PEOPLE“The man who smiles in the face of
trouble…
Has found someone to blame it on.”
Anatomy
forebrain is responsible for "thinking," behavior, and final integration of sensory information
Brain: Neoplasia
Enlarging mass in brain; causes compression of healthy tissue or replacement with cancerous tissue
• Primary:____________,______________, choroid plexus papilloma, pituitary adenoma or adenocarcinoma (____________), and others.
• Secondary (metastasis): hemangiosarcoma, mammary carcinoma and melanoma
• Dogs most common meningiomas and gliomas
• Sagittal MRI of the brain of an 8 year old female German Shepherd dog.
• Seizure • Well encapsulated mass in the olfactory bulb
and frontal cortex of the brain • Meningioma (histopathology)• TX: surgical removal of the tumor followed by
radiation• PX: Good not touching brain (unlike gliomas:
radiation therapy)
Hemangiosarcoma
Brain: Neoplasia• Forebrain
– Behavior• ______________, loss
of learned behavior– Seizures: acute onset, 5-6
yrs old– Pacing and circling
(Vestibular signs)– Ipsilateral vision: bump– E.g. Glioma’s and new
treatments• ___________________
breeds: such as the Boxer, the Boston terrier, and the French and English bulldog
Brain - Neoplasia
• The Brainstem
– ___________ function (the ability to walk, CV and resp function), consciousness and balance
– 1st signs: loss of balance (vestibular signs) and paresis of one side of the body
– Dysphagia, change in voice and inability to move the eyes
– Progresses into paralysis, coma and death.
• Vestibular signs:
• Head __________________
• Leaning and falling to the side of the head tilt
• Drunken gait with loss of balance (ataxia)
• ________________ to the side of the head tilt
• nystagmus
• Anorexia and vomiting
• Strabismus
• Kasey, a 10-year-old female Golden retriever
• trigeminal nerve root tumor• sensation to the face and
motor function to the muscles of mastication
• 15 months
Brain - Neoplasia
• The Cerebellum - coordination of movements and interacts closely with the vestibular system to control ____________ and posture. – Uncoordinated gait characterized by dramatic goosestepping
(___________________)
– Intention tremors: Head tremors that are worst when the animal is intent on something (i.e., food) but disappear when the animal is relaxed Swaying of the trunk
– Wide based stance
– Sometimes there can be vestibular signs such as a head tilt
– The animal's strength remains ____________________
Brain: Neoplasia
• Dx– Systematic screening for tumors in other organs– CBC, chem panel– Radiographs: _______________– CSF tap to assess increased cerebral spinal
pressure– Ophthalmic exam may indicate optic nerve
edema– Computed tomography (CT) scanning or
magnetic resonance imaging (MRI) to locate tumor
CT or MRI
• MRI
– shows the brain in ________________ than CT
– the test of choice when assessing for brain tumors
– more expensive test and less widely available
– CT images (more artifacts for brainstem/ cerebellum): meningiomas, choroid plexus papillomas
– MRI:______________, brainstem or cerebellar disease or Boston Terrier.
Brain: Neoplasia• Rx— surgical removal, radiation therapy,
chemotherapy, and palliative treatment of the symptoms
– Surgical removal of superficial single lesions
• Tumors of the brainstem pose problems
• Forebrain: you can resect certain parts of the forebrain without long-term effects.
• _________________ tend to be located on the surface of the brain and are therefore the best candidates for surgical removal.
• Gliomas are more difficult to remove because they lie deep within the substance of the brain.
MRI of a 6 year female old Boxeroligodendroglioma
Brain: Neoplasia
– Radiation therapy
– Chemotherapy; efficacy varies with tumor
type (lymphomas respond well; other less so)
– Palliative: Anti-seizure medication (Phenobarbital PO 2-3 times/day), Corticosteroids—prednisone
• Client info– The more severe the signs, the worse the outcome
– The larger the tumor, the worse the outcome
– _________________________ tumors (tumors of the forebrain) have a better prognosis than infratentorial tumors (tumors of the brainstem and cerebellum)
– Radiation therapy does prolong lifespan in most cases
– Meningiomas have a better outcome than tumors that lie within the brain (e.g. gliomas)
Epilepsy
• Signs of seizure– short aura (stare into distance,
seek comfort/protection from
someone, vocalize)
– seizure lasts_________________ ; may consist of total body muscle twitching with extended arms and legs and arching of neck dorsally (opisthotonus)
– dog will be disoriented/blind for a few minutes
– may be a single event (no veterinary intervention needed) or followed shortly by other seizures (__________________; requires veterinary intervention)
– may be incited by certain events
– normal at other times
Click for video
• http://www.thepetcenter.com/gen/epilepsy.html
Epilepsy• Dx
– CBC, chem panel—r/o metabolic diseases causing seizures• ________________________________• hypocalcemia• hepatic encephalopathy (failure to detox blood)
– Shunt– Cirrhosis
• Pb poisoning– Radiographs—r/o head trauma or __________________– CT scan or MRI—r/o space-occupying lesion in brain
• Rx—directed at cause if one can be found– treat if >1 every mo or two (Rx will not completely stop seizures)– Phenobarbital is _________________________
Status Epilepticus• Signs—prolonged, uninterrupted seizures (>5-10
minutes)• Rx
– Diazepam (2-10 mg to effect); can be repeated over several minutes
• Phenobarbital - – Time to steady state blood levels: 10-14 days– Side effects: sedation, ataxia, PU/PD/PP,
hepatotoxicity, blood _______________________ (Rare)
– Establish an open airway– IV cath with IV fluids to keep an open vein– Monitor blood Ca and glucose; treat is needed– Monitor body temp; if elevated, treat appropriately– If cerebral edema is suspected, treat with _____________(IV)– Phenobarbital—IV or IM
Status Epilepticus
• Client info—– Epilepsy is an __________________ disease
– Even with treatment, animal may still seize; • goal is to reduce frequency and intensity of seizures
– Spaying/neutering will remove any hormonal influence on seizures
– Medications will probably be required for life
– Most animals that seize can live a normal life
– If seizure free for 6-9 mo, may reduced or discontinued Rx
LIFE“Life is the art of drawing without an
eraser.”
-John w. Gardner
Spinal Cord
• Function– Nerve fibers carry signals
between brain - rest of body
• Anatomy– Like brain, protected by
hard covering – _______________
Intervertebral disk (cushion):• between vertebral body
• increases range of motion
• prevents vertebrae rubbing
Spinal Cord: Anatomy
Like brain, spinal cord enclosed in hard coveringIVDD problem in both humans and canineAnatomical differences—cervical same; lumbar—human bears weight, canine doesn’tAttached rib (thorax) helps stabilize the IV joint; worse at T-L junction (dogs)
Degenerative Disc Disease: Humans
Degeneration of disk occurs with ageDries out, shrinks (we get shorter as we age)
IV Disk Disease: AnatomyNormal spinal column and disk Prolapsed disk
nucleus fibrosus
1/3 thickness
Intervertebral Disk Disease
• Etiology– IVD dries out with age →_____________, less
compliant
– ↑Pressure from jumping
– Occurs most commonly in_____________, caudal thoracic, and lumbar vertebrae
– Most __________________ spinal cord disorder in companion animals
Intervertebral Disk Disease
• Hansen TYPE I: ________________ herniates upward; narrowest part of annulus fibrosus– TYPE I: Most common in chondrodystrophic
(“faulty development of cartilage”) breeds• ______________________ , shih tzus, Lhasa apsos,
beagles, basset hounds (poodles also affected)
• Acute onset
• Can occur at any age, but generally younger dogs
Intervertebral Disk disease
• Hansen TYPE 2: dorsal protrusion of the annulus into the _____________________– Common in older dogs and nonchondrodystrophic
breeds• Occurs over a longer period of time
• Clinical signs may be less severe
• Generally ________________ dogs
Intervertebral Disk Disease• Signs:
– Pain
– Paresis/paralysis; nerve function is lost in this order:• _____________________—largest fibers; most susceptible to
pressure; signs are ataxia
• ____________ fibers—next smallest fibers; signs are weakness/paresis
• Cutaneous sensory fibers—small; require a lot of pressure to disrupt function; decreased panniculus reflex
• _______________ fibers—smallest fibers; require the most pressure to disrupt; loss is associated with poor prognosis
• Severity of clinical signs depends on:• Speed at which disk material is deposited
• Degree of compression
• Duration of compression
IVDD – Paralysis of rear legs
Cervical IVDD
Loss of Deep Pain
IVDD Dx: Spine X-Rays
Normal horse’s head consistent IV space
Subluxation L2-3(old lesion)
IV Disk Disease: Myelogram: Definitive diagnosis
Which disk space?
IV Disk Disease: MyelogramIV Disk Disease: Myelogram
Which disk space?
Cervical IVDD
Myelogram: Disk herniation at C2-3 (narrowed IV space, narrowed spinal canal)
IVDD• Rx TYPE I, acute onset
• Medical Rx is recommended for animals, with deep pain intact, with or w/o neuro deficit– High levels of corticosteroids is CONTROVERSIAL
• Strict _________________—2 wk minimum (easy when dog hurts; not so easy after steroids/other pain medications take effect)
• Nursing care– Soft padded cage– Urinary cath or express bladder several times/day
• Surgery is recommended for– repeat offenders– No voluntary motor function– loss of deep pain (needs to be done QUICKLY!)– worsening neuro signs (_____________________)
Laminectomy
IVDD: Possible sequela
IVDD
IVDD - rehabilitation
http://www.youtube.com/watch?v=7AkNVDc4lig&feature=related
IVDD – Alternative/Optional Treatment
• __________________ (muscle relaxant)15-20 mg/kg q 8hr
• High-dose Methylprednisolone sodium succinate (CONTROVERSIAL!) and should be given within 8 hours– Although there is proven benefit in humans, results have not
been proven in dogs• Low dose prednisone – various regimens• NSAIDS
– Carprofen, deracoxib, etodolac• Gastroprotectants• Acupuncture
Veterinary Acupuncture
• http://www.youtube.com/watch?v=Z-JjZPnk_Mw&feature=related
• http://www.youtube.com/watch?v=vJIJDUQyOmw&feature=fvw
IVDD
• Client info• Do not let susceptible breeds get _________________
• Encourage animals to keep spine parallel to ground– No jumping on/off couch
– No begging on hind legs
– No stair climbing
• Loss of deep pain >24 h has ________________ prognosis
• If surgery is done soon enough, there is a good Px of recovery
• Almost half of animals treated medically will have recurrence
• Extensive home care is required for medical and surgical patients
• Severe damage to spinal cord is not reparable
Atlantoaxial Joint
Atlanto-Axial Joint
Atlantoaxial Instability (Subluxation)
• Signs– ________________ and miniature breeds (<1 yr)
– Reluctance to be patted on head
– Neck pain
– May have ____________________ (weakness in all 4 limbs) or tetraplegia (paralysis in all 4 legs)
– Sudden death due to respiratory paralysis
• Diagnosis—– Radiographs: lateral x-ray of neck in slight ventroflexion
• avoid further spinal cord damage with positioning
Atlantoaxial Instability (Subluxation)
CT scan:dens is marked by *
Normal toy breed dog Toy breed dog with atlantoaxial subluxation
X-rays of same dogs; note separation of C1 and C2 when dog’s neck is flexed in B
Narrowed spinal canal
Atlantoaxial Instability (Subluxation)
• Treatment—– Medical
• splint neck in extension with cage _________________ x 6 weeks
• treat like other spinal cord trauma– Surgical (if unresponsive to medical Rx)
• stabilize/decompress• attach dorsal process of axis to arch of atlas• fuse atlas and axis joint with pins and bone graft• ________________________ to relieve spinal cord compression
• Client info—– prognosis is fair to good for animals with mild signs– animals should not be used for breeding; may be
hereditary
Atlantoaxial Instability: Surgical Correction
Stabilization using screws and bone cement
Stabilization using trans-articularscrews
References
• Alleice Summers, Common Diseases of Companion Animals
• http://cvm.ncsu.edu/vhc/tc/clinical_services/neuro/brain_tumor.html