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Ancillary Diagnostic Tests forNeurological Patients

Patient Evaluation

� Signalment� History� Physical and Neurological Exams� Localization of Lesion� Differential diagnosis� Diagnostic plan� Diagnosis/Prognosis� Treatment/Evaluate

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Minimum Database

� CBC� Chemistry

• Bile acids• Cholinesterase

� Urinalysis� Chest and

abdominal radiographs

� Abdominal ultrasound

� Heartworm test� Fecal

Ancillary Neurologic Tests

� Electrodiagnostics• EEG• EMG• BAER

� CSF tap & analysis• Cells & protein• Cholinesterase• Titers

� Radiographs• Skull or spine• Myelography• CT scan• MRI

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Electrodiagnostics

� EEG• Measures electrical

activity of the outer 3 mm of the cerebral cortex

• Normal activity is low amplitude, fast waves

EEG -- Normal

� The normal EEG shows primarily Beta wave activity (15-30 Hz) with low amplitude (5-15 V)

� The EEG is normal in Idiopathic Epilepsy, except during a seizure.

Left Occipital

Right Occipital

Left Frontal

Right Frontal

Left Side

Right Side

Occipitals

Frontals

Left Parietal

Right Parietal50 :V 1 second

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EEG -- Encephalitis

� In active encephalitis, the EEG show high-amplitude, slow- waves with spikeactivity.

Left Occipital

Right Occipital

Left Frontal

Right Frontal

Left Side

Right Side

Occipitals

Frontals

Left Parietal

Right Parietal50 :V 1 second

Electrodiagnostics

� EMG• Evaluates the LM

Unit– Spinal nerve– Neuromuscular

junction– muscle

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Electrodiagnostics

� EMG• Needle EMG looks

for abnormal spontaneous potentials– Fibrillation

potentials– Fasciculation– Complex repetitive

potentials

Electrodiagnostics

� EMG• Motor conduction

velocity– Measured from

several locations along the nerve

– Disstance/Time delay for response

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Electrodiagnostics

� EMG• F wave

– Indication of integrity of the axons

– Measured at 2 sites

– proximal– distal

Electrodiagnostics

� EMG• Repetitive Nerve

Stimulation– Decremental in

Myasthenia gravis and OP intoxication

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Electrodiagnostics

� EMG• Spinal Evoked

Potential– Acute spinal trauma– Chronic spinal cord

disease

Electrodiagnostics

� BAER• Evaluation of

auditory system in the ear and brainstem

• Same instrument as for EMG

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BAER

� Deafness in puppies• Particularly useful

in unilateral disease

BAER

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Cerebrospinal Fluid tap

� Routinely done on most neurological patients

� Collection from the cisterna magna (cerebellomedullary cistern) or L4-L5 lumbar space

Cerebrospinal Fluid Analysis

� Analyze• RBC and WBC cell

number• Cytology• Protein

� Abnormalities• Increased types of

cells• Increased protein• Increased pressure

� Titers for infectious disease• Species specific

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Cerebrospinal Fluid Titers

� Viral• Canine Distemper

� Bacterial • Lyme

� Protozoal• Toxoplasmosis• Neospora

� Rickettsial• RMSF• Ehrlichia

� Fungal• Aspergillus• Cryptococcus

� Viral• FeLV• FIV• F

IP� Protozoal

• Toxoplasmosis� Fungal

• Cryptococcus

DogDog CatCat

Neuroradiology

� Plain X-rays of head and vertebrae• Bone fractures, infection, neoplasia

� Myelogram-compressive and expanding spinal cord lesions

� CT and MRI lesions of the head or vertebrae

� CT better for bone; MRI better for soft tissue

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When all else fails…

Look at the patient!!!Look at the patient!!!

CNS Neoplasia

Today’s FrontierToday’s Frontier

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CNS Neoplasia- -Dogs

� Common Types• Meningioma• Astocytoma• Oligodendroglioma• Choroid plexus

papilloma• Lympoma• Neuroectodermal

tumors• Metastatic tumor

CNS Neoplasia- -Dogs

� Dog has 1-18 months average survival time• 1-3 with nothing• 6-9 with surgery• 12-18 with

radiation treatment� All tumors are

invasive (malignant)

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CNS Neoplasia- -Cats

� Most common is meningioma

� Usually extra-axial and benign

� Seen in aged cats� Present with

depression and dementia

Treatment

� Prednisolone (0.25-0.5 mg/kg q12h)• Treats secondary

effects• Cover with

gastroprotectants� Chemotherapy� Radiation therapy

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Chemotherapy

� Lomustine• 60 mg/M2 given• Monitor CBC

weekly• If WBC and

platelets okay in 5 weeks, then give 80 mg/M2

• Repeat every 5-8 weeks

� Procarbazine• 2-4 mg/kg/day for

1 week, then 4-6 mg/kg/day

• Monitor CBC• Continue as long as

WBC levels are > 4000/µl & platelet count is > 100,000/µl

Treatment

� Diet• Low carbohydrate

� Supplements• Antioxidants &

membrane stabilizers� Herbal medications

• Western• Traditional Chinese

medicine

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Radiosurgery (3D radiation therapy)

� McKnight Brain Institute at UF

� High, single dose radiotherapy

� 5 arcs of radiation provide sphere of death• Based upon the

focal size and tissue treated

Radiosurgery- -MRI

� Tumors are identified with MRI

� Fusion studies are performed

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Radiosurgery- -Bite plate

� A molded “bite plate” is made for the patient and secured in position

� Can be taken off and re-applied for later treatment

Radiosurgery- -3D alignment

� Special orientation system is applied to bite plate before CT scan

� Infrared cameras are used to align device for radiosurgery

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Radiosurgery- -CT scan

� Fusion CT scan is obtained is bite-plate and alignment guide in place

� CT guided biopsy is obtained for tissue type

Image fusion snapshots

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Radiosurgery- -Treatment plan

� Fused MRI and CT images provide target

� Provides anatomic detail of MRI with precision of CT

� Tumor margins outlined with combined spheres of radiation

Treatment plan

� Treatment plan generated & evaluated in transverse, dorsal and sagittal planes

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Radiosurgery- -Treatment

� Treatment is applied with LINAC unit at UFBI

� Cost of radiosurgery• procedure is around

$3000.00 • plus workup &

conventional surgery