Neurology Flashcards
A dog presents with a history paresis of the hind limbs for the past 3 days. Cranial tibial and patellar reflexes are decreased to absent and you note muscle atrophy on the hind limbs. Reflexes are normal on the forelimbs. Where is the lesion located?
L4-S3
A dog presents with paresis of the hind limbs and you perform a neuro exam. The cranial tibial reflex is absent and the patellar reflex is slightly exaggerated. Perineal reflex is also absent. Where is the lesion?
~ L6-S3
*Since the patellar reflex is present (and pseudo hyper), the femoral nerve is intact and the lesion has to be caudal to L4/L5.
Absence of cranial tibial and perineal reflexes indicate that the sciatic and pudendal nerves are affected.
A canine patient presents for sudden ataxia after being outside unsupervised. Head tilt is not observed and the pupillary light reflex is present. Percussion of the extensor carpi radialis muscle elicits an exaggerated extension of the carpus. Reflexes on the hind limb are also exaggerated. Where is the SC lesion?
C1-C5
*Reflexes exaggerated on all 4 limbs indicates an UMN problem. The lesion will be located cranial to C6. Since the dog is not exhibiting brain signs (circling, seizures, changes in mentation), it is assumed that the lesion is not in the brain.
A feline patient presents after inability to walk at home. The extensor carpi radialis reflex is absent, and the patellar and cranial tibial reflexes are exaggerated. The bladder is large and turgid. Toe pinch does not elicit flexion of the forelimb, and the patient does not respond. Toe pinch on the hind limb elicits flexion and a pain response. Crossed extensor reflect of the hind limb is also present. Where is the lesion?
C6-T2
*LMN signs to the forelimbs and UMN signs to the pelvic limbs and bladder.
A dog diagnosed with peripheral neuropathy presents for second opinion. If the original diagnosis is correct, what should the patient’s reflexes be like?
Areflexia in all 4 limbs
A dog presents lame, and on neuro exam exhibits extreme pain with manipulation of the hip joint. What is a possible cause for this reaction?
Nerve root stretching
What is axonotmesis?
Tramuatic nerve injury in which the axon dies but the myelin sheath remains intact. The nerve can regrow with the guidance from the myelin sheath at a rate of 1mm per day.
Traumatic nerve injury in which loss of the neuron AND myelin sheath results in NO regrowth of the nerve.
Neurotmesis
What is neuropraxia?
Temporary nerve trauma mainly due to transient loss of blood supply (legs falls asleep).
No nerve degeneration occurs, but myelin may degenerate
What’s likely damaged in this cat?
Radial nerve
A cat presents to your clinic with a dropped hock. What nerve do you suspect is damaged?
Sciatic
A dog presents dragging his left front limb. The limb has no reflexes or pain response. Neuro exam is normal on all other limbs. What is the likely diagnosis?
Brachial Plexus avulsion
*Traumatic injury to nerve roots C6-T2
A feline patient presents with miosis and enopthalmus of the right eye. The third eyelid is visible and you note ptosis as well. What is a likely location for the spinal cord lesion?
T1
*Horner’s Syndrome
A dog presents dragging her RF limb. Reflexes are absent in the limb, and toe pinch test elicits no response, however, the dog reacts when the toe is clamped with a hemostat. What is the treatment plan?
Since deep pain is still intact, aggressive physiotherapy 3 times per day and protection of the limb may be indicated. If this is not possible, or the limb is not recovering, amputation is indicated (usually after 6 months).
A dog suffering from an abduction injury to the left forelimb is unable to extend or flex his elbow and carpus, but still has movement in his shouler. What area of the spinal cord is likely damaged?
C7 and T1
A dog with an abduction injury to the left forelimb is unable to extend or flex his shoulder, but retains ability to move his elbow and carpus. What area of the spinal cord is damaged?
C6 and C7
Where do nerve sheath tumors occur 80% of the time?
Caudal cervical area, usually associated with the brachial plexus
Nerve sheath tumors usually start ______ and spread proximally into the _____ ____.
Peripherally
Spinal Cord
A 9 year old dog presents to your clinic with paresis of the right front limb. You note muscle atrophy of the affected limb, and upon manual flexion, the dog cries out in pain. The owner states that the limb has been slowly getting worse, and that the dog seems to be in pain more recently. What is a probable diagnosis?
Nerve sheath tumor
*CS: slowly progressive monoparesis and “root signs” are suggestive of neoplasia.
A dog presents with monoparesis and “root signs”, suggesting neoplasia of the peripheral nerves. What tests can you use to localize the tumor and confirm your diagnosis?
Localize: Myelogram, CT, MRI
Confirm diagnosis with histopath collected during surgery
You diagnose a nerve sheath tumor in a cat. What is the best treatment plan?
Surgery (complete removal is highly unlikely and the tumor will grow back within a few months)
Radiation and chemo post surgery will delay regrowth by another month
A client brings in her Great Dane who suddenly collapsed after going for a run, and is now unable to walk. Reflexes are exaggerated on all 4 limbs, but paresis seems worse on the left side. There is no pain on palpation of the spine. Radiographs and myelography are normal. MRI is performed and you see a lighter area, as pictured. What is the most likely diagnosis?
Fibrocartilagenous embolus
*Peracute, non-painful, many times after exercise. Large breeds most susceptible, and Schnauzers.
*Non-progressive! Pain/paresis will NOT get worse in the hours after the event as it would with a traumatic injury due to inflammation. etc.
Now that you’ve diagnosed the Great Dane with a fibrocartilagenous embolus, what is your treatment plan?
TIME (very slow recovery, if the patient recovers at all)
Supportive care, physiotherapy, turning to avoid sores
*Can medically treat bladder problems with prazosin/phenoxybenzamine (UMN) or Bethanecol/PPA (LMN).
Regarding fibrocartilagenous emboli, which patient has a better chance of recovery; one with UMN signs or one with LMN signs?
Patients with UMN signs have a better chance of recovery than patients with LMN signs.
With LMN signs, the entire cell (body and axon) is damaged.
A German Shepherd presents for increasing weakness of the hind limbs over the past year. The dog is knuckling while walking, and has difficulty turning without crossing his legs. The muscles of the hind limbs are atrophied and reflexes are exaggerated. Palpation of the spine and flexion/stretching of the hind limbs are performed without eliciting pain, however, toe pinch still elicits a response. The thoracic limbs are normal. What is the likely diagnosis?
Degenerative Myelopathy
*Degeneration of axons and myeline sheaths in thoracolumbar spinal cord. Genetic! Retain superficial and deep pain, and urinary/fecal incontinence usually intact.
The owners of the dog with degenerative myelopathy want to know if there are any diagnostics we can use to confirm the disease, since they discovered there is no treatment besides physiotherapy.
pNF-H (phosphorylated neurofilament heavy)
and
myelin basic protein are elevated in the CSF of these patients. (But it still isn’t specific for this disease)
*Imaging will be normal in these patients
In degenerative lumbosacral stenosis, or cauda equina syndrome, the spinal cord between L7 and S1 becomes compressed. What type of disc degeneration is the cause?
Hansen type II
*slowly pushes dorsally over time
In a patient with degenerative lumbosacral stenosis, instability at L7/S1 can cause spinal cord compression as the vertebrae move relative to one another, in a step-like formation. What is this called?
Spondylolisthesis
How does proliferation of the interarcuate ligaments make degenerative lumbosacral stenosis worse?
Compresses the spinal cord dorsally, so now it’s being compressed ventrally and dorsally.
An 8 year old Viszla presents for progressive weakness and pain in the hind limbs. The dog has recently been dribbling urine while sleeping. On exam, the dog is hunched over. Patellar reflexes are present to exaggerated on the hind limbs, but you are not able to elicit a cranial tibial reflex. What is a likely diagnosis in this patient?
Degenerative lumbosacral stenosis
*LMN signs to the pelvic limbs and bladder. Patellar reflexes remain because the femoral nerve exits at L4/L5. Patellar reflex may be exaggerated due to lack of tone in the hamstrings, not an UMN problem.
In DLS, additional compression is placed on the spinal cord by osteophytes (pictured). What causes osteophytes to form in this disease?
Tearing of the joint capsule when vertebrae are moving dorsally/ventrally past each other.
This dog has been diagnosed with degenerative lumbosacral stenosis. What is causing his hunched over, bent knee stance?
Compression of the sciatic nerve prevents muscles in the leg from working properly.
Also could be in pain due to nerve stretching.
What is the difference between a myelogram and an epidurogram?
Myelogram: contrast medium is injected into the subarachnoid space between L7 and S1. It only goes as far as the intact SC.
Epidurogram: contrast is injected into the epidural space, and can show abnormalities throughout the cauda equina and SC as it moves cranially.
You’ve done an MRI on the Viszla with degenerative lumbosacral stenosis to confirm the diagnosis. What’s your treatment plan?
Cage rest, NSAIDs, prednisone.
(Signs will recur when exercise/work increases)
Surgery (dorsal laminectomy or dorsolateral foraminotomy) may be performed if medical treatment fails, but many patients still do not recover completely.
Diaplacement of the nucleus pulposus in a 3 year old Dachshund that generally happens in a quick, explosive manner.
Hansen type I
*Nucleus pulposus is replaced with hyaline cartilage
Displacement of the nucleus pulposus in an 8 year old large breed dog that occurs gradually/chronically, and generally causes pain due to stretching of the dorsal longitudinal ligament.
Hansen type II
*Nucleus pulposus replaced with fibrocartilage
Where do 75% of disc protrusions occur?
T11 - L2
*Not common between T2 - T10 because of the intercapital ligament.
A 9 year old retriever presents for sudden inability to walk on all 4 limbs. On exam, the dog is able to move the limbs, and reflexes are exaggerated. Xrays of the neck show a narrowed disc space between C5 and C6. On MRI you see compression of the spinal cord and a seagull shaped area of hyperintense material within the spinal canal. What is the diagnosis?
Hydrated Nucleus Pulposus Extrusion (HNPE)
*Extrusion of normal NP into the spinal canal in older dogs. Generally occurs in the neck. Dogs with tetraparalysis and respiratory signs have a poor prognosis, but less severely affected patients have a high success rate with medical or surgical intervention.
A 7 year old Border Collie presents for paresis of the RF and RR legs after running on the golf course today. The dog is non painful, and has increased reflexes on the affected limbs. MRI of the neck shows a hyperintense area located over a narrowed disk space, but there is no evidence of spinal cord compression. What is the diagnosis?
Acute Noncompressive Nucelus Pulposus Extrusion (ANNPE)
*Forceful extrusion of normal NP, that causes a contusion to the SC. Usually associated with trauma or exercise, and usually lateralizes.
*Diff from FCE: not seen in giant breeds, commonly in the neck, MRI will show NP extrusion on cross-sectional view.
A 6 year old male Golden Retriever presents for depression and weight loss. The dog is painful on exam and temp is 104.2F. Reflexes on the front limbs are normal. The hinds limbs are hyporeflexic. Radiographs are taken and blood and CSF are sent off for culture.
Culture results: CSF WNL, blood shows infection with S. intermedius.
What is the treatment plan for this patient?
At least 5 days of IV antibiotics and up to 54 weeks of a bacteriocidal antibiotic. (Treat until radiographic resolution)
Dogs with neuro signs may be candidates for hemilaminectomy
*DISCOSPONDYLITIS: infection of end plates and discs. Test all intact male dogs with these signs for Brucella! Usual suspects are S. intermedius, B. canis, Strep.
A patient presents for progressive hind limb weakness and pain with movement and manipulation. Myelogram of the lumbar spine shows thinning and divergence of the spinal cord. What is the most likely diagnosis?
Intramedullary tumor
*Thinning and divergence of the spinal cord on myelogram, slowly progressive neuro signs, nerve root signs.
Myelogram of a dog with back pain, showing a golf-tee appearance in the spinal cord. What is the diagnosis?
Intradural tumor
*Meningiomas may be surgically resected to give a MST of 6m
Myelogram of a FeLV positive cat with back pain and ataxia shows deviatiation of the spinal cord over pathologic vertebral bodies. What is the treatment plan for this cat?
Chemotherapy
*This is an extradural tumor, causing devition of the spinal cord. Prognosis for LSA with chemo is about 6m.
Radiograph of a dog who presented ataxic. Spinal palpation is painful and the dog has a Shiff-Sherrington gait (rigid extension of the forelimbs). What is the diagnosis based on the radiograph?
Vertebral fracture and severe compression of the spinal cord.
*prognosis poor in these patients as the SC doesn’t recover well
In what dog breeds is this generally asymptomatic condition usually found?
Bulldogs and Boston Terriers
*Hemivertebra - caused by incomplete fusion of the L and R centers of ossification
What dat?
Fused vertebrae
This malformation of the cervial vertebrae in Doberman Pinschers predisposes them to what disease?
Wobblers
*Cervical spodylomyelopathy. Vertebral malformation and the presence of a craniodorsal ridge leads to stenosis of the SC.
Traction radiographs are used to tell the difference between what types of cervical spondylomyelopathy?
Static (compression of SC at all times)
vs
Dynamic (compression of SC when neck is flexed or extended)
Your patient today is a 10 month old Golden Retriever. Ultrasound confirms the cause of exopthalmus is swelling of the muscles behind the eyes. What is the diagnosis?
Extraocular myositis
*Prednisone 2-4mg/kg
A client brings in her 5 month old puppy for progressive muscle weakness and weight loss. The puppy is bunny-hopping on his hocks and carpus, as pictured. You tell the owner this is a sex-linked dystrophic myopathy seen in male puppes that causes muscle atrophy and fibrotic replacement. What do these dogs usually die from?
DCM
