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LOVE & FRIENDSHIP. “The truth is, everyone is going to hurt you. You just have to find the ones worth suffering for.” - Bob Marley. The Nervous System. And its associated diseases. Diseases of the Brain: Head Trauma. Dog skull and brain 1º Trauma—Direct trauma to brain tissue
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LOVE & FRIENDSHIP “The truth is, everyone is going to hurt you. You just have to find the ones worth suffering for.” - Bob Marley
The Nervous System And its associated diseases
Diseases of the Brain: Head Trauma Dog skull and brain 1º Trauma—Direct trauma to brain tissue 2º Trauma: edema, hemorrhage (↑ intracranial pressure)
Head Trauma • Signs: • Seizures • Blood in eyes, ears, nose, oral cavity • Loss of consciousness or decrease in response to external stimuli • Shock, altered respiratory patterns • Diagnosis: • History of trauma (HBC, falling) • Chem panel to rule out other metabolic diseases
Head Trauma • Treatment aimed at reducing 2° effects (edema) • Osmotic agents: Mannitol • Diuretics: Furosemide • Anti-epileptics: diazepam, phenobarbital • Client info • Some brain injury is irreversible • Dog in coma >48 hrs usually does not survive • Worsening neuro signs → bad prognosis
Idiopathic Vestibular Disease • Signs - ACUTE • Loss of balance • Head tilt • Nystagmus • Disorientation • Ataxia • Vomiting/anorexia SIGNALMENT: Middle-aged dogs & cats
Idiopathic Vestibular disease http://www.youtube.com/watch?v=ZccUdSH91zc&feature=PlayList&p=E13C63C661759E7C&playnext_from=PL&playnext=3&index=30 http://www.youtube.com/watch?v=Y25T7dZ77T4&feature=related
Idiopathic Vestibular Disease • Diagnosis • History & clinical signs • Blood work to r/o other diseases of nervous system • Otoscopic exam to r/o inner ear infection • Treatment • No specific treatment recommended; does not alter course of disease • antibiotics, steroids often given to cover possible causes not found by PE and lab work • Clinical signs resolve in 3-6 wks
Brain Disorders: Neoplasia • Enlarging mass in brain; causes compression of healthy tissue or replacement with cancerous tissue • Signs - usually progressive • Depends on tumor location • Seizures increasing in frequency and intensity • Vestibular signs (depending on location) • Tremors, ataxia
Neoplasia • Diagnosis • 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
Brain disorders: Neoplasia • Treatment: • Surgical removal of superficial single lesions • Radiation therapy • Chemotherapy; efficacy varies with tumor type (lymphomas respond well; other less so) • Anti-epileptic medication - Phenobarbital • Corticosteroids—prednisone • Client info • Unless tumor is surgically removed, medications will not cure disease • Symptoms will worsen as tumor grows larger
Brain Disorders: Epilepsy • Signs of seizure • short aura (stare into distance, seek comfort/protection from someone, vocalize) • seizure lasts 1-2 min; 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 (status epilepticus- requires veterinary intervention) • may be incited by certain events
Epilepsy • Diagnosis • CBC, chem panel—r/o metabolic diseases causing seizures • hypoglycemia • hypocalcemia • hepatic encephalopathy • Radiographs—r/o head trauma or hydrocephalus • CT scan or MRI – rule out a brain tumor • Treatment directed at cause if one can be found • treat if >1 every mo or two (may not completely stop seizures) • Phenobarbital is treatment of choice • Potassium Bromide may be added if seizures not controlled
Status Epilepticus • prolonged, uninterrupted seizures • Treatment • Establish an open airway • IV cath with IV fluids to keep an open vein • Monitor blood Ca and glucose • Monitor body temp • If cerebral edema is suspected, treat with mannitol (IV) • Phenobarbital—IV or IM • Drugs • Diazepam (2-10 mg to effect); can be repeated over several minutes • Phenobarbital - • Time to steady state blood levels: 7-10 days • Side effects: sedation, ataxia, PU/PD/PP, hepatotoxicity, blood dyscrasias (Rare)
Epilepsy • Client info • Epilepsy is an incurable 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 reduce or discontinue Rx
Diseases of the Spinal Cord • Function • Nerve fibers carry signals between brain and rest of body • Anatomy • Like brain, protected by hard covering, the vertebral canal
Spinal Cord: Anatomy Like brain, spinal cord enclosed in hard covering IVDD problem in both humans and canine Anatomical differences—cervical same; lumbar—human bears weight, canine doesn’t Attached rib (thorax) helps stabilize the IV joint; worse at T-L junction (dogs)
Intervertebral Disk Disease Normal spinal column and disk 1/3 thickness nucleus fibrosus
Intervertebral Disk Disease • Etiology • IVD dries out with age → hardened, less compliant • ↑Pressure from jumping • Occurs most commonly in cervical, caudal thoracic, and lumbar vertebrae
Intervertebral Disk Disease • Hansen TYPE I: Nucleus pulposus herniates upward; narrowest part of annulus fibrosus • TYPE I: Most common in chondrodystrophic (“faulty development of cartilage”) breeds • Dachshunds, shih tzus, Lhasa apsos, beagles, basset hounds (poodles also affected) • Acute onset • Can occur at any age, but generally younger dogs
Intervertebral Disk Disease Prolapsed Disk
Intervertebral Disk disease • Hansen TYPE 2: dorsal protrusion of the annulus into the spinal canal • Common in older dogs and nonchondrodystrophic breeds • Occurs over a longer period of time • Clinical signs may be less severe • Generally older dogs
Intervertebral Disk Disease • Signs • Pain • Paresis/paralysis; nerve function is lost in this order: • Proprioception—largest fibers; most susceptible to pressure; signs are ataxia • Motor fibers—next smallest fibers; signs are weakness/paresis • Cutaneous sensory fibers—small; require a lot of pressure to disrupt function; decreased panniculus reflex • Deep pain fibers—smallest fibers; require the most pressure to disrupt; loss is associated with poor prognosis
Intervertebral Disk disease • Severity of clinical signs depends on: • Speed at which disk material is deposited • Degree of compression • Duration of compression
IVDD: Paralysis of rear legs http://www.youtube.com/watch?v=vP-IXafwGVU
IVDD: Spinal Radiographs Normal horse’s head consistent IV space Subluxation L2-3 (old lesion)
IV Disk Disease: Myelogram Which disk space?
IV Disk Disease: Myelogram Which disk space?
Cervical IVDD Myelogram: Disk herniation at C2-3 (narrowed IV space, narrowed spinal canal)
IVDD • TYPE I, acute onset • Medical Rx is recommended for animals, with deep pain intact • High levels of corticosteroids is CONTROVERSIAL • Strict confinement—6-8 wk minimum • 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 (poor prognosis)
IVDD: Rehabilitation http://www.youtube.com/watch?v=7AkNVDc4lig&feature=related
IVDD: Medical Management • Methocarbamol • 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 • 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 overweight • 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 poor prognosis • If surgery is done soon enough, there is a good prognosis • 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