, culture, and sensitivity from CSF.	Sulpha-trimethoprim, Enrofloxacin, Clindamycin	NA	Good if treated early
Atlantoaxial Subluxation	Congenital or traumatic. The dens of axis projects towards the atlas. Any abnormality in the ligament /attachment leads to clinical signs. Toy and miniature breeds	Cervical pain, UMN tetraparesis. Neurologic exam consistent with findings of C1-C5 spinal segment disease.	Radiography, CT for detailed bone resolution, MRI	Exercise restriction, cage rest, external cooptation,	Ventral fusion, Odontoidectomy, implants like K-wire, threaded pins, dorsal wire fixation	Poor – good depending on modality of fixation used
Chiari-like malformation	AKA caudal occipital malformation syndrome or occipital dysplasia. Syringomyelia / syringohydromyelia is the characteristic finding.	Severe cervical pain, tetraparesis/plegia	Contrast MRI and CT	Palliative care including opioid analgesics and nutraceuticals, neck splint with neck in extension	Suboccipital decompressive craniectomy	Good with surgery. Medical management usually ends with the owner opting for euthanasia.
Steroid-responsive meningitis arteritis (SRMA)	Large breed dogs, <2 years of age. Cervical spinal hyperesthesia occurs in more than 90% cases.	CSF analysis – pleocytosis and increased protein. Negative culture	Leukocytosis with shift to left seen in 2/3rd cases. CSF analysis - elevated neutrophils and protein.	Prednisolone 2-4mg/kg q24h. Cyclosporine at 10mg/kg for long-term management	NA	Long term prognosis is poor
Rickettsial meningitis (Ehrlichial meningitis)	Meningitis and encephalitis in addition to vascular disorders.	Acute cervical pain, minimal signs of CNS disease.	PCR and other sero-diagnostics	Doxycycline - 5-10 mg/kg.	NA	Good
Meningo-encephalomyelitis of unknown origin (MUE)	Includes disorders like Necrotizing Meningeal vasculitis, Granulomatous Meningo-encephalomyelitis, (GME), Necrotizing meningoencephalitis (NME), necrotizing leukoencephalitis (NLE) and Eosinophilic Meningo-encephalomyelitis (EME)	Varying neurological signs not limited to paraparesis and tetraparesis. Depends on the location and severity of the lesion	Neurodiagnostics help in presumptive diagnosis and in ruling out other differentials but definitive diagnosis mostly possible post-mortem after histopathology. Hence classified under MUE	Cytosine arabinoside 50mg/m2 twice a day for 2 weeks and the cycle is repeated every 3 weeks. Cyclosporine 10 mg/kg/day for 6 weeks Prednisolone 2-4mg/kg/day for 6 weeks.	NA	Guarded

 

The cornerstone of the management of neurological conditions includes the use of corticosteroids and antibiotics although it is highly controversial and not based on evidence. Assuming you have no diagnostics at reach, let’s have a peek at how this ‘any neurological condition – one treatment’ fares in practicality.

 

	Use of steroids	Use of an antibiotic	Class IV LASER
Thoracolumbar intervertebral disc disease Hansen Type 1	Might help initially although no evidence. Used as part of palliative care	Not likely to help	Palliative care
Thoracolumbar intervertebral disc disease Hansen Type 2	Might help initially although no evidence. Used as part of palliative care	Not likely to help	Palliative care
Spinal Epidural Empyema	Might worsen the signs	Treatment of choice (based on sensitivity)	Possibly contraindicated
Acute Spinal Cord Trauma (Fracture/ Luxation)	Use of high-dose steroids is warranted by some authors till spinal decompression is performed.	Not likely to help	Palliative care
Fibro-cartilaginous Embolic Myelopathy and Spinal Cord Infarction	Not likely to help	Not likely to help	Not likely to help
Aortic Thromboembolism	Not likely to help	Not likely to help	Not likely to help
Degenerative myelopathy	Although an immune-mediated degenerative disease, immunosuppressive doses of corticosteroids have shown no benefit	Not likely to help	No evidence of LASER helping
Spondylosis Deformans	Palliative care initially in the course of the disease, as an anti-inflammatory	Not likely to help	Palliative care
Disseminated Idiopathic Skeletal Hyperostosis (DISH)	Not likely to help	Not likely to help	Not likely to help
Solitary or Multiple Cartilaginous Exostoses	Not likely to help	Not likely to help	Not likely to help
Spinal Synovial Cysts	Not likely to help	Not likely to help	Not likely to help
Degenerative lumbosacral stenosis	Palliative care initially in the course of the disease, as an anti-inflammatory	Not likely to help	Palliative care
Spinal Arachnoid Cysts	Not likely to help	Not likely to help	Not likely to help
Cervical intervertebral disc disease	A possible option to reduce inflammation	Not likely to help	A good modality to treat palliatively
Bacterial meningomyelitis	Debatable	Treatment of choice based on culture and sensitivity	Contraindicated
Atlantoaxial Subluxation	Not likely to help	Not likely to help	Not likely to help
Chiari-like malformation	Palliative based on severity	Not likely to help	Palliative care
Steroid responsive meningitis arteritis	Treatment of choice	Not likely to help	Palliative care
Rickettsial (Ehrlichial) meningitis	Possible palliative care	Treatment of choice (Doxycycline)	Not likely to help
Meningitis of unknown origin	One of the treatment options	Not likely to help	Not likely to help

 

Reference 

Handbook of Veterinary Neurology 5th edition by Michael D Lorenz, Joan Coates, and Marc Kent