40. Congenital and neoplastic diseases of the nervous system in dogs and cats Flashcards
Congenital Brain diseases (Hydrocephalus)?
Congenital Brain Diseases
Hydrocephalus
↑ Volume of cerebrospinal fluid (CSF); Abnormal dilation of the cranial ventricular system
Predisposed: Dog > Cat; Toy & brachycephalic breeds; Persian cat
Compensatory hydrocephalus: CSF replaces the lost parenchyma
Obstructive hydrocephalus: Flow/absorption of CSF is obstructed
Communicating: Flow between ventricles ✓
Non-communicating: Obstruction; Flow between ventricles ✗
Congenital hydrocephalus
Caused by embryological defects of:
§ Drainage canals & foramina between the ventricles
§ Between ventricles & subarachnoid space
§ Absorptive mechanism (by the arachnoid villi)
Acquired hydrocephalus
Caused by:
§ Neoplasia
§ Inflammation
§ Trauma
FIP & Toxoplasma spp. → Intrauterine infection
Pathogenesis
↑ Intracranial pressure in foetus before the syndesmosis of skull fuses
→ Hydrocephalus & enlarged cranium
Fusion → Suture lines are now ridged → ↑ Intracranial pressure →
Secondary compression of the brain & atrophy
Clinical signs
§ Skull deformity § Dull
§ Enlarged head § Excitement
§ Patent fontanelles § Depression
§ Cerebral dysfunction § Blindness
§ Bilateral strabismus § Seizures
§ Slow postural reflexes § Tetraparesis
§ Poor proprioception § ↑ IOP
Lissencephaly?
LISSENCEPHALY
“Smooth brain”; No or minimal gyri & sulci on the brain; Thickened
cerebral cortex
Predisposed: Inherited abnormality; Lhasa apso
Clinical signs: Learning difficulty; Abnormal behaviour
Cerebellar hypoplasia?
CEREBELLAR HYPOPLASIA
Cerebellar malformation; Ventricular dilation; Lissencephaly
Cats: After utero-perinatal infection with Feline Panleukopenia virus
Dogs: After utero-perinatal infection with Parvo virus
Chiari-like Malformation?
CHIARI-LIKE MALFORMATION
Herniation of the cerebellum through the foramen magnum
Predisposed: Cavalier King Charles Spaniel
Cause: Short cranium; Occipital malformation
Syringomyelia?
SYRINGOMYELIA
Multifocal/continuous cavitation in the spinal cord parenchyma
(common in the cervical region)
Occurs secondary to cerebella herniation
Clinical signs
§ Excessive scratching
§ Proprioceptive ataxia
§ Postural reaction deficits
§ Neuropathic pain
Hydromyelia: Dilation of the spinal cord’s central canal (it is
difficult to differentiate this from syringomyelia)
Lower motor and upper motor neurons difference?
Wobbler syndrome?
WOBBLER SYNDROME
Soft tissue alteration → Spinal cord compression; Multifactorial;
Static or dynamic
Predisposed
Great Dane: Bony malformation of the cervical vertebra
Doberman: Soft tissue hypertrophy/redundancy; Disc disease
Clinical signs
§ Hyperreflexia (HL) § Cervical pain
§ Shortened FL strides § Ataxy
§ Tetraplegia § Ataxic FLs
§ Proprioception deficit § Lowered head
Diagnosis – Radiology
§ Vertebral malformation
§ Stenotic spinal canal
§ Narrow intervertebral space
§ Exostosis
Myelography: Essential to find the side of compression
Causes that may be seen: Discus protrusion; Lig. flavum
hypertrophy, Bony compression
Treatment
§ Glucocorticoids; NSAIDs
§ Neck bandages
§ Surgery (moderately successful)
Atlantoaxial luxation?
ATLANTOAXIAL LUXATION
Dorsal luxation of C2
Attributed to the unique anatomy of the joint: Ø Vertebral disk;
Minimal intervertebral movement
Predisposed: Toy breeds of dog
Clinical signs: Neck pain → Ataxia → Tetraplegia
Myelomalatia?
MYELOMALATIA
Acute, progressive & ischaemic necrosis of the spinal cord after
injury → Area of necrosis spreads
Degenerative Myelopathy?
DEGENERATIVE MYELOPATHY
Progressive ataxia & paresis of the HL
Predisposed: Older dogs
Clinical signs
As the disease progresses
§ Non-painful
§ Loss of HL reflexes
§ Paresis of the FL
§ Urinary incontinence
§ Faecal incontinence
Treatment: Ø; Physiotherapy prolongs survival
Spinal cord neosplasia?
SPINAL CORD NEOSPLASIA
Spinal tumours are classified by their location
Extradural:
§ Hemangiosarcoma § Fibrosarcoma
§ Chondrosarcoma § Osteosarcoma
§ Lymphosarcoma
Subarachnoid
§ Nerve sheath tumours
§ Meningioma
§ Lymphosarcoma
§ Neuroepithelioma
Intramedullary
§ Glioma
§ Lymphosarcoma
§ Hemangiosarcoma
Intravertebral disc disease(IVDD)?
INTRAVERTEBRAL DISC DISEASE (IVDD)
Intervertebral disc herniation
Displacement of part of a disc
Most herniation cases are secondary to a pre-existing degeneration of
the disc
Clinical signs: Pain; Neurological deficit
Intervertebral disc disease
Types
§ Hansen 1 (extrusion) Full rupture of annulus fibrosus;
Prolapse of nucleus pulposus into the vertebral canal
→ Spinal cord compression; Swelling; Necrosis
→ Ascending/descending myelomalacia
→ Acute onset paresis/paralysis
§ Hansen 2 (protrusion) Partial rupture of annulus fibrosus;
Nucleus pulposus bulges into the vertebral canal → Spinal
cord compromised
→ Chronic onset paresis/paralysis
Clinical signs (progressive)
Pain → Propionic deficit → Mild paresis & ataxia → Severe paresis
& ataxia → Paraplegia with intact pain sensation → Paraplegia with
Ø pain sensation
Grading of IVDD
§ Hyperaesthesia
§ Mild paraparesis
§ Moderate paraparesis
§ Severe paraparesis + ataxia
§ Paraplegia
Rehabilitation
- Post op: Cryotherapy; NSAIDs;
- Supporting weight → Initial motor function
- Achieve good motor function
- Achieve normal gait
- Normal gait & strengthenin
Spondylosis deformans?
SPONDYLOSIS DEFORMANS
IV disc degeneration → IV joint laxity → Osteophyte build-up →Locomotion disorders
Rarely seen: CNS/PNS lesions
Treatment: NSAIDs; Analgesia (tramadol); Surgery
Discospondylosis?
DISCOSPONDYLOSIS
Bacterial infection → Haematogenous spread → Progressive spinal cord lesion
Clinical signs (non-specific): Pain; Ataxia; Paralysis
CSx last from days to weeks
Diagnosis: Radiology; CT
Treatment: Abx for 2-6 months
Fibrocartilage embolism (infarct)?
FIBROCARTILAGE EMBOLISM (INFARCT)
Embolism composed of cartilage → Ischaemia & necrosis of the spinal cord → Neurological deficit
50% chance of spontaneous recovery
Predisposed: Labrador; German Shepherd; Golden retriever;
Doberman
Clinical signs
Frequently unilateral
§ Sudden paralysis & pain at the site of injury
§ Max. neurological deficit at 1-2 days
Non-chondrodystrophic breeds:
§ Diagnosis: MRI
§ Treatment: Glucocorticoids; Rehabilitation
Neoplastic diseases?
